Updated to 4.4

Testbed/FilmGrain.gdshader

@@ -0,0 +1,108 @@
+shader_type canvas_item;
+
+uniform sampler2D screen_texture : hint_screen_texture;
+uniform float grain_amount : hint_range(0.0, 1.0) = 0.05; // Adjust the amount of grain
+uniform float grain_size : hint_range(0.1, 10.0) = 1.0; // Adjust the size of the grain
+uniform bool animate = false;
+
+//void fragment() {
+	//// Sample the original screen texture
+	//vec4 original_color = texture(screen_texture, SCREEN_UV);
+	//
+	//float noise = 0.0;
+	//
+	//if (animate) {
+		//// Generate random noise
+		//noise = (fract(sin(dot(UV * TIME, vec2(12.9898, 78.233))) * 43758.5453) - 0.5) * 2.0;
+	//} else {
+		 //noise = (fract(sin(dot(UV, vec2(12.9898, 78.233))) * 43758.5453) - 0.5) * 2.0;
+	//}
+	//// Add noise to the original color
+	//original_color.rgb += noise * grain_amount * grain_size;
+	//
+	//// Clamp the final color to make sure it stays in the valid range
+	//COLOR = clamp(original_color, 0.0, 1.0);
+//}
+
+
+// Feel free to steal this :^)
+// Consider it MIT licensed, you can link to this page if you want to.
+
+#define SHOW_NOISE 0
+#define SRGB 0
+// 0: Addition, 1: Screen, 2: Overlay, 3: Soft Light, 4: Lighten-Only
+#define BLEND_MODE 4
+#define SPEED 1.0
+#define INTENSITY 0.05
+// What gray level noise should tend to.
+#define MEAN 0.0
+// Controls the contrast/variance of noise.
+#define VARIANCE 0.5
+
+vec3 channel_mix(vec3 a, vec3 b, vec3 w) {
+    return vec3(mix(a.r, b.r, w.r), mix(a.g, b.g, w.g), mix(a.b, b.b, w.b));
+}
+
+float gaussian(float z, float u, float o) {
+    return (1.0 / (o * sqrt(2.0 * 3.1415))) * exp(-(((z - u) * (z - u)) / (2.0 * (o * o))));
+}
+
+vec3 madd(vec3 a, vec3 b, float w) {
+    return a + a * b * w;
+}
+
+vec3 screen(vec3 a, vec3 b, float w) {
+    return mix(a, vec3(1.0) - (vec3(1.0) - a) * (vec3(1.0) - b), w);
+}
+
+vec3 overlay(vec3 a, vec3 b, float w) {
+    return mix(a, channel_mix(
+        2.0 * a * b,
+        vec3(1.0) - 2.0 * (vec3(1.0) - a) * (vec3(1.0) - b),
+        step(vec3(0.5), a)
+    ), w);
+}
+
+vec3 soft_light(vec3 a, vec3 b, float w) {
+    return mix(a, pow(a, pow(vec3(2.0), 2.0 * (vec3(0.5) - b))), w);
+}
+
+void fragment() {
+    vec2 ps = vec2(1.0) / (1.0 / SCREEN_PIXEL_SIZE).xy;
+    vec2 uv = SCREEN_UV; //coord * ps;
+    COLOR = texture(screen_texture, uv);
+    #if SRGB
+    color = pow(color, vec4(2.2));
+    #endif
+
+    float t = TIME * float(SPEED);
+    float seed = dot(uv, vec2(12.9898, 78.233));
+    float noise = fract(sin(seed) * 43758.5453 + t);
+    noise = gaussian(noise, float(MEAN), float(VARIANCE) * float(VARIANCE));
+
+    #if SHOW_NOISE
+    COLOR = vec4(noise);
+    #else
+    // Ignore these mouse stuff if you're porting this
+    // and just use an arbitrary intensity value.
+    float w = float(INTENSITY);
+
+    vec3 grain = vec3(noise) * (1.0 - COLOR.rgb);
+
+    #if BLEND_MODE == 0
+    COLOR.rgb += grain * w;
+    #elif BLEND_MODE == 1
+    COLOR.rgb = screen(COLOR.rgb, grain, w);
+    #elif BLEND_MODE == 2
+    COLOR.rgb = overlay(COLOR.rgb, grain, w);
+    #elif BLEND_MODE == 3
+    COLOR.rgb = soft_light(COLOR.rgb, grain, w);
+    #elif BLEND_MODE == 4
+    COLOR.rgb = max(COLOR.rgb, grain * w);
+    #endif
+
+    #if SRGB
+    COLOR = pow(COLOR, vec4(1.0 / 2.2));
+    #endif
+    #endif
+}