57 lines
1.4 KiB
GLSL
57 lines
1.4 KiB
GLSL
#version 100
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precision highp float;
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uniform float u_time;
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uniform vec2 u_resolution;
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uniform float u_zoom;
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uniform vec2 u_center;
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void main() {
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// Current pixel coordinate in 0..1
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vec2 st = gl_FragCoord.xy / u_resolution.xy;
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st.x *= u_resolution.x / u_resolution.y; // Aspect ratio correction
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// Map to Mandelbrot space using Zoom and Center
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// Default (Zoom 1): -2.5 to 1.5 X, -1.5 to 1.5 Y approx?
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// Let's say center is 0,0. Range -2..2.
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// st is 0..AspectRatio (approx 0..1.7)
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// Center the coords:
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vec2 c_uv = (gl_FragCoord.xy - u_resolution.xy * 0.5) / u_resolution.y;
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// Apply Zoom and Pan
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vec2 c = (c_uv / u_zoom) + u_center;
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// Mandelbrot iteration
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vec2 z = vec2(0.0);
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float iter = 0.0;
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float max_iter = 100.0 + log(u_zoom) * 20.0; // Increase details with zoom
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for (float i = 0.0; i < 500.0; i++) {
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if (i > max_iter) break;
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// Z = Z^2 + C
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float x = (z.x * z.x - z.y * z.y) + c.x;
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float y = (z.y * z.x + z.x * z.y) + c.y;
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if ((x * x + y * y) > 4.0) {
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iter = i;
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break;
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}
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z.x = x;
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z.y = y;
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}
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// Coloring
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float t = iter / max_iter;
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if (iter == 0.0) {
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gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
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} else {
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gl_FragColor = vec4(
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sqrt(t),
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t * t,
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sin(t * 3.1415),
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1.0
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);
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}
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}
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