collision.c

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#include "quakedef.h"
#include "polygon.h"
#include "collision.h"
 
#define COLLISION_EDGEDIR_DOT_EPSILON (0.999f)
#define COLLISION_EDGECROSS_MINLENGTH2 (1.0f / 4194304.0f)
#define COLLISION_SNAPSCALE (32.0f)
#define COLLISION_SNAP (1.0f / COLLISION_SNAPSCALE)
#define COLLISION_SNAP2 (2.0f / COLLISION_SNAPSCALE)
#define COLLISION_PLANE_DIST_EPSILON (2.0f / COLLISION_SNAPSCALE)
 
cvar_t collision_impactnudge = {CF_CLIENT | CF_SERVER, "collision_impactnudge", "0.03125", "how much to back off from the impact"};
cvar_t collision_extendmovelength = {CF_CLIENT | CF_SERVER, "collision_extendmovelength", "16", "internal bias on trace length to ensure detection of collisions within the collision_impactnudge distance so that short moves do not degrade across frames (this does not alter the final trace length)"};
cvar_t collision_extendtraceboxlength = {CF_CLIENT | CF_SERVER, "collision_extendtraceboxlength", "1", "internal bias for tracebox() qc builtin to account for collision_impactnudge (this does not alter the final trace length)"};
cvar_t collision_extendtracelinelength = {CF_CLIENT | CF_SERVER, "collision_extendtracelinelength", "1", "internal bias for traceline() qc builtin to account for collision_impactnudge (this does not alter the final trace length)"};
cvar_t collision_debug_tracelineasbox = {CF_CLIENT | CF_SERVER, "collision_debug_tracelineasbox", "0", "workaround for any bugs in Collision_TraceLineBrushFloat by using Collision_TraceBrushBrushFloat"};
cvar_t collision_cache = {CF_CLIENT | CF_SERVER, "collision_cache", "1", "store results of collision traces for next frame to reuse if possible (optimization)"};
cvar_t collision_triangle_bevelsides = {CF_CLIENT | CF_SERVER, "collision_triangle_bevelsides", "0", "generate sloped edge planes on triangles - if 0, see axialedgeplanes"};
cvar_t collision_triangle_axialsides = {CF_CLIENT | CF_SERVER, "collision_triangle_axialsides", "1", "generate axially-aligned edge planes on triangles - otherwise use perpendicular edge planes"};
cvar_t collision_bih_fullrecursion = {CF_CLIENT | CF_SERVER, "collision_bih_fullrecursion", "0", "debugging option to disable the bih recursion optimizations by iterating the entire tree"};
 
mempool_t *collision_mempool;
 
void Collision_Init (void)
{
    Cvar_RegisterVariable(&collision_impactnudge);
    Cvar_RegisterVariable(&collision_extendmovelength);
    Cvar_RegisterVariable(&collision_extendtracelinelength);
    Cvar_RegisterVariable(&collision_extendtraceboxlength);
    Cvar_RegisterVariable(&collision_debug_tracelineasbox);
    Cvar_RegisterVariable(&collision_cache);
    Cvar_RegisterVariable(&collision_triangle_bevelsides);
    Cvar_RegisterVariable(&collision_triangle_axialsides);
    Cvar_RegisterVariable(&collision_bih_fullrecursion);
    collision_mempool = Mem_AllocPool("collision cache", 0, NULL);
    Collision_Cache_Init(collision_mempool);
}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
static void Collision_PrintBrushAsQHull(colbrushf_t *brush, const char *name)
{
    int i;
    Con_Printf("3 %s\n%i\n", name, brush->numpoints);
    for (i = 0;i < brush->numpoints;i++)
        Con_Printf("%f %f %f\n", brush->points[i].v[0], brush->points[i].v[1], brush->points[i].v[2]);
    // FIXME: optimize!
    Con_Printf("4\n%i\n", brush->numplanes);
    for (i = 0;i < brush->numplanes;i++)
        Con_Printf("%f %f %f %f\n", brush->planes[i].normal[0], brush->planes[i].normal[1], brush->planes[i].normal[2], brush->planes[i].dist);
}
 
static void Collision_ValidateBrush(colbrushf_t *brush)
{
    int j, k, pointsoffplanes, pointonplanes, pointswithinsufficientplanes, printbrush;
    float d;
    printbrush = false;
    if (!brush->numpoints)
    {
        Con_Print("Collision_ValidateBrush: brush with no points!\n");
        printbrush = true;
    }
#if 0
    // it's ok for a brush to have one point and no planes...
    if (brush->numplanes == 0 && brush->numpoints != 1)
    {
        Con_Print("Collision_ValidateBrush: brush with no planes and more than one point!\n");
        printbrush = true;
    }
#endif
    if (brush->numplanes)
    {
        pointsoffplanes = 0;
        pointswithinsufficientplanes = 0;
        for (k = 0;k < brush->numplanes;k++)
            if (DotProduct(brush->planes[k].normal, brush->planes[k].normal) < 0.0001f)
                Con_Printf("Collision_ValidateBrush: plane #%i (%f %f %f %f) is degenerate\n", k, brush->planes[k].normal[0], brush->planes[k].normal[1], brush->planes[k].normal[2], brush->planes[k].dist);
        for (j = 0;j < brush->numpoints;j++)
        {
            pointonplanes = 0;
            for (k = 0;k < brush->numplanes;k++)
            {
                d = DotProduct(brush->points[j].v, brush->planes[k].normal) - brush->planes[k].dist;
                if (d > COLLISION_PLANE_DIST_EPSILON)
                {
                    Con_Printf("Collision_ValidateBrush: point #%i (%f %f %f) infront of plane #%i (%f %f %f %f)\n", j, brush->points[j].v[0], brush->points[j].v[1], brush->points[j].v[2], k, brush->planes[k].normal[0], brush->planes[k].normal[1], brush->planes[k].normal[2], brush->planes[k].dist);
                    printbrush = true;
                }
                if (fabs(d) > COLLISION_PLANE_DIST_EPSILON)
                    pointsoffplanes++;
                else
                    pointonplanes++;
            }
            if (pointonplanes < 3)
                pointswithinsufficientplanes++;
        }
        if (pointswithinsufficientplanes)
        {
            Con_Print("Collision_ValidateBrush: some points have insufficient planes, every point must be on at least 3 planes to form a corner.\n");
            printbrush = true;
        }
        if (pointsoffplanes == 0) // all points are on all planes
        {
            Con_Print("Collision_ValidateBrush: all points lie on all planes (degenerate, no brush volume!)\n");
            printbrush = true;
        }
    }
    if (printbrush)
        Collision_PrintBrushAsQHull(brush, "unnamed");
}
 
static float nearestplanedist_float(const float *normal, const colpointf_t *points, int numpoints)
{
    float dist, bestdist;
    if (!numpoints)
        return 0;
    bestdist = DotProduct(points->v, normal);
    points++;
    while(--numpoints)
    {
        dist = DotProduct(points->v, normal);
        bestdist = min(bestdist, dist);
        points++;
    }
    return bestdist;
}
 
static float furthestplanedist_float(const float *normal, const colpointf_t *points, int numpoints)
{
    float dist, bestdist;
    if (!numpoints)
        return 0;
    bestdist = DotProduct(points->v, normal);
    points++;
    while(--numpoints)
    {
        dist = DotProduct(points->v, normal);
        bestdist = max(bestdist, dist);
        points++;
    }
    return bestdist;
}
 
static void Collision_CalcEdgeDirsForPolygonBrushFloat(colbrushf_t *brush)
{
    int i, j;
    for (i = 0, j = brush->numpoints - 1;i < brush->numpoints;j = i, i++)
        VectorSubtract(brush->points[i].v, brush->points[j].v, brush->edgedirs[j].v);
}
 
colbrushf_t *Collision_NewBrushFromPlanes(mempool_t *mempool, int numoriginalplanes, const colplanef_t *originalplanes, int supercontents, int q3surfaceflags, const texture_t *texture, int hasaabbplanes)
{
    // TODO: planesbuf could be replaced by a remapping table
    int j, k, w, xyzflags;
    int numpointsbuf = 0, maxpointsbuf = 256, numedgedirsbuf = 0, maxedgedirsbuf = 256, numplanesbuf = 0, maxplanesbuf = 256, numelementsbuf = 0, maxelementsbuf = 256;
    int isaabb = true;
    double maxdist;
    colbrushf_t *brush;
    colpointf_t pointsbuf[256];
    colpointf_t edgedirsbuf[256];
    colplanef_t planesbuf[256];
    int elementsbuf[1024];
    int polypointbuf[256];
    int pmaxpoints = 64;
    int pnumpoints;
    double p[2][3*64];
#if 0
    // enable these if debugging to avoid seeing garbage in unused data-
    memset(pointsbuf, 0, sizeof(pointsbuf));
    memset(edgedirsbuf, 0, sizeof(edgedirsbuf));
    memset(planesbuf, 0, sizeof(planesbuf));
    memset(elementsbuf, 0, sizeof(elementsbuf));
    memset(polypointbuf, 0, sizeof(polypointbuf));
    memset(p, 0, sizeof(p));
#endif
 
    // check if there are too many planes and skip the brush
    if (numoriginalplanes >= maxplanesbuf)
    {
        Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many planes for buffer\n");
        return NULL;
    }
 
    // figure out how large a bounding box we need to properly compute this brush
    maxdist = 0;
    for (j = 0;j < numoriginalplanes;j++)
        maxdist = max(maxdist, fabs(originalplanes[j].dist));
    // now make it large enough to enclose the entire brush, and round it off to a reasonable multiple of 1024
    maxdist = floor(maxdist * (4.0 / 1024.0) + 2) * 1024.0;
    // construct a collision brush (points, planes, and renderable mesh) from
    // a set of planes, this also optimizes out any unnecessary planes (ones
    // whose polygon is clipped away by the other planes)
    for (j = 0;j < numoriginalplanes;j++)
    {
        int n;
        // add the new plane
        VectorCopy(originalplanes[j].normal, planesbuf[numplanesbuf].normal);
        planesbuf[numplanesbuf].dist = originalplanes[j].dist;
        planesbuf[numplanesbuf].q3surfaceflags = originalplanes[j].q3surfaceflags;
        planesbuf[numplanesbuf].texture = originalplanes[j].texture;
        numplanesbuf++;
 
        // create a large polygon from the plane
        w = 0;
        PolygonD_QuadForPlane(p[w], originalplanes[j].normal[0], originalplanes[j].normal[1], originalplanes[j].normal[2], originalplanes[j].dist, maxdist);
        pnumpoints = 4;
        // clip it by all other planes
        for (k = 0;k < numoriginalplanes && pnumpoints >= 3 && pnumpoints <= pmaxpoints;k++)
        {
            // skip the plane this polygon
            // (nothing happens if it is processed, this is just an optimization)
            if (k != j)
            {
                // we want to keep the inside of the brush plane so we flip
                // the cutting plane
                PolygonD_Divide(pnumpoints, p[w], -originalplanes[k].normal[0], -originalplanes[k].normal[1], -originalplanes[k].normal[2], -originalplanes[k].dist, COLLISION_PLANE_DIST_EPSILON, pmaxpoints, p[!w], &pnumpoints, 0, NULL, NULL, NULL);
                w = !w;
            }
        }
 
