add mc_kuwahara_shader

mc_kuwahara_shader/final.fsh.settings

@@ -0,0 +1 @@
+shadowmap=false

mc_kuwahara_shader/shaders.properties

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+separateAo=true
+shadowMapResolution=0
+generateShadowMap=false

mc_kuwahara_shader/shaders/final.fsh

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+#version 150
+
+uniform float viewWidth;
+uniform float viewHeight;
+uniform sampler2D colortex0;
+
+in vec2 texCoord;
+out vec4 fragColor;
+
+// Tune these to trade quality vs performance:
+//   RADIUS 36, STEP 1 → 5476 samples/pixel (original, ~9fps)
+//   RADIUS 36, STEP 3 → 676  samples/pixel (~8x faster)
+//   RADIUS 36, STEP 4 → 400  samples/pixel (~14x faster)
+//   RADIUS 16, STEP 2 → 324  samples/pixel (smaller brush, fast)
+#define RADIUS 36
+#define STEP 3
+
+vec3 kuwahara_region(vec2 uv, vec2 ts, int x0, int x1, int y0, int y1, out float outVariance) {
+    vec3 colorSum = vec3(0.0);
+    float lumaSum = 0.0;
+    float lumaSqSum = 0.0;
+    float count = 0.0;
+
+    for (int i = x0; i <= x1; i += STEP) {
+        for (int j = y0; j <= y1; j += STEP) {
+            vec3 c = texture(colortex0, uv + vec2(float(i), float(j)) * ts).rgb;
+            float luma = dot(c, vec3(0.299, 0.587, 0.114));
+            colorSum  += c;
+            lumaSum   += luma;
+            lumaSqSum += luma * luma;
+            count     += 1.0;
+        }
+    }
+
+    vec3  mean     = colorSum / count;
+    float meanLuma = lumaSum  / count;
+    float variance = (lumaSqSum / count) - (meanLuma * meanLuma);
+    outVariance = variance * variance; // square for harder selection
+    return mean;
+}
+
+void main() {
+    vec2 ts = vec2(1.0 / viewWidth, 1.0 / viewHeight);
+
+    float v_tr, v_tl, v_bl, v_br;
+    vec3 mean_tr = kuwahara_region(texCoord, ts,       0, RADIUS,       0, RADIUS, v_tr);
+    vec3 mean_tl = kuwahara_region(texCoord, ts, -RADIUS,      0,       0, RADIUS, v_tl);
+    vec3 mean_bl = kuwahara_region(texCoord, ts, -RADIUS,      0, -RADIUS,      0, v_bl);
+    vec3 mean_br = kuwahara_region(texCoord, ts,       0, RADIUS, -RADIUS,      0, v_br);
+
+    vec3  finalColor = mean_tr;
+    float minVar     = v_tr;
+
+    if (v_tl < minVar) { minVar = v_tl; finalColor = mean_tl; }
+    if (v_bl < minVar) { minVar = v_bl; finalColor = mean_bl; }
+    if (v_br < minVar) { minVar = v_br; finalColor = mean_br; }
+
+    fragColor = vec4(finalColor, 1.0);
+}

mc_kuwahara_shader/shaders/final.vsh

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+#version 150
+
+in vec3 vaPosition;
+in vec2 vaUV0;
+
+out vec2 texCoord;
+
+void main() {
+    gl_Position = vec4(vaPosition.xy * 2.0 - 1.0, 0.0, 1.0);
+    texCoord = vaUV0;
+}

mc_kuwahara_shader/shaders/gbuffers_terrain.fsh

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+#version 150
+
+/* DRAWBUFFERS:0 */
+
+uniform sampler2D gtexture;
+uniform sampler2D lightmap;
+
+in vec2 texCoord;
+in vec4 tintColor;
+in vec2 lightCoord;
+
+out vec4 fragColor;
+
+void main() {
+    vec4 color = texture(gtexture, texCoord);
+    if (color.a < 0.1) discard;
+    color *= tintColor;
+    color.rgb *= texture(lightmap, lightCoord).rgb;
+    fragColor = color;
+}

mc_kuwahara_shader/shaders/gbuffers_terrain.vsh

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+#version 150
+
+uniform mat4 modelViewMatrix;
+uniform mat4 projectionMatrix;
+uniform vec3 chunkOffset;
+
+in vec3 vaPosition;
+in vec4 vaColor;
+in vec2 vaUV0;
+in ivec2 vaUV2;
+
+out vec2 texCoord;
+out vec4 tintColor;
+out vec2 lightCoord;
+
+void main() {
+    gl_Position = projectionMatrix * modelViewMatrix * vec4(vaPosition + chunkOffset, 1.0);
+    texCoord = vaUV0;
+    tintColor = vaColor;
+    lightCoord = vaUV2 / 256.0;
+}