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