        // if nothing is left, skip it
        if (pnumpoints < 3)
        {
            //Con_DPrintf("Collision_NewBrushFromPlanes: warning: polygon for plane %f %f %f %f clipped away\n", originalplanes[j].normal[0], originalplanes[j].normal[1], originalplanes[j].normal[2], originalplanes[j].dist);
            continue;
        }
 
        for (k = 0;k < pnumpoints;k++)
        {
            int l, m;
            m = 0;
            for (l = 0;l < numoriginalplanes;l++)
                if (fabs(DotProduct(&p[w][k*3], originalplanes[l].normal) - originalplanes[l].dist) < COLLISION_PLANE_DIST_EPSILON)
                    m++;
            if (m < 3)
                break;
        }
        if (k < pnumpoints)
        {
            Con_DPrintf("Collision_NewBrushFromPlanes: warning: polygon point does not lie on at least 3 planes\n");
            //return NULL;
        }
 
        // check if there are too many polygon vertices for buffer
        if (pnumpoints > pmaxpoints)
        {
            Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many points for buffer\n");
            return NULL;
        }
 
        // check if there are too many triangle elements for buffer
        if (numelementsbuf + (pnumpoints - 2) * 3 > maxelementsbuf)
        {
            Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many triangle elements for buffer\n");
            return NULL;
        }
 
        // add the unique points for this polygon
        for (k = 0;k < pnumpoints;k++)
        {
            int m;
            float v[3];
            // downgrade to float precision before comparing
            VectorCopy(&p[w][k*3], v);
 
            // check if there is already a matching point (no duplicates)
            for (m = 0;m < numpointsbuf;m++)
                if (VectorDistance2(v, pointsbuf[m].v) < COLLISION_SNAP2)
                    break;
 
            // if there is no match, add a new one
            if (m == numpointsbuf)
            {
                // check if there are too many and skip the brush
                if (numpointsbuf >= maxpointsbuf)
                {
                    Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many points for buffer\n");
                    return NULL;
                }
                // add the new one
                VectorCopy(&p[w][k*3], pointsbuf[numpointsbuf].v);
                numpointsbuf++;
            }
 
            // store the index into a buffer
            polypointbuf[k] = m;
        }
 
        // add the triangles for the polygon
        // (this particular code makes a triangle fan)
        for (k = 0;k < pnumpoints - 2;k++)
        {
            elementsbuf[numelementsbuf++] = polypointbuf[0];
            elementsbuf[numelementsbuf++] = polypointbuf[k + 1];
            elementsbuf[numelementsbuf++] = polypointbuf[k + 2];
        }
 
        // add the unique edgedirs for this polygon
        for (k = 0, n = pnumpoints-1;k < pnumpoints;n = k, k++)
        {
            int m;
            float dir[3];
            // downgrade to float precision before comparing
            VectorSubtract(&p[w][k*3], &p[w][n*3], dir);
            VectorNormalize(dir);
 
            // check if there is already a matching edgedir (no duplicates)
            for (m = 0;m < numedgedirsbuf;m++)
                if (DotProduct(dir, edgedirsbuf[m].v) >= COLLISION_EDGEDIR_DOT_EPSILON)
                    break;
            // skip this if there is
            if (m < numedgedirsbuf)
                continue;
 
            // try again with negated edgedir
            VectorNegate(dir, dir);
            // check if there is already a matching edgedir (no duplicates)
            for (m = 0;m < numedgedirsbuf;m++)
                if (DotProduct(dir, edgedirsbuf[m].v) >= COLLISION_EDGEDIR_DOT_EPSILON)
                    break;
            // if there is no match, add a new one
            if (m == numedgedirsbuf)
            {
                // check if there are too many and skip the brush
                if (numedgedirsbuf >= maxedgedirsbuf)
                {
                    Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many edgedirs for buffer\n");
                    return NULL;
                }
                // add the new one
                VectorCopy(dir, edgedirsbuf[numedgedirsbuf].v);
                numedgedirsbuf++;
            }
        }
 
        // if any normal is not purely axial, it's not an axis-aligned box
        if (isaabb && (originalplanes[j].normal[0] == 0) + (originalplanes[j].normal[1] == 0) + (originalplanes[j].normal[2] == 0) < 2)
            isaabb = false;
    }
 
    // if nothing is left, there's nothing to allocate
    if (numplanesbuf < 4)
    {
        Con_DPrintf("Collision_NewBrushFromPlanes: failed to build collision brush: %i triangles, %i planes (input was %i planes), %i vertices\n", numelementsbuf / 3, numplanesbuf, numoriginalplanes, numpointsbuf);
        return NULL;
    }
 
    // if no triangles or points could be constructed, then this routine failed but the brush is not discarded
    if (numelementsbuf < 12 || numpointsbuf < 4)
        Con_DPrintf("Collision_NewBrushFromPlanes: unable to rebuild triangles/points for collision brush: %i triangles, %i planes (input was %i planes), %i vertices\n", numelementsbuf / 3, numplanesbuf, numoriginalplanes, numpointsbuf);
 
    // validate plane distances
    for (j = 0;j < numplanesbuf;j++)
    {
        float d = furthestplanedist_float(planesbuf[j].normal, pointsbuf, numpointsbuf);
        if (fabs(planesbuf[j].dist - d) > COLLISION_PLANE_DIST_EPSILON)
            Con_DPrintf("plane %f %f %f %f mismatches dist %f\n", planesbuf[j].normal[0], planesbuf[j].normal[1], planesbuf[j].normal[2], planesbuf[j].dist, d);
    }
 
    // allocate the brush and copy to it
    brush = (colbrushf_t *)Mem_Alloc(mempool, sizeof(colbrushf_t) + sizeof(colpointf_t) * numpointsbuf + sizeof(colpointf_t) * numedgedirsbuf + sizeof(colplanef_t) * numplanesbuf + sizeof(int) * numelementsbuf);
    brush->isaabb = isaabb;
    brush->hasaabbplanes = hasaabbplanes;
    brush->supercontents = supercontents;
    brush->numplanes = numplanesbuf;
    brush->numedgedirs = numedgedirsbuf;
    brush->numpoints = numpointsbuf;
    brush->numtriangles = numelementsbuf / 3;
    brush->planes = (colplanef_t *)(brush + 1);
    brush->points = (colpointf_t *)(brush->planes + brush->numplanes);
    brush->edgedirs = (colpointf_t *)(brush->points + brush->numpoints);
    brush->elements = (int *)(brush->points + brush->numpoints);
    brush->q3surfaceflags = q3surfaceflags;
    brush->texture = texture;
    for (j = 0;j < brush->numpoints;j++)
    {
        brush->points[j].v[0] = pointsbuf[j].v[0];
        brush->points[j].v[1] = pointsbuf[j].v[1];
        brush->points[j].v[2] = pointsbuf[j].v[2];
    }
    for (j = 0;j < brush->numedgedirs;j++)
    {
        brush->edgedirs[j].v[0] = edgedirsbuf[j].v[0];
        brush->edgedirs[j].v[1] = edgedirsbuf[j].v[1];
        brush->edgedirs[j].v[2] = edgedirsbuf[j].v[2];
    }
    for (j = 0;j < brush->numplanes;j++)
    {
        brush->planes[j].normal[0] = planesbuf[j].normal[0];
        brush->planes[j].normal[1] = planesbuf[j].normal[1];
        brush->planes[j].normal[2] = planesbuf[j].normal[2];
        brush->planes[j].dist = planesbuf[j].dist;
        brush->planes[j].q3surfaceflags = planesbuf[j].q3surfaceflags;
        brush->planes[j].texture = planesbuf[j].texture;
    }
    for (j = 0;j < brush->numtriangles * 3;j++)
        brush->elements[j] = elementsbuf[j];
 
    xyzflags = 0;
    VectorClear(brush->mins);
    VectorClear(brush->maxs);
    for (j = 0;j < min(6, numoriginalplanes);j++)
    {
             if (originalplanes[j].normal[0] ==  1) {xyzflags |=  1;brush->maxs[0] =  originalplanes[j].dist;}
        else if (originalplanes[j].normal[0] == -1) {xyzflags |=  2;brush->mins[0] = -originalplanes[j].dist;}
        else if (originalplanes[j].normal[1] ==  1) {xyzflags |=  4;brush->maxs[1] =  originalplanes[j].dist;}
        else if (originalplanes[j].normal[1] == -1) {xyzflags |=  8;brush->mins[1] = -originalplanes[j].dist;}
        else if (originalplanes[j].normal[2] ==  1) {xyzflags |= 16;brush->maxs[2] =  originalplanes[j].dist;}
        else if (originalplanes[j].normal[2] == -1) {xyzflags |= 32;brush->mins[2] = -originalplanes[j].dist;}
    }
    // if not all xyzflags were set, then this is not a brush from q3map/q3map2, and needs reconstruction of the bounding box
    // (this case works for any brush with valid points, but sometimes brushes are not reconstructed properly and hence the points are not valid, so this is reserved as a fallback case)
    if (xyzflags != 63)
    {
        VectorCopy(brush->points[0].v, brush->mins);
        VectorCopy(brush->points[0].v, brush->maxs);
        for (j = 1;j < brush->numpoints;j++)
        {
            brush->mins[0] = min(brush->mins[0], brush->points[j].v[0]);
            brush->mins[1] = min(brush->mins[1], brush->points[j].v[1]);
            brush->mins[2] = min(brush->mins[2], brush->points[j].v[2]);
            brush->maxs[0] = max(brush->maxs[0], brush->points[j].v[0]);
            brush->maxs[1] = max(brush->maxs[1], brush->points[j].v[1]);
            brush->maxs[2] = max(brush->maxs[2], brush->points[j].v[2]);
        }
    }
    brush->mins[0] -= 1;
    brush->mins[1] -= 1;
    brush->mins[2] -= 1;
    brush->maxs[0] += 1;
    brush->maxs[1] += 1;
    brush->maxs[2] += 1;
    Collision_ValidateBrush(brush);
    return brush;
}
 
 
 
void Collision_CalcPlanesForTriangleBrushFloat(colbrushf_t *brush)
{
    float edge0[3], edge1[3], edge2[3];
    colpointf_t *p;
 
    TriangleNormal(brush->points[0].v, brush->points[1].v, brush->points[2].v, brush->planes[0].normal);
    if (DotProduct(brush->planes[0].normal, brush->planes[0].normal) < 0.0001f)
    {
        // there's no point in processing a degenerate triangle (GIGO - Garbage In, Garbage Out)
        // note that some of these exist in q3bsp bspline patches
        brush->numplanes = 0;
        return;
    }
 
