portals.c

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#include "quakedef.h"
#include "polygon.h"
#include "portals.h"
 
#define MAXRECURSIVEPORTALPLANES 1024
#define MAXRECURSIVEPORTALS 256
 
static tinyplane_t portalplanes[MAXRECURSIVEPORTALPLANES];
static int ranoutofportalplanes;
static int ranoutofportals;
static float portaltemppoints[2][256][3];
static float portaltemppoints2[256][3];
static int portal_markid = 0;
static float boxpoints[4*3];
 
static int Portal_PortalThroughPortalPlanes(tinyplane_t *clipplanes, int clipnumplanes, float *targpoints, int targnumpoints, float *out, int maxpoints)
{
    int numpoints = targnumpoints, i, w;
    if (numpoints < 1)
        return numpoints;
    if (maxpoints > 256)
        maxpoints = 256;
    w = 0;
    memcpy(&portaltemppoints[w][0][0], targpoints, numpoints * 3 * sizeof(float));
    for (i = 0;i < clipnumplanes && numpoints > 0;i++)
    {
        PolygonF_Divide(numpoints, &portaltemppoints[w][0][0], clipplanes[i].normal[0], clipplanes[i].normal[1], clipplanes[i].normal[2], clipplanes[i].dist, 1.0f/32.0f, 256, &portaltemppoints[1-w][0][0], &numpoints, 0, NULL, NULL, NULL);
        w = 1-w;
        numpoints = min(numpoints, 256);
    }
    numpoints = min(numpoints, maxpoints);
    if (numpoints > 0)
        memcpy(out, &portaltemppoints[w][0][0], numpoints * 3 * sizeof(float));
    return numpoints;
}
 
static int Portal_RecursiveFlowSearch (mleaf_t *leaf, vec3_t eye, int firstclipplane, int numclipplanes)
{
    mportal_t *p;
    int newpoints, i, prev;
    vec3_t center, v1, v2;
    tinyplane_t *newplanes;
 
    if (leaf->portalmarkid == portal_markid)
        return true;
 
    // follow portals into other leafs
    for (p = leaf->portals;p;p = p->next)
    {
        // only flow through portals facing away from the viewer
        if (PlaneDiff(eye, (&p->plane)) < 0)
        {
            newpoints = Portal_PortalThroughPortalPlanes(&portalplanes[firstclipplane], numclipplanes, (float *) p->points, p->numpoints, &portaltemppoints2[0][0], 256);
            if (newpoints < 3)
                continue;
            else if (firstclipplane + numclipplanes + newpoints > MAXRECURSIVEPORTALPLANES)
                ranoutofportalplanes = true;
            else
            {
                // find the center by averaging
                VectorClear(center);
                for (i = 0;i < newpoints;i++)
                    VectorAdd(center, portaltemppoints2[i], center);
                // ixtable is a 1.0f / N table
                VectorScale(center, ixtable[newpoints], center);
                // calculate the planes, and make sure the polygon can see it's own center
                newplanes = &portalplanes[firstclipplane + numclipplanes];
                for (prev = newpoints - 1, i = 0;i < newpoints;prev = i, i++)
                {
                    VectorSubtract(eye, portaltemppoints2[i], v1);
                    VectorSubtract(portaltemppoints2[prev], portaltemppoints2[i], v2);
                    CrossProduct(v1, v2, newplanes[i].normal);
                    VectorNormalize(newplanes[i].normal);
                    newplanes[i].dist = DotProduct(eye, newplanes[i].normal);
                    if (DotProduct(newplanes[i].normal, center) <= newplanes[i].dist)
                    {
                        // polygon can't see it's own center, discard and use parent portal
                        break;
                    }
                }
                if (i == newpoints)
                {
                    if (Portal_RecursiveFlowSearch(p->past, eye, firstclipplane + numclipplanes, newpoints))
                        return true;
                }
                else
                {
                    if (Portal_RecursiveFlowSearch(p->past, eye, firstclipplane, numclipplanes))
                        return true;
                }
            }
        }
    }
 
