From: havoc <havoc@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Thu, 8 May 2014 01:02:39 +0000 (+0000)
Subject: Fixed LightPoint code to deal better with lightmap bounds checking, this resolves... 
X-Git-Tag: xonotic-v0.8.0~67
X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=52bddfc758c05c770c862ac7f78f9d79fb4afe6d;p=xonotic%2Fdarkplaces.git

Fixed LightPoint code to deal better with lightmap bounds checking, this resolves several issues with item pickups in specific maps being lit wrong, thanks to jitspoe for discussion that led to this fix.

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 eba42f52..96ea11ea 100644
--- 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);