986c7fb8ca
The Metal return type from main() diverges from the SkSL source, so we
patch it in the Metal code generator. This CL improves the patching
process in multiple ways:
- A `return` statement from a fragment processor main() is rewritten to:
return *_out;
- A `return` statement from a vertex processor main() is rewritten to:
return (_out->sk_Position.y = -_out->sk_Position.y, *_out);
- We avoid emitting a duplicate `return *_out;` statement if we can
determine that main() already ends in a return statement. This is
harmless either way so it doesn't necessarily catch everything. (e.g.
it doesn't detect an if/else which returns at the end of both blocks.)
Also added a unit test which returns from the middle of a vertex shader,
since we didn't test this anywhere and we need to verify that
sk_Position.y will be negated. (This didn't work properly before.)
Change-Id: I14cf18375894fc712fa6c6466df3888ebaeba7c8
Bug: skia:10903
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/339636
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
30 lines
775 B
Metal
30 lines
775 B
Metal
#include <metal_stdlib>
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#include <simd/simd.h>
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using namespace metal;
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struct Inputs {
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};
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struct Outputs {
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float4 sk_FragColor [[color(0)]];
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};
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fragment Outputs fragmentMain(Inputs _in [[stage_in]], bool _frontFacing [[front_facing]], float4 _fragCoord [[position]]) {
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Outputs _outputStruct;
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thread Outputs* _out = &_outputStruct;
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if (sqrt(2.0) > 5.0) {
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_out->sk_FragColor = float4(0.75);
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} else {
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discard_fragment();
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}
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int i = 0;
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while (i < 10) {
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_out->sk_FragColor *= 0.5;
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i++;
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}
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do {
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_out->sk_FragColor += 0.25;
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} while (_out->sk_FragColor.x < 0.75);
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for (int i = 0;i < 10; i++) {
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if (i % 2 == 1) break; else if (i > 100) return *_out; else continue;
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}
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return *_out;
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}
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