    return false;
}
 
static void Portal_PolygonRecursiveMarkLeafs(mnode_t *node, float *polypoints, int numpoints)
{
    int i, front;
    float *p;
 
loc0:
    if (!node->plane)
    {
        ((mleaf_t *)node)->portalmarkid = portal_markid;
        return;
    }
 
    front = 0;
    for (i = 0, p = polypoints;i < numpoints;i++, p += 3)
    {
        if (DotProduct(p, node->plane->normal) > node->plane->dist)
            front++;
    }
    if (front > 0)
    {
        if (front == numpoints)
        {
            node = node->children[0];
            goto loc0;
        }
        else
            Portal_PolygonRecursiveMarkLeafs(node->children[0], polypoints, numpoints);
    }
    node = node->children[1];
    goto loc0;
}
 
int Portal_CheckPolygon(model_t *model, vec3_t eye, float *polypoints, int numpoints)
{
    int i, prev, returnvalue;
    mleaf_t *eyeleaf;
    vec3_t center, v1, v2;
 
    // if there is no model, it can not block visibility
    if (model == NULL || !model->brush.PointInLeaf)
        return true;
 
    portal_markid++;
 
    Portal_PolygonRecursiveMarkLeafs(model->brush.data_nodes, polypoints, numpoints);
 
    eyeleaf = model->brush.PointInLeaf(model, eye);
 
    // find the center by averaging
    VectorClear(center);
    for (i = 0;i < numpoints;i++)
        VectorAdd(center, (&polypoints[i * 3]), center);
    // ixtable is a 1.0f / N table
    VectorScale(center, ixtable[numpoints], center);
 
    // calculate the planes, and make sure the polygon can see it's own center
    for (prev = numpoints - 1, i = 0;i < numpoints;prev = i, i++)
    {
        VectorSubtract(eye, (&polypoints[i * 3]), v1);
        VectorSubtract((&polypoints[prev * 3]), (&polypoints[i * 3]), v2);
        CrossProduct(v1, v2, portalplanes[i].normal);
        VectorNormalize(portalplanes[i].normal);
        portalplanes[i].dist = DotProduct(eye, portalplanes[i].normal);
        if (DotProduct(portalplanes[i].normal, center) <= portalplanes[i].dist)
        {
            // polygon can't see it's own center, discard
            return false;
        }
    }
 
    ranoutofportalplanes = false;
    ranoutofportals = false;
 
    returnvalue = Portal_RecursiveFlowSearch(eyeleaf, eye, 0, numpoints);
 
    if (ranoutofportalplanes)
        Con_Printf("Portal_RecursiveFlowSearch: ran out of %d plane stack when recursing through portals\n", MAXRECURSIVEPORTALPLANES);
    if (ranoutofportals)
        Con_Printf("Portal_RecursiveFlowSearch: ran out of %d portal stack when recursing through portals\n", MAXRECURSIVEPORTALS);
 
    return returnvalue;
}
 
#define Portal_MinsBoxPolygon(axis, axisvalue, x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4) \
{\
    if (eye[(axis)] < ((axisvalue) - 0.5f))\
    {\
        boxpoints[ 0] = x1;boxpoints[ 1] = y1;boxpoints[ 2] = z1;\
        boxpoints[ 3] = x2;boxpoints[ 4] = y2;boxpoints[ 5] = z2;\
        boxpoints[ 6] = x3;boxpoints[ 7] = y3;boxpoints[ 8] = z3;\
        boxpoints[ 9] = x4;boxpoints[10] = y4;boxpoints[11] = z4;\
        if (Portal_CheckPolygon(model, eye, boxpoints, 4))\
            return true;\
    }\
}
 
