From 261557e936a5fe2299c47faa750b78250c8b455c Mon Sep 17 00:00:00 2001
From: Jeroen Bakker <j.bakker@atmind.nl>
Date: Mon, 13 Mar 2023 19:16:51 +0100
Subject: [PATCH 1/2] Vulkan: Add initial VkPixelBuffer.

VK Pixel buffer is used by external render engines to allocate
buffers using the same GPU backend that Blender runs in.

In a later stage we should test what exact binding flags are
needed. I expect that it should be able to use as a transfer
buffer to copy the pixels over to a texture using transfer
commands.
---
 source/blender/gpu/vulkan/vk_buffer.cc       |  6 ++++++
 source/blender/gpu/vulkan/vk_buffer.hh       |  7 +++++++
 source/blender/gpu/vulkan/vk_pixel_buffer.cc | 12 ++++++++++--
 source/blender/gpu/vulkan/vk_pixel_buffer.hh |  4 ++++
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/source/blender/gpu/vulkan/vk_buffer.cc b/source/blender/gpu/vulkan/vk_buffer.cc
index 134190c11d0..dbb91905d0d 100644
--- a/source/blender/gpu/vulkan/vk_buffer.cc
+++ b/source/blender/gpu/vulkan/vk_buffer.cc
@@ -90,6 +90,12 @@ void VKBuffer::read(void *data) const
   memcpy(data, mapped_memory_, size_in_bytes_);
 }
 
+void *VKBuffer::mapped_memory_get() const
+{
+  BLI_assert_msg(is_mapped(), "Cannot read a non-mapped buffer.");
+  return mapped_memory_;
+}
+
 bool VKBuffer::is_mapped() const
 {
   return mapped_memory_ != nullptr;
diff --git a/source/blender/gpu/vulkan/vk_buffer.hh b/source/blender/gpu/vulkan/vk_buffer.hh
index 2cbd7f1205b..917103114a5 100644
--- a/source/blender/gpu/vulkan/vk_buffer.hh
+++ b/source/blender/gpu/vulkan/vk_buffer.hh
@@ -49,6 +49,13 @@ class VKBuffer {
     return vk_buffer_;
   }
 
+  /**
+   * Get the reference to the mapped memory.
+   *
+   * Can only be called when the buffer is (still) mapped.
+   */
+  void *mapped_memory_get() const;
+
  private:
   /** Check if this buffer is mapped. */
   bool is_mapped() const;
diff --git a/source/blender/gpu/vulkan/vk_pixel_buffer.cc b/source/blender/gpu/vulkan/vk_pixel_buffer.cc
index 609c6ec68a8..f673d444f27 100644
--- a/source/blender/gpu/vulkan/vk_pixel_buffer.cc
+++ b/source/blender/gpu/vulkan/vk_pixel_buffer.cc
@@ -11,20 +11,28 @@ namespace blender::gpu {
 
 VKPixelBuffer::VKPixelBuffer(int64_t size) : PixelBuffer(size)
 {
+  VKContext &context = *VKContext::get();
+  buffer_.create(context,
+                 size,
+                 GPU_USAGE_STATIC,
+                 static_cast<VkBufferUsageFlagBits>(VK_BUFFER_USAGE_TRANSFER_SRC_BIT |
+                                                    VK_BUFFER_USAGE_TRANSFER_DST_BIT));
 }
 
 void *VKPixelBuffer::map()
 {
-  return nullptr;
+  /* Vulkan buffers are always mapped between allocation and freeing. */
+  return buffer_.mapped_memory_get();
 }
 
 void VKPixelBuffer::unmap()
 {
+  /* Vulkan buffers are always mapped between allocation and freeing. */
 }
 
 int64_t VKPixelBuffer::get_native_handle()
 {
-  return -1;
+  return int64_t(buffer_.vk_handle());
 }
 
 uint VKPixelBuffer::get_size()
diff --git a/source/blender/gpu/vulkan/vk_pixel_buffer.hh b/source/blender/gpu/vulkan/vk_pixel_buffer.hh
index 7ea1529fd46..c5430444052 100644
--- a/source/blender/gpu/vulkan/vk_pixel_buffer.hh
+++ b/source/blender/gpu/vulkan/vk_pixel_buffer.hh
@@ -9,9 +9,13 @@
 
 #include "gpu_texture_private.hh"
 
+#include "vk_buffer.hh"
+
 namespace blender::gpu {
 
 class VKPixelBuffer : public PixelBuffer {
+  VKBuffer buffer_;
+
  public:
   VKPixelBuffer(int64_t size);
   void *map() override;
-- 
2.30.2


From ebae6659ad04e082df0f2ed40f90925b54dc8680 Mon Sep 17 00:00:00 2001
From: Jeroen Bakker <j.bakker@atmind.nl>
Date: Mon, 13 Mar 2023 19:21:34 +0100
Subject: [PATCH 2/2] Improve assert message.

---
 source/blender/gpu/vulkan/vk_buffer.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/blender/gpu/vulkan/vk_buffer.cc b/source/blender/gpu/vulkan/vk_buffer.cc
index dbb91905d0d..a5afcde7162 100644
--- a/source/blender/gpu/vulkan/vk_buffer.cc
+++ b/source/blender/gpu/vulkan/vk_buffer.cc
@@ -92,7 +92,7 @@ void VKBuffer::read(void *data) const
 
 void *VKBuffer::mapped_memory_get() const
 {
-  BLI_assert_msg(is_mapped(), "Cannot read a non-mapped buffer.");
+  BLI_assert_msg(is_mapped(), "Cannot access a non-mapped buffer.");
   return mapped_memory_;
 }
 
-- 
2.30.2