    // there are 5 planes (front, back, sides) and 3 edges
    brush->numplanes = 5;
    brush->numedgedirs = 3;
    VectorNormalize(brush->planes[0].normal);
    brush->planes[0].dist = DotProduct(brush->points->v, brush->planes[0].normal);
    VectorNegate(brush->planes[0].normal, brush->planes[1].normal);
    brush->planes[1].dist = -brush->planes[0].dist;
    // edge directions are easy to calculate
    VectorSubtract(brush->points[2].v, brush->points[0].v, edge0);
    VectorSubtract(brush->points[0].v, brush->points[1].v, edge1);
    VectorSubtract(brush->points[1].v, brush->points[2].v, edge2);
    VectorCopy(edge0, brush->edgedirs[0].v);
    VectorCopy(edge1, brush->edgedirs[1].v);
    VectorCopy(edge2, brush->edgedirs[2].v);
    // now select an algorithm to generate the side planes
    if (collision_triangle_bevelsides.integer)
    {
        // use 45 degree slopes at the edges of the triangle to make a sinking trace error turn into "riding up" the slope rather than getting stuck
        CrossProduct(edge0, brush->planes->normal, brush->planes[2].normal);
        CrossProduct(edge1, brush->planes->normal, brush->planes[3].normal);
        CrossProduct(edge2, brush->planes->normal, brush->planes[4].normal);
        VectorNormalize(brush->planes[2].normal);
        VectorNormalize(brush->planes[3].normal);
        VectorNormalize(brush->planes[4].normal);
        VectorAdd(brush->planes[2].normal, brush->planes[0].normal, brush->planes[2].normal);
        VectorAdd(brush->planes[3].normal, brush->planes[0].normal, brush->planes[3].normal);
        VectorAdd(brush->planes[4].normal, brush->planes[0].normal, brush->planes[4].normal);
        VectorNormalize(brush->planes[2].normal);
        VectorNormalize(brush->planes[3].normal);
        VectorNormalize(brush->planes[4].normal);
    }
    else if (collision_triangle_axialsides.integer)
    {
        float projectionnormal[3], projectionedge0[3], projectionedge1[3], projectionedge2[3];
        int i, best;
        float dist, bestdist;
        bestdist = fabs(brush->planes[0].normal[0]);
        best = 0;
        for (i = 1;i < 3;i++)
        {
            dist = fabs(brush->planes[0].normal[i]);
            if (bestdist < dist)
            {
                bestdist = dist;
                best = i;
            }
        }
        VectorClear(projectionnormal);
        if (brush->planes[0].normal[best] < 0)
            projectionnormal[best] = -1;
        else
            projectionnormal[best] = 1;
        VectorCopy(edge0, projectionedge0);
        VectorCopy(edge1, projectionedge1);
        VectorCopy(edge2, projectionedge2);
        projectionedge0[best] = 0;
        projectionedge1[best] = 0;
        projectionedge2[best] = 0;
        CrossProduct(projectionedge0, projectionnormal, brush->planes[2].normal);
        CrossProduct(projectionedge1, projectionnormal, brush->planes[3].normal);
        CrossProduct(projectionedge2, projectionnormal, brush->planes[4].normal);
        VectorNormalize(brush->planes[2].normal);
        VectorNormalize(brush->planes[3].normal);
        VectorNormalize(brush->planes[4].normal);
    }
    else
    {
        CrossProduct(edge0, brush->planes->normal, brush->planes[2].normal);
        CrossProduct(edge1, brush->planes->normal, brush->planes[3].normal);
        CrossProduct(edge2, brush->planes->normal, brush->planes[4].normal);
        VectorNormalize(brush->planes[2].normal);
        VectorNormalize(brush->planes[3].normal);
        VectorNormalize(brush->planes[4].normal);
    }
    brush->planes[2].dist = DotProduct(brush->points[2].v, brush->planes[2].normal);
    brush->planes[3].dist = DotProduct(brush->points[0].v, brush->planes[3].normal);
    brush->planes[4].dist = DotProduct(brush->points[1].v, brush->planes[4].normal);
 
    if (developer_extra.integer)
    {
        int i;
        // validity check - will be disabled later
        Collision_ValidateBrush(brush);
        for (i = 0;i < brush->numplanes;i++)
        {
            int j;
            for (j = 0, p = brush->points;j < brush->numpoints;j++, p++)
                if (DotProduct(p->v, brush->planes[i].normal) > brush->planes[i].dist + COLLISION_PLANE_DIST_EPSILON)
                    Con_DPrintf("Error in brush plane generation, plane %i\n", i);
        }
    }
}
 
// NOTE: start and end of each brush pair must have same numplanes/numpoints
void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_start, const colbrushf_t *trace_end, const colbrushf_t *other_start, const colbrushf_t *other_end)
{
    int nplane, nplane2, nedge1, nedge2, hitq3surfaceflags = 0;
    int tracenumedgedirs = trace_start->numedgedirs;
    //int othernumedgedirs = other_start->numedgedirs;
    int tracenumpoints = trace_start->numpoints;
    int othernumpoints = other_start->numpoints;
    int numplanes1 = other_start->numplanes;
    int numplanes2 = numplanes1 + trace_start->numplanes;
    int numplanes3 = numplanes2 + trace_start->numedgedirs * other_start->numedgedirs * 2;
    vec_t enterfrac = -1, leavefrac = 1, startdist, enddist, ie, f, imove, enterfrac2 = -1;
    vec4_t startplane;
    vec4_t endplane;
    vec4_t newimpactplane;
    const texture_t *hittexture = NULL;
    vec_t startdepth = 1;
    vec3_t startdepthnormal;
    const texture_t *starttexture = NULL;
 
    VectorClear(startdepthnormal);
    Vector4Clear(newimpactplane);
 
    // fast case for AABB vs compiled brushes (which begin with AABB planes and also have precomputed bevels for AABB collisions)
    if (trace_start->isaabb && other_start->hasaabbplanes)
        numplanes3 = numplanes2 = numplanes1;
 
    // Separating Axis Theorem:
    // if a supporting vector (plane normal) can be found that separates two
    // objects, they are not colliding.
    //
    // Minkowski Sum:
    // reduce the size of one object to a point while enlarging the other to
    // represent the space that point can not occupy.
    //
    // try every plane we can construct between the two brushes and measure
    // the distance between them.
    for (nplane = 0;nplane < numplanes3;nplane++)
    {
        if (nplane < numplanes1)
        {
            nplane2 = nplane;
            VectorCopy(other_start->planes[nplane2].normal, startplane);
            VectorCopy(other_end->planes[nplane2].normal, endplane);
        }
        else if (nplane < numplanes2)
        {
            nplane2 = nplane - numplanes1;
            VectorCopy(trace_start->planes[nplane2].normal, startplane);
            VectorCopy(trace_end->planes[nplane2].normal, endplane);
        }
        else
        {
            // pick an edgedir from each brush and cross them
            nplane2 = nplane - numplanes2;
            nedge1 = nplane2 >> 1;
            nedge2 = nedge1 / tracenumedgedirs;
            nedge1 -= nedge2 * tracenumedgedirs;
            if (nplane2 & 1)
            {
                CrossProduct(trace_start->edgedirs[nedge1].v, other_start->edgedirs[nedge2].v, startplane);
                CrossProduct(trace_end->edgedirs[nedge1].v, other_end->edgedirs[nedge2].v, endplane);
            }
            else
            {
                CrossProduct(other_start->edgedirs[nedge2].v, trace_start->edgedirs[nedge1].v, startplane);
                CrossProduct(other_end->edgedirs[nedge2].v, trace_end->edgedirs[nedge1].v, endplane);
            }
            if (VectorLength2(startplane) < COLLISION_EDGECROSS_MINLENGTH2 || VectorLength2(endplane) < COLLISION_EDGECROSS_MINLENGTH2)
                continue; // degenerate crossproducts
            VectorNormalize(startplane);
            VectorNormalize(endplane);
        }
        startplane[3] = furthestplanedist_float(startplane, other_start->points, othernumpoints);
        endplane[3] = furthestplanedist_float(endplane, other_end->points, othernumpoints);
        startdist = nearestplanedist_float(startplane, trace_start->points, tracenumpoints) - startplane[3];
        enddist = nearestplanedist_float(endplane, trace_end->points, tracenumpoints) - endplane[3];
        //Con_Printf("%c%i: startdist = %f, enddist = %f, startdist / (startdist - enddist) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, startdist, enddist, startdist / (startdist - enddist));
 
        // aside from collisions, this is also used for error correction
        if (startdist <= 0.0f && nplane < numplanes1 && (startdepth < startdist || startdepth == 1))
        {
            startdepth = startdist;
            VectorCopy(startplane, startdepthnormal);
            starttexture = other_start->planes[nplane2].texture;
        }
 
        if (startdist > enddist)
        {
            // moving into brush
            if (enddist > 0.0f)
                return;
            if (startdist >= 0)
            {
                // enter
                imove = 1 / (startdist - enddist);
                f = startdist * imove;
                // check if this will reduce the collision time range
                if (enterfrac < f)
                {
                    // reduced collision time range
                    enterfrac = f;
                    // if the collision time range is now empty, no collision
                    if (enterfrac > leavefrac)
                        return;
                    // calculate the nudged fraction and impact normal we'll
                    // need if we accept this collision later
                    enterfrac2 = (startdist - collision_impactnudge.value) * imove;
                    // if the collision would be further away than the trace's
                    // existing collision data, we don't care about this
                    // collision
                    if (enterfrac2 >= trace->fraction)
                        return;
                    ie = 1.0f - enterfrac;
                    newimpactplane[0] = startplane[0] * ie + endplane[0] * enterfrac;
                    newimpactplane[1] = startplane[1] * ie + endplane[1] * enterfrac;
                    newimpactplane[2] = startplane[2] * ie + endplane[2] * enterfrac;
                    newimpactplane[3] = startplane[3] * ie + endplane[3] * enterfrac;
                    if (nplane < numplanes1)
                    {
                        // use the plane from other
                        nplane2 = nplane;
                        hitq3surfaceflags = other_start->planes[nplane2].q3surfaceflags;
                        hittexture = other_start->planes[nplane2].texture;
                    }
                    else if (nplane < numplanes2)
                    {
                        // use the plane from trace
                        nplane2 = nplane - numplanes1;
                        hitq3surfaceflags = trace_start->planes[nplane2].q3surfaceflags;
                        hittexture = trace_start->planes[nplane2].texture;
                    }
                    else
                    {
                        hitq3surfaceflags = other_start->q3surfaceflags;
                        hittexture = other_start->texture;
                    }
                }
            }
        }
        else
        {
            // moving out of brush
            if (startdist >= 0)
                return;
            if (enddist > 0)
            {
                // leave
                f = startdist / (startdist - enddist);
                // check if this will reduce the collision time range
                if (leavefrac > f)
                {
                    // reduced collision time range
                    leavefrac = f;
                    // if the collision time range is now empty, no collision
                    if (enterfrac > leavefrac)
                        return;
                }
            }
        }
    }
 