#define Portal_MaxsBoxPolygon(axis, axisvalue, x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4) \
{\
    if (eye[(axis)] > ((axisvalue) + 0.5f))\
    {\
        boxpoints[ 0] = x1;boxpoints[ 1] = y1;boxpoints[ 2] = z1;\
        boxpoints[ 3] = x2;boxpoints[ 4] = y2;boxpoints[ 5] = z2;\
        boxpoints[ 6] = x3;boxpoints[ 7] = y3;boxpoints[ 8] = z3;\
        boxpoints[ 9] = x4;boxpoints[10] = y4;boxpoints[11] = z4;\
        if (Portal_CheckPolygon(model, eye, boxpoints, 4))\
            return true;\
    }\
}
 
int Portal_CheckBox(model_t *model, vec3_t eye, vec3_t a, vec3_t b)
{
    if (eye[0] >= (a[0] - 1.0f) && eye[0] < (b[0] + 1.0f)
     && eye[1] >= (a[1] - 1.0f) && eye[1] < (b[1] + 1.0f)
     && eye[2] >= (a[2] - 1.0f) && eye[2] < (b[2] + 1.0f))
        return true;
 
    Portal_MinsBoxPolygon
    (
        0, a[0],
        a[0], a[1], a[2],
        a[0], b[1], a[2],
        a[0], b[1], b[2],
        a[0], a[1], b[2]
    );
    Portal_MaxsBoxPolygon
    (
        0, b[0],
        b[0], b[1], a[2],
        b[0], a[1], a[2],
        b[0], a[1], b[2],
        b[0], b[1], b[2]
    );
    Portal_MinsBoxPolygon
    (
        1, a[1],
        b[0], a[1], a[2],
        a[0], a[1], a[2],
        a[0], a[1], b[2],
        b[0], a[1], b[2]
    );
    Portal_MaxsBoxPolygon
    (
        1, b[1],
        a[0], b[1], a[2],
        b[0], b[1], a[2],
        b[0], b[1], b[2],
        a[0], b[1], b[2]
    );
    Portal_MinsBoxPolygon
    (
        2, a[2],
        a[0], a[1], a[2],
        b[0], a[1], a[2],
        b[0], b[1], a[2],
        a[0], b[1], a[2]
    );
    Portal_MaxsBoxPolygon
    (
        2, b[2],
        b[0], a[1], b[2],
        a[0], a[1], b[2],
        a[0], b[1], b[2],
        b[0], b[1], b[2]
    );
 
    return false;
}
 
typedef struct portalrecursioninfo_s
{
    int exact;
    int numfrustumplanes;
    vec3_t boxmins;
    vec3_t boxmaxs;
    int numsurfaces;
    int *surfacelist;
    unsigned char *surfacepvs;
    int numleafs;
    unsigned char *visitingleafpvs; // used to prevent infinite loops
    int *leaflist;
    unsigned char *leafpvs;
    unsigned char *shadowtrispvs;
    unsigned char *lighttrispvs;
    model_t *model;
    vec3_t eye;
    float *updateleafsmins;
    float *updateleafsmaxs;
}
portalrecursioninfo_t;
 
static void Portal_RecursiveFlow (portalrecursioninfo_t *info, mleaf_t *leaf, int firstclipplane, int numclipplanes)
{
    mportal_t *p;
    int newpoints, i, prev;
    float dist;
    vec3_t center;
    tinyplane_t *newplanes;
    int leafindex = leaf - info->model->brush.data_leafs;
 
    if (CHECKPVSBIT(info->visitingleafpvs, leafindex))
        return; // recursive loop of leafs (cmc.bsp for megatf coop)
 
