skip backfaces in surface traceline

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10884 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/model_brush.c b/model_brush.c
index 7a16f6d7f6942cfc1b82000d5a92efdbb3f93b81..7786be2d7f8936205c474bc4ecfedfd0cf05589a 100644 (file)
--- a/model_brush.c
+++ b/model_brush.c
@@ -1314,6 +1314,7 @@ static const texture_t *Mod_Q1BSP_TraceLineAgainstSurfacesFindTextureOnNode(Recu
        surface = model->data_surfaces + node->firstsurface;
        for (i = 0;i < node->numsurfaces;i++, surface++)
        {
+               // skip surfaces whose bounding box does not include the point
                if (axis < 3)
                {
                        if (mid[axis] < surface->mins[axis] || mid[axis] > surface->maxs[axis])
@@ -1324,10 +1325,15 @@ static const texture_t *Mod_Q1BSP_TraceLineAgainstSurfacesFindTextureOnNode(Recu
                        if (!BoxesOverlap(mid, mid, surface->mins, surface->maxs))
                                continue;
                }
+               // skip faces with contents we don't care about
                if (!(t->trace->hitsupercontentsmask & surface->texture->supercontents))
                        continue;
+               // get the surface normal - since it is flat we know any vertex normal will suffice
                VectorCopy(model->surfmesh.data_normal3f + 3 * surface->num_firstvertex, normal);
-               //VectorCopy(node->plane->normal, normal);
+               // skip backfaces
+               if (DotProduct(t->dist, normal) > 0)
+                       continue;
+               // iterate edges and see if the point is outside one of them
                for (j = 0, k = surface->num_vertices - 1;j < surface->num_vertices;k = j, j++)
                {
                        VectorCopy(model->surfmesh.data_vertex3f + 3 * (surface->num_firstvertex + k), v0);
@@ -1337,6 +1343,7 @@ static const texture_t *Mod_Q1BSP_TraceLineAgainstSurfacesFindTextureOnNode(Recu
                        if (DotProduct(edgenormal, p) > DotProduct(edgenormal, v0))
                                break;
                }
+               // if the point is outside one of the edges, it is not within the surface
                if (j < surface->num_vertices)
                        continue;