WebGL着色器中无法使用可变数组索引? [英] Variable array index not possible in webgl shaders?

问题描述

正如标题所述，我不能在webgl顶点着色器中执行vector_array[foo](假设foo在范围内并且是整数)，对吗?

As the title says, I can't do vector_array[foo] (assuming foo is in-range and integer) in webgl vertex shaders, correct?

纹理是最好的选择吗?还是有替代方法或某种更好的方法来模仿查找表?

Are textures the best alternative, or is there a workaround or some better way to mimick a lookup table?

推荐答案

http ://www.khronos.org/registry/webgl/specs/latest/#DYNAMIC_INDEXING_OF_ARRAYS "WebGL只允许使用常量表达式，循环索引或它们的组合进行动态索引.唯一的例外是顶点着色器中的统一访问，可以使用任何表达式对其进行索引."

http://www.khronos.org/registry/webgl/specs/latest/#DYNAMIC_INDEXING_OF_ARRAYS "WebGL only allows dynamic indexing with constant expressions, loop indices or a combination. The only exception is for uniform access in vertex shaders, which can be indexed using any expression."

您尝试过吗?如果不起作用，则有两种选择.

Did you try it? If it didn't work, there are a couple options.

如果值的数量较少，则if-else可以正常工作. AFAIK统一值将以任何方式加载到寄存器中，因此对它们进行十二个数学运算周期不会使着色器变慢.

If you have a small number of values, if-else could work ok. AFAIK the uniform values are going to be loaded into registers anyhow, so doing a dozen cycles of math on them isn't going to make your shader much slower.

对于大量的值来说，纹理是最好的选择.

For a large number of values, textures are your best bet.

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