#version 300 es precision highp float; uniform vec2 center; uniform float width; uniform float height; uniform float scale; uniform int hasGrid; uniform float iteration; uniform vec3 startColor; uniform vec3 endColor; uniform vec3 centerColor; out vec4 outColor; int mandelbrot(vec2 c) { vec2 z = c; int i = 0; // 最大反復回数になるまで繰り返す while (float(i) < iteration) { float x = z.x * z.x - z.y * z.y + c.x; float y = 2.0 * z.x * z.y + c.y; if (x * x + y * y > 4.0) { break; } z = vec2(x, y); i++; } return i; } float rgbMax(vec3 hsl) { float s = hsl.y; float l = hsl.z; if (l < 0.5) return l + l * s; return l + (1.0 - l) * s; } float rgbMin(vec3 hsl) { float s = hsl.y; float l = hsl.z; if (l < 0.5) { return l - l * s; } return l - (1.0 - l) * s; } float red(vec3 hsl) { float max = rgbMax(hsl); float min = rgbMin(hsl); float h = hsl.x * 360.0; if (h <= 60.0) { return max; } if (h <= 120.0) { return ((120.0 - h) / 60.0) * (max - min) + min; } if (h <= 240.0) { return min; } if (h <= 300.0) { return ((h - 240.0) / 60.0) * (max - min) + min; } return max; } float green(vec3 hsl) { float max = rgbMax(hsl); float min = rgbMin(hsl); float h = hsl.x * 360.0; if (h <= 60.0) { return (h / 60.0) * (max - min) + min; } if (h <= 180.0) { return max; } if (h <= 240.0) { return ((240.0 - h) / 60.0) * (max - min) + min; } return min; } float blue(vec3 hsl) { float max = rgbMax(hsl); float min = rgbMin(hsl); float h = hsl.x * 360.0; if (h <= 120.0) { return min; } if (h <= 180.0) { return ((h - 120.0) / 60.0) * (max - min) + min; } if (h <= 300.0) { return max; } return ((360.0 - h) / 60.0) * (max - min) + min; } vec3 hsl2rgb(vec3 hsl) { float h = hsl.x * 360.0; float s = hsl.y; float l = hsl.z; float hx = (h < 0.0 ? mod(h, 360.0) + 360.0 : mod(h, 360.0)) / 360.0; float sx = clamp(s, 0.0, 1.0); float lx = clamp(l, 0.0, 1.0); vec3 hslx = vec3(hx, sx, lx); float r = red(hslx); float g = green(hslx); float b = blue(hslx); return vec3(r, g, b); } void main() { float centerWidth = width / 2.0; float centerHeight = height / 2.0; float x = (gl_FragCoord.x - centerWidth) / height * 3.0 / pow(2.0, scale) + center.x; float y = (gl_FragCoord.y - centerHeight) / height * 3.0 / pow(2.0, scale) + center.y; float i = float(mandelbrot(vec2(x, y))); vec3 hsl; if ( hasGrid == 1 && ( int(gl_FragCoord.x - centerWidth) % int(height / 4.0) == 0 || int(gl_FragCoord.y - centerHeight) % int(height / 4.0) == 0 || pow(gl_FragCoord.x - centerWidth, 2.0) + pow(gl_FragCoord.y - centerHeight, 2.0) < height / 20.0 ) ) { hsl = vec3(240.0 / 360.0, 1.0, 0.5); } else if (i >= iteration) { hsl = centerColor; } else { float itRate = clamp(i / iteration, 0.0, 1.0); float h = itRate * (endColor.x - startColor.x) + startColor.x; float s = itRate * (endColor.y - startColor.y) + startColor.y; float l = itRate * (endColor.z - startColor.z) + startColor.z; hsl = vec3(h, s, l); } vec3 rgb = hsl2rgb(hsl); outColor = vec4(rgb, 1.0); }