[orx-fx] convert to MPP

orx-fx/src/shaders/glsl/grain/film-grain.frag

@@ -0,0 +1,91 @@
+// Licensed under the MIT license:
+// https://opensource.org/licenses/MIT.
+
+// Ad[a|o]pted from shader by "noby" https://www.shadertoy.com/view/3sGSWV
+uniform sampler2D tex0;
+in vec2 v_texCoord0;
+
+uniform bool useColor;// false
+uniform float time;
+uniform float grainLiftRatio;// = 0.5;
+uniform float grainStrength;//= 1.0;
+uniform float grainRate;// = 1.0;
+// Range: [0.5, 1.0].
+uniform float grainPitch;// = 1.0;
+
+uniform float colorLevel;// = 1.0;
+
+out vec4 o_output;
+
+
+// From Dave Hoskins: https://www.shadertoy.com/view/4djSRW.
+float hash(vec3 p3){
+    p3 = fract(p3 * 0.1031);
+    p3 += dot(p3, p3.yzx + 19.19);
+    return fract((p3.x + p3.y) * p3.z);
+}
+
+// From iq: https://www.shadertoy.com/view/4sfGzS.
+float noise(vec3 x){
+    vec3 i = floor(x);
+    vec3 f = fract(x);
+    f = f*f*(3.0-2.0*f);
+    return mix(mix(mix(hash(i+vec3(0, 0, 0)),
+    hash(i+vec3(1, 0, 0)), f.x),
+    mix(hash(i+vec3(0, 1, 0)),
+    hash(i+vec3(1, 1, 0)), f.x), f.y),
+    mix(mix(hash(i+vec3(0, 0, 1)),
+    hash(i+vec3(1, 0, 1)), f.x),
+    mix(hash(i+vec3(0, 1, 1)),
+    hash(i+vec3(1, 1, 1)), f.x), f.y), f.z);
+}
+
+// Slightly high-passed continuous value-noise.
+float grain_source(vec3 x, float strength, float pitch){
+    float center = noise(x);
+    float v1 = center - noise(vec3(1, 0, 0)/pitch + x) + 0.5;
+    float v2 = center - noise(vec3(0, 1, 0)/pitch + x) + 0.5;
+    float v3 = center - noise(vec3(-1, 0, 0)/pitch + x) + 0.5;
+    float v4 = center - noise(vec3(0, -1, 0)/pitch + x) + 0.5;
+
+    float total = (v1 + v2 + v3 + v4) / 4.0;
+    return mix(1.0, 0.5 + total, strength);
+}
+
+void main() {
+    vec2 uv = v_texCoord0;
+    vec2 x = gl_FragCoord.xy;
+
+    // Alternatively use iTime here instead and change the grain_rate
+    // parameter to correspond to frames-per-second.
+    float t = time;
+    vec4 colorAlpha = texture(tex0, uv);
+    vec3 color = colorAlpha.rgb;
+    vec3 grain = vec3(0);
+
+    if (useColor) {
+        float rg = grain_source(vec3(x, floor(grainRate*(t))), grainStrength, grainPitch);
+        float gg = grain_source(vec3(x, floor(grainRate*(t+9.0))), grainStrength, grainPitch);
+        float bg = grain_source(vec3(x, floor(grainRate*(t-9.0))), grainStrength, grainPitch);
+
+        // Consider using values outside the [0, 1] range as well
+        // to introduce interesting color shifts to the source.
+
+        vec3 color_grain = vec3(rg, gg, bg);
+        color_grain = mix(vec3(dot(color_grain, vec3(0.2126, 0.7152, 0.0722))), color_grain, colorLevel);
+        grain = color_grain;
+    } else {
+        const float neutral_grain_factor = sqrt(2.0);
+        grain = vec3(grain_source(vec3(x, floor(grainRate*t)), grainStrength/neutral_grain_factor, grainPitch));
+    }
+
+    // Control whether to add or multiply or lift the source with the grain.
+    // Multiply (0.0) should be more true to life, but adjust to taste.
+
+    color = max(mix(color*grain, color+(grain-1.0), grainLiftRatio), 0.0);
+
+    // After this you would normally perform tone mapping,
+    // apply the grain before that.
+    o_output.rgb = color;
+    o_output.a = 1.0;
+}