Fixed LightPoint code to deal better with lightmap bounds checking, this resolves...

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12070 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=5dc898f93ba0af06ee3eef1f587caab804d6969f

diff --git a/model_brush.c b/model_brush.c
index eba42f526e937d9191ff8708d46d1a1677872b3f..96ea11ea2735aa51db65756b98475b3455ddf85f 100644 (file)
--- a/model_brush.c
+++ b/model_brush.c
@@ -1263,22 +1263,44 @@ loc0:
                                dt = ((x * surface->lightmapinfo->texinfo->vecs[1][0] + y * surface->lightmapinfo->texinfo->vecs[1][1] + mid * surface->lightmapinfo->texinfo->vecs[1][2] + surface->lightmapinfo->texinfo->vecs[1][3]) - surface->lightmapinfo->texturemins[1]) * 0.0625f;
 
                                // check the bounds
-                               dsi = (int)ds;
-                               dti = (int)dt;
+                               // thanks to jitspoe for pointing out that this int cast was
+                               // rounding toward zero, so we floor it
+                               dsi = (int)floor(ds);
+                               dti = (int)floor(dt);
                                lmwidth = ((surface->lightmapinfo->extents[0]>>4)+1);
                                lmheight = ((surface->lightmapinfo->extents[1]>>4)+1);
 
                                // is it in bounds?
-                               if (dsi >= 0 && dsi < lmwidth-1 && dti >= 0 && dti < lmheight-1)
+                               // we have to tolerate a position of lmwidth-1 for some rare
+                               // cases - in which case the sampling position still gets
+                               // clamped but the color gets interpolated to that edge.
+                               if (dsi >= 0 && dsi < lmwidth && dti >= 0 && dti < lmheight)
                                {
+                                       // in the rare cases where we're sampling slightly off
+                                       // the polygon, clamp the sampling position (we can still
+                                       // interpolate outside it, where it becomes extrapolation)
+                                       if (dsi < 0)
+                                               dsi = 0;
+                                       if (dti < 0)
+                                               dti = 0;
+                                       if (dsi > lmwidth-2)
+                                               dsi = lmwidth-2;
+                                       if (dti > lmheight-2)
+                                               dti = lmheight-2;
+                                       
                                        // calculate bilinear interpolation factors
-                                       // and also multiply by fixedpoint conversion factors
+                                       // and also multiply by fixedpoint conversion factors to
+                                       // compensate for lightmaps being 0-255 (as 0-2), we use
+                                       // r_refdef.scene.rtlightstylevalue here which is already
+                                       // 0.000-2.148 range
+                                       // (if we used r_refdef.scene.lightstylevalue this
+                                       //  divisor would be 32768 rather than 128)
                                        dsfrac = ds - dsi;
                                        dtfrac = dt - dti;
-                                       w00 = (1 - dsfrac) * (1 - dtfrac) * (1.0f / 32768.0f);
-                                       w01 = (    dsfrac) * (1 - dtfrac) * (1.0f / 32768.0f);
-                                       w10 = (1 - dsfrac) * (    dtfrac) * (1.0f / 32768.0f);
-                                       w11 = (    dsfrac) * (    dtfrac) * (1.0f / 32768.0f);
+                                       w00 = (1 - dsfrac) * (1 - dtfrac) * (1.0f / 128.0f);
+                                       w01 = (    dsfrac) * (1 - dtfrac) * (1.0f / 128.0f);
+                                       w10 = (1 - dsfrac) * (    dtfrac) * (1.0f / 128.0f);
+                                       w11 = (    dsfrac) * (    dtfrac) * (1.0f / 128.0f);
 
                                        // values for pointer math
                                        line3 = lmwidth * 3; // LordHavoc: *3 for colored lighting
@@ -1290,7 +1312,7 @@ loc0:
                                        // bilinear filter each lightmap style, and sum them
                                        for (maps = 0;maps < MAXLIGHTMAPS && surface->lightmapinfo->styles[maps] != 255;maps++)
                                        {
-                                               scale = r_refdef.scene.lightstylevalue[surface->lightmapinfo->styles[maps]];
+                                               scale = r_refdef.scene.rtlightstylevalue[surface->lightmapinfo->styles[maps]];
                                                w = w00 * scale;VectorMA(ambientcolor, w, lightmap            , ambientcolor);
                                                w = w01 * scale;VectorMA(ambientcolor, w, lightmap + 3        , ambientcolor);
                                                w = w10 * scale;VectorMA(ambientcolor, w, lightmap + line3    , ambientcolor);