所以我一直在研究Perlin和Simplex噪声是如何工作的,虽然我得到了常规Perlin噪声的核心原理,但我对于置换和渐变表的工作原理有点困惑。Perlin和Simplex Noise的排列和渐变表如何在实践中工作?
从我的理解来看,它们提供比种子随机数生成器更好的性能,因为它们是预先计算的值的表格,它们为快速访问提供了很好的索引。
我不完全知道的是他们是如何工作的。我见过的洗牌值的阵列,像这样实现从0-255置换表:
permutation[] = { 151,160,137,91,90,15,
131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
};
但我不确定这个是什么的practial目的。我想知道的是:
- 如何使用与网格点相关的置换表?
- 如何生成渐变表?
- 如何使用梯度表的排列表中的值?置换值是否与梯度表中的索引相对应?