    SETPVSBIT(info->visitingleafpvs, leafindex);
 
    for (i = 0;i < 3;i++)
    {
        if (info->updateleafsmins && info->updateleafsmins[i] > leaf->mins[i]) info->updateleafsmins[i] = leaf->mins[i];
        if (info->updateleafsmaxs && info->updateleafsmaxs[i] < leaf->maxs[i]) info->updateleafsmaxs[i] = leaf->maxs[i];
    }
 
 
    if (info->leafpvs)
    {
        if (!CHECKPVSBIT(info->leafpvs, leafindex))
        {
            SETPVSBIT(info->leafpvs, leafindex);
            info->leaflist[info->numleafs++] = leafindex;
        }
    }
 
    // mark surfaces in leaf that can be seen through portal
    if (leaf->numleafsurfaces && info->surfacepvs)
    {
        for (i = 0;i < leaf->numleafsurfaces;i++)
        {
            int surfaceindex = leaf->firstleafsurface[i];
            msurface_t *surface = info->model->data_surfaces + surfaceindex;
            if (BoxesOverlap(surface->mins, surface->maxs, info->boxmins, info->boxmaxs))
            {
                qbool insidebox = BoxInsideBox(surface->mins, surface->maxs, info->boxmins, info->boxmaxs);
                qbool addedtris = false;
                int t, tend;
                const int *elements;
                const float *vertex3f;
                float v[9];
                vertex3f = info->model->surfmesh.data_vertex3f;
                elements = (info->model->surfmesh.data_element3i + 3 * surface->num_firsttriangle);
                for (t = surface->num_firsttriangle, tend = t + surface->num_triangles;t < tend;t++, elements += 3)
                {
                    VectorCopy(vertex3f + elements[0] * 3, v + 0);
                    VectorCopy(vertex3f + elements[1] * 3, v + 3);
                    VectorCopy(vertex3f + elements[2] * 3, v + 6);
                    if (PointInfrontOfTriangle(info->eye, v + 0, v + 3, v + 6)
                     && (insidebox || TriangleBBoxOverlapsBox(v, v + 3, v + 6, info->boxmins, info->boxmaxs))
                     && (!info->exact || Portal_PortalThroughPortalPlanes(&portalplanes[firstclipplane], numclipplanes, v, 3, &portaltemppoints2[0][0], 256) > 0))
                    {
                        addedtris = true;
                        if (info->shadowtrispvs)
                            SETPVSBIT(info->shadowtrispvs, t);
                        if (info->lighttrispvs)
                            SETPVSBIT(info->lighttrispvs, t);
                    }
                }
                if (addedtris && !CHECKPVSBIT(info->surfacepvs, surfaceindex))
                {
                    SETPVSBIT(info->surfacepvs, surfaceindex);
                    info->surfacelist[info->numsurfaces++] = surfaceindex;
                }
            }
        }
    }
 
    // follow portals into other leafs
    for (p = leaf->portals;p;p = p->next)
    {
        // only flow through portals facing the viewer
        dist = PlaneDiff(info->eye, (&p->plane));
        if (dist < 0 && BoxesOverlap(p->past->mins, p->past->maxs, info->boxmins, info->boxmaxs))
        {
            newpoints = Portal_PortalThroughPortalPlanes(&portalplanes[firstclipplane], numclipplanes, (float *) p->points, p->numpoints, &portaltemppoints2[0][0], 256);
            if (newpoints < 3)
                continue;
            else if (firstclipplane + numclipplanes + newpoints > MAXRECURSIVEPORTALPLANES)
                ranoutofportalplanes = true;
            else
            {
                // find the center by averaging
                VectorClear(center);
                for (i = 0;i < newpoints;i++)
                    VectorAdd(center, portaltemppoints2[i], center);
                // ixtable is a 1.0f / N table
                VectorScale(center, ixtable[newpoints], center);
                // calculate the planes, and make sure the polygon can see its own center
                newplanes = &portalplanes[firstclipplane + numclipplanes];
                for (prev = newpoints - 1, i = 0;i < newpoints;prev = i, i++)
                {
                    TriangleNormal(portaltemppoints2[prev], portaltemppoints2[i], info->eye, newplanes[i].normal);
                    VectorNormalize(newplanes[i].normal);
                    newplanes[i].dist = DotProduct(info->eye, newplanes[i].normal);
                    if (DotProduct(newplanes[i].normal, center) <= newplanes[i].dist)
                    {
                        // polygon can't see its own center, discard and use parent portal
                        break;
                    }
                }
                if (i == newpoints)
                    Portal_RecursiveFlow(info, p->past, firstclipplane + numclipplanes, newpoints);
                else
                    Portal_RecursiveFlow(info, p->past, firstclipplane, numclipplanes);
            }
        }
    }
 
