From e25d561b7cd0626da87f7166c0093c1ec0056bd0 Mon Sep 17 00:00:00 2001
From: Yunus Shaikh <75296019+EagleBearerYS@users.noreply.github.com>
Date: Tue, 13 Oct 2026 00:57:30 -0700
Subject: [PATCH] fix(shader): take a hull's input stride from its patch term
 when it reads one control point

derive() learned the LS-to-HS stride from the control-point term of hull LDS reads, or from the patch term of reads at a computed control-point index. A hull with one input control point reads it at constant offsets, so neither applies and the stride stays unknown ('the hull shader reads no LDS per control point, so the local stride is unknown'). Every hull read already has a patch term of exactly inputControlPoints * localStride, so take the stride from it for reads without a control-point term too. Resident Evil Village's quad patches have one input control point.
---
 .../tests/execution/Tessellation.cpp          | 28 +++++++++++++++++++
 .../Optimization/src/TessellationLowering.cpp |  2 +-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/core/libs/prx/libSceAgcDriver/tests/execution/Tessellation.cpp b/core/libs/prx/libSceAgcDriver/tests/execution/Tessellation.cpp
index b3cf120de6..6edeb88bb1 100644
--- a/core/libs/prx/libSceAgcDriver/tests/execution/Tessellation.cpp
+++ b/core/libs/prx/libSceAgcDriver/tests/execution/Tessellation.cpp
@@ -63,6 +63,16 @@ alignas(256) constexpr std::array<std::uint32_t, 54> HullCompareBranch{
     0x16161690, 0x4c1616ff, 0x00008000, 0xe0741000, 0x0202070b, 0xbf810000,
 };
 
+alignas(256) constexpr std::array<std::uint32_t, 49> HullSingleInput{
+    0xd7650000, 0x000100c1, 0xd7660000, 0x000200c1, 0xbf8a0000, 0x7da206f9, 0x81060000, 0xd5480014,
+    0x02151101, 0x362402ff, 0x000000ff, 0x160028a0, 0xd5430015, 0x022224ff, 0x00000020, 0xdbfc0000,
+    0x02000015, 0x162c2890, 0xd5430016, 0x045a24ff, 0x00000030, 0xbf8cc07f, 0xe0781000, 0x02020216,
+    0x7da82881, 0xbe94047e, 0xb06a0020, 0x162602f9, 0x0086066a, 0xd8d80008, 0x06000013, 0xd8dc0201,
+    0x07000013, 0xbf8cc07f, 0x7e300306, 0x7e320306, 0x7e340306, 0x7e360306, 0x34142484, 0xbefe0414,
+    0xe0781000, 0x0403180a, 0x4a162481, 0x16161690, 0x4c1616ff, 0x00008000, 0xe0741000, 0x0202070b,
+    0xbf810000,
+};
+
 alignas(256) constexpr std::array<std::uint32_t, 51> HullRestoredExecSaved{
     0xd7650000, 0x000100c1, 0xd7660000, 0x000200c1, 0xbf8a0000, 0x7da206f9, 0x81060000, 0xd5480014,
     0x02151101, 0x362402ff, 0x000000ff, 0x160028a0, 0xd5430015, 0x040224ff, 0x00000060, 0xdbfc0000,
@@ -717,6 +727,23 @@ void RequireRegisteredStages() {
     AgcDriverShutdown_nid_postfix();
 }
 
+ShaderRecompiler::RecompileResult CompileHull(const ShaderRecompiler::SpirvTarget& target, std::span<const std::uint32_t> code, const ShaderRecompiler::TessellationConfiguration& configuration) {
+    static const std::array<std::uint32_t, 16> userData{0x1000u};
+    const std::array<ShaderRecompiler::MemoryRegion, 1> memory{{{reinterpret_cast<std::uintptr_t>(code.data()), std::as_bytes(code)}}};
+    const ShaderRecompiler::RecompileRequest request{
+        {ShaderStage::TessellationControl, reinterpret_cast<std::uintptr_t>(code.data()), code, 0, {}},
+        {64, 0u, userData, std::nullopt, std::nullopt, ShaderRecompiler::ShaderVertexStageInfo{}, memory},
+        target,
+        ShaderRecompiler::BindingLayout{0, 0, 0, AgcDriver::Graphics::PipelinePushSlotBytes},
+        ShaderRecompiler::GraphicsCompileContext{0u, {}, std::nullopt, configuration, {reinterpret_cast<std::uintptr_t>(Indices.data()), static_cast<std::uint32_t>(Indices.size()), 2, 1}},
+    };
+    return ShaderRecompiler::Recompile(request);
+}
+
+void RequireSingleControlPointHulls(const ShaderRecompiler::SpirvTarget& target) {
+    Require(!CompileHull(target, HullSingleInput, {1u, 3u, 1u, 2u, 2u}).spirv.empty(), "a hull that reads only the one input control point of its patch was not compiled");
+}
+
 }
 
 int main() {
@@ -728,6 +755,7 @@ int main() {
             std::puts("tessellation: skipped, the device has no tessellation shaders");
             return VulkanTestSkipped;
         }
+        RequireSingleControlPointHulls(target);
         ExpectRefusal(target, ShaderStage::TessellationControl, HullUnguardedFactors, "not written by control point 0 alone");
         ExpectRefusal(target, ShaderStage::TessellationControl, HullSquaredAddress, "not a whole number of control points");
         ExpectRefusal(target, ShaderStage::TessellationControl, HullHalfSlotIndex, "not a whole number of control points");
diff --git a/core/shader/recompiler/Optimization/src/TessellationLowering.cpp b/core/shader/recompiler/Optimization/src/TessellationLowering.cpp
index 8d9e91c426..3834b28369 100644
--- a/core/shader/recompiler/Optimization/src/TessellationLowering.cpp
+++ b/core/shader/recompiler/Optimization/src/TessellationLowering.cpp
@@ -659,7 +659,7 @@ private:
         for (auto& access : accesses) {
             if (access.kind == TessellationAttribute::LocalOutput) agree(localStride, access.address.relative, access.pc);
             if (access.kind == TessellationAttribute::ControlInput && access.address.vertex != 0) agree(localStride, access.address.vertex, access.pc);
-            if (access.kind == TessellationAttribute::ControlInput && access.address.dynamic && access.address.relative > 0 && access.address.relative % inputs == 0) agree(localStride, access.address.relative / inputs, access.pc);
+            if (access.kind == TessellationAttribute::ControlInput && (access.address.dynamic || access.address.vertex == 0) && access.address.relative > 0 && access.address.relative % inputs == 0) agree(localStride, access.address.relative / inputs, access.pc);
             if (access.kind == TessellationAttribute::ControlOutput && access.address.vertex != 0) agree(controlStride, access.address.vertex, access.pc);
             if (access.kind == TessellationAttribute::EvaluationInput) {
                 const auto end = access.address.constant + 4 * static_cast<std::int64_t>(access.components);