tr_image: store the fog alpha channel in red one

Author: illwieckz

src/engine/renderer/glsl_source/fogGlobal_fp.glsl

@@ -49,7 +49,7 @@ void	main()
 	st.s = distance(u_ViewOrigin, P.xyz) * u_FogDensity;
 	st.t = 1.0;
 
-	vec4 color = texture2D(u_ColorMap, st);
+	vec4 color = vec4( vec3( 1.0 ), texture2D( u_ColorMap, st ).r );
 
 	outputColor = UnpackColor( u_Color ) * color;
 }

src/engine/renderer/glsl_source/fogQuake3_fp.glsl

@@ -35,7 +35,7 @@ void	main()
 {
 	#insert material_fp
 
-	vec4 color = texture2D(u_FogMap, var_TexCoords);
+	vec4 color = vec4( vec3( 1.0 ), texture2D( u_FogMap, var_TexCoords ).r );
 
 	color *= var_Color;
 

src/engine/renderer/tr_image.cpp

@@ -2418,8 +2418,8 @@ static void R_CreateFogImage()
 		{
 			float d = R_FogFactor( ( x + 0.5f ) / FOG_S, ( y + 0.5f ) / FOG_T );
 
-			ptr[ 0 ] = ptr[ 1 ] = ptr[ 2 ] = 255;
-			ptr[ 3 ] = 255 * d;
+			ptr[ 0 ] = 255 * d;
+			ptr[ 1 ] = ptr[ 2 ] = ptr[ 3 ] = 255;
 			ptr += channels;
 		}
 	}