skia2/tests/sksl/intrinsics/Inverse.metal

#include <metal_stdlib>
#include <simd/simd.h>
using namespace metal;
struct Inputs {
};
struct Outputs {
    float4 sk_FragColor [[color(0)]];
};
struct Globals {
    float4x4 a;
};

float4x4 float4x4_inverse(float4x4 m) {
    float a00 = m[0][0], a01 = m[0][1], a02 = m[0][2], a03 = m[0][3];
    float a10 = m[1][0], a11 = m[1][1], a12 = m[1][2], a13 = m[1][3];
    float a20 = m[2][0], a21 = m[2][1], a22 = m[2][2], a23 = m[2][3];
    float a30 = m[3][0], a31 = m[3][1], a32 = m[3][2], a33 = m[3][3];
    float b00 = a00*a11 - a01*a10;
    float b01 = a00*a12 - a02*a10;
    float b02 = a00*a13 - a03*a10;
    float b03 = a01*a12 - a02*a11;
    float b04 = a01*a13 - a03*a11;
    float b05 = a02*a13 - a03*a12;
    float b06 = a20*a31 - a21*a30;
    float b07 = a20*a32 - a22*a30;
    float b08 = a20*a33 - a23*a30;
    float b09 = a21*a32 - a22*a31;
    float b10 = a21*a33 - a23*a31;
    float b11 = a22*a33 - a23*a32;
    float det = b00*b11 - b01*b10 + b02*b09 + b03*b08 - b04*b07 + b05*b06;
    return float4x4(a11*b11 - a12*b10 + a13*b09,
                    a02*b10 - a01*b11 - a03*b09,
                    a31*b05 - a32*b04 + a33*b03,
                    a22*b04 - a21*b05 - a23*b03,
                    a12*b08 - a10*b11 - a13*b07,
                    a00*b11 - a02*b08 + a03*b07,
                    a32*b02 - a30*b05 - a33*b01,
                    a20*b05 - a22*b02 + a23*b01,
                    a10*b10 - a11*b08 + a13*b06,
                    a01*b08 - a00*b10 - a03*b06,
                    a30*b04 - a31*b02 + a33*b00,
                    a21*b02 - a20*b04 - a23*b00,
                    a11*b07 - a10*b09 - a12*b06,
                    a00*b09 - a01*b07 + a02*b06,
                    a31*b01 - a30*b03 - a32*b00,
                    a20*b03 - a21*b01 + a22*b00) * (1/det);
}

fragment Outputs fragmentMain(Inputs _in [[stage_in]], bool _frontFacing [[front_facing]], float4 _fragCoord [[position]]) {
    Globals _globals{{}};
    (void)_globals;
    Outputs _out;
    (void)_out;
    _out.sk_FragColor = float4x4_inverse(_globals.a)[0];
    return _out;
}