fixed fog-only shaders being recognized as sky shaders

changelog.txt

@@ -107,6 +107,8 @@ chg: r_fullbright is now latched again
 
 chg: negative r_swapInterval values will request adaptive v-sync when using an OpenGL back-end
 
+fix: fog-only non-sky shaders were incorrectly handled as sky shaders, which broke fog on many maps
+
 fix: r_monitor on Linux is now 0-based and the value doesn't change incorrectly on its own anymore
 
 fix: when a latched cvar's value is set to its default, the cvar is no longer marked as changed

code/renderer/tr_local.h

@@ -383,6 +383,7 @@ struct shader_t {
 
 	qbool		entityMergable;			// multiple refentities can be combined in one batch (smoke, blood)
 
+	qbool		isSky;
 	skyParms_t	sky;
 	fogParms_t	fogParms;
 

code/renderer/tr_shader.cpp

@@ -1151,6 +1151,7 @@ static void ParseSkyParms( const char** text )
 	}
 
 	shader.sort = SS_ENVIRONMENT;
+	shader.isSky = qtrue;
 }
 
 
@@ -1443,7 +1444,7 @@ static qbool ParseShader( const char** text )
 	//
 	// ignore shaders that don't have any stages, unless it is a sky or fog
 	//
-	if ( !s && (shader.sort != SS_ENVIRONMENT) && !(shader.contentFlags & CONTENTS_FOG) ) {
+	if ( s == 0 && !shader.isSky && !(shader.contentFlags & CONTENTS_FOG ) ) {
 		return qfalse;
 	}
 
@@ -2176,9 +2177,8 @@ static shader_t* FinishShader()
 	}
 */
 
-	// fogonly shaders don't have any normal passes
-	// !!! nor does sky, and this is utterly retarded logic in the first place
-	if ( !stage && (shader.sort == SS_BAD) ) {
+	// non-sky fog-only shaders don't have any normal passes
+	if ( !shader.isSky && stage == 0 ) {
 		shader.sort = SS_FOG;
 	}