Create/Update assets for version 1.21.5-pre2

assets/minecraft/shaders/post/bits.fsh

@@ -0,0 +1,30 @@
+#version 150
+
+uniform sampler2D InSampler;
+
+in vec2 texCoord;
+in vec2 oneTexel;
+
+uniform vec2 InSize;
+
+uniform float Resolution;
+uniform float MosaicSize;
+
+out vec4 fragColor;
+
+const float Saturation = 1.5;
+
+void main() {
+    vec2 mosaicInSize = InSize / MosaicSize;
+    vec2 fractPix = fract(texCoord * mosaicInSize) / mosaicInSize;
+
+    vec4 baseTexel = texture(InSampler, texCoord - fractPix);
+
+    vec3 fractTexel = baseTexel.rgb - fract(baseTexel.rgb * Resolution) / Resolution;
+    float luma = dot(fractTexel, vec3(0.3, 0.59, 0.11));
+    vec3 chroma = (fractTexel - luma) * Saturation;
+    baseTexel.rgb = luma + chroma;
+    baseTexel.a = 1.0;
+
+    fragColor = baseTexel;
+}