    // at this point we know the trace overlaps the brush because it was not
    // rejected at any point in the loop above
 
    // see if the trace started outside the brush or not
    if (enterfrac > -1)
    {
        // started outside, and overlaps, therefore there is a collision here
        // store out the impact information
        if ((trace->hitsupercontentsmask & other_start->supercontents) && !(trace->skipsupercontentsmask & other_start->supercontents) && !(trace->skipmaterialflagsmask & (hittexture ? hittexture->currentmaterialflags : 0)))
        {
            trace->hitsupercontents = other_start->supercontents;
            trace->hitq3surfaceflags = hitq3surfaceflags;
            trace->hittexture = hittexture;
            trace->fraction = bound(0, enterfrac2, 1);
            VectorCopy(newimpactplane, trace->plane.normal);
            trace->plane.dist = newimpactplane[3];
        }
    }
    else
    {
        // started inside, update startsolid and friends
        trace->startsupercontents |= other_start->supercontents;
        if ((trace->hitsupercontentsmask & other_start->supercontents) && !(trace->skipsupercontentsmask & other_start->supercontents) && !(trace->skipmaterialflagsmask & (starttexture ? starttexture->currentmaterialflags : 0)))
        {
            trace->startsolid = true;
            if (leavefrac < 1)
                trace->allsolid = true;
            VectorCopy(newimpactplane, trace->plane.normal);
            trace->plane.dist = newimpactplane[3];
            if (trace->startdepth > startdepth)
            {
                trace->startdepth = startdepth;
                VectorCopy(startdepthnormal, trace->startdepthnormal);
                trace->starttexture = starttexture;
            }
        }
    }
}
 
// NOTE: start and end of each brush pair must have same numplanes/numpoints
void Collision_TraceLineBrushFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, const colbrushf_t *other_start, const colbrushf_t *other_end)
{
    int nplane, hitq3surfaceflags = 0;
    int numplanes = other_start->numplanes;
    vec_t enterfrac = -1, leavefrac = 1, startdist, enddist, ie, f, imove, enterfrac2 = -1;
    vec4_t startplane;
    vec4_t endplane;
    vec4_t newimpactplane;
    const texture_t *hittexture = NULL;
    vec_t startdepth = 1;
    vec3_t startdepthnormal;
    const texture_t *starttexture = NULL;
 
    if (collision_debug_tracelineasbox.integer)
    {
        colboxbrushf_t thisbrush_start, thisbrush_end;
        Collision_BrushForBox(&thisbrush_start, linestart, linestart, 0, 0, NULL);
        Collision_BrushForBox(&thisbrush_end, lineend, lineend, 0, 0, NULL);
        Collision_TraceBrushBrushFloat(trace, &thisbrush_start.brush, &thisbrush_end.brush, other_start, other_end);
        return;
    }
 
    VectorClear(startdepthnormal);
    Vector4Clear(newimpactplane);
 
    // Separating Axis Theorem:
    // if a supporting vector (plane normal) can be found that separates two
    // objects, they are not colliding.
    //
    // Minkowski Sum:
    // reduce the size of one object to a point while enlarging the other to
    // represent the space that point can not occupy.
    //
    // try every plane we can construct between the two brushes and measure
    // the distance between them.
    for (nplane = 0;nplane < numplanes;nplane++)
    {
        VectorCopy(other_start->planes[nplane].normal, startplane);
        startplane[3] = other_start->planes[nplane].dist;
        VectorCopy(other_end->planes[nplane].normal, endplane);
        endplane[3] = other_end->planes[nplane].dist;
        startdist = DotProduct(linestart, startplane) - startplane[3];
        enddist = DotProduct(lineend, endplane) - endplane[3];
        //Con_Printf("%c%i: startdist = %f, enddist = %f, startdist / (startdist - enddist) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, startdist, enddist, startdist / (startdist - enddist));
 
        // aside from collisions, this is also used for error correction
        if (startdist <= 0.0f && (startdepth < startdist || startdepth == 1))
        {
            startdepth = startdist;
            VectorCopy(startplane, startdepthnormal);
            starttexture = other_start->planes[nplane].texture;
        }
 
        if (startdist > enddist)
        {
            // moving into brush
            if (enddist > 0.0f)
                return;
            if (startdist > 0)
            {
                // enter
                imove = 1 / (startdist - enddist);
                f = startdist * imove;
                // check if this will reduce the collision time range
                if (enterfrac < f)
                {
                    // reduced collision time range
                    enterfrac = f;
                    // if the collision time range is now empty, no collision
                    if (enterfrac > leavefrac)
                        return;
                    // calculate the nudged fraction and impact normal we'll
                    // need if we accept this collision later
                    enterfrac2 = (startdist - collision_impactnudge.value) * imove;
                    // if the collision would be further away than the trace's
                    // existing collision data, we don't care about this
                    // collision
                    if (enterfrac2 >= trace->fraction)
                        return;
                    ie = 1.0f - enterfrac;
                    newimpactplane[0] = startplane[0] * ie + endplane[0] * enterfrac;
                    newimpactplane[1] = startplane[1] * ie + endplane[1] * enterfrac;
                    newimpactplane[2] = startplane[2] * ie + endplane[2] * enterfrac;
                    newimpactplane[3] = startplane[3] * ie + endplane[3] * enterfrac;
                    hitq3surfaceflags = other_start->planes[nplane].q3surfaceflags;
                    hittexture = other_start->planes[nplane].texture;
                }
            }
        }
        else
        {
            // moving out of brush
            if (startdist > 0)
                return;
            if (enddist > 0)
            {
                // leave
                f = startdist / (startdist - enddist);
                // check if this will reduce the collision time range
                if (leavefrac > f)
                {
                    // reduced collision time range
                    leavefrac = f;
                    // if the collision time range is now empty, no collision
                    if (enterfrac > leavefrac)
                        return;
                }
            }
        }
    }
 
    // at this point we know the trace overlaps the brush because it was not
    // rejected at any point in the loop above
 
    // see if the trace started outside the brush or not
    if (enterfrac > -1)
    {
        // started outside, and overlaps, therefore there is a collision here
        // store out the impact information
        if ((trace->hitsupercontentsmask & other_start->supercontents) && !(trace->skipsupercontentsmask & other_start->supercontents) && !(trace->skipmaterialflagsmask & (hittexture ? hittexture->currentmaterialflags : 0)))
        {
            trace->hitsupercontents = other_start->supercontents;
            trace->hitq3surfaceflags = hitq3surfaceflags;
            trace->hittexture = hittexture;
            trace->fraction = bound(0, enterfrac2, 1);
            VectorCopy(newimpactplane, trace->plane.normal);
            trace->plane.dist = newimpactplane[3];
        }
    }
    else
    {
        // started inside, update startsolid and friends
        trace->startsupercontents |= other_start->supercontents;
        if ((trace->hitsupercontentsmask & other_start->supercontents) && !(trace->skipsupercontentsmask & other_start->supercontents) && !(trace->skipmaterialflagsmask & (starttexture ? starttexture->currentmaterialflags : 0)))
        {
            trace->startsolid = true;
            if (leavefrac < 1)
                trace->allsolid = true;
            VectorCopy(newimpactplane, trace->plane.normal);
            trace->plane.dist = newimpactplane[3];
            if (trace->startdepth > startdepth)
            {
                trace->startdepth = startdepth;
                VectorCopy(startdepthnormal, trace->startdepthnormal);
                trace->starttexture = starttexture;
            }
        }
    }
}
 
qbool Collision_PointInsideBrushFloat(const vec3_t point, const colbrushf_t *brush)
{
    int nplane;
    const colplanef_t *plane;
 
    if (!BoxesOverlap(point, point, brush->mins, brush->maxs))
        return false;
    for (nplane = 0, plane = brush->planes;nplane < brush->numplanes;nplane++, plane++)
        if (DotProduct(plane->normal, point) > plane->dist)
            return false;
    return true;
}
 
void Collision_TracePointBrushFloat(trace_t *trace, const vec3_t linestart, const colbrushf_t *other_start)
{
    int nplane;
    int numplanes = other_start->numplanes;
    vec_t startdist;
    vec4_t startplane;
    vec4_t newimpactplane;
    vec_t startdepth = 1;
    vec3_t startdepthnormal;
    const texture_t *starttexture = NULL;
 
    VectorClear(startdepthnormal);
    Vector4Clear(newimpactplane);
 
    // Separating Axis Theorem:
    // if a supporting vector (plane normal) can be found that separates two
    // objects, they are not colliding.
    //
    // Minkowski Sum:
    // reduce the size of one object to a point while enlarging the other to
    // represent the space that point can not occupy.
    //
    // try every plane we can construct between the two brushes and measure
    // the distance between them.
    for (nplane = 0; nplane < numplanes; nplane++)
    {
        VectorCopy(other_start->planes[nplane].normal, startplane);
        startplane[3] = other_start->planes[nplane].dist;
        startdist = DotProduct(linestart, startplane) - startplane[3];
 
        if (startdist > 0)
            return;
 
        // aside from collisions, this is also used for error correction
        if (startdepth < startdist || startdepth == 1)
        {
            startdepth = startdist;
            VectorCopy(startplane, startdepthnormal);
            starttexture = other_start->planes[nplane].texture;
        }
    }
 
    // at this point we know the trace overlaps the brush because it was not
    // rejected at any point in the loop above
 
