URL: http://glslsandbox.com/e#27339.3
Notes:
Typically Fractional Brownian Motion ( aka “fbm” ) is used in conjunction with a noise pattern.
When adding noise textures together at different frequencies, you can produce a detailed cloud based texture.
I was curious what would happen if I took a cellular based texture patten like Voronoi and ran that through an fbm.
Some Cellular Noise ran through an fbm with a touch of some Artistic expression produces what I like to call
“The Voronoi Portal” =)
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// Voronoi Portal // Voronoi Variation + Fractional Brownian Motion // By: Brandon Fogerty // bfogerty at gmail dot com // xdpixel.com #ifdef GL_ES precision mediump float; #endif uniform float time; uniform vec2 mouse; uniform vec2 resolution; vec2 hash( vec2 p ) { mat2 m = mat2( 15.32, 83.43, 117.38, 289.59 ); return fract( sin( m * p) * 46783.289 ); } float voronoi( vec2 p ) { vec2 g = floor( p ); vec2 f = fract( p ); float distanceFromPointToCloestFeaturePoint = 1.0; for( int y = -1; y <= 1; ++y ) { for( int x = -1; x <= 1; ++x ) { vec2 latticePoint = vec2( x, y ); float h = distance( latticePoint + hash( g + latticePoint), f ); distanceFromPointToCloestFeaturePoint = min( distanceFromPointToCloestFeaturePoint, h ); } } return 1.0 - sin(distanceFromPointToCloestFeaturePoint); } float texture(vec2 uv ) { float t = voronoi( uv * 8.0 + vec2(time,time) ); t *= 1.0-length(uv * 2.0); return t; } float fbm( vec2 uv ) { float sum = 0.00; float amp = 1.0; for( int i = 0; i < 4; ++i ) { sum += texture( uv ) * amp; uv += uv; amp *= 0.8; } return sum; } void main( void ) { vec2 uv = ( gl_FragCoord.xy / resolution.xy ) * 2.0 - 1.0; uv.x *= resolution.x / resolution.y; float t = pow( fbm( uv * 0.3 ), 2.0); gl_FragColor = vec4( vec3( t * 2.0, t * 4.0, t * 8.0 ), 1.0 ); } |