renderer: add r_showFXAA

Author: illwieckz

src/engine/renderer/gl_shader.cpp

@@ -803,6 +803,11 @@ static std::string GenEngineConstants() {
 	if ( r_FXAA.Get() )
 	{
 		AddDefine( str, "r_FXAA", 1 );
+
+		if ( r_showFXAA.Get() )
+		{
+			AddDefine( str, "r_showFXAA", 1 );
+		}
 	}
 
 	if ( r_highPrecisionRendering.Get() ) {

src/engine/renderer/glsl_source/fxaa_fp.glsl

@@ -75,5 +75,18 @@ void	main()
 		vec4(0.0) //not used
 	);
 
+	#if defined(r_showFXAA)
+	{
+		vec4 originalColor = FxaaTexTop( u_ColorMap, gl_FragCoord.xy / r_FBufSize );
+
+		if ( color.r != originalColor.r
+			|| color.g != originalColor.g
+			|| color.b != originalColor.b )
+		{
+			color.rgb = vec3(1.0, 0.0, 0.0);
+		}
+	}
+	#endif
+
 	outputColor = vec4( color.rgb, 1.0f );
 }

src/engine/renderer/tr_init.cpp

@@ -289,6 +289,7 @@ Cvar::Cvar<int> r_rendererAPI( "r_rendererAPI", "Renderer API: 0: OpenGL, 1: Vul
 	Cvar::Cvar<bool> r_showLuminance( "r_showLuminance", "Show luminance", Cvar::CHEAT, false );
 
 	Cvar::Cvar<bool> r_FXAA( "r_FXAA", "Fast approximate anti-aliasing", Cvar::NONE, false );
+	Cvar::Cvar<bool> r_showFXAA( "r_showFXAA", "Show pixels modified by FXAA", Cvar::CHEAT, false );
 
 	Cvar::Range<Cvar::Cvar<int>> r_msaa( "r_msaa", "Amount of MSAA samples. 0 to disable", Cvar::NONE, 0, 0, 64 );
 
@@ -1215,6 +1216,7 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 		Cvar::Latch( r_showLuminance );
 
 		Cvar::Latch( r_FXAA );
+		Cvar::Latch( r_showFXAA );
 
 		Cvar::Latch( r_msaa );
 

src/engine/renderer/tr_local.h

@@ -2783,6 +2783,7 @@ enum
 	extern Cvar::Cvar<bool> r_showLuminance;
 
 	extern Cvar::Cvar<bool> r_FXAA;
+	extern Cvar::Cvar<bool> r_showFXAA;
 
 	extern Cvar::Range<Cvar::Cvar<int>> r_msaa;