[Fix] (DirectVulkan): suppress blended depth writes on Qualcomm and mark gl_Position invariant to fix MC 26.3 OIT cloud flicker

This commit is contained in:
2026-07-19 05:47:23 -04:00
parent fc0688c223
commit f3def150e7
6 changed files with 145 additions and 0 deletions
@@ -21,6 +21,7 @@
#include "ShaderSourceProcessor.h"
#include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
#include <MG_Util/Converters/GLToGlslang/ProgramEnumConverter.h>
#include <cstdlib>
namespace MobileGL {
namespace MG_Util {
@@ -322,6 +323,75 @@ namespace MobileGL {
return optimizer.Run(inputBinary.data(), inputBinary.size(), &outputBinary, options);
}
bool ShaderCompiler::DecoratePositionInvariantForVulkan(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary) {
static constexpr Uint32 kHeaderWords = 5;
static constexpr Uint32 kOpDecorate = 71;
static constexpr Uint32 kOpMemberDecorate = 72;
static constexpr Uint32 kDecorationInvariant = 18;
static constexpr Uint32 kDecorationBuiltIn = 11;
static constexpr Uint32 kBuiltInPosition = 0;
if (inputBinary.size() < kHeaderWords) {
return false;
}
// First pass: find targets that already carry Invariant so we never duplicate.
struct MemberKey {
Uint32 id;
Uint32 member;
bool operator==(const MemberKey& o) const { return id == o.id && member == o.member; }
};
Vector<Uint32> invariantIds;
Vector<MemberKey> invariantMembers;
for (SizeT i = kHeaderWords; i < inputBinary.size();) {
const Uint32 word0 = inputBinary[i];
const Uint32 opcode = word0 & 0xFFFFu;
const Uint32 length = word0 >> 16;
if (length == 0 || i + length > inputBinary.size()) {
return false;
}
if (opcode == kOpDecorate && length >= 3 && inputBinary[i + 2] == kDecorationInvariant) {
invariantIds.push_back(inputBinary[i + 1]);
} else if (opcode == kOpMemberDecorate && length >= 4 &&
inputBinary[i + 3] == kDecorationInvariant) {
invariantMembers.push_back({inputBinary[i + 1], inputBinary[i + 2]});
}
i += length;
}
outputBinary.clear();
outputBinary.reserve(inputBinary.size() + 8);
outputBinary.insert(outputBinary.end(), inputBinary.begin(), inputBinary.begin() + kHeaderWords);
for (SizeT i = kHeaderWords; i < inputBinary.size();) {
const Uint32 word0 = inputBinary[i];
const Uint32 opcode = word0 & 0xFFFFu;
const Uint32 length = word0 >> 16;
outputBinary.insert(outputBinary.end(), inputBinary.begin() + i,
inputBinary.begin() + i + length);
if (opcode == kOpDecorate && length == 4 &&
inputBinary[i + 2] == kDecorationBuiltIn && inputBinary[i + 3] == kBuiltInPosition) {
const Uint32 target = inputBinary[i + 1];
if (std::find(invariantIds.begin(), invariantIds.end(), target) == invariantIds.end()) {
outputBinary.push_back((3u << 16) | kOpDecorate);
outputBinary.push_back(target);
outputBinary.push_back(kDecorationInvariant);
}
} else if (opcode == kOpMemberDecorate && length == 5 &&
inputBinary[i + 3] == kDecorationBuiltIn && inputBinary[i + 4] == kBuiltInPosition) {
const MemberKey key{inputBinary[i + 1], inputBinary[i + 2]};
if (std::find(invariantMembers.begin(), invariantMembers.end(), key) ==
invariantMembers.end()) {
outputBinary.push_back((4u << 16) | kOpMemberDecorate);
outputBinary.push_back(key.id);
outputBinary.push_back(key.member);
outputBinary.push_back(kDecorationInvariant);
}
}
i += length;
}
return true;
}
Result<String> ShaderCompiler::DecompileShader(SpvcSession& session) {
spvc_compiler_options options;
session.CreateOptions(&options);
@@ -39,6 +39,13 @@ namespace MobileGL {
// which wrongly includes baseInstance).
static bool RebaseInstanceIndexForVulkan(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary);
// Adds the Invariant decoration to every Position builtin output. GL apps
// routinely rely on cross-program position invariance for multi-pass
// equality depth tests (e.g. GEQUAL re-draws of the same geometry), and
// mobile drivers that optimize per-pipeline break that without the
// decoration. DirectVulkan only.
static bool DecoratePositionInvariantForVulkan(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary);
static Result<String> DecompileShader(SpvcSession& session);
};
} // namespace ShaderTranspiler