Qt: Refactor render widget state transitions

Recreate widget each time. Fixes fullscreen mode switches on D3D11 and
hopefully Wayland.

src/duckstation-qt/d3d11hostdisplay.h

@@ -0,0 +1,80 @@
+#pragma once
+#include "common/d3d11/staging_texture.h"
+#include "common/d3d11/stream_buffer.h"
+#include "common/d3d11/texture.h"
+#include "common/windows_headers.h"
+#include "core/host_display.h"
+#include "qthostdisplay.h"
+#include <d3d11.h>
+#include <dxgi.h>
+#include <memory>
+#include <wrl/client.h>
+
+class D3D11HostDisplay final : public QtHostDisplay
+{
+public:
+  template<typename T>
+  using ComPtr = Microsoft::WRL::ComPtr<T>;
+
+  D3D11HostDisplay(QtHostInterface* host_interface);
+  ~D3D11HostDisplay();
+
+  bool hasDeviceContext() const override;
+  bool createDeviceContext(bool debug_device) override;
+  void destroyDeviceContext() override;
+  bool createSurface() override;
+  void destroySurface() override;
+
+  RenderAPI GetRenderAPI() const override;
+  void* GetRenderDevice() const override;
+  void* GetRenderContext() const override;
+  void WindowResized(s32 new_window_width, s32 new_window_height) override;
+
+  std::unique_ptr<HostDisplayTexture> CreateTexture(u32 width, u32 height, const void* initial_data,
+                                                    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;
+
+  void Render() override;
+
+private:
+  static constexpr u32 DISPLAY_UNIFORM_BUFFER_SIZE = 16;
+
+  bool createImGuiContext() override;
+  void destroyImGuiContext() override;
+  bool createDeviceResources() override;
+  void destroyDeviceResources() override;
+
+  bool shouldUseFlipModelSwapChain() const;
+  bool createSwapChainRTV();
+
+  void renderDisplay();
+
+  ComPtr<IDXGIFactory> m_dxgi_factory;
+
+  ComPtr<ID3D11Device> m_device;
+  ComPtr<ID3D11DeviceContext> m_context;
+  ComPtr<IDXGISwapChain> m_swap_chain;
+  ComPtr<ID3D11RenderTargetView> m_swap_chain_rtv;
+
+  ComPtr<ID3D11RasterizerState> m_display_rasterizer_state;
+  ComPtr<ID3D11DepthStencilState> m_display_depth_stencil_state;
+  ComPtr<ID3D11BlendState> m_display_blend_state;
+  ComPtr<ID3D11VertexShader> m_display_vertex_shader;
+  ComPtr<ID3D11PixelShader> m_display_pixel_shader;
+  ComPtr<ID3D11SamplerState> m_point_sampler;
+  ComPtr<ID3D11SamplerState> m_linear_sampler;
+
+  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_using_flip_model_swap_chain = false;
+  bool m_using_allow_tearing = false;
+  bool m_vsync = false;
+};