42 lines
880 B
GLSL
42 lines
880 B
GLSL
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#version 330
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out vec4 fragColor;
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uniform vec2 res;
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uniform float time;
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const float sharpness = 300;
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const float PI = 3.14159265358979323846;
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mat2 rot(float a) {
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return mat2(
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cos(a), -sin(a),
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sin(a), cos(a)
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);
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}
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float square(vec2 m, float a, float r, vec2 p) {
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vec2 diff = abs((m - p) * rot(r));
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float d = max(diff.x, diff.y);
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return clamp((a - d)*sharpness, 0.0, 1.0);
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}
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void main(void) {
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vec2 m = res/2;
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float s = min(m.x, m.y);
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vec2 p = (gl_FragCoord.xy - m) / s;
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float scene = 0;
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int n = 24;
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for (int i = 0; i < n; i++) {
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float c = square(vec2(0.5, 0) * rot(PI/2*(4.0*i/n)) * vec2(1, 1), 0.3, PI/2*(24.0*i/n - time/800), p);
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scene = abs(scene - c);
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}
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fragColor = vec4(vec3(1, 1, 1) * scene, 1);
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}
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