From 4dbb9b34c6b4d38779e55d36a79d252cc4e2fc2a Mon Sep 17 00:00:00 2001
From: Jeroen Bakker <jeroen@blender.org>
Date: Thu, 30 Jan 2025 15:51:09 +0100
Subject: [PATCH] Fix: Vulkan: Compositor cryptomatte

When using cryptomatte the last identifier was never used due to a
memory alignment issue. Scalar types should not be aligned, but they
were.

Pull Request: https://projects.blender.org/blender/blender/pulls/133815
---
 .../gpu/vulkan/tests/vk_memory_layout_test.cc | 12 ++++++++++
 source/blender/gpu/vulkan/vk_memory_layout.cc | 22 ++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/source/blender/gpu/vulkan/tests/vk_memory_layout_test.cc b/source/blender/gpu/vulkan/tests/vk_memory_layout_test.cc
index dda8787818a..ec9efef5957 100644
--- a/source/blender/gpu/vulkan/tests/vk_memory_layout_test.cc
+++ b/source/blender/gpu/vulkan/tests/vk_memory_layout_test.cc
@@ -134,4 +134,16 @@ TEST(std430, simple_lighting)
   EXPECT_EQ(offset, 112);
 }
 
+TEST(std430, compositor_cryptomatte_matte_compute)
+{
+  uint32_t offset = 0;
+
+  def_attr<Std430>(shader::Type::VEC2, 0, 0, 8, &offset);
+  def_attr<Std430>(shader::Type::FLOAT, 0, 8, 12, &offset);
+  def_attr<Std430>(shader::Type::FLOAT, 32, 12, 140, &offset);
+
+  align_end_of_struct<Std430>(&offset);
+  EXPECT_EQ(offset, 144);
+}
+
 }  // namespace blender::gpu
diff --git a/source/blender/gpu/vulkan/vk_memory_layout.cc b/source/blender/gpu/vulkan/vk_memory_layout.cc
index 8d526c16eb9..6f596a59656 100644
--- a/source/blender/gpu/vulkan/vk_memory_layout.cc
+++ b/source/blender/gpu/vulkan/vk_memory_layout.cc
@@ -22,7 +22,27 @@ uint32_t Std430::component_mem_size(const shader::Type /*type*/)
 uint32_t Std430::element_alignment(const shader::Type type, const bool is_array)
 {
   if (is_array) {
-    return 16;
+    switch (type) {
+      case shader::Type::FLOAT:
+      case shader::Type::UINT:
+      case shader::Type::INT:
+      case shader::Type::BOOL:
+        return 4;
+      case shader::Type::VEC2:
+      case shader::Type::UVEC2:
+      case shader::Type::IVEC2:
+      case shader::Type::VEC3:
+      case shader::Type::UVEC3:
+      case shader::Type::IVEC3:
+      case shader::Type::VEC4:
+      case shader::Type::UVEC4:
+      case shader::Type::IVEC4:
+      case shader::Type::MAT3:
+      case shader::Type::MAT4:
+        return 16;
+      default:
+        BLI_assert_msg(false, "Type not supported in dynamic structs.");
+    }
   }
   switch (type) {
     case shader::Type::FLOAT: