80 lines
2.1 KiB
GLSL
Executable file
80 lines
2.1 KiB
GLSL
Executable file
// Based on work by David Li(http://david.li/waves)
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#version 450
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#ifdef GL_ES
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precision mediump float;
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#endif
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in vec2 texCoord;
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out vec4 fragColor;
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const float PI = 3.14159265359;
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const float G = 9.81;
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const float KM = 370.0;
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const float CM = 0.23;
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const vec2 wind = vec2(10.0, 10.0);
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const float resolution = 512.0;
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const float size = 250.0;
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float square(float x) {
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return x * x;
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}
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float omega(float k) {
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return sqrt(G * k * (1.0 + square(k / KM)));
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}
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float tanh(float x) {
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return (1.0 - exp(-2.0 * x)) / (1.0 + exp(-2.0 * x));
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}
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void main() {
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vec2 coordinates = texCoord.xy * resolution;//gl_FragCoord.xy - 0.5;
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float n = (coordinates.x < resolution * 0.5) ? coordinates.x : coordinates.x - resolution;
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float m = (coordinates.y < resolution * 0.5) ? coordinates.y : coordinates.y - resolution;
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vec2 K = (2.0 * PI * vec2(n, m)) / size;
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float k = length(K);
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float l_wind = length(wind);
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float Omega = 0.84;
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float kp = G * square(Omega / l_wind);
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float c = omega(k) / k;
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float cp = omega(kp) / kp;
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float Lpm = exp(-1.25 * square(kp / k));
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float gamma = 1.7;
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float sigma = 0.08 * (1.0 + 4.0 * pow(Omega, -3.0));
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float Gamma = exp(-square(sqrt(k / kp) - 1.0) / 2.0 * square(sigma));
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float Jp = pow(gamma, Gamma);
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float Fp = Lpm * Jp * exp(-Omega / sqrt(10.0) * (sqrt(k / kp) - 1.0));
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float alphap = 0.006 * sqrt(Omega);
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float Bl = 0.5 * alphap * cp / c * Fp;
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float z0 = 0.000037 * square(l_wind) / G * pow(l_wind / cp, 0.9);
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float uStar = 0.41 * l_wind / log(10.0 / z0);
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float alpham = 0.01 * ((uStar < CM) ? (1.0 + log(uStar / CM)) : (1.0 + 3.0 * log(uStar / CM)));
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float Fm = exp(-0.25 * square(k / KM - 1.0));
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float Bh = 0.5 * alpham * CM / c * Fm * Lpm;
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float a0 = log(2.0) / 4.0;
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float am = 0.13 * uStar / CM;
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float Delta = tanh(a0 + 4.0 * pow(c / cp, 2.5) + am * pow(CM / c, 2.5));
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float cosPhi = dot(normalize(wind), normalize(K));
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float S = (1.0 / (2.0 * PI)) * pow(k, -4.0) * (Bl + Bh) * (1.0 + Delta * (2.0 * cosPhi * cosPhi - 1.0));
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float dk = 2.0 * PI / size;
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float h = sqrt(S / 2.0) * dk;
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if (K.x == 0.0 && K.y == 0.0) {
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h = 0.0; //no DC term
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}
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fragColor = vec4(h, 0.0, 0.0, 0.0);
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}
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