How to specify LOD bias in Metal?

Question

I'm rewriting an OpenGL filter from the Android version of the app I'm currently working at in Metal. It uses the following texture lookup function: vec4 texture2D(sampler2D sampler, vec2 coord, float bias)

Assuming my filter kernel function looks like this:

float4 fname(sampler src) {
    ...
}

The texture lookup call would be the following:

src.sample(coord)

But how can I pass the bias parameter? (the sample function takes only 1 argument)

Answer 1

恐怕Core Image仅支持2D纹理-没有mipmapping和LOD选择。仅双线性采样可用。

如果需要不同的LOD，则需要将不同的采样器传递给内核，然后自己进行插值。