gpu: add toggle for color banding

Co-authored-by: Toocanzs <dupanzszs@gmail.com>

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GpuPlugin.java

@@ -220,6 +220,7 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 	private int uniBlockSmall;
 	private int uniBlockLarge;
 	private int uniBlockMain;
+	private int uniSmoothBanding;
 
 	@Override
 	protected void startUp()
@@ -469,6 +470,7 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 	{
 		uniProjectionMatrix = gl.glGetUniformLocation(glProgram, "projectionMatrix");
 		uniBrightness = gl.glGetUniformLocation(glProgram, "brightness");
+		uniSmoothBanding = gl.glGetUniformLocation(glProgram, "smoothBanding");
 
 		uniTex = gl.glGetUniformLocation(glUiProgram, "tex");
 		uniTextures = gl.glGetUniformLocation(glProgram, "textures");
@@ -937,6 +939,7 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 
 			// Brightness happens to also be stored in the texture provider, so we use that
 			gl.glUniform1f(uniBrightness, (float) textureProvider.getBrightness());
+			gl.glUniform1f(uniSmoothBanding, config.smoothBanding() ? 0f : 1f);
 
 			for (int id = 0; id < textures.length; ++id)
 			{

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GpuPluginConfig.java

@@ -34,10 +34,22 @@ public interface GpuPluginConfig extends Config
 	@ConfigItem(
 		keyName = "drawDistance",
 		name = "Draw Distance",
-		description = "Draw distance"
+		description = "Draw distance",
+		position = 1
 	)
 	default int drawDistance()
 	{
 		return 25;
 	}
+
+	@ConfigItem(
+		keyName = "smoothBanding",
+		name = "Remove Color Banding",
+		description = "Smooths out the color banding that is present in the CPU renderer",
+		position = 2
+	)
+	default boolean smoothBanding()
+	{
+		return false;
+	}
 }

runelite-client/src/main/resources/net/runelite/client/plugins/gpu/frag.glsl

@@ -27,14 +27,23 @@
 uniform sampler2DArray textures;
 uniform vec2 textureOffsets[64];
 uniform float brightness;
+uniform float smoothBanding;
 
 in vec4 Color;
+in float fHsl;
 in vec4 fUv;
+
 out vec4 FragColor;
 
+#include hsl_to_rgb.glsl
+
 void main() {
   float n = fUv.x;
 
+  int hsl = int(fHsl);
+  vec3 rgb = hslToRgb(hsl) * smoothBanding + Color.rgb * (1.f - smoothBanding);
+  vec4 smoothColor = vec4(rgb, Color.a);
+
   if (n > 0.0) {
     n -= 1.0;
     int textureIdx = int(n);
@@ -45,8 +54,8 @@ void main() {
     vec4 textureColor = texture(textures, vec3(animatedUv, n));
     vec4 textureColorBrightness = pow(textureColor, vec4(brightness, brightness, brightness, 1.0f));
 
-    FragColor = textureColorBrightness * Color;
+    FragColor = textureColorBrightness * smoothColor;
   } else {
-    FragColor = Color;
+    FragColor = smoothColor;
   }
 }

runelite-client/src/main/resources/net/runelite/client/plugins/gpu/geom.glsl

@@ -47,9 +47,11 @@ uniform mat4 projectionMatrix;
 
 in ivec3 vPosition[];
 in vec4 vColor[];
+in float vHsl[];
 in vec4 vUv[];
 
 out vec4 Color;
+out float fHsl;
 out vec4 fUv;
 
 #include to_screen.glsl
@@ -67,18 +69,21 @@ void main() {
 
   vec4 tmp = vec4(screenA.xyz, 1.0);
   Color = vColor[0];
+  fHsl = vHsl[0];
   fUv = vUv[0];
   gl_Position  = projectionMatrix * tmp;
   EmitVertex();
 
   tmp = vec4(screenB.xyz, 1.0);
   Color = vColor[1];
+  fHsl = vHsl[1];
   fUv = vUv[1];
   gl_Position  = projectionMatrix * tmp;
   EmitVertex();
 
   tmp = vec4(screenC.xyz, 1.0);
   Color = vColor[2];
+  fHsl = vHsl[2];
   fUv = vUv[2];
   gl_Position  = projectionMatrix * tmp;
   EmitVertex();

runelite-client/src/main/resources/net/runelite/client/plugins/gpu/vert.glsl

@@ -32,6 +32,7 @@ uniform float brightness;
 
 out ivec3 vPosition;
 out vec4 vColor;
+out float vHsl;
 out vec4 vUv;
 
 #include hsl_to_rgb.glsl
@@ -47,5 +48,6 @@ void main()
 
   vPosition = vertex;
   vColor = vec4(rgb, 1.f - a);
+  vHsl = float(hsl);
   vUv = uv;
 }