49 lines
1.3 KiB
Plaintext
49 lines
1.3 KiB
Plaintext
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#ifndef _MATH_GLSL_
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#define _MATH_GLSL_
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float hash(const vec2 p) {
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float h = dot(p, vec2(127.1, 311.7));
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return fract(sin(h) * 43758.5453123);
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}
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vec2 envMapEquirect(const vec3 normal) {
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const float PI = 3.1415926535;
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const float PI2 = PI * 2.0;
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float phi = acos(normal.z);
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float theta = atan(-normal.y, normal.x) + PI;
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return vec2(theta / PI2, phi / PI);
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}
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float rand(const vec2 co) { // Unreliable
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return fract(sin(dot(co.xy, vec2(12.9898, 78.233))) * 43758.5453);
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}
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vec2 rand2(const vec2 coord) {
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const float width = 1100.0;
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const float height = 500.0;
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float noiseX = ((fract(1.0 - coord.s * (width / 2.0)) * 0.25) + (fract(coord.t * (height / 2.0)) * 0.75)) * 2.0 - 1.0;
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float noiseY = ((fract(1.0 - coord.s * (width / 2.0)) * 0.75) + (fract(coord.t * (height / 2.0)) * 0.25)) * 2.0 - 1.0;
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return vec2(noiseX, noiseY);
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}
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float linearize(const float depth, vec2 cameraProj) {
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// to viewz
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return cameraProj.y / (depth - cameraProj.x);
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}
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float attenuate(const float dist) {
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// float attenuate(float dist, float constant, float linear, float quadratic) {
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return 1.0 / (dist * dist);
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// 1.0 / (constant * 1.0)
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// 1.0 / (linear * dist)
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// 1.0 / (quadratic * dist * dist);
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}
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float safe_acos(const float x) {
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// acos is undefined if |x| > 1
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return acos(clamp(x, -1.0, 1.0));
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}
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#endif
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