    // started inside, update startsolid and friends
    trace->startsupercontents |= other_start->supercontents;
    if ((trace->hitsupercontentsmask & other_start->supercontents) && !(trace->skipsupercontentsmask & other_start->supercontents) && !(trace->skipmaterialflagsmask & (starttexture ? starttexture->currentmaterialflags : 0)))
    {
        trace->startsolid = true;
        trace->allsolid = true;
        VectorCopy(newimpactplane, trace->plane.normal);
        trace->plane.dist = newimpactplane[3];
        if (trace->startdepth > startdepth)
        {
            trace->startdepth = startdepth;
            VectorCopy(startdepthnormal, trace->startdepthnormal);
            trace->starttexture = starttexture;
        }
    }
}
 
static void Collision_SnapCopyPoints(int numpoints, const colpointf_t *in, colpointf_t *out, float fractionprecision, float invfractionprecision)
{
    int i;
    for (i = 0;i < numpoints;i++)
    {
        out[i].v[0] = floor(in[i].v[0] * fractionprecision + 0.5f) * invfractionprecision;
        out[i].v[1] = floor(in[i].v[1] * fractionprecision + 0.5f) * invfractionprecision;
        out[i].v[2] = floor(in[i].v[2] * fractionprecision + 0.5f) * invfractionprecision;
    }
}
 
void Collision_TraceBrushTriangleMeshFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, int numtriangles, const int *element3i, const float *vertex3f, int stride, float *bbox6f, int supercontents, int q3surfaceflags, const texture_t *texture, const vec3_t segmentmins, const vec3_t segmentmaxs)
{
    int i;
    colpointf_t points[3];
    colpointf_t edgedirs[3];
    colplanef_t planes[5];
    colbrushf_t brush;
    memset(&brush, 0, sizeof(brush));
    brush.isaabb = false;
    brush.hasaabbplanes = false;
    brush.numpoints = 3;
    brush.numedgedirs = 3;
    brush.numplanes = 5;
    brush.points = points;
    brush.edgedirs = edgedirs;
    brush.planes = planes;
    brush.supercontents = supercontents;
    brush.q3surfaceflags = q3surfaceflags;
    brush.texture = texture;
    for (i = 0;i < brush.numplanes;i++)
    {
        brush.planes[i].q3surfaceflags = q3surfaceflags;
        brush.planes[i].texture = texture;
    }
    if(stride > 0)
    {
        int k, cnt, tri;
        cnt = (numtriangles + stride - 1) / stride;
        for(i = 0; i < cnt; ++i)
        {
            if(BoxesOverlap(bbox6f + i * 6, bbox6f + i * 6 + 3, segmentmins, segmentmaxs))
            {
                for(k = 0; k < stride; ++k)
                {
                    tri = i * stride + k;
                    if(tri >= numtriangles)
                        break;
                    VectorCopy(vertex3f + element3i[tri * 3 + 0] * 3, points[0].v);
                    VectorCopy(vertex3f + element3i[tri * 3 + 1] * 3, points[1].v);
                    VectorCopy(vertex3f + element3i[tri * 3 + 2] * 3, points[2].v);
                    Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
                    Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
                    Collision_CalcPlanesForTriangleBrushFloat(&brush);
                    //Collision_PrintBrushAsQHull(&brush, "brush");
                    Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
                }
            }
        }
    }
    else if(stride == 0)
    {
        for (i = 0;i < numtriangles;i++, element3i += 3)
        {
            if (TriangleBBoxOverlapsBox(vertex3f + element3i[0]*3, vertex3f + element3i[1]*3, vertex3f + element3i[2]*3, segmentmins, segmentmaxs))
            {
                VectorCopy(vertex3f + element3i[0] * 3, points[0].v);
                VectorCopy(vertex3f + element3i[1] * 3, points[1].v);
                VectorCopy(vertex3f + element3i[2] * 3, points[2].v);
                Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
                Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
                Collision_CalcPlanesForTriangleBrushFloat(&brush);
                //Collision_PrintBrushAsQHull(&brush, "brush");
                Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
            }
        }
    }
    else
    {
        for (i = 0;i < numtriangles;i++, element3i += 3)
        {
            VectorCopy(vertex3f + element3i[0] * 3, points[0].v);
            VectorCopy(vertex3f + element3i[1] * 3, points[1].v);
            VectorCopy(vertex3f + element3i[2] * 3, points[2].v);
            Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
            Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
            Collision_CalcPlanesForTriangleBrushFloat(&brush);
            //Collision_PrintBrushAsQHull(&brush, "brush");
            Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
        }
    }
}
 
void Collision_TraceLineTriangleMeshFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, int numtriangles, const int *element3i, const float *vertex3f, int stride, float *bbox6f, int supercontents, int q3surfaceflags, const texture_t *texture, const vec3_t segmentmins, const vec3_t segmentmaxs)
{
    int i;
    // FIXME: snap vertices?
    if(stride > 0)
    {
        int k, cnt, tri;
        cnt = (numtriangles + stride - 1) / stride;
        for(i = 0; i < cnt; ++i)
        {
            if(BoxesOverlap(bbox6f + i * 6, bbox6f + i * 6 + 3, segmentmins, segmentmaxs))
            {
                for(k = 0; k < stride; ++k)
                {
                    tri = i * stride + k;
                    if(tri >= numtriangles)
                        break;
                    Collision_TraceLineTriangleFloat(trace, linestart, lineend, vertex3f + element3i[tri * 3 + 0] * 3, vertex3f + element3i[tri * 3 + 1] * 3, vertex3f + element3i[tri * 3 + 2] * 3, supercontents, q3surfaceflags, texture);
                }
            }
        }
    }
    else
    {
        for (i = 0;i < numtriangles;i++, element3i += 3)
            Collision_TraceLineTriangleFloat(trace, linestart, lineend, vertex3f + element3i[0] * 3, vertex3f + element3i[1] * 3, vertex3f + element3i[2] * 3, supercontents, q3surfaceflags, texture);
    }
}
 
void Collision_TraceBrushTriangleFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, const float *v0, const float *v1, const float *v2, int supercontents, int q3surfaceflags, const texture_t *texture)
{
    int i;
    colpointf_t points[3];
    colpointf_t edgedirs[3];
    colplanef_t planes[5];
    colbrushf_t brush;
    memset(&brush, 0, sizeof(brush));
    brush.isaabb = false;
    brush.hasaabbplanes = false;
    brush.numpoints = 3;
    brush.numedgedirs = 3;
    brush.numplanes = 5;
    brush.points = points;
    brush.edgedirs = edgedirs;
    brush.planes = planes;
    brush.supercontents = supercontents;
    brush.q3surfaceflags = q3surfaceflags;
    brush.texture = texture;
    for (i = 0;i < brush.numplanes;i++)
    {
        brush.planes[i].q3surfaceflags = q3surfaceflags;
        brush.planes[i].texture = texture;
    }
    VectorCopy(v0, points[0].v);
    VectorCopy(v1, points[1].v);
    VectorCopy(v2, points[2].v);
    Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
    Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
    Collision_CalcPlanesForTriangleBrushFloat(&brush);
    //Collision_PrintBrushAsQHull(&brush, "brush");
    Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
}
 
void Collision_BrushForBox(colboxbrushf_t *boxbrush, const vec3_t mins, const vec3_t maxs, int supercontents, int q3surfaceflags, const texture_t *texture)
{
    int i;
    memset(boxbrush, 0, sizeof(*boxbrush));
    boxbrush->brush.isaabb = true;
    boxbrush->brush.hasaabbplanes = true;
    boxbrush->brush.points = boxbrush->points;
    boxbrush->brush.edgedirs = boxbrush->edgedirs;
    boxbrush->brush.planes = boxbrush->planes;
    boxbrush->brush.supercontents = supercontents;
    boxbrush->brush.q3surfaceflags = q3surfaceflags;
    boxbrush->brush.texture = texture;
    if (VectorCompare(mins, maxs))
    {
        // point brush
        boxbrush->brush.numpoints = 1;
        boxbrush->brush.numedgedirs = 0;
        boxbrush->brush.numplanes = 0;
        VectorCopy(mins, boxbrush->brush.points[0].v);
    }
    else
    {
        boxbrush->brush.numpoints = 8;
        boxbrush->brush.numedgedirs = 3;
        boxbrush->brush.numplanes = 6;
        // there are 8 points on a box
        // there are 3 edgedirs on a box (both signs are tested in collision)
        // there are 6 planes on a box
        VectorSet(boxbrush->brush.points[0].v, mins[0], mins[1], mins[2]);
        VectorSet(boxbrush->brush.points[1].v, maxs[0], mins[1], mins[2]);
        VectorSet(boxbrush->brush.points[2].v, mins[0], maxs[1], mins[2]);
        VectorSet(boxbrush->brush.points[3].v, maxs[0], maxs[1], mins[2]);
        VectorSet(boxbrush->brush.points[4].v, mins[0], mins[1], maxs[2]);
        VectorSet(boxbrush->brush.points[5].v, maxs[0], mins[1], maxs[2]);
        VectorSet(boxbrush->brush.points[6].v, mins[0], maxs[1], maxs[2]);
        VectorSet(boxbrush->brush.points[7].v, maxs[0], maxs[1], maxs[2]);
        VectorSet(boxbrush->brush.edgedirs[0].v, 1, 0, 0);
        VectorSet(boxbrush->brush.edgedirs[1].v, 0, 1, 0);
        VectorSet(boxbrush->brush.edgedirs[2].v, 0, 0, 1);
        VectorSet(boxbrush->brush.planes[0].normal, -1,  0,  0);boxbrush->brush.planes[0].dist = -mins[0];
        VectorSet(boxbrush->brush.planes[1].normal,  1,  0,  0);boxbrush->brush.planes[1].dist =  maxs[0];
        VectorSet(boxbrush->brush.planes[2].normal,  0, -1,  0);boxbrush->brush.planes[2].dist = -mins[1];
        VectorSet(boxbrush->brush.planes[3].normal,  0,  1,  0);boxbrush->brush.planes[3].dist =  maxs[1];
        VectorSet(boxbrush->brush.planes[4].normal,  0,  0, -1);boxbrush->brush.planes[4].dist = -mins[2];
        VectorSet(boxbrush->brush.planes[5].normal,  0,  0,  1);boxbrush->brush.planes[5].dist =  maxs[2];
        for (i = 0;i < 6;i++)
        {
            boxbrush->brush.planes[i].q3surfaceflags = q3surfaceflags;
            boxbrush->brush.planes[i].texture = texture;
        }
    }
    boxbrush->brush.supercontents = supercontents;
    boxbrush->brush.q3surfaceflags = q3surfaceflags;
    boxbrush->brush.texture = texture;
    VectorSet(boxbrush->brush.mins, mins[0] - 1, mins[1] - 1, mins[2] - 1);
    VectorSet(boxbrush->brush.maxs, maxs[0] + 1, maxs[1] + 1, maxs[2] + 1);
    //Collision_ValidateBrush(&boxbrush->brush);
}
 
//pseudocode for detecting line/sphere overlap without calculating an impact point
//linesphereorigin = sphereorigin - linestart;linediff = lineend - linestart;linespherefrac = DotProduct(linesphereorigin, linediff) / DotProduct(linediff, linediff);return VectorLength2(linesphereorigin - bound(0, linespherefrac, 1) * linediff) >= sphereradius*sphereradius;
 
