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52 lines
1.1 KiB
GLSL
52 lines
1.1 KiB
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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uniform vec2 u_resolution;
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uniform vec2 u_mouse;
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uniform float u_time;
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// 2D Random
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float random (in vec2 st) {
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return fract(sin(dot(st.xy,
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vec2(12.9898,78.233)))
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* 43758.5453123);
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}
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// 2D Noise based on Morgan McGuire @morgan3d
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// https://www.shadertoy.com/view/4dS3Wd
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float noise (in vec2 st) {
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vec2 i = floor(st);
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vec2 f = fract(st);
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// Four corners in 2D of a tile
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float a = random(i);
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float b = random(i + vec2(1.0, 0.0));
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float c = random(i + vec2(0.0, 1.0));
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float d = random(i + vec2(1.0, 1.0));
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// Smooth Interpolation
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// Cubic Hermine Curve. Same as SmoothStep()
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vec2 u = f*f*(3.0-2.0*f);
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// u = smoothstep(0.,1.,f);
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// Mix 4 coorners percentages
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return mix(a, b, u.x) +
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(c - a)* u.y * (1.0 - u.x) +
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(d - b) * u.x * u.y;
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}
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void main() {
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vec2 st = gl_FragCoord.xy/u_resolution.xy;
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// Scale the coordinate system to see
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// some noise in action
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vec2 pos = vec2(st*5.0);
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// Use the noise function
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float n = noise(pos);
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gl_FragColor = vec4(vec3(n), 1.0);
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}
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