VideoBackends: Store a backbuffer 'scale'

This is a scaling factor, used for hi-dpi configurations.

Source/Core/Common/WindowSystemInfo.h

@@ -32,4 +32,7 @@ struct WindowSystemInfo
   // on the platform. e.g. HWND for Windows, Window for X11. If the surface is
   // set to nullptr, the video backend will run in headless mode.
   void* render_surface = nullptr;
+
+  // Scale of the render surface. For hidpi systems, this will be >1.
+  float render_surface_scale = 1.0f;
 };

Source/Core/DolphinQt/MainWindow.cpp

@@ -164,6 +164,7 @@ static WindowSystemInfo GetWindowSystemInfo(QWindow* window)
   else
     wsi.render_surface = window ? reinterpret_cast<void*>(window->winId()) : nullptr;
 #endif
+  wsi.render_surface_scale = window ? static_cast<float>(window->devicePixelRatio()) : 1.0f;
 
   return wsi;
 }

Source/Core/VideoBackends/D3D/Render.cpp

@@ -62,8 +62,9 @@ typedef struct _Nv_Stereo_Image_Header
 
 #define NVSTEREO_IMAGE_SIGNATURE 0x4433564e
 
-Renderer::Renderer(int backbuffer_width, int backbuffer_height)
+Renderer::Renderer(int backbuffer_width, int backbuffer_height, float backbuffer_scale)
-    : ::Renderer(backbuffer_width, backbuffer_height, AbstractTextureFormat::RGBA8)
+    : ::Renderer(backbuffer_width, backbuffer_height, backbuffer_scale,
+                 AbstractTextureFormat::RGBA8)
 {
   m_last_multisamples = g_ActiveConfig.iMultisamples;
   m_last_stereo_mode = g_ActiveConfig.stereo_mode != StereoMode::Off;

Source/Core/VideoBackends/D3D/Render.h

@@ -18,7 +18,7 @@ class D3DTexture2D;
 class Renderer : public ::Renderer
 {
 public:
-  Renderer(int backbuffer_width, int backbuffer_height);
+  Renderer(int backbuffer_width, int backbuffer_height, float backbuffer_scale);
   ~Renderer() override;
 
   StateCache& GetStateCache() { return m_state_cache; }

Source/Core/VideoBackends/D3D/main.cpp

@@ -147,7 +147,8 @@ bool VideoBackend::Initialize(const WindowSystemInfo& wsi)
   }
 
   // internal interfaces
-  g_renderer = std::make_unique<Renderer>(backbuffer_width, backbuffer_height);
+  g_renderer =
+      std::make_unique<Renderer>(backbuffer_width, backbuffer_height, wsi.render_surface_scale);
   g_shader_cache = std::make_unique<VideoCommon::ShaderCache>();
   g_texture_cache = std::make_unique<TextureCache>();
   g_vertex_manager = std::make_unique<VertexManager>();

Source/Core/VideoBackends/Null/Render.cpp

@@ -14,7 +14,7 @@
 namespace Null
 {
 // Init functions
-Renderer::Renderer() : ::Renderer(1, 1, AbstractTextureFormat::RGBA8)
+Renderer::Renderer() : ::Renderer(1, 1, 1.0f, AbstractTextureFormat::RGBA8)
 {
   UpdateActiveConfig();
 }

Source/Core/VideoBackends/OGL/Render.cpp

@@ -351,10 +351,10 @@ static void InitDriverInfo()
 }
 
 // Init functions
-Renderer::Renderer(std::unique_ptr<GLContext> main_gl_context)
+Renderer::Renderer(std::unique_ptr<GLContext> main_gl_context, float backbuffer_scale)
     : ::Renderer(static_cast<int>(std::max(main_gl_context->GetBackBufferWidth(), 1u)),
                  static_cast<int>(std::max(main_gl_context->GetBackBufferHeight(), 1u)),
-                 AbstractTextureFormat::RGBA8),
+                 backbuffer_scale, AbstractTextureFormat::RGBA8),
       m_main_gl_context(std::move(main_gl_context)),
       m_current_rasterization_state(RenderState::GetInvalidRasterizationState()),
       m_current_depth_state(RenderState::GetInvalidDepthState()),

Source/Core/VideoBackends/OGL/Render.h

@@ -83,7 +83,7 @@ extern VideoConfig g_ogl_config;
 class Renderer : public ::Renderer
 {
 public:
-  Renderer(std::unique_ptr<GLContext> main_gl_context);
+  Renderer(std::unique_ptr<GLContext> main_gl_context, float backbuffer_scale);
   ~Renderer() override;
 
   bool IsHeadless() const override;

Source/Core/VideoBackends/OGL/main.cpp

@@ -172,7 +172,7 @@ bool VideoBackend::Initialize(const WindowSystemInfo& wsi)
   if (!InitializeGLExtensions(main_gl_context.get()) || !FillBackendInfo())
     return false;
 
