gpu: add toggle for color banding

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

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;
 }