From bb9768bec6a7474def1b802438c52349b5150a1b Mon Sep 17 00:00:00 2001
From: sezero <sezero@af15c1b1-3010-417e-b628-4374ebc0bcbd>
Date: Wed, 20 Feb 2013 06:01:10 +0000
Subject: [PATCH] convert our GL_RGB lightmaps to GL_RGBA which gives
 considerable performance boost on some systems. add GL_BGRA as an option,
 thanks to Kristian Duske. the format is hardcoded as GL_RGBA for now, need a
 way to make it configurable later.

git-svn-id: http://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@813 af15c1b1-3010-417e-b628-4374ebc0bcbd
---
 Quake/r_brush.c | 58 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 46 insertions(+), 12 deletions(-)

diff --git a/Quake/r_brush.c b/Quake/r_brush.c
index a7e38a63..598525e7 100644
--- a/Quake/r_brush.c
+++ b/Quake/r_brush.c
@@ -884,13 +884,17 @@ void GL_BuildLightmaps (void)
 		lightmap_textures[i] = NULL;
 	//johnfitz
 
-	gl_lightmap_format = GL_RGB; //johnfitz
+	gl_lightmap_format = GL_RGBA; //johnfitz
 
 	//johnfitz -- only support GL_RGB lightmaps
+	//kristian -- now with GL_BGRA support
 	switch (gl_lightmap_format)
 	{
-	case GL_RGB:
-		lightmap_bytes = 3;
+	case GL_RGBA:
+		lightmap_bytes = 4;
+		break;
+	case GL_BGRA:
+		lightmap_bytes = 4;
 		break;
 	default:
 		Sys_Error ("GL_BuildLightmaps: bad lightmap format");
@@ -1040,7 +1044,7 @@ Combine and scale multiple lightmaps into the 8.8 format in blocklights
 void R_BuildLightMap (msurface_t *surf, byte *dest, int stride)
 {
 	int			smax, tmax;
-	int			t;
+	int			r,g,b;
 	int			i, j, size;
 	byte		*lightmap;
 	unsigned	scale;
@@ -1093,8 +1097,8 @@ void R_BuildLightMap (msurface_t *surf, byte *dest, int stride)
 	//johnfitz -- only support GL_RGB lightmaps
 	switch (gl_lightmap_format)
 	{
-	case GL_RGB:
-		stride -= smax * 3;
+	case GL_RGBA:
+		stride -= smax * 4;
 		bl = blocklights;
 		for (i=0 ; i<tmax ; i++, dest += stride)
 		{
@@ -1102,16 +1106,46 @@ void R_BuildLightMap (msurface_t *surf, byte *dest, int stride)
 			{
 				if (gl_overbright.value)
 				{
-					t = *bl++ >> 8;if (t > 255) t = 255;*dest++ = t;
-					t = *bl++ >> 8;if (t > 255) t = 255;*dest++ = t;
-					t = *bl++ >> 8;if (t > 255) t = 255;*dest++ = t;
+					r = *bl++ >> 8;
+					g = *bl++ >> 8;
+					b = *bl++ >> 8;
 				}
 				else
 				{
-					t = *bl++ >> 7;if (t > 255) t = 255;*dest++ = t;
-					t = *bl++ >> 7;if (t > 255) t = 255;*dest++ = t;
-					t = *bl++ >> 7;if (t > 255) t = 255;*dest++ = t;
+					r = *bl++ >> 7;
+					g = *bl++ >> 7;
+					b = *bl++ >> 7;
 				}
+				if (r > 255) r = 255; *dest++ = r;
+				if (g > 255) g = 255; *dest++ = g;
+				if (b > 255) b = 255; *dest++ = b;
+				*dest++ = 255;
+			}
+		}
+		break;
+	case GL_BGRA:
+		stride -= smax * 4;
+		bl = blocklights;
+		for (i=0 ; i<tmax ; i++, dest += stride)
+		{
+			for (j=0 ; j<smax ; j++)
+			{
+				if (gl_overbright.value)
+				{
+					r = *bl++ >> 8;
+					g = *bl++ >> 8;
+					b = *bl++ >> 8;
+				}
+				else
+				{
+					r = *bl++ >> 7;
+					g = *bl++ >> 7;
+					b = *bl++ >> 7;
+				}
+				if (b > 255) b = 255; *dest++ = b;
+				if (g > 255) g = 255; *dest++ = g;
+				if (r > 255) r = 255; *dest++ = r;
+				*dest++ = 255;
 			}
 		}
 		break;