shaders-msl/comp/local-invocation-index.comp

#version 450
layout(set = 0, binding = 0) buffer myBlock {
    int a;
    float b[1];
} myStorage;
void main() {
    myStorage.a = (myStorage.a + 1) % 256;
    myStorage.b[gl_LocalInvocationIndex.x] = mod((myStorage.b[gl_LocalInvocationIndex.x] + 0.02), 1.0);
}