101 lines
3.1 KiB
GLSL
101 lines
3.1 KiB
GLSL
precision mediump float;
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uniform float u_time;
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uniform vec2 u_resolution;
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const float PI = 3.1415926535897932384626433832795;
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const vec2 zero = vec2(0.0);
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// const vec4 darker = vec4(0.0235, 0.0274, 0.0549, 1.0);
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// const vec4 lighter = vec4(0.1058, 0.1137, 0.1450, 1.0);
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const vec4 darker = vec4(-0.2, -0.2, -0.2, 1.0);
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const vec4 lighter = vec4(0.082, 0.082, 0.099, 1.0);
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vec3 mod289(vec3 x) {
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return x - floor(x * (1.0 / 289.0)) * 289.0;
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}
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vec2 mod289(vec2 x) {
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return x - floor(x * (1.0 / 289.0)) * 289.0;
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}
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vec3 permute(vec3 x) {
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return mod289(((x * 34.0) + 10.0) * x);
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}
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float snoise(vec2 v) {
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const vec4 C = vec4(0.211324865405187,
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0.366025403784439,
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-0.577350269189626,
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0.024390243902439);
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vec2 i = floor(v + dot(v, C.yy));
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vec2 x0 = v - i + dot(i, C.xx);
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vec2 i1;
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i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
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vec4 x12 = x0.xyxy + C.xxzz;
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x12.xy -= i1;
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i = mod289(i);
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vec3 p = permute(permute(i.y + vec3(0.0, i1.y, 1.0))
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+ i.x + vec3(0.0, i1.x, 1.0));
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vec3 m = max(0.5 - vec3(dot(x0, x0), dot(x12.xy, x12.xy), dot(x12.zw, x12.zw)), 0.0);
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m = m * m;
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m = m * m;
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vec3 x = 2.0 * fract(p * C.www) - 1.0;
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vec3 h = abs(x) - 0.5;
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vec3 ox = floor(x + 0.5);
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vec3 a0 = x - ox;
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m *= 1.79284291400159 - 0.85373472095314 * (a0 * a0 + h * h);
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vec3 g;
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g.x = a0.x * x0.x + h.x * x0.y;
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g.yz = a0.yz * x12.xz + h.yz * x12.yw;
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return 130.0 * dot(m, g);
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}
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void main() {
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vec2 center = u_resolution / 2.0;
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// calculate coord scale factor
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float shortside = min(u_resolution.x, u_resolution.y);
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vec2 scale2square = u_resolution / vec2(shortside);
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// subtract center to avoid misalignment
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vec2 herescaled = ((gl_FragCoord.xy - center) / scale2square) + center;
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// get distance from center
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float dist = distance(herescaled, center);
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float distf = smoothstep(0.0, shortside, dist);
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// at lower clock values, we make vignette gradient denser
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// (at kinda slow rate for a breathing effect)
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float slowtime = u_time / 1.3;
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float timing = sin(slowtime) + 1.0;
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// map 0-1 timing value into a slight offset
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// (lower = farther out)
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float vig = distf + mix(-0.13, -0.1, timing);
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// get coords relative to center, and then get angle
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vec2 herer2c = herescaled - center;
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float angle = atan(herer2c.y, herer2c.x);
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// determine our offset based on this
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// so it looks wavy
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float slowtime2 = u_time / 1.2;
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float slowtime3 = u_time / 1.5;
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float off = 0.2 + (0.02 * sin(20.0 * angle + slowtime2)) * (1.4 * sin(10.0 * angle + slowtime3));
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// apply cutoff if we are too close to center,
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float vigc = (vig * step(off / 3.0, vig) - off);
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// randomize noise pattern every second ish
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float fasttime = u_time * 1.1;
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float second = floor(fasttime);
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float noise = snoise(vec2(gl_FragCoord.x * gl_FragCoord.y, second));
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// quantize vignette colors
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float vigq = floor(vigc * 13.0) / 13.0;
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// blend noise
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float final = 1.0 - vigq;
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gl_FragColor = mix(darker, lighter, final);
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}
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