allow disabling use of 10 bit depth for lightmaps with -nopackedpixels

.. which disables the EXT_packed_pixels extension.

Linux/sgml/Quakespasm.sgml

@@ -160,7 +160,7 @@ QuakeSpasm 0.94 has support for playing the 2021 re-release content: Copy the qu
 <item> Fix a potential crash after loading of saved game.
 <item> Fix possible out-of-bound reads when handling progs type sizes.
 <item> Fix Dutch angle VP_PARALLEL_UPRIGHT sprites.
-<item> Fix an issue with blending of lights.
+<item> Fix an issue with blending of lights by using 10 bit depth for lightmaps. (GLSL mode only. Disable with "-nopackedpixels" if necessarry.)
 <item> No relative motions when the window is not focused.
 <item> Status bar and intermission screen tweaks.
 <item> Properly display monster counts > 3 digits.

Quake/gl_vidsdl.c

@@ -1267,19 +1267,24 @@ static void GL_CheckExtensions (void)
 	else if (gl_glsl_able && gl_vbo_able && gl_max_texture_units >= 3)
 	{
 		gl_glsl_alias_able = true;
-		gl_packed_pixels = true;
 		Con_Printf("Enabled: GLSL alias model rendering\n");
-		Con_Printf("Enabled: EXT_packed_pixels\n");
 	}
 	else
 	{
 		Con_Warning ("GLSL alias model rendering not available, using Fitz renderer\n");
 	}
 
+	if (COM_CheckParm("-nopackedpixels"))
+		Con_Warning ("EXT_packed_pixels disabled at command line\n");
+	else if (gl_glsl_alias_able)
+	{
+		gl_packed_pixels = true;
+		Con_Printf("Enabled: EXT_packed_pixels\n");
+	}
 #if 0 /* Disabling for non-GLSL path, needs more surgery. See: https://github.com/sezero/quakespasm/issues/47#issuecomment-1681540278 */
 	// packed_pixels
 	//
-	if (!gl_packed_pixels)
+	else
 	{
 		if (GL_ParseExtensionList(gl_extensions, "GL_APPLE_packed_pixels"))
 		{

Quake/r_world.c

@@ -553,6 +553,7 @@ static GLuint fullbrightTexLoc;
 static GLuint useFullbrightTexLoc;
 static GLuint useOverbrightLoc;
 static GLuint useAlphaTestLoc;
+static GLuint usePackedPixelsLoc;
 static GLuint alphaLoc;
 
 #define vertAttrIndex 0
@@ -633,6 +634,7 @@ void R_DrawTextureChains_Water (qmodel_t *model, entity_t *ent, texchain_t chain
 		GL_Uniform1iFunc (fullbrightTexLoc, 2);
 		GL_Uniform1iFunc (useFullbrightTexLoc, 0);
 		GL_Uniform1iFunc (useOverbrightLoc, (int)gl_overbright.value);
+		GL_Uniform1iFunc (usePackedPixelsLoc, gl_packed_pixels);
 		GL_Uniform1iFunc (useAlphaTestLoc, 0);
 
 		for (i=0 ; i<model->numtextures ; i++)
@@ -843,6 +845,7 @@ void GLWorld_CreateShaders (void)
 		"uniform bool UseFullbrightTex;\n"
 		"uniform bool UseOverbright;\n"
 		"uniform bool UseAlphaTest;\n"
+		"uniform bool UsePackedPixels;\n"
 		"uniform float Alpha;\n"
 		"\n"
 		"varying float FogFragCoord;\n"
@@ -853,7 +856,8 @@ void GLWorld_CreateShaders (void)
 		"	if (UseAlphaTest && (result.a < 0.666))\n"
 		"		discard;\n"
 		"	result *= texture2D(LMTex, gl_TexCoord[1].xy);\n"
-		"	result.rgb *= 4.0;\n"
+		"	if (UsePackedPixels)\n"
+		"	    result.rgb *= 4.0;\n"
 		"	if (UseOverbright)\n"
 		"		result.rgb *= 2.0;\n"
 		"	if (UseFullbrightTex)\n"
@@ -880,6 +884,7 @@ void GLWorld_CreateShaders (void)
 		useFullbrightTexLoc = GL_GetUniformLocation (&r_world_program, "UseFullbrightTex");
 		useOverbrightLoc = GL_GetUniformLocation (&r_world_program, "UseOverbright");
 		useAlphaTestLoc = GL_GetUniformLocation (&r_world_program, "UseAlphaTest");
+		usePackedPixelsLoc = GL_GetUniformLocation (&r_world_program, "UsePackedPixels");
 		alphaLoc = GL_GetUniformLocation (&r_world_program, "Alpha");
 	}
 }
@@ -932,6 +937,7 @@ void R_DrawTextureChains_GLSL (qmodel_t *model, entity_t *ent, texchain_t chain)
 	GL_Uniform1iFunc (useFullbrightTexLoc, 0);
 	GL_Uniform1iFunc (useOverbrightLoc, (int)gl_overbright.value);
 	GL_Uniform1iFunc (useAlphaTestLoc, 0);
+	GL_Uniform1iFunc (usePackedPixelsLoc, gl_packed_pixels);
 	GL_Uniform1fFunc (alphaLoc, entalpha);
 
 	for (i=0 ; i<model->numtextures ; i++)

Quakespasm.html

@@ -234,7 +234,7 @@ <H2><A NAME="ss5.1">5.1</A> <A HREF="#toc5.1">Changes in 0.96.0</A>
 <LI> Fix a potential crash after loading of saved game.</LI>
 <LI> Fix possible out-of-bound reads when handling progs type sizes.</LI>
 <LI> Fix Dutch angle VP_PARALLEL_UPRIGHT sprites.</LI>
-<LI> Fix an issue with blending of lights.</LI>
+<LI> Fix an issue with blending of lights by using 10 bit depth for lightmaps. (GLSL mode only. Disable with "-nopackedpixels" if necessarry.)</LI>
 <LI> No relative motions when the window is not focused.</LI>
 <LI> Status bar and intermission screen tweaks.</LI>
 <LI> Properly display monster counts &gt; 3 digits.</LI>

Quakespasm.txt

@@ -269,7 +269,9 @@
 
   -  Fix Dutch angle VP_PARALLEL_UPRIGHT sprites.
 
-  -  Fix an issue with blending of lights.
+  -  Fix an issue with blending of lights by using 10 bit depth for
+     lightmaps.  (GLSL mode only. Disable with "-nopackedpixels" if
+     necessarry.)
 
   -  No relative motions when the window is not focused.