-  g_renderer = std::make_unique<Renderer>(std::move(main_gl_context));
+  g_renderer = std::make_unique<Renderer>(std::move(main_gl_context), wsi.render_surface_scale);
   g_vertex_manager = std::make_unique<VertexManager>();
   g_perf_query = GetPerfQuery();
   ProgramShaderCache::Init();

Source/Core/VideoBackends/Software/SWRenderer.cpp

@@ -25,7 +25,7 @@
 #include "VideoCommon/VideoConfig.h"
 
 SWRenderer::SWRenderer(std::unique_ptr<SWOGLWindow> window)
-    : ::Renderer(static_cast<int>(MAX_XFB_WIDTH), static_cast<int>(MAX_XFB_HEIGHT),
+    : ::Renderer(static_cast<int>(MAX_XFB_WIDTH), static_cast<int>(MAX_XFB_HEIGHT), 1.0f,
                  AbstractTextureFormat::RGBA8),
       m_window(std::move(window))
 {

Source/Core/VideoBackends/Vulkan/Renderer.cpp

@@ -46,9 +46,9 @@
 
 namespace Vulkan
 {
-Renderer::Renderer(std::unique_ptr<SwapChain> swap_chain)
+Renderer::Renderer(std::unique_ptr<SwapChain> swap_chain, float backbuffer_scale)
     : ::Renderer(swap_chain ? static_cast<int>(swap_chain->GetWidth()) : 1,
-                 swap_chain ? static_cast<int>(swap_chain->GetHeight()) : 0,
+                 swap_chain ? static_cast<int>(swap_chain->GetHeight()) : 0, backbuffer_scale,
                  swap_chain ? swap_chain->GetTextureFormat() : AbstractTextureFormat::Undefined),
       m_swap_chain(std::move(swap_chain))
 {

Source/Core/VideoBackends/Vulkan/Renderer.h

@@ -29,7 +29,7 @@ class VKTexture;
 class Renderer : public ::Renderer
 {
 public:
-  Renderer(std::unique_ptr<SwapChain> swap_chain);
+  Renderer(std::unique_ptr<SwapChain> swap_chain, float backbuffer_scale);
   ~Renderer() override;
 
   static Renderer* GetInstance();

Source/Core/VideoBackends/Vulkan/main.cpp

@@ -225,7 +225,7 @@ bool VideoBackend::Initialize(const WindowSystemInfo& wsi)
 
   // Create main wrapper instances.
   g_framebuffer_manager = std::make_unique<FramebufferManager>();
-  g_renderer = std::make_unique<Renderer>(std::move(swap_chain));
+  g_renderer = std::make_unique<Renderer>(std::move(swap_chain), wsi.render_surface_scale);
   g_vertex_manager = std::make_unique<VertexManager>();
   g_texture_cache = std::make_unique<TextureCache>();
   ::g_shader_cache = std::make_unique<VideoCommon::ShaderCache>();

Source/Core/VideoCommon/RenderBase.cpp

@@ -81,10 +81,10 @@ static float AspectToWidescreen(float aspect)
   return aspect * ((16.0f / 9.0f) / (4.0f / 3.0f));
 }
 
-Renderer::Renderer(int backbuffer_width, int backbuffer_height,
+Renderer::Renderer(int backbuffer_width, int backbuffer_height, float backbuffer_scale,
                    AbstractTextureFormat backbuffer_format)
     : m_backbuffer_width(backbuffer_width), m_backbuffer_height(backbuffer_height),
-      m_backbuffer_format(backbuffer_format)
+      m_backbuffer_scale(backbuffer_scale), m_backbuffer_format(backbuffer_format)
 {
   UpdateActiveConfig();
   UpdateDrawRectangle();

Source/Core/VideoCommon/RenderBase.h

@@ -63,7 +63,8 @@ extern int frameCount;
 class Renderer
 {
 public:
-  Renderer(int backbuffer_width, int backbuffer_height, AbstractTextureFormat backbuffer_format);
+  Renderer(int backbuffer_width, int backbuffer_height, float backbuffer_scale,
+           AbstractTextureFormat backbuffer_format);
   virtual ~Renderer();
 
   using ClearColor = std::array<float, 4>;
@@ -125,6 +126,7 @@ public:
   // Display resolution
   int GetBackbufferWidth() const { return m_backbuffer_width; }
   int GetBackbufferHeight() const { return m_backbuffer_height; }
+  float GetBackbufferScale() const { return m_backbuffer_scale; }
   void SetWindowSize(int width, int height);
 
   // EFB coordinate conversion functions
@@ -229,6 +231,7 @@ protected:
   // Backbuffer (window) size and render area
   int m_backbuffer_width = 0;
   int m_backbuffer_height = 0;
+  float m_backbuffer_scale = 1.0f;
   AbstractTextureFormat m_backbuffer_format = AbstractTextureFormat::Undefined;
   TargetRectangle m_target_rectangle = {};