use*_*776 11 graphics fractals noise terrain perlin-noise
我正在研究用于地形生成的各种类型的噪声,当有噪声变成perlin噪声并且perlin噪声变为fbm时,我有点困惑.我希望有人可以在任何地方澄清我出错了.我目前假设以下内容
噪声:包含幅度和频率,它决定了最终值以及某种形式的插值,如线性,余弦或立方.
Perlin Noise:八度噪声函数的总和(每个连续函数包含两倍的频率).从我到目前为止所读到的,幅度似乎总是表现为一致的减少.例如,Noise1包含A为1,Noise2包含A为0.5,Noise3包含A为0.25,这意味着每次振幅减半.它必须始终像这样一致吗？
FBM:多个perlin噪声函数的总和,其中每个Perlin噪声函数必须只包含幅度减小的八度音程.
小智 25
Perlin Noise is actually a method to calculate what you call Noise. It is a form of coherent noise computed as the interpolated normalized gradients of a pseudo-random underlying function (or pseudo-randomly generated gradients). The frequency controls the "sampling" distance of the gradients, so the higher the frequency, the smaller the sampling distance, and more gradients per unit of space. Amplitude controls the max and min values of the noise function.
Hugo Elias' page on Perlin Noise has a good description of the concept, the algorithm, etc. Perlin Noise FAQ explains the algorithm in a very intuitive manner.
Noise is a general term. Perlin Noise is only a type of coherent noise. But there is many different types with different characteristics.
Fractal Brownian Motion is, in fact, what you call Perlin Noise. It is a combination of multiple steps of Perlin Noise (or another similar noise function), each with a different frequency and amplitude. In the context of procedural generation, the variation in frequency from a step to the next is called lacunarity. The variation in amplitude from a step to the next is called gain.
Look at this. This project on terrain generation gives a very good description of what fBM is and how it is computed.
I hope this helps!