// LadyHavoc: currently unused, but tested
// note: this can be used for tracing a moving sphere vs a stationary sphere,
// by simply adding the moving sphere's radius to the sphereradius parameter,
// all the results are correct (impactpoint, impactnormal, and fraction)
float Collision_ClipTrace_Line_Sphere(double *linestart, double *lineend, double *sphereorigin, double sphereradius, double *impactpoint, double *impactnormal)
{
    double dir[3], scale, v[3], deviationdist2, impactdist, linelength;
    // make sure the impactpoint and impactnormal are valid even if there is
    // no collision
    VectorCopy(lineend, impactpoint);
    VectorClear(impactnormal);
    // calculate line direction
    VectorSubtract(lineend, linestart, dir);
    // normalize direction
    linelength = VectorLength(dir);
    if (linelength)
    {
        scale = 1.0 / linelength;
        VectorScale(dir, scale, dir);
    }
    // this dotproduct calculates the distance along the line at which the
    // sphere origin is (nearest point to the sphere origin on the line)
    impactdist = DotProduct(sphereorigin, dir) - DotProduct(linestart, dir);
    // calculate point on line at that distance, and subtract the
    // sphereorigin from it, so we have a vector to measure for the distance
    // of the line from the sphereorigin (deviation, how off-center it is)
    VectorMA(linestart, impactdist, dir, v);
    VectorSubtract(v, sphereorigin, v);
    deviationdist2 = sphereradius * sphereradius - VectorLength2(v);
    // if squared offset length is outside the squared sphere radius, miss
    if (deviationdist2 < 0)
        return 1; // miss (off to the side)
    // nudge back to find the correct impact distance
    impactdist -= sqrt(deviationdist2);
    if (impactdist >= linelength)
        return 1; // miss (not close enough)
    if (impactdist < 0)
        return 1; // miss (linestart is past or inside sphere)
    // calculate new impactpoint
    VectorMA(linestart, impactdist, dir, impactpoint);
    // calculate impactnormal (surface normal at point of impact)
    VectorSubtract(impactpoint, sphereorigin, impactnormal);
    // normalize impactnormal
    VectorNormalize(impactnormal);
    // return fraction of movement distance
    return impactdist / linelength;
}
 
void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, const float *point0, const float *point1, const float *point2, int supercontents, int q3surfaceflags, const texture_t *texture)
{
    float d1, d2, d, f, f2, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, faceplanenormallength2, edge01[3], edge21[3], edge02[3];
 
    // this function executes:
    // 32 ops when line starts behind triangle
    // 38 ops when line ends infront of triangle
    // 43 ops when line fraction is already closer than this triangle
    // 72 ops when line is outside edge 01
    // 92 ops when line is outside edge 21
    // 115 ops when line is outside edge 02
    // 123 ops when line impacts triangle and updates trace results
 
    // this code is designed for clockwise triangles, conversion to
    // counterclockwise would require swapping some things around...
    // it is easier to simply swap the point0 and point2 parameters to this
    // function when calling it than it is to rewire the internals.
 
    // calculate the faceplanenormal of the triangle, this represents the front side
    // 15 ops
    VectorSubtract(point0, point1, edge01);
    VectorSubtract(point2, point1, edge21);
    CrossProduct(edge01, edge21, faceplanenormal);
    // there's no point in processing a degenerate triangle (GIGO - Garbage In, Garbage Out)
    // 6 ops
    faceplanenormallength2 = DotProduct(faceplanenormal, faceplanenormal);
    if (faceplanenormallength2 < 0.0001f)
        return;
    // calculate the distance
    // 5 ops
    faceplanedist = DotProduct(point0, faceplanenormal);
 
    // if start point is on the back side there is no collision
    // (we don't care about traces going through the triangle the wrong way)
 
    // calculate the start distance
    // 6 ops
    d1 = DotProduct(faceplanenormal, linestart);
    if (d1 <= faceplanedist)
        return;
 
    // calculate the end distance
    // 6 ops
    d2 = DotProduct(faceplanenormal, lineend);
    // if both are in front, there is no collision
    if (d2 >= faceplanedist)
        return;
 
    // from here on we know d1 is >= 0 and d2 is < 0
    // this means the line starts infront and ends behind, passing through it
 
    // calculate the recipricol of the distance delta,
    // so we can use it multiple times cheaply (instead of division)
    // 2 ops
    d = 1.0f / (d1 - d2);
    // calculate the impact fraction by taking the start distance (> 0)
    // and subtracting the face plane distance (this is the distance of the
    // triangle along that same normal)
    // then multiply by the recipricol distance delta
    // 4 ops
    f = (d1 - faceplanedist) * d;
    f2  = f - collision_impactnudge.value * d;
    // skip out if this impact is further away than previous ones
    // 1 ops
    if (f2 >= trace->fraction)
        return;
    // calculate the perfect impact point for classification of insidedness
    // 9 ops
    impact[0] = linestart[0] + f * (lineend[0] - linestart[0]);
    impact[1] = linestart[1] + f * (lineend[1] - linestart[1]);
    impact[2] = linestart[2] + f * (lineend[2] - linestart[2]);
 
    // calculate the edge normal and reject if impact is outside triangle
    // (an edge normal faces away from the triangle, to get the desired normal
    //  a crossproduct with the faceplanenormal is used, and because of the way
    // the insidedness comparison is written it does not need to be normalized)
 
    // first use the two edges from the triangle plane math
    // the other edge only gets calculated if the point survives that long
 
    // 20 ops
    CrossProduct(edge01, faceplanenormal, edgenormal);
    if (DotProduct(impact, edgenormal) > DotProduct(point1, edgenormal))
        return;
 
    // 20 ops
    CrossProduct(faceplanenormal, edge21, edgenormal);
    if (DotProduct(impact, edgenormal) > DotProduct(point2, edgenormal))
        return;
 
    // 23 ops
    VectorSubtract(point0, point2, edge02);
    CrossProduct(faceplanenormal, edge02, edgenormal);
    if (DotProduct(impact, edgenormal) > DotProduct(point0, edgenormal))
        return;
 
    // 8 ops (rare)
 
    // skip if this trace should not be blocked by these contents
    if (!(supercontents & trace->hitsupercontentsmask) || (supercontents & trace->skipsupercontentsmask) || (texture->currentmaterialflags & trace->skipmaterialflagsmask))
        return;
 
    // store the new trace fraction
    trace->fraction = f2;
 
    // store the new trace plane (because collisions only happen from
    // the front this is always simply the triangle normal, never flipped)
    d = 1.0 / sqrt(faceplanenormallength2);
    VectorScale(faceplanenormal, d, trace->plane.normal);
    trace->plane.dist = faceplanedist * d;
 
    trace->hitsupercontents = supercontents;
    trace->hitq3surfaceflags = q3surfaceflags;
    trace->hittexture = texture;
}
 
void Collision_BoundingBoxOfBrushTraceSegment(const colbrushf_t *start, const colbrushf_t *end, vec3_t mins, vec3_t maxs, float startfrac, float endfrac)
{
    int i;
    colpointf_t *ps, *pe;
    float tempstart[3], tempend[3];
    VectorLerp(start->points[0].v, startfrac, end->points[0].v, mins);
    VectorCopy(mins, maxs);
    for (i = 0, ps = start->points, pe = end->points;i < start->numpoints;i++, ps++, pe++)
    {
        VectorLerp(ps->v, startfrac, pe->v, tempstart);
        VectorLerp(ps->v, endfrac, pe->v, tempend);
        mins[0] = min(mins[0], min(tempstart[0], tempend[0]));
        mins[1] = min(mins[1], min(tempstart[1], tempend[1]));
        mins[2] = min(mins[2], min(tempstart[2], tempend[2]));
        maxs[0] = min(maxs[0], min(tempstart[0], tempend[0]));
        maxs[1] = min(maxs[1], min(tempstart[1], tempend[1]));
        maxs[2] = min(maxs[2], min(tempstart[2], tempend[2]));
    }
    mins[0] -= 1;
    mins[1] -= 1;
    mins[2] -= 1;
    maxs[0] += 1;
    maxs[1] += 1;
    maxs[2] += 1;
}
 
//===========================================
 
static void Collision_TranslateBrush(const vec3_t shift, colbrushf_t *brush)
{
    int i;
    // now we can transform the data
    for(i = 0; i < brush->numplanes; ++i)
    {
        brush->planes[i].dist += DotProduct(shift, brush->planes[i].normal);
    }
    for(i = 0; i < brush->numpoints; ++i)
    {
        VectorAdd(brush->points[i].v, shift, brush->points[i].v);
    }
    VectorAdd(brush->mins, shift, brush->mins);
    VectorAdd(brush->maxs, shift, brush->maxs);
}
 
static void Collision_TransformBrush(const matrix4x4_t *matrix, colbrushf_t *brush)
{
    int i;
    vec3_t v;
    // we're breaking any AABB properties here...
    brush->isaabb = false;
    brush->hasaabbplanes = false;
    // now we can transform the data
    for(i = 0; i < brush->numplanes; ++i)
    {
        Matrix4x4_TransformPositivePlane(matrix, brush->planes[i].normal[0], brush->planes[i].normal[1], brush->planes[i].normal[2], brush->planes[i].dist, brush->planes[i].normal_and_dist);
    }
    for(i = 0; i < brush->numedgedirs; ++i)
    {
        Matrix4x4_Transform(matrix, brush->edgedirs[i].v, v);
        VectorCopy(v, brush->edgedirs[i].v);
    }
    for(i = 0; i < brush->numpoints; ++i)
    {
        Matrix4x4_Transform(matrix, brush->points[i].v, v);
        VectorCopy(v, brush->points[i].v);
    }
    VectorCopy(brush->points[0].v, brush->mins);
    VectorCopy(brush->points[0].v, brush->maxs);
    for(i = 1; i < brush->numpoints; ++i)
    {
        if(brush->points[i].v[0] < brush->mins[0]) brush->mins[0] = brush->points[i].v[0];
        if(brush->points[i].v[1] < brush->mins[1]) brush->mins[1] = brush->points[i].v[1];
        if(brush->points[i].v[2] < brush->mins[2]) brush->mins[2] = brush->points[i].v[2];
        if(brush->points[i].v[0] > brush->maxs[0]) brush->maxs[0] = brush->points[i].v[0];
        if(brush->points[i].v[1] > brush->maxs[1]) brush->maxs[1] = brush->points[i].v[1];
        if(brush->points[i].v[2] > brush->maxs[2]) brush->maxs[2] = brush->points[i].v[2];
    }
}
 
typedef struct collision_cachedtrace_parameters_s
{
    model_t *model;
    vec3_t end;
    vec3_t start;
    int hitsupercontentsmask;
    int skipsupercontentsmask;
    int skipmaterialflagsmask;
    matrix4x4_t matrix;
}
collision_cachedtrace_parameters_t;
 
typedef struct collision_cachedtrace_s
{
    qbool valid;
    collision_cachedtrace_parameters_t p;
    trace_t result;
}
collision_cachedtrace_t;
 
static mempool_t *collision_cachedtrace_mempool;
static collision_cachedtrace_t *collision_cachedtrace_array;
static int collision_cachedtrace_firstfree;
static int collision_cachedtrace_lastused;
static int collision_cachedtrace_max;
static unsigned char collision_cachedtrace_sequence;
static int collision_cachedtrace_hashsize;
static int *collision_cachedtrace_hash;
static unsigned int *collision_cachedtrace_arrayfullhashindex;
static unsigned int *collision_cachedtrace_arrayhashindex;
static unsigned int *collision_cachedtrace_arraynext;
static unsigned char *collision_cachedtrace_arrayused;
static qbool collision_cachedtrace_rebuildhash;
 
