fixup-partial-dithering

Author: illwieckz

src/engine/renderer/gl_shader.cpp

@@ -808,6 +808,10 @@ static std::string GenEngineConstants() {
 		AddDefine( str, "r_dithering", 1 );
 	}
 
+	if ( r_showDithering.Get() ) {
+		AddDefine( str, "r_showDithering", 1 );
+	}
+
 	return str;
 }
 

src/engine/renderer/glsl_source/cameraEffects_fp.glsl

@@ -144,19 +144,34 @@ void main()
 #endif
 
 #if defined(r_dithering)
-	const float bayer[ 16 ] = {
-		 0.0f,  8.0f,  2.0f, 10.0f,
-		12.0f,  4.0f, 14.0f,  6.0f,
-		 3.0f, 11.0f,  1.0f,  9.0f,
-		15.0f,  7.0f, 13.0f,  5.0f
-	};
-
-	float dither = bayer[
-			int( mod( gl_FragCoord.x, 4.0 ) ) +
-			int( mod( gl_FragCoord.y, 4.0 ) ) * 4
-		] / 16.0;
-
-	color.rgb += vec3( ( dither - 0.50 ) / 255.0 );
+	{
+		vec3 dithered = color.rgb;
+
+		const float bayer[ 16 ] = {
+			 0.0f,  8.0f,  2.0f, 10.0f,
+			12.0f,  4.0f, 14.0f,  6.0f,
+			 3.0f, 11.0f,  1.0f,  9.0f,
+			15.0f,  7.0f, 13.0f,  5.0f
+		};
+
+		float dither = bayer[
+				int( mod( gl_FragCoord.x, 4.0 ) ) +
+				int( mod( gl_FragCoord.y, 4.0 ) ) * 4
+			] / 16.0;
+
+		dithered += vec3( ( dither - 0.50 ) / 255.0 );
+
+		float threshold = 0.0004f;
+
+		if ( ( color.r + color.g + color.b ) < ( 3 * threshold ) )
+		{
+			color.rgb = dithered;
+
+#if defined(r_showDithering)
+			color.r = 1.0f;
+#endif
+		}
+	}
 #endif
 
 	color.rgb = clamp( color.rgb, vec3( 0.0f ), vec3( 1.0f ) );

src/engine/renderer/tr_init.cpp

@@ -214,6 +214,8 @@ Cvar::Cvar<int> r_rendererAPI( "r_rendererAPI", "Renderer API: 0: OpenGL, 1: Vul
 
 	Cvar::Cvar<bool> r_dithering(
 		"r_dithering", "Use dithering", Cvar::NONE, true );
+	Cvar::Cvar<bool> r_showDithering(
+		"r_showDithering", "Show dithering", Cvar::CHEAT, false );
 
 	cvar_t      *r_lockpvs;
 	cvar_t      *r_noportals;
@@ -1279,6 +1281,7 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 		Cvar::Latch( r_toneMappingLowLightRestorationSteps );
 		Cvar::Latch( r_toneMappingLowLightRestorationThreshold );
 		Cvar::Latch( r_dithering );
+		Cvar::Latch( r_showDithering );
 
 		r_drawBuffer = Cvar_Get( "r_drawBuffer", "GL_BACK", CVAR_CHEAT );
 		r_lockpvs = Cvar_Get( "r_lockpvs", "0", CVAR_CHEAT );

src/engine/renderer/tr_local.h

@@ -2719,6 +2719,7 @@ enum
 	extern Cvar::Range<Cvar::Cvar<int>> r_toneMappingLowLightRestorationSteps;
 	extern Cvar::Range<Cvar::Cvar<int>> r_toneMappingLowLightRestorationThreshold;
 	extern Cvar::Cvar<bool> r_dithering;
+	extern Cvar::Cvar<bool> r_showDithering;
 
 	extern Cvar::Range<Cvar::Cvar<int>> r_shadows;