    CLEARPVSBIT(info->visitingleafpvs, leafindex);
}
 
static void Portal_RecursiveFindLeafForFlow(portalrecursioninfo_t *info, mnode_t *node)
{
    if (node->plane)
    {
        float f = DotProduct(info->eye, node->plane->normal) - node->plane->dist;
        if (f > -0.1)
            Portal_RecursiveFindLeafForFlow(info, node->children[0]);
        if (f < 0.1)
            Portal_RecursiveFindLeafForFlow(info, node->children[1]);
    }
    else
    {
        mleaf_t *leaf = (mleaf_t *)node;
        if (leaf->clusterindex >= 0)
            Portal_RecursiveFlow(info, leaf, 0, info->numfrustumplanes);
    }
}
 
void Portal_Visibility(model_t *model, const vec3_t eye, int *leaflist, unsigned char *leafpvs, int *numleafspointer, int *surfacelist, unsigned char *surfacepvs, int *numsurfacespointer, const mplane_t *frustumplanes, int numfrustumplanes, int exact, const float *boxmins, const float *boxmaxs, float *updateleafsmins, float *updateleafsmaxs, unsigned char *shadowtrispvs, unsigned char *lighttrispvs, unsigned char *visitingleafpvs)
{
    int i;
    portalrecursioninfo_t info;
 
    // if there is no model, it can not block visibility
    if (model == NULL)
    {
        Con_Print("Portal_Visibility: NULL model\n");
        return;
    }
 
    if (!model->brush.data_nodes)
    {
        Con_Print("Portal_Visibility: not a brush model\n");
        return;
    }
 
    // put frustum planes (if any) into tinyplane format at start of buffer
    for (i = 0;i < numfrustumplanes;i++)
    {
        VectorCopy(frustumplanes[i].normal, portalplanes[i].normal);
        portalplanes[i].dist = frustumplanes[i].dist;
    }
 
    ranoutofportalplanes = false;
    ranoutofportals = false;
 
    VectorCopy(boxmins, info.boxmins);
    VectorCopy(boxmaxs, info.boxmaxs);
    info.exact = exact;
    info.numsurfaces = 0;
    info.surfacelist = surfacelist;
    info.surfacepvs = surfacepvs;
    info.numleafs = 0;
    info.visitingleafpvs = visitingleafpvs;
    info.leaflist = leaflist;
    info.leafpvs = leafpvs;
    info.model = model;
    VectorCopy(eye, info.eye);
    info.numfrustumplanes = numfrustumplanes;
    info.updateleafsmins = updateleafsmins;
    info.updateleafsmaxs = updateleafsmaxs;
    info.shadowtrispvs = shadowtrispvs;
    info.lighttrispvs = lighttrispvs;
 
    Portal_RecursiveFindLeafForFlow(&info, model->brush.data_nodes);
 
    if (ranoutofportalplanes)
        Con_Printf("Portal_RecursiveFlow: ran out of %d plane stack when recursing through portals\n", MAXRECURSIVEPORTALPLANES);
    if (ranoutofportals)
        Con_Printf("Portal_RecursiveFlow: ran out of %d portal stack when recursing through portals\n", MAXRECURSIVEPORTALS);
    if (numsurfacespointer)
        *numsurfacespointer = info.numsurfaces;
    if (numleafspointer)
        *numleafspointer = info.numleafs;
}