Dither out geom that is about the clip with the near plane

src/main/resources/rs117/hd/scene_frag.glsl

@@ -32,6 +32,8 @@
 #define DISPLAY_SHADOWS 0
 #define DISPLAY_LIGHTING 0
 
+#define NEAR_PLANE_DITHER_START 0.2
+
 #include <uniforms/global.glsl>
 #include <uniforms/world_views.glsl>
 #include <uniforms/materials.glsl>
@@ -55,6 +57,9 @@ flat in ivec3 fTerrainData;
 #endif
 
 in FragmentData {
+#if ZONE_RENDERER
+    vec4 positionCS;
+#endif
     vec3 position;
     vec2 uv;
     vec3 normal;
@@ -84,6 +89,15 @@ vec2 worldUvs(float scale) {
 
 void main() {
     vec3 downDir = vec3(0, -1, 0);
+#if ZONE_RENDERER
+    float viewZ = 1.0 - (0.5 + (IN.positionCS.z / IN.positionCS.w) * 0.5);
+    if(viewZ < NEAR_PLANE_DITHER_START) {
+        float fadeAmount = 1.0 - saturate(viewZ / NEAR_PLANE_DITHER_START);
+        if(orderedDither(gl_FragCoord.xy, pow(fadeAmount, 1.5) - 0.01, 1.75))
+            discard;
+    }
+#endif
+
     // View & light directions are from the fragment to the camera/light
     vec3 viewDir = normalize(cameraPos - IN.position);
 

src/main/resources/rs117/hd/scene_vert.glsl

@@ -60,6 +60,7 @@ layout (location = 0) in vec3 vPosition;
     #endif
 
     out FragmentData {
+        vec4 positionCS;
         vec3 position;
         vec2 uv;
         vec3 normal;
@@ -109,12 +110,12 @@ layout (location = 0) in vec3 vPosition;
             fFlatNormal = worldNormal;
         #endif
 
-        vec4 clipPosition = projectionMatrix * vec4(worldPosition, 1.0);
         int depthBias = (alphaBiasHsl >> 16) & 0xff;
-        if (projectionMatrix[2][3] != 0) // Disable depth bias for orthographic projection
-            clipPosition.z += depthBias / 128.0;
+        OUT.positionCS = projectionMatrix * vec4(worldPosition, 1.0);
+	if (projectionMatrix[2][3] != 0) // Disable depth bias for orthographic projection
+        	OUT.positionCS.z += depthBias / 128.0;
 
-        gl_Position = clipPosition;
+        gl_Position = OUT.positionCS;
     }
 #else
     out vec3 gPosition;

src/main/resources/rs117/hd/utils/misc.glsl

@@ -112,6 +112,25 @@ void undoVanillaShading(inout int hsl, vec3 unrotatedNormal) {
     }
 #endif
 
+const int DITHER_MAP_LEN = 4;
+const float DITHER_MAP_SCALE = 16.0;
+
+const float DITHER_MAP[DITHER_MAP_LEN * DITHER_MAP_LEN] = float[](
+     0.0 / DITHER_MAP_SCALE,  8.0 / DITHER_MAP_SCALE,  2.0 / DITHER_MAP_SCALE, 10.0 / DITHER_MAP_SCALE,
+    12.0 / DITHER_MAP_SCALE,  4.0 / DITHER_MAP_SCALE, 14.0 / DITHER_MAP_SCALE,  6.0 / DITHER_MAP_SCALE,
+     3.0 / DITHER_MAP_SCALE, 11.0 / DITHER_MAP_SCALE,  1.0 / DITHER_MAP_SCALE,  9.0 / DITHER_MAP_SCALE,
+    15.0 / DITHER_MAP_SCALE,  7.0 / DITHER_MAP_SCALE, 13.0 / DITHER_MAP_SCALE,  5.0 / DITHER_MAP_SCALE
+);
+
+// ------------------------------------------------------------
+// Based on https://www.shadertoy.com/view/4t2cRt
+// Returns a dither value (0.0 or 1.0) based on coords + opacity
+// ------------------------------------------------------------
+bool orderedDither(vec2 pixelCoord, float opacity, float scaleFactor) {
+    ivec2 coord = ivec2(pixelCoord / scaleFactor) & (DITHER_MAP_LEN - 1);
+    return DITHER_MAP[coord.x + coord.y * DITHER_MAP_LEN] < clamp(opacity, 0.0, 1.0);
+}
+
 // 2D Random
 float hash(in vec2 st) {
     return fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453123);