material-maker/addons/material_maker/nodes/perlin.mmn

{"global":"float perlin(vec2 uv, vec2 size, int iterations, float persistence, int seed) {\n\tvec2 seed2 = rand2(vec2(float(seed), 1.0-float(seed)));\n    float rv = 0.0;\n    float coef = 1.0;\n    float acc = 0.0;\n    for (int i = 0; i < iterations; ++i) {\n    \tvec2 step = vec2(1.0)/size;\n\t\tvec2 xy = floor(uv*size);\n        float f0 = rand(seed2+mod(xy, size));\n        float f1 = rand(seed2+mod(xy+vec2(1.0, 0.0), size));\n        float f2 = rand(seed2+mod(xy+vec2(0.0, 1.0), size));\n        float f3 = rand(seed2+mod(xy+vec2(1.0, 1.0), size));\n        vec2 mixval = smoothstep(0.0, 1.0, fract(uv*size));\n        rv += coef * mix(mix(f0, f1, mixval.x), mix(f2, f3, mixval.x), mixval.y);\n        acc += coef;\n        size *= 2.0;\n        coef *= persistence;\n    }\n    \n    return rv / acc;\n}\n","instance":"","name":"Perlin","outputs":[{"f":"perlin($(uv), vec2($(scale_x), $(scale_y)), int($(iterations)), $(persistence), $(seed))"}],"parameters":[{"default":4,"label":"Scale X","max":32,"min":1,"name":"scale_x","step":1,"type":"float","widget":"spinbox"},{"default":4,"label":"Scale Y","max":32,"min":1,"name":"scale_y","step":1,"type":"float","widget":"spinbox"},{"default":3,"label":"Iterations","max":10,"min":1,"name":"iterations","step":1,"type":"float","widget":"spinbox"},{"default":0.5,"label":"Persistance","max":1,"min":0,"name":"persistence","step":0.05,"type":"float","widget":"spinbox"}]}