skia2/tests/sksl/intrinsics/DFdx.metal
John Stiles 9078a89b26 Avoid mix-up between MAIN_COORDS and FRAGCOORD.
When compiling test shaders, we were setting SK_FRAGCOORD_BUILTIN on the
`coords` parameter to main() instead of SK_MAIN_COORDS_BUILTIN. These
two built-ins don't have the same type (float2 vs. float4) and don't
mean quite the same thing.

The SPIR-V code generator saw a variable with the SK_FRAGCOORD_BUILTIN
builtin value and assumed the presence of a global variable named
`sk_FragCoord`, which didn't exist (because it was never referenced in
the code, so it was never cloned in from the sksl_frag module).

This is only a concern when compiling test shaders with skslc; real
shaders don't hit these code paths. The generated code here is still
imperfect; if you look closely, you'll see the GLSL and Metal code is
referencing the `coords` variable but it's never declared anywhere.

Change-Id: I3ad249469927ff35eb1e75d6536f95317502708f
Bug: skia:12340
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/440520
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2021-08-18 20:11:19 +00:00

21 lines
916 B
Metal

#include <metal_stdlib>
#include <simd/simd.h>
using namespace metal;
struct Uniforms {
float4 testInputs;
float4 colorGreen;
float4 colorRed;
};
struct Inputs {
};
struct Outputs {
float4 sk_FragColor [[color(0)]];
};
fragment Outputs fragmentMain(Inputs _in [[stage_in]], constant Uniforms& _uniforms [[buffer(0)]], bool _frontFacing [[front_facing]], float4 _fragCoord [[position]]) {
Outputs _out;
(void)_out;
float4 expected = float4(0.0);
_out.sk_FragColor = (((((dfdx(_uniforms.testInputs.x) == expected.x && all(dfdx(_uniforms.testInputs.xy) == expected.xy)) && all(dfdx(_uniforms.testInputs.xyz) == expected.xyz)) && all(dfdx(_uniforms.testInputs) == expected)) && all(sign(dfdx(coords.xx)) == float2(1.0, 1.0))) && all(sign(dfdx(coords.yy)) == float2(0.0, 0.0))) && all(sign(dfdx(coords)) == float2(1.0, 0.0)) ? _uniforms.colorGreen : _uniforms.colorRed;
return _out;
}