diff --git a/plasma.glsl b/plasma.glsl new file mode 100644 index 0000000..6804d00 --- /dev/null +++ b/plasma.glsl @@ -0,0 +1,147 @@ +#ifdef GL_ES +precision mediump float; +#extension GL_OES_standard_derivatives : enable +#endif + +uniform float time; +uniform vec2 mouse; +uniform vec2 resolution; + + +// START ASHIMA + +// +// Description : Array and textureless GLSL 2D/3D/4D simplex +// noise functions. +// Author : Ian McEwan, Ashima Arts. +// Maintainer : ijm +// Lastmod : 20110822 (ijm) +// License : Copyright (C) 2011 Ashima Arts. All rights reserved. +// Distributed under the MIT License. See LICENSE file. +// https://github.com/ashima/webgl-noise +// + +vec3 mod289(vec3 x) { + return x - floor(x * (1.0 / 289.0)) * 289.0; +} + +vec4 mod289(vec4 x) { + return x - floor(x * (1.0 / 289.0)) * 289.0; +} + +vec4 permute(vec4 x) { + return mod289(((x*34.0)+1.0)*x); +} + +vec4 taylorInvSqrt(vec4 r) +{ + return 1.79284291400159 - 0.85373472095314 * r; +} + +float snoise(vec3 v) + { + const vec2 C = vec2(1.0/6.0, 1.0/3.0) ; + const vec4 D = vec4(0.0, 0.5, 1.0, 2.0); + +// First corner + vec3 i = floor(v + dot(v, C.yyy) ); + vec3 x0 = v - i + dot(i, C.xxx) ; + +// Other corners + vec3 g = step(x0.yzx, x0.xyz); + vec3 l = 1.0 - g; + vec3 i1 = min( g.xyz, l.zxy ); + vec3 i2 = max( g.xyz, l.zxy ); + + // x0 = x0 - 0.0 + 0.0 * C.xxx; + // x1 = x0 - i1 + 1.0 * C.xxx; + // x2 = x0 - i2 + 2.0 * C.xxx; + // x3 = x0 - 1.0 + 3.0 * C.xxx; + vec3 x1 = x0 - i1 + C.xxx; + vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y + vec3 x3 = x0 - D.yyy; // -1.0+3.0*C.x = -0.5 = -D.y + +// Permutations + i = mod289(i); + vec4 p = permute( permute( permute( + i.z + vec4(0.0, i1.z, i2.z, 1.0 )) + + i.y + vec4(0.0, i1.y, i2.y, 1.0 )) + + i.x + vec4(0.0, i1.x, i2.x, 1.0 )); + +// Gradients: 7x7 points over a square, mapped onto an octahedron. +// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294) + float n_ = 0.142857142857; // 1.0/7.0 + vec3 ns = n_ * D.wyz - D.xzx; + + vec4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7) + + vec4 x_ = floor(j * ns.z); + vec4 y_ = floor(j - 7.0 * x_ ); // mod(j,N) + + vec4 x = x_ *ns.x + ns.yyyy; + vec4 y = y_ *ns.x + ns.yyyy; + vec4 h = 1.0 - abs(x) - abs(y); + + vec4 b0 = vec4( x.xy, y.xy ); + vec4 b1 = vec4( x.zw, y.zw ); + + //vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0; + //vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0; + vec4 s0 = floor(b0)*2.0 + 1.0; + vec4 s1 = floor(b1)*2.0 + 1.0; + vec4 sh = -step(h, vec4(0.0)); + + vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ; + vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ; + + vec3 p0 = vec3(a0.xy,h.x); + vec3 p1 = vec3(a0.zw,h.y); + vec3 p2 = vec3(a1.xy,h.z); + vec3 p3 = vec3(a1.zw,h.w); + +//Normalise gradients + vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3))); + p0 *= norm.x; + p1 *= norm.y; + p2 *= norm.z; + p3 *= norm.w; + +// Mix final noise value + vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0); + m = m * m; + return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1), + dot(p2,x2), dot(p3,x3) ) ); + } + +// END ASHIMA + +vec3 rgb2hsv(vec3 c) +{ + vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0); + vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g)); + vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r)); + + float d = q.x - min(q.w, q.y); + float e = 1.0e-10; + return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x); +} + +vec3 hsv2rgb(vec3 c) { + vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0); + vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www); + return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y); +} + +void main(void) { + vec2 position = gl_FragCoord.xy / min(resolution.x, resolution.y); + + const float scale = 0.5; + float x = position.x * scale; + float y = position.y * scale; + float t = time; + + float hue = snoise(vec3(x, y, t)); + vec3 rgb = hsv2rgb(vec3(hue, 1.0, 1.0)); + + gl_FragColor = vec4(rgb, 1.0); +}