void Collision_Cache_Reset(qbool resetlimits)
{
    if (collision_cachedtrace_hash)
        Mem_Free(collision_cachedtrace_hash);
    if (collision_cachedtrace_array)
        Mem_Free(collision_cachedtrace_array);
    if (collision_cachedtrace_arrayfullhashindex)
        Mem_Free(collision_cachedtrace_arrayfullhashindex);
    if (collision_cachedtrace_arrayhashindex)
        Mem_Free(collision_cachedtrace_arrayhashindex);
    if (collision_cachedtrace_arraynext)
        Mem_Free(collision_cachedtrace_arraynext);
    if (collision_cachedtrace_arrayused)
        Mem_Free(collision_cachedtrace_arrayused);
    if (resetlimits || !collision_cachedtrace_max)
        collision_cachedtrace_max = collision_cache.integer ? 128 : 1;
    collision_cachedtrace_firstfree = 1;
    collision_cachedtrace_lastused = 0;
    collision_cachedtrace_hashsize = collision_cachedtrace_max;
    collision_cachedtrace_array = (collision_cachedtrace_t *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(collision_cachedtrace_t));
    collision_cachedtrace_hash = (int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_hashsize * sizeof(int));
    collision_cachedtrace_arrayfullhashindex = (unsigned int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned int));
    collision_cachedtrace_arrayhashindex = (unsigned int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned int));
    collision_cachedtrace_arraynext = (unsigned int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned int));
    collision_cachedtrace_arrayused = (unsigned char *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned char));
    collision_cachedtrace_sequence = 1;
    collision_cachedtrace_rebuildhash = false;
}
 
void Collision_Cache_Init(mempool_t *mempool)
{
    collision_cachedtrace_mempool = mempool;
    Collision_Cache_Reset(true);
}
 
static void Collision_Cache_RebuildHash(void)
{
    int index;
    int range = collision_cachedtrace_lastused + 1;
    unsigned char sequence = collision_cachedtrace_sequence;
    int firstfree = collision_cachedtrace_max;
    int lastused = 0;
    int *hash = collision_cachedtrace_hash;
    unsigned int hashindex;
    unsigned int *arrayhashindex = collision_cachedtrace_arrayhashindex;
    unsigned int *arraynext = collision_cachedtrace_arraynext;
    collision_cachedtrace_rebuildhash = false;
    memset(collision_cachedtrace_hash, 0, collision_cachedtrace_hashsize * sizeof(int));
    for (index = 1;index < range;index++)
    {
        if (collision_cachedtrace_arrayused[index] == sequence)
        {
            hashindex = arrayhashindex[index];
            arraynext[index] = hash[hashindex];
            hash[hashindex] = index;
            lastused = index;
        }
        else
        {
            if (firstfree > index)
                firstfree = index;
            collision_cachedtrace_arrayused[index] = 0;
        }
    }
    collision_cachedtrace_firstfree = firstfree;
    collision_cachedtrace_lastused = lastused;
}
 
void Collision_Cache_NewFrame(void)
{
    if (collision_cache.integer)
    {
        if (collision_cachedtrace_max < 128)
            Collision_Cache_Reset(true);
    }
    else
    {
        if (collision_cachedtrace_max > 1)
            Collision_Cache_Reset(true);
    }
    // rebuild hash if sequence would overflow byte, otherwise increment
    if (collision_cachedtrace_sequence == 255)
    {
        Collision_Cache_RebuildHash();
        collision_cachedtrace_sequence = 1;
    }
    else
    {
        collision_cachedtrace_rebuildhash = true;
        collision_cachedtrace_sequence++;
    }
}
 
static unsigned int Collision_Cache_HashIndexForArray(unsigned int *array, unsigned int size)
{
    unsigned int i;
    unsigned int hashindex = 0;
    // this is a super-cheesy checksum, designed only for speed
    for (i = 0;i < size;i++)
        hashindex += array[i] * (1 + i);
    return hashindex;
}
 
static collision_cachedtrace_t *Collision_Cache_Lookup(model_t *model, const matrix4x4_t *matrix, const matrix4x4_t *inversematrix, const vec3_t start, const vec3_t end, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask)
{
    int hashindex = 0;
    unsigned int fullhashindex;
    int index = 0;
    int range;
    unsigned char sequence = collision_cachedtrace_sequence;
    int *hash = collision_cachedtrace_hash;
    unsigned int *arrayfullhashindex = collision_cachedtrace_arrayfullhashindex;
    unsigned int *arraynext = collision_cachedtrace_arraynext;
    collision_cachedtrace_t *cached = collision_cachedtrace_array + index;
    collision_cachedtrace_parameters_t params;
    // all non-cached traces use the same index
    if (!collision_cache.integer)
        r_refdef.stats[r_stat_photoncache_traced]++;
    else
    {
        // cached trace lookup
        memset(&params, 0, sizeof(params));
        params.model = model;
        VectorCopy(start, params.start);
        VectorCopy(end,   params.end);
        params.hitsupercontentsmask = hitsupercontentsmask;
        params.skipsupercontentsmask = skipsupercontentsmask;
        params.skipmaterialflagsmask = skipmaterialflagsmask;
        params.matrix = *matrix;
        fullhashindex = Collision_Cache_HashIndexForArray((unsigned int *)&params, sizeof(params) / sizeof(unsigned int));
        hashindex = (int)(fullhashindex % (unsigned int)collision_cachedtrace_hashsize);
        for (index = hash[hashindex];index;index = arraynext[index])
        {
            if (arrayfullhashindex[index] != fullhashindex)
                continue;
            cached = collision_cachedtrace_array + index;
            //if (memcmp(&cached->p, &params, sizeof(params)))
            if (cached->p.model != params.model
             || cached->p.end[0] != params.end[0]
             || cached->p.end[1] != params.end[1]
             || cached->p.end[2] != params.end[2]
             || cached->p.start[0] != params.start[0]
             || cached->p.start[1] != params.start[1]
             || cached->p.start[2] != params.start[2]
             || cached->p.hitsupercontentsmask != params.hitsupercontentsmask
             || cached->p.skipsupercontentsmask != params.skipsupercontentsmask
             || cached->p.skipmaterialflagsmask != params.skipmaterialflagsmask
             || cached->p.matrix.m[0][0] != params.matrix.m[0][0]
             || cached->p.matrix.m[0][1] != params.matrix.m[0][1]
             || cached->p.matrix.m[0][2] != params.matrix.m[0][2]
             || cached->p.matrix.m[0][3] != params.matrix.m[0][3]
             || cached->p.matrix.m[1][0] != params.matrix.m[1][0]
             || cached->p.matrix.m[1][1] != params.matrix.m[1][1]
             || cached->p.matrix.m[1][2] != params.matrix.m[1][2]
             || cached->p.matrix.m[1][3] != params.matrix.m[1][3]
             || cached->p.matrix.m[2][0] != params.matrix.m[2][0]
             || cached->p.matrix.m[2][1] != params.matrix.m[2][1]
             || cached->p.matrix.m[2][2] != params.matrix.m[2][2]
             || cached->p.matrix.m[2][3] != params.matrix.m[2][3]
             || cached->p.matrix.m[3][0] != params.matrix.m[3][0]
             || cached->p.matrix.m[3][1] != params.matrix.m[3][1]
             || cached->p.matrix.m[3][2] != params.matrix.m[3][2]
             || cached->p.matrix.m[3][3] != params.matrix.m[3][3]
            )
                continue;
            // found a matching trace in the cache
            r_refdef.stats[r_stat_photoncache_cached]++;
            cached->valid = true;
            collision_cachedtrace_arrayused[index] = collision_cachedtrace_sequence;
            return cached;
        }
        r_refdef.stats[r_stat_photoncache_traced]++;
        // find an unused cache entry
        for (index = collision_cachedtrace_firstfree, range = collision_cachedtrace_max;index < range;index++)
            if (collision_cachedtrace_arrayused[index] == 0)
                break;
        if (index == range)
        {
            // all claimed, but probably some are stale...
            for (index = 1, range = collision_cachedtrace_max;index < range;index++)
                if (collision_cachedtrace_arrayused[index] != sequence)
                    break;
            if (index < range)
            {
                // found a stale one, rebuild the hash
                Collision_Cache_RebuildHash();
            }
            else
            {
                // we need to grow the cache
                collision_cachedtrace_max *= 2;
                Collision_Cache_Reset(false);
                index = 1;
            }
        }
        // link the new cache entry into the hash bucket
        collision_cachedtrace_firstfree = index + 1;
        if (collision_cachedtrace_lastused < index)
            collision_cachedtrace_lastused = index;
        cached = collision_cachedtrace_array + index;
        collision_cachedtrace_arraynext[index] = collision_cachedtrace_hash[hashindex];
        collision_cachedtrace_hash[hashindex] = index;
        collision_cachedtrace_arrayhashindex[index] = hashindex;
        cached->valid = false;
        cached->p = params;
        collision_cachedtrace_arrayfullhashindex[index] = fullhashindex;
        collision_cachedtrace_arrayused[index] = collision_cachedtrace_sequence;
    }
    return cached;
}
 
void Collision_Cache_ClipLineToGenericEntitySurfaces(trace_t *trace, model_t *model, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, const vec3_t end, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask)
{
    collision_cachedtrace_t *cached = Collision_Cache_Lookup(model, matrix, inversematrix, start, end, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    if (cached->valid)
    {
        *trace = cached->result;
        return;
    }
 
    Collision_ClipLineToGenericEntity(trace, model, NULL, NULL, vec3_origin, vec3_origin, 0, matrix, inversematrix, start, end, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask, collision_extendmovelength.value, true);
 
    cached->result = *trace;
}
 
void Collision_Cache_ClipLineToWorldSurfaces(trace_t *trace, model_t *model, const vec3_t start, const vec3_t end, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask)
{
    collision_cachedtrace_t *cached = Collision_Cache_Lookup(model, &identitymatrix, &identitymatrix, start, end, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    if (cached->valid)
    {
        *trace = cached->result;
        return;
    }
 
    Collision_ClipLineToWorld(trace, model, start, end, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask, collision_extendmovelength.value, true);
 
    cached->result = *trace;
}
 
typedef struct extendtraceinfo_s
{
    trace_t *trace;
    float realstart[3];
    float realend[3];
    float realdelta[3];
    float extendstart[3];
    float extendend[3];
    float extenddelta[3];
    float reallength;
    float extendlength;
    float scaletoextend;
    float extend;
}
extendtraceinfo_t;
 
static void Collision_ClipExtendPrepare(extendtraceinfo_t *extendtraceinfo, trace_t *trace, const vec3_t tstart, const vec3_t tend, float textend)
{
    memset(trace, 0, sizeof(*trace));
    trace->fraction = 1;
 
    extendtraceinfo->trace = trace;
    VectorCopy(tstart, extendtraceinfo->realstart);
    VectorCopy(tend, extendtraceinfo->realend);
    VectorSubtract(extendtraceinfo->realend, extendtraceinfo->realstart, extendtraceinfo->realdelta);
    VectorCopy(extendtraceinfo->realstart, extendtraceinfo->extendstart);
    VectorCopy(extendtraceinfo->realend, extendtraceinfo->extendend);
    VectorCopy(extendtraceinfo->realdelta, extendtraceinfo->extenddelta);
    extendtraceinfo->reallength = VectorLength(extendtraceinfo->realdelta);
    extendtraceinfo->extendlength = extendtraceinfo->reallength;
    extendtraceinfo->scaletoextend = 1.0f;
    extendtraceinfo->extend = textend;
 
