44 lines
1.2 KiB
Plaintext
44 lines
1.2 KiB
Plaintext
shader_type canvas_item;
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// source: https://godotshaders.com/shader/smooth-2d-cloud/
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// inspired by: https://www.youtube.com/watch?v=8OrvIQUFptA&t=2s
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uniform sampler2D perlin_noise: repeat_enable;
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uniform sampler2D cell_noise: repeat_enable;
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#define pow2(x) (x * x)
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//#define iResolution 1.0/SCREEN_PIXEL_SIZE
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const int samples = 35;
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const float sigma = float(samples) * 0.25;
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float gaussian(vec2 i) {
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return 1.0 / (2.0 * PI * pow2(sigma)) * exp(-((pow2(i.x) + pow2(i.y)) / (2.0 * pow2(sigma))));
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}
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vec3 blur(sampler2D sp, vec2 uv, vec2 scale) {
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vec3 col = vec3(0.0);
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float accum = 0.0;
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float weight;
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vec2 offset;
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for (int x = - samples >> 1 ; x < samples >> 1; ++x) {
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for (int y = -samples >> 1; y < samples >> 1; ++y) {
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offset = vec2(float(x), float(y));
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weight = gaussian(offset);
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col += texture(sp, uv + scale * offset).rgb * weight;
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accum += weight;
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}
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}
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return col / accum;
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}
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void fragment() {
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vec2 uv1 = vec2(UV.x + TIME * .02, UV.y + TIME * .005);
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vec2 uv2 = vec2(UV.x + TIME * .03, UV.y + TIME * .005);
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float noise1 = blur(perlin_noise, uv1, SCREEN_PIXEL_SIZE).r;
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float noise2 = blur(cell_noise, uv2, SCREEN_PIXEL_SIZE).r;
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float noise = smoothstep(noise1 * noise2 * 1.0, .0, .15);
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COLOR.a *= noise;
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}
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