precision highp float; uniform vec2 resolution; uniform float time; uniform vec2 mouse; uniform sampler2D backbuffer; #define iResolution resolution #define iTime time #define iMouse mouse vec2 cmul(in vec2 a, in vec2 b) { return vec2(a.x * b.x - a.y * b.y, a.y * b.x + a.x * b.y); } vec2 re(in vec2 a) { return vec2(a.x, 0); } vec2 im(in vec2 a) { return vec2(0, a.y); } vec2 conj(in vec2 a) { return vec2(a.x, -a.y); } vec2 cinv(in vec2 a) { return vec2(conj(a))/ dot(a, a); } vec2 cpow(in vec2 a, in int n) { vec2 z = vec2(1, 0); if (n < 0) { n *= -1; a = cinv(a); } for (int i = 0; i < 1000; i++) { if (i >= n) {break;} z = cmul(z, a); } return z; } vec2 cexp(in vec2 a) { return exp(a.x)* vec2(cos(a.y), sin(a.y)); } const float PI = 3.141592653589793; vec3 hsvToRgb(float h, float s, float v) { // h: -π - +π, s: 0.0 - 1.0, v: 0.0 - 1.0 h = (h + PI) / (2.* PI) * 360.; float c = s; // float c = v * s; float h2 = h / 60.0; float x = c * (1.0 - abs(mod(h2, 2.0) - 1.0)); vec3 rgb = (v - c) * vec3(1.0, 1.0, 1.0); if (0.0 <= h2 && h2 < 1.0) { rgb += vec3(c, x, 0.0); } else if (1.0 <= h2 && h2 < 2.0) { rgb += vec3(x, c, 0.0); } else if (2.0 <= h2 && h2 < 3.0) { rgb += vec3(0.0, c, x); } else if (3.0 <= h2 && h2 < 4.0) { rgb += vec3(0.0, x, c); } else if (4.0 <= h2 && h2 < 5.0) { rgb += vec3(x, 0.0, c); } else if (5.0 <= h2 && h2 < 6.0) { rgb += vec3(c, 0.0, x); } return rgb; } // hsvToRgb borrowed from // https://qiita.com/sw1227/items/4be9b9f928724a389a85 // (slightly modified by Kanata) void mainImage(out vec4 fragColor, in vec2 fragCoord); void main(void) { vec4 col; mainImage(col, gl_FragCoord.xy); gl_FragColor = col; } vec2 f (in vec2 z) { return cpow(z, 6)- vec2(1.11, 0.); } void mainImage( out vec4 O, vec2 u ) { vec2 res = iResolution.xy, z = ( u* 2. - res) / min(res.x, res.y); float t = iTime; float scale = 2.; z *= scale; vec2 w = cmul(z, cexp(vec2(0., t* 0.1))); for (int i = 0; i < 8; i++) { w = f(w); } w += cmul(z, cexp(vec2(0., t))); float theta = atan(w.x, w.y); float r = length(w); O = vec4(hsvToRgb(0., 0.1/r+0.1, 0.5/r), 1.); }

A snowflake in the dark