    // make the trace longer according to the extend parameter
    if (extendtraceinfo->reallength && extendtraceinfo->extend)
    {
        extendtraceinfo->extendlength = extendtraceinfo->reallength + extendtraceinfo->extend;
        extendtraceinfo->scaletoextend = extendtraceinfo->extendlength / extendtraceinfo->reallength;
        VectorMA(extendtraceinfo->realstart, extendtraceinfo->scaletoextend, extendtraceinfo->realdelta, extendtraceinfo->extendend);
        VectorSubtract(extendtraceinfo->extendend, extendtraceinfo->extendstart, extendtraceinfo->extenddelta);
    }
}
 
static void Collision_ClipExtendFinish(extendtraceinfo_t *extendtraceinfo)
{
    trace_t *trace = extendtraceinfo->trace;
 
    if (trace->fraction != 1.0f)
    {
        // undo the extended trace length
        trace->fraction *= extendtraceinfo->scaletoextend;
 
        // if the extended trace hit something that the unextended trace did not hit (even considering the collision_impactnudge), then we have to clear the hit information
        if (trace->fraction > 1.0f)
        {
            // note that ent may refer to either startsolid or fraction<1, we can't restore the startsolid ent unfortunately
            trace->ent = NULL;
            trace->hitq3surfaceflags = 0;
            trace->hitsupercontents = 0;
            trace->hittexture = NULL;
            VectorClear(trace->plane.normal);
            trace->plane.dist = 0.0f;
        }
    }
 
    // clamp things
    trace->fraction = bound(0, trace->fraction, 1);
 
    // calculate the end position
    VectorMA(extendtraceinfo->realstart, trace->fraction, extendtraceinfo->realdelta, trace->endpos);
}
 
void Collision_ClipToGenericEntity(trace_t *trace, model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t tstart, const vec3_t mins, const vec3_t maxs, const vec3_t tend, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask, float extend)
{
    vec3_t starttransformed, endtransformed;
    extendtraceinfo_t extendtraceinfo;
    Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
 
    Matrix4x4_Transform(inversematrix, extendtraceinfo.extendstart, starttransformed);
    Matrix4x4_Transform(inversematrix, extendtraceinfo.extendend, endtransformed);
#if COLLISIONPARANOID >= 3
    Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", extendtraceinfo.extendstart[0], extendtraceinfo.extendstart[1], extendtraceinfo.extendstart[2], starttransformed[0], starttransformed[1], starttransformed[2], extendtraceinfo.extendend[0], extendtraceinfo.extendend[1], extendtraceinfo.extendend[2], endtransformed[0], endtransformed[1], endtransformed[2]);
#endif
 
    if (model && model->TraceBox)
    {
        if(model->TraceBrush && (inversematrix->m[0][1] || inversematrix->m[0][2] || inversematrix->m[1][0] || inversematrix->m[1][2] || inversematrix->m[2][0] || inversematrix->m[2][1]))
        {
            // we get here if TraceBrush exists, AND we have a rotation component (SOLID_BSP case)
            // using starttransformed, endtransformed is WRONG in this case!
            // should rather build a brush and trace using it
            colboxbrushf_t thisbrush_start, thisbrush_end;
            Collision_BrushForBox(&thisbrush_start, mins, maxs, 0, 0, NULL);
            Collision_BrushForBox(&thisbrush_end, mins, maxs, 0, 0, NULL);
            Collision_TranslateBrush(extendtraceinfo.extendstart, &thisbrush_start.brush);
            Collision_TranslateBrush(extendtraceinfo.extendend, &thisbrush_end.brush);
            Collision_TransformBrush(inversematrix, &thisbrush_start.brush);
            Collision_TransformBrush(inversematrix, &thisbrush_end.brush);
            //Collision_TranslateBrush(starttransformed, &thisbrush_start.brush);
            //Collision_TranslateBrush(endtransformed, &thisbrush_end.brush);
            model->TraceBrush(model, frameblend, skeleton, trace, &thisbrush_start.brush, &thisbrush_end.brush, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
        }
        else // this is only approximate if rotated, quite useless
            model->TraceBox(model, frameblend, skeleton, trace, starttransformed, mins, maxs, endtransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    }
    else // and this requires that the transformation matrix doesn't have angles components, like SV_TraceBox ensures; FIXME may get called if a model is SOLID_BSP but has no TraceBox function
        Collision_ClipTrace_Box(trace, bodymins, bodymaxs, starttransformed, mins, maxs, endtransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask, bodysupercontents, 0, NULL);
 
    Collision_ClipExtendFinish(&extendtraceinfo);
 
    // transform plane
    // NOTE: this relies on plane.dist being directly after plane.normal
    Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal_and_dist);
}
 
void Collision_ClipToWorld(trace_t *trace, model_t *model, const vec3_t tstart, const vec3_t mins, const vec3_t maxs, const vec3_t tend, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask, float extend)
{
    extendtraceinfo_t extendtraceinfo;
    Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
    // ->TraceBox: TraceBrush not needed here, as worldmodel is never rotated
    if (model && model->TraceBox)
        model->TraceBox(model, NULL, NULL, trace, extendtraceinfo.extendstart, mins, maxs, extendtraceinfo.extendend, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    Collision_ClipExtendFinish(&extendtraceinfo);
}
 
void Collision_ClipLineToGenericEntity(trace_t *trace, model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t tstart, const vec3_t tend, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask, float extend, qbool hitsurfaces)
{
    vec3_t starttransformed, endtransformed;
    extendtraceinfo_t extendtraceinfo;
    Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
 
    Matrix4x4_Transform(inversematrix, extendtraceinfo.extendstart, starttransformed);
    Matrix4x4_Transform(inversematrix, extendtraceinfo.extendend, endtransformed);
#if COLLISIONPARANOID >= 3
    Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", extendtraceinfo.extendstart[0], extendtraceinfo.extendstart[1], extendtraceinfo.extendstart[2], starttransformed[0], starttransformed[1], starttransformed[2], extendtraceinfo.extendend[0], extendtraceinfo.extendend[1], extendtraceinfo.extendend[2], endtransformed[0], endtransformed[1], endtransformed[2]);
#endif
 
    if (model && model->TraceLineAgainstSurfaces && hitsurfaces)
        model->TraceLineAgainstSurfaces(model, frameblend, skeleton, trace, starttransformed, endtransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    else if (model && model->TraceLine)
        model->TraceLine(model, frameblend, skeleton, trace, starttransformed, endtransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    else
        Collision_ClipTrace_Box(trace, bodymins, bodymaxs, starttransformed, vec3_origin, vec3_origin, endtransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask, bodysupercontents, 0, NULL);
 
    Collision_ClipExtendFinish(&extendtraceinfo);
 
    // transform plane
    // NOTE: this relies on plane.dist being directly after plane.normal
    Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal_and_dist);
}
 
void Collision_ClipLineToWorld(trace_t *trace, model_t *model, const vec3_t tstart, const vec3_t tend, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask, float extend, qbool hitsurfaces)
{
    extendtraceinfo_t extendtraceinfo;
    Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
 
    if (model && model->TraceLineAgainstSurfaces && hitsurfaces)
        model->TraceLineAgainstSurfaces(model, NULL, NULL, trace, extendtraceinfo.extendstart, extendtraceinfo.extendend, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    else if (model && model->TraceLine)
        model->TraceLine(model, NULL, NULL, trace, extendtraceinfo.extendstart, extendtraceinfo.extendend, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
 
    Collision_ClipExtendFinish(&extendtraceinfo);
}
 
void Collision_ClipPointToGenericEntity(trace_t *trace, model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask)
{
    float starttransformed[3];
    memset(trace, 0, sizeof(*trace));
    trace->fraction = 1;
 
    Matrix4x4_Transform(inversematrix, start, starttransformed);
#if COLLISIONPARANOID >= 3
    Con_Printf("trans(%f %f %f -> %f %f %f)", start[0], start[1], start[2], starttransformed[0], starttransformed[1], starttransformed[2]);
#endif
 
    if (model && model->TracePoint)
        model->TracePoint(model, NULL, NULL, trace, starttransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    else
        Collision_ClipTrace_Point(trace, bodymins, bodymaxs, starttransformed, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask, bodysupercontents, 0, NULL);
 
    VectorCopy(start, trace->endpos);
    // transform plane
    // NOTE: this relies on plane.dist being directly after plane.normal
    Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal_and_dist);
}
 
void Collision_ClipPointToWorld(trace_t *trace, model_t *model, const vec3_t start, int hitsupercontentsmask, int skipsupercontentsmask, int skipmaterialflagsmask)
{
    memset(trace, 0, sizeof(*trace));
    trace->fraction = 1;
    if (model && model->TracePoint)
        model->TracePoint(model, NULL, NULL, trace, start, hitsupercontentsmask, skipsupercontentsmask, skipmaterialflagsmask);
    VectorCopy(start, trace->endpos);
}
 
void Collision_CombineTraces(trace_t *cliptrace, const trace_t *trace, void *touch, qbool isbmodel)
{
    // take the 'best' answers from the new trace and combine with existing data
    if (trace->allsolid)
        cliptrace->allsolid = true;
    if (trace->startsolid)
    {
        if (isbmodel)
            cliptrace->bmodelstartsolid = true;
        cliptrace->startsolid = true;
        if (cliptrace->fraction == 1)
            cliptrace->ent = touch;
        if (cliptrace->startdepth > trace->startdepth)
        {
            cliptrace->startdepth = trace->startdepth;
            VectorCopy(trace->startdepthnormal, cliptrace->startdepthnormal);
        }
    }
    // don't set this except on the world, because it can easily confuse
    // monsters underwater if there's a bmodel involved in the trace
    // (inopen && inwater is how they check water visibility)
    //if (trace->inopen)
    //  cliptrace->inopen = true;
    if (trace->inwater)
        cliptrace->inwater = true;
    if ((trace->fraction < cliptrace->fraction) && (VectorLength2(trace->plane.normal) > 0))
    {
        cliptrace->fraction = trace->fraction;
        VectorCopy(trace->endpos, cliptrace->endpos);
        cliptrace->plane = trace->plane;
        cliptrace->ent = touch;
        cliptrace->hitsupercontents = trace->hitsupercontents;
        cliptrace->hitq3surfaceflags = trace->hitq3surfaceflags;
        cliptrace->hittexture = trace->hittexture;
    }
    cliptrace->startsupercontents |= trace->startsupercontents;
}