shaders-msl/comp/complex-composite-constant-array.comp

#version 450

layout(std430, set = 0, binding = 0) buffer SSBO
{
	mat4 a;
	uint index;
};

const mat4 as[] = mat4[](mat4(1.0), mat4(2.0));

void write_global()
{
	a = as[index];
}

void main()
{
	write_global();
}