replace random noise with Bayer for dithering

core/src/main/resources/shaders/flat_shaded.frag

@@ -2,13 +2,13 @@
 
 in vec4 vertexColor;
 in vec3 vertexWorldPos;
-//in float vertexYPos;
 in vec4 vPos;
+in vec4 gl_FragCoord;
 
 out vec4 fragColor;
 
 
-// Fog/Clip Uniforms
+// Fade/Clip Uniforms
 uniform float uClipDistance = 0.0;
 
 // Noise Uniforms
@@ -61,7 +61,26 @@ void applyNoise(inout vec4 fragColor, const in float viewDist)
     fragColor.rgb = newCol;
 }
 
-float worldPosToNoise(vec2 st) { return fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453); }
+/** returns a normalized value between 0.0 and 1.0 */
+float bayerMatrix4x4(vec2 st) 
+{
+    int x = int(mod(st.x, 4.0));
+    int y = int(mod(st.y, 4.0));
+
+    // Flattened 4x4 Bayer matrix
+    float bayer4x4[16] = float[16](
+        0.0,  8.0,  2.0, 10.0,
+        12.0,  4.0, 14.0,  6.0,
+        3.0, 11.0,  1.0,  9.0,
+        15.0,  7.0, 13.0,  5.0
+    );
+
+    // Calculate the 1D index from the 2D coordinates
+    int index = y * 4 + x;
+
+    // Return the Bayer value normalized between 0.0 and 1.0
+    return bayer4x4[index] / 16.0;
+}
 
 
 
@@ -75,20 +94,19 @@ void main()
     {
         // Dither out the fragment based on distance and noise.
         // Dithering is used since it works for both opaque and transparent rendering
-        
+
         // noise increases as the distance increases
-        float worldNoise = worldPosToNoise(vertexWorldPos.xy);
+        // the fragCoord is used since it is stable and small so the dithering is cleaner
+        float worldNoise = bayerMatrix4x4(gl_FragCoord.xy);
+        // minor fudge factor to make sure all pixels fade out
+        // if not included 1 in 16 pixels would never fade away
+        worldNoise += 0.001;
+        
         float fadeStep = smoothstep(uClipDistance, uClipDistance * 1.5, viewDist);
-        if (fadeStep < worldNoise)
+        if (fadeStep <= worldNoise)
         {
             discard;
         }
-        
-        
-        // this logic could be used for transparent rendering,
-        // however we don't currently have the logic needed to differentiate opaque/transparenet rendering
-        //float fadeStep = smoothstep(uClipDistance, uClipDistance * 2, viewDist);
-        //fragColor.a = min(fadeStep, fragColor.a);
     }
     else
     {