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Implementing 3D GLSL Noise on ATI Graphics Cards

I tried so many different strategies to get a useful noise function, and none of them work. So how do you apply perlin noise on an ATI graphics card in GLSL?

Here are the methods I tried: I tried to put the permutation and gradient data in the GL_RGBA 1D texture and call the texture1D function. However, one call to this noise implementation results in 12 texture calls and kills the frame rate.

I tried loading the permutation and gradient data into a single vec4 array, but the compiler will not let me get the element in the array if the index is not constant. For instance:

int i = 10; vec4 a = noise_data[i];

will give a compiler error:

ERROR: 0:43: Not supported when using the indirect index of a temporary array.

Value I can only get the data as follows:

 vec4 a = noise_data[10];

I also tried to program the array directly into the shader, but I have the same problem with the index. I heard that NVIDIA graphics cards will indeed enable this method, but ATI will not.

I tried to make a function that returned a certain hard-coded data point depending on the input index, but a function called 12 times and having 64 if statements made the binding time unbearable.

ATI does not support “built-in” noise functions for glsl, and I cannot just pre-comprehend the noise and import it as a texture, because I am dealing with fractals. This means that I need infinite precision in calculating noise at runtime.

So the main question ...

How?

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5 answers

noise () is known for not being executed ...

order yourself:

 int c; int Xn; srand(int x, int y, int width){// in pixel c = x+y*width; }; int rand(){ Xn = (a*Xn+c)%m; return Xn; }

for a and m values, see wikipedia

This is not ideal, but often good enough.

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For a better distribution of random values, I suggest these very good articles:

Enjoy!

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There is a github project with GLSL noise features. It has both "classic" and newer noise functions in 2,3 and 4D.

IOS has a noise function.

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This SimpleX noise material can do what you want.

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Try adding #version 150 to the top of your shader.

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