tests/sksl/compute/DesaturateReadWrite.metal

#include <metal_stdlib>
#include <simd/simd.h>
using namespace metal;
struct Inputs {
    uint3 sk_ThreadPosition;
};
struct Outputs {
};
struct Globals {
    texture2d<half, access::read_write> tex;
};
kernel void computeMain(texture2d<half, access::read_write> tex[[texture(0)]], uint3 sk_ThreadPosition [[thread_position_in_grid]]) {
    Globals _globals{tex};
    (void)_globals;
    Inputs _in = { sk_ThreadPosition };
    Outputs _out = {  };
    if (_in.sk_ThreadPosition.x < _globals.tex.get_width() && _in.sk_ThreadPosition.y < _globals.tex.get_height()) {
        half4 _0_color = _globals.tex.read(_in.sk_ThreadPosition.xy);
        _0_color.xyz = half3(dot(_0_color.xyz, half3(0.2199999988079071h, 0.67000001668930054h, 0.10999999940395355h)));
        _globals.tex.write(_0_color, _in.sk_ThreadPosition.xy);
    }
    return;
}