1 files changed, 38 insertions, 0 deletions
diff --git a/assets/shaders/psx_filter.fs b/assets/shaders/psx_filter.fs
new file mode 100644
index 0000000..21eaada
--- /dev/null
+++ b/assets/shaders/psx_filter.fs
@@ -0,0 +1,38 @@
+#version 330
+
+uniform sampler2D texture0;
+
+in vec2 fragTexCoord;
+
+out vec4 finalColor;
+
+const float neareight = 255.0;
+vec3 dither(vec3 col, uvec2 fc)
+{
+    const int mat[16] = int[16] (
+        -4, 0, -3, 1,
+        2, -2, 3, -1,
+        -3, 1, -4, 0,
+        3, -1, 2, -2
+    );
+
+    ivec3 uncol = ivec3(col * neareight) + mat[(fc.y & uint(3)) * uint(4) + (fc.x & uint(3))];
+    return vec3(uncol) / neareight;
+}
+
+vec3 band_color(vec3 lol)
+{
+	ivec3 res = ivec3(clamp(lol, 0.0, 1.0) * neareight) & ivec3(0xFF);
+	ivec3 ires = res >> 3;
+	ivec3 dres = (ires >> 2) & ivec3(7);
+	res = (ires << 3) | dres;
+	return vec3(res) / neareight;
+}
+
+void main()
+{
+    vec4 texelColor = texture(texture0, fragTexCoord);
+    texelColor.rgb = band_color(dither(texelColor.rgb, uvec2(gl_FragCoord.xy)));
+
+    finalColor = texelColor;
+}
+\ No newline at end of file