VideoBackends: Add AbstractStagingTexture class

Can be used for asynchronous readback or upload of textures.

Source/Core/VideoBackends/Null/NullTexture.cpp

@@ -25,4 +25,43 @@ void NullTexture::Load(u32 level, u32 width, u32 height, u32 row_length, const u
 {
 }
 
+NullStagingTexture::NullStagingTexture(StagingTextureType type, const TextureConfig& config)
+    : AbstractStagingTexture(type, config)
+{
+  m_texture_buf.resize(m_texel_size * config.width * config.height);
+  m_map_pointer = reinterpret_cast<char*>(m_texture_buf.data());
+  m_map_stride = m_texel_size * config.width;
+}
+
+NullStagingTexture::~NullStagingTexture() = default;
+
+void NullStagingTexture::CopyFromTexture(const AbstractTexture* src,
+                                         const MathUtil::Rectangle<int>& src_rect, u32 src_layer,
+                                         u32 src_level, const MathUtil::Rectangle<int>& dst_rect)
+{
+  m_needs_flush = true;
+}
+
+void NullStagingTexture::CopyToTexture(const MathUtil::Rectangle<int>& src_rect,
+                                       AbstractTexture* dst,
+                                       const MathUtil::Rectangle<int>& dst_rect, u32 dst_layer,
+                                       u32 dst_level)
+{
+  m_needs_flush = true;
+}
+
+bool NullStagingTexture::Map()
+{
+  return true;
+}
+
+void NullStagingTexture::Unmap()
+{
+}
+
+void NullStagingTexture::Flush()
+{
+  m_needs_flush = false;
+}
+
 }  // namespace Null

Source/Core/VideoBackends/Null/NullTexture.h

@@ -4,8 +4,11 @@
 
 #pragma once
 
+#include <vector>
+
 #include "Common/CommonTypes.h"
 
+#include "VideoCommon/AbstractStagingTexture.h"
 #include "VideoCommon/AbstractTexture.h"
 
 namespace Null
@@ -25,4 +28,25 @@ public:
             size_t buffer_size) override;
 };
 
+class NullStagingTexture final : public AbstractStagingTexture
+{
+public:
+  explicit NullStagingTexture(StagingTextureType type, const TextureConfig& config);
+  ~NullStagingTexture();
+
+  void CopyFromTexture(const AbstractTexture* src, const MathUtil::Rectangle<int>& src_rect,
+                       u32 src_layer, u32 src_level,
+                       const MathUtil::Rectangle<int>& dst_rect) override;
+  void CopyToTexture(const MathUtil::Rectangle<int>& src_rect, AbstractTexture* dst,
+                     const MathUtil::Rectangle<int>& dst_rect, u32 dst_layer,
+                     u32 dst_level) override;
+
+  bool Map() override;
+  void Unmap() override;
+  void Flush() override;
+
+private:
+  std::vector<u8> m_texture_buf;
+};
+
 }  // namespace Null

Source/Core/VideoBackends/Null/Render.cpp

@@ -27,6 +27,12 @@ std::unique_ptr<AbstractTexture> Renderer::CreateTexture(const TextureConfig& co
   return std::make_unique<NullTexture>(config);
 }
 
+std::unique_ptr<AbstractStagingTexture> Renderer::CreateStagingTexture(StagingTextureType type,
+                                                                       const TextureConfig& config)
+{
+  return std::make_unique<NullStagingTexture>(type, config);
+}
+
 void Renderer::RenderText(const std::string& text, int left, int top, u32 color)
 {
   NOTICE_LOG(VIDEO, "RenderText: %s", text.c_str());

Source/Core/VideoBackends/Null/Render.h

@@ -15,6 +15,8 @@ public:
   ~Renderer() override;
 
   std::unique_ptr<AbstractTexture> CreateTexture(const TextureConfig& config) override;
+  std::unique_ptr<AbstractStagingTexture>
+  CreateStagingTexture(StagingTextureType type, const TextureConfig& config) override;
 
   void RenderText(const std::string& pstr, int left, int top, u32 color) override;
   u32 AccessEFB(EFBAccessType type, u32 x, u32 y, u32 poke_data) override { return 0; }