major speedup to alias model fake shadow rendering

now traces in direction of light instead of straight down, this causes a shadow to be cast on a wall in some cases (desirable)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@2465 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/gl_models.c b/gl_models.c
index 5667f1e9a65aeadcca23f3fd39bcd5202262179a..87357618c28d89add98da700a27ab682abe19b28 100644 (file)
--- a/gl_models.c
+++ b/gl_models.c
@@ -476,10 +476,14 @@ void R_DrawQ1Q2AliasModelFakeShadow (entity_render_t *ent)
        int i;
        rmeshstate_t m;
        model_t *model;
-       float *v, lightdirection[3], surfnormal[3], planenormal[3], planedist, floororigin[3], v2[3], offset[3], dist1, dist2, frac;
+       float *v, planenormal[3], planedist, dist, projection[3], floororigin[3], surfnormal[3], lightdirection[3], v2[3];
 
-       VectorCopy(ent->origin, v2);
-       v2[2] -= 65536.0f;
+       lightdirection[0] = 0.5;
+       lightdirection[1] = 0.2;
+       lightdirection[2] = -1;
+       VectorNormalizeFast(lightdirection);
+
+       VectorMA(ent->origin, 65536.0f, lightdirection, v2);
        if (CL_TraceLine(ent->origin, v2, floororigin, surfnormal, 0, false, NULL) == 1)
                return;
 
@@ -498,12 +502,8 @@ void R_DrawQ1Q2AliasModelFakeShadow (entity_render_t *ent)
        R_FillColors(varray_color, model->numverts, 0, 0, 0, 0.5);
 
        // put a light direction in the entity's coordinate space
-       lightdirection[0] = 0.3;
-       lightdirection[1] = 0.1;
-       lightdirection[2] = -1;
-       Matrix4x4_Transform3x3(&ent->inversematrix, lightdirection, offset);
-       VectorNormalizeFast(offset);
-       VectorScale(offset, 65536.0f, offset);
+       Matrix4x4_Transform3x3(&ent->inversematrix, lightdirection, projection);
+       VectorNormalizeFast(projection);
 
        // put the plane's normal in the entity's coordinate space
        Matrix4x4_Transform3x3(&ent->inversematrix, surfnormal, planenormal);
@@ -511,33 +511,16 @@ void R_DrawQ1Q2AliasModelFakeShadow (entity_render_t *ent)
 
        // put the plane's distance in the entity's coordinate space
        VectorSubtract(floororigin, ent->origin, floororigin);
-       planedist = DotProduct(floororigin, surfnormal) + 1;
+       planedist = DotProduct(floororigin, surfnormal) + 2;
 
-       //Con_Printf("sn: %f %f %f pn: %f %f %f pd: %f\n", surfnormal[0], surfnormal[1], surfnormal[2], planenormal[0], planenormal[1], planenormal[2], planedist);
-       {
-       //int count1 = 0, count2 = 0, count3 = 0;
+       dist = -1.0f / DotProduct(projection, planenormal);
+       VectorScale(projection, dist, projection);
        for (i = 0, v = varray_vertex;i < model->numverts;i++, v += 4)
        {
-               v2[0] = v[0] + offset[0];
-               v2[1] = v[1] + offset[1];
-               v2[2] = v[2] + offset[2];
-               dist1 = DotProduct(v, planenormal) - planedist;
-               dist2 = DotProduct(v2, planenormal) - planedist;
-               //if (dist1 > 0)
-               //      count1++;
-               //if (dist2 > 0)
-               //      count2++;
-               //if (dist1 > 0 != dist2 > 0)
-               //      count3++;
-               if (dist1 > 0 && dist2 < 0)
+               dist = DotProduct(v, planenormal) - planedist;
+               if (dist > 0)
                //if (i & 1)
-               {
-                       // clipped
-                       frac = dist1 / (dist1 - dist2);
-                       VectorMA(v, frac, offset, v);
-               }
-       }
-       //Con_Printf("counts %d %d %d\n", count1, count2, count3);
+                       VectorMA(v, dist, projection, v);
        }
        R_Mesh_Draw(model->numverts, model->numtris, model->mdlmd2data_indices);
 }