From 562aa0dd917b3773f41d6e41aba8840ace8e6991 Mon Sep 17 00:00:00 2001
From: oreyg <chouthe25@gmail.com>
Date: Fri, 15 May 2026 05:20:52 +0200
Subject: [PATCH] [Vulkan] Only declare the clip-distance or cull-distance
 array that is written

---
 src/xenia/gpu/spirv_shader_translator.cc      | 23 +++++++++++++------
 src/xenia/gpu/vulkan/vulkan_pipeline_cache.cc | 15 ++++++++----
 src/xenia/gpu/vulkan/vulkan_pipeline_cache.h  |  1 +
 3 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/src/xenia/gpu/spirv_shader_translator.cc b/src/xenia/gpu/spirv_shader_translator.cc
index e4e7e36e2..0999febdd 100644
--- a/src/xenia/gpu/spirv_shader_translator.cc
+++ b/src/xenia/gpu/spirv_shader_translator.cc
@@ -1328,9 +1328,15 @@ void SpirvShaderTranslator::StartVertexOrTessEvalShaderBeforeMain() {
   // actually enabled (count > 0).
   uint32_t user_clip_plane_count =
       shader_modification.vertex.user_clip_plane_count;
+  uint32_t clip_distance_count = 0;
+  uint32_t cull_distance_count = 0;
+  if (shader_modification.vertex.user_clip_plane_cull) {
+    cull_distance_count = user_clip_plane_count;
+  } else {
+    clip_distance_count = user_clip_plane_count;
+  }
   output_per_vertex_clip_distance_member_index_ = 0;
   output_per_vertex_cull_distance_member_index_ = 0;
-  constexpr uint32_t kMaxUserClipPlanes = 6;
   if (user_clip_plane_count > 0) {
     // Create separate uniform buffer for clip planes.
     spv::Id type_float4_array_6 = builder_->makeArrayType(
@@ -1356,16 +1362,18 @@ void SpirvShaderTranslator::StartVertexOrTessEvalShaderBeforeMain() {
     if (features_.spirv_version >= spv::Spv_1_4) {
       main_interface_.push_back(uniform_clip_plane_constants_);
     }
-
+  }
+  if (clip_distance_count > 0) {
     output_per_vertex_clip_distance_member_index_ =
         static_cast<unsigned int>(struct_per_vertex_members.size());
     struct_per_vertex_members.push_back(builder_->makeArrayType(
-        type_float_, builder_->makeUintConstant(user_clip_plane_count), 0));
-
+        type_float_, builder_->makeUintConstant(clip_distance_count), 0));
+  }
+  if (cull_distance_count > 0) {
     output_per_vertex_cull_distance_member_index_ =
         static_cast<unsigned int>(struct_per_vertex_members.size());
     struct_per_vertex_members.push_back(builder_->makeArrayType(
-        type_float_, builder_->makeUintConstant(user_clip_plane_count), 0));
+        type_float_, builder_->makeUintConstant(cull_distance_count), 0));
   }
 
   spv::Id type_struct_per_vertex =
@@ -1377,14 +1385,15 @@ void SpirvShaderTranslator::StartVertexOrTessEvalShaderBeforeMain() {
       spv::DecorationBuiltIn, static_cast<int>(spv::BuiltIn::Position));
 
   // Decorate clip/cull arrays only if allocated.
-  if (user_clip_plane_count > 0) {
+  if (clip_distance_count > 0) {
     builder_->addMemberName(type_struct_per_vertex,
                             output_per_vertex_clip_distance_member_index_,
                             "gl_ClipDistance");
     builder_->addMemberDecoration(
         type_struct_per_vertex, output_per_vertex_clip_distance_member_index_,
         spv::DecorationBuiltIn, static_cast<int>(spv::BuiltIn::ClipDistance));
-
+  }
+  if (cull_distance_count > 0) {
     builder_->addMemberName(type_struct_per_vertex,
                             output_per_vertex_cull_distance_member_index_,
                             "gl_CullDistance");
diff --git a/src/xenia/gpu/vulkan/vulkan_pipeline_cache.cc b/src/xenia/gpu/vulkan/vulkan_pipeline_cache.cc
index 784d369ad..100729680 100644
--- a/src/xenia/gpu/vulkan/vulkan_pipeline_cache.cc
+++ b/src/xenia/gpu/vulkan/vulkan_pipeline_cache.cc
@@ -1407,6 +1407,8 @@ bool VulkanPipelineCache::GetGeometryShaderKey(
   // Single bit to indicate if clip planes are enabled.
   key.has_user_clip_planes =
       uint32_t(vertex_shader_modification.vertex.user_clip_plane_count > 0);
+  key.user_clip_plane_cull =
+      vertex_shader_modification.vertex.user_clip_plane_cull;
   key_out = key;
   return true;
 }
@@ -1453,11 +1455,16 @@ VkShaderModule VulkanPipelineCache::GetGeometryShader(GeometryShaderKey key) {
 
   // When enabled, use max size to reduce variants from different counts.
   constexpr uint32_t kMaxUserClipPlanes = 6;
-  uint32_t clip_distance_count =
+  uint32_t user_clip_plane_count =
       key.has_user_clip_planes ? kMaxUserClipPlanes : 0;
-  uint32_t cull_distance_count =
-      (key.has_user_clip_planes ? kMaxUserClipPlanes : 0) +
-      key.has_vertex_kill_and;
+  uint32_t clip_distance_count = 0;
+  uint32_t cull_distance_count = 0;
+  if (key.user_clip_plane_cull) {
+    cull_distance_count = user_clip_plane_count;
+  } else {
+    clip_distance_count = user_clip_plane_count;
+  }
+  cull_distance_count += key.has_vertex_kill_and;
 
   SpirvBuilder builder(spv::Spv_1_0,
                        (SpirvShaderTranslator::kSpirvMagicToolId << 16) | 1,
diff --git a/src/xenia/gpu/vulkan/vulkan_pipeline_cache.h b/src/xenia/gpu/vulkan/vulkan_pipeline_cache.h
index fdab3c061..1e33c5a5e 100644
--- a/src/xenia/gpu/vulkan/vulkan_pipeline_cache.h
+++ b/src/xenia/gpu/vulkan/vulkan_pipeline_cache.h
@@ -312,6 +312,7 @@ class VulkanPipelineCache {
       PipelineGeometryShader type : 2;
       uint32_t interpolator_count : 5;
       uint32_t has_user_clip_planes : 1;
+      uint32_t user_clip_plane_cull : 1;
       uint32_t has_vertex_kill_and : 1;
       uint32_t has_point_size : 1;
       uint32_t has_point_coordinates : 1;