aa5a8c482e
Some Metal devices have a bug where storage resources can still be written to even if the fragment is discarded. This is obviously a bug in Metal, but bothering Apple to fix it will only fix it for newer versions; therefore, a workaround is needed for older versions. I have made this an option so that, in case the bug is ever fixed, the workaround can be disabled. This workaround is simple: if a fragment shader may discard its fragment and writes to a storage resource, a variable representing the `HelperInvocation` built-in is created and passed to all functions. The flag is checked on all resource writes; writes do not occur when `HelperInvocation` is `true`. This relies on the earlier workaround to update `HelperInvocation` when the fragment is discarded. Fixes at least 3 failures in the CTS.
66 lines
3.5 KiB
GLSL
66 lines
3.5 KiB
GLSL
#pragma clang diagnostic ignored "-Wmissing-prototypes"
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#pragma clang diagnostic ignored "-Wunused-variable"
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#include <metal_stdlib>
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#include <simd/simd.h>
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#include <metal_atomic>
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using namespace metal;
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// The required alignment of a linear texture of R32Uint format.
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constant uint spvLinearTextureAlignmentOverride [[function_constant(65535)]];
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constant uint spvLinearTextureAlignment = is_function_constant_defined(spvLinearTextureAlignmentOverride) ? spvLinearTextureAlignmentOverride : 4;
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// Returns buffer coords corresponding to 2D texture coords for emulating 2D texture atomics
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#define spvImage2DAtomicCoord(tc, tex) (((((tex).get_width() + spvLinearTextureAlignment / 4 - 1) & ~( spvLinearTextureAlignment / 4 - 1)) * (tc).y) + (tc).x)
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struct foo_t
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{
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float x;
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uint y;
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};
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struct main0_out
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{
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float4 fragColor [[color(0)]];
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};
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fragment main0_out main0(device foo_t& foo [[buffer(0)]], texture2d<uint, access::write> bar [[texture(0)]], device atomic_uint* bar_atomic [[buffer(1)]], float4 gl_FragCoord [[position]])
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{
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main0_out out = {};
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bool gl_HelperInvocation = {};
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gl_HelperInvocation = simd_is_helper_thread();
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if (!gl_HelperInvocation)
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{
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foo.x = 1.0;
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}
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uint _91 = (!gl_HelperInvocation ? atomic_exchange_explicit((device atomic_uint*)&foo.y, 0u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&foo.y, memory_order_relaxed));
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if (int(gl_FragCoord.x) == 3)
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{
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gl_HelperInvocation = true, discard_fragment();
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}
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int2 _101 = int2(gl_FragCoord.xy);
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(gl_HelperInvocation ? ((void)0) : bar.write(uint4(1u), uint2(_101)));
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uint _103 = (!gl_HelperInvocation ? atomic_fetch_add_explicit((device atomic_uint*)&foo.y, 42u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&foo.y, memory_order_relaxed));
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uint _108 = (!gl_HelperInvocation ? atomic_fetch_or_explicit((device atomic_uint*)&bar_atomic[spvImage2DAtomicCoord(_101, bar)], 62u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&bar_atomic[spvImage2DAtomicCoord(_101, bar)], memory_order_relaxed));
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uint _110 = (!gl_HelperInvocation ? atomic_fetch_and_explicit((device atomic_uint*)&foo.y, 65535u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&foo.y, memory_order_relaxed));
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uint _112 = (!gl_HelperInvocation ? atomic_fetch_xor_explicit((device atomic_uint*)&foo.y, 4294967040u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&foo.y, memory_order_relaxed));
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uint _114 = (!gl_HelperInvocation ? atomic_fetch_min_explicit((device atomic_uint*)&foo.y, 1u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&foo.y, memory_order_relaxed));
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uint _119 = (!gl_HelperInvocation ? atomic_fetch_max_explicit((device atomic_uint*)&bar_atomic[spvImage2DAtomicCoord(_101, bar)], 100u, memory_order_relaxed) : atomic_load_explicit((device atomic_uint*)&bar_atomic[spvImage2DAtomicCoord(_101, bar)], memory_order_relaxed));
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uint _124;
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if (!gl_HelperInvocation)
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{
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do
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{
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_124 = 100u;
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} while (!atomic_compare_exchange_weak_explicit((device atomic_uint*)&bar_atomic[spvImage2DAtomicCoord(_101, bar)], &_124, 42u, memory_order_relaxed, memory_order_relaxed) && _124 == 100u);
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}
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else
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{
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_124 = atomic_load_explicit((device atomic_uint*)&bar_atomic[spvImage2DAtomicCoord(_101, bar)], memory_order_relaxed);
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}
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bool _125 = gl_HelperInvocation;
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out.fragColor = float4(1.0, float(_125), 0.0, 1.0);
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return out;
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}
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