game_dir: glsl: fixed incorrect fog blending on some of brush entities

Author: SNMetamorph

game_dir/glsl/forward/decal_bmodel_fp.glsl

@@ -160,9 +160,9 @@ void main( void )
 
 #if defined( APPLY_FOG_EXP )
 #if defined( APPLY_COLORBLEND )
-	result.rgb = CalculateFog(result.rgb, u_FogParams, length(u_ViewOrigin - var_Position));
+	result.rgb = CalculateFog(result.rgb, u_FogParams, gl_FragCoord.z / gl_FragCoord.w);
 #else
-	float fogFactor = saturate(exp2(-u_FogParams.w * length(u_ViewOrigin - var_Position)));
+	float fogFactor = saturate(exp2(-u_FogParams.w * gl_FragCoord.z / gl_FragCoord.w));
 	result.a *= fogFactor; // modulate alpha
 #endif
 #endif

game_dir/glsl/forward/decal_studio_fp.glsl

@@ -133,7 +133,7 @@ void main( void )
 #endif // LIGHTING_FULLBRIGHT
 
 #if defined( APPLY_FOG_EXP )
-	result.rgb = CalculateFog(result.rgb, u_FogParams, length(u_ViewOrigin - var_Position));
+	result.rgb = CalculateFog(result.rgb, u_FogParams, gl_FragCoord.z / gl_FragCoord.w);
 #endif
 	gl_FragColor = result;
 }

game_dir/glsl/forward/scene_bmodel_fp.glsl

@@ -283,7 +283,7 @@ void main( void )
 #endif // USING_SCREENCOPY
 
 #if defined( APPLY_FOG_EXP )
-	result.rgb = CalculateFog(result.rgb, u_FogParams, length(u_ViewOrigin - var_Position));
+	result.rgb = CalculateFog(result.rgb, u_FogParams, gl_FragCoord.z / gl_FragCoord.w);
 #endif
 
 #if defined( LIGHTMAP_DEBUG ) || defined( LIGHTVEC_DEBUG )

game_dir/glsl/forward/scene_grass_fp.glsl

@@ -44,7 +44,7 @@ void main( void )
 #endif//LIGHTING_FULLBRIGHT
 
 #if defined( APPLY_FOG_EXP )
-	diffuse.rgb = CalculateFog(diffuse.rgb, u_FogParams, length(u_ViewOrigin - var_Position));
+	diffuse.rgb = CalculateFog(diffuse.rgb, u_FogParams, gl_FragCoord.z / gl_FragCoord.w);
 #endif
 	gl_FragColor = diffuse;
 }

game_dir/glsl/forward/scene_studio_fp.glsl

@@ -220,7 +220,7 @@ lighting.diffuse += var_AmbientLight;
 #endif
 
 #if defined( APPLY_FOG_EXP )
-	result.rgb = CalculateFog(result.rgb, u_FogParams, length(u_ViewOrigin - var_Position));
+	result.rgb = CalculateFog(result.rgb, u_FogParams, gl_FragCoord.z / gl_FragCoord.w);
 #endif
 	// compute final color
 	gl_FragColor = result;