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{ RCSid $Id$ } |
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{ 2-D Perlin Noise function } |
| 3 |
|
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frac(x):x-floor(x); |
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|
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hermite(p0,p1,r0,r1,t) : p0 * ((2*t-3)*t*t+1) + |
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p1 * (-2*t+3)*t*t + |
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r0 * (((t-2)*t+1)*t) + |
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r1 * ((t-1)*t*t); |
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|
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rand2a(x,y) : 1-2*rand(.69692*x+.35084*y); |
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rand2b(x,y) : 1-2*rand(.05393*x+.96196*y); |
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rand2c(x,y) : 1-2*rand(.04234*x+.46180*y); |
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|
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noise_2(xl,xd,xu,yl,yd,yu) : |
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hermite( |
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hermite(rand2c(xl,yl), |
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rand2c(xu,yl), |
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rand2a(xl,yl), |
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rand2a(xu,yl), |
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xd), |
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hermite(rand2c(xl,yu), |
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rand2c(xu,yu), |
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rand2a(xl,yu), |
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rand2a(xu,yu), |
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xd), |
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(1-xd)*rand2b(xl,yl)+ |
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xd*rand2b(xu,yl), |
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(1-xd)*rand2b(xl,yu)+ |
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xd*rand2b(xu,yu), |
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yd); |
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|
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noise2(x,y) : noise_2( floor(x),frac(x),ceil(x), |
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floor(y),frac(y),ceil(y) ); |
