HostDisplay: Add texture dumping/saving support

src/duckstation-qt/d3d11displaywidget.cpp

@@ -141,6 +141,24 @@ void D3D11DisplayWidget::UpdateTexture(HostDisplayTexture* texture, u32 x, u32 y
   }
 }
 
+bool D3D11DisplayWidget::DownloadTexture(const void* texture_handle, u32 x, u32 y, u32 width, u32 height,
+                                         void* out_data, u32 out_data_stride)
+{
+  ID3D11ShaderResourceView* srv =
+    const_cast<ID3D11ShaderResourceView*>(static_cast<const ID3D11ShaderResourceView*>(texture_handle));
+  ID3D11Resource* srv_resource;
+  D3D11_SHADER_RESOURCE_VIEW_DESC srv_desc;
+  srv->GetResource(&srv_resource);
+  srv->GetDesc(&srv_desc);
+
+  if (!m_readback_staging_texture.EnsureSize(m_context.Get(), width, height, srv_desc.Format, false))
+    return false;
+
+  m_readback_staging_texture.CopyFromTexture(m_context.Get(), srv_resource, 0, x, y, 0, 0, width, height);
+  return m_readback_staging_texture.ReadPixels<u32>(m_context.Get(), 0, 0, width, height, out_data_stride / sizeof(u32),
+                                                    static_cast<u32*>(out_data));
+}
+
 void D3D11DisplayWidget::SetVSync(bool enabled)
 {
   m_vsync = enabled;

src/duckstation-qt/d3d11displaywidget.h

@@ -1,4 +1,5 @@
 #pragma once
+#include "common/d3d11/staging_texture.h"
 #include "common/d3d11/stream_buffer.h"
 #include "common/d3d11/texture.h"
 #include "common/windows_headers.h"
@@ -39,6 +40,8 @@ public:
                                                     u32 initial_data_stride, bool dynamic) override;
   void UpdateTexture(HostDisplayTexture* texture, u32 x, u32 y, u32 width, u32 height, const void* texture_data,
                      u32 texture_data_stride) override;
+  bool DownloadTexture(const void* texture_handle, u32 x, u32 y, u32 width, u32 height, void* out_data,
+                       u32 out_data_stride) override;
 
   void SetVSync(bool enabled) override;
 
@@ -74,6 +77,7 @@ private:
 
   D3D11::Texture m_display_pixels_texture;
   D3D11::StreamBuffer m_display_uniform_buffer;
+  D3D11::AutoStagingTexture m_readback_staging_texture;
 
   bool m_allow_tearing_supported = false;
   bool m_vsync = false;

src/duckstation-qt/opengldisplaywidget.cpp

@@ -164,6 +164,24 @@ void OpenGLDisplayWidget::UpdateTexture(HostDisplayTexture* texture, u32 x, u32
   glBindTexture(GL_TEXTURE_2D, old_texture_binding);
 }
 
+bool OpenGLDisplayWidget::DownloadTexture(const void* texture_handle, u32 x, u32 y, u32 width, u32 height,
+                                          void* out_data, u32 out_data_stride)
+{
+  GLint old_alignment = 0, old_row_length = 0;
+  glGetIntegerv(GL_PACK_ALIGNMENT, &old_alignment);
+  glGetIntegerv(GL_PACK_ROW_LENGTH, &old_row_length);
+  glPixelStorei(GL_PACK_ALIGNMENT, sizeof(u32));
+  glPixelStorei(GL_PACK_ROW_LENGTH, out_data_stride / sizeof(u32));
+
+  const GLuint texture = static_cast<GLuint>(reinterpret_cast<uintptr_t>(texture_handle));
+  GL::Texture::GetTextureSubImage(texture, 0, x, y, 0, width, height, 1, GL_RGBA, GL_UNSIGNED_BYTE,
+                                  height * out_data_stride, out_data);
+
+  glPixelStorei(GL_PACK_ALIGNMENT, old_alignment);
+  glPixelStorei(GL_PACK_ROW_LENGTH, old_row_length);
+  return true;
+}
+
 void OpenGLDisplayWidget::SetVSync(bool enabled)
 {
   // Window framebuffer has to be bound to call SetSwapInterval.

src/duckstation-qt/opengldisplaywidget.h

@@ -44,6 +44,8 @@ public:
                                                     u32 initial_data_stride, bool dynamic) override;
   void UpdateTexture(HostDisplayTexture* texture, u32 x, u32 y, u32 width, u32 height, const void* texture_data,
                      u32 texture_data_stride) override;
+  bool DownloadTexture(const void* texture_handle, u32 x, u32 y, u32 width, u32 height, void* out_data,
+                       u32 out_data_stride) override;
 
   void SetVSync(bool enabled) override;