graphics_threaded.h

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#ifndef ENGINE_CLIENT_GRAPHICS_THREADED_H
#define ENGINE_CLIENT_GRAPHICS_THREADED_H
 
#include <base/dbg.h>
#include <base/sphore.h>
 
#include <engine/graphics.h>
#include <engine/shared/config.h>
 
#include <atomic>
#include <cstddef>
#include <mutex>
#include <string>
#include <vector>
 
constexpr int CMD_BUFFER_DATA_BUFFER_SIZE = 1024 * 1024 * 2;
constexpr int CMD_BUFFER_CMD_BUFFER_SIZE = 1024 * 256;
 
namespace TextureFlag
{
    inline constexpr uint32_t NO_MIPMAPS = 1 << 0;
    inline constexpr uint32_t TO_3D_TEXTURE = 1 << 1;
    inline constexpr uint32_t TO_2D_ARRAY_TEXTURE = 1 << 2;
    inline constexpr uint32_t NO_2D_TEXTURE = 1 << 3;
};
 
enum class EPrimitiveType
{
    LINES,
    QUADS,
    TRIANGLES,
};
 
enum class EBlendMode
{
    NONE,
    ALPHA,
    ADDITIVE,
};
 
enum class EWrapMode
{
    REPEAT,
    CLAMP,
};
 
class CCommandBuffer
{
    class CBuffer
    {
        unsigned char *m_pData;
        unsigned m_Size;
        unsigned m_Used;
 
    public:
        CBuffer(unsigned BufferSize)
        {
            m_Size = BufferSize;
            m_pData = new unsigned char[m_Size];
            m_Used = 0;
        }
 
        ~CBuffer()
        {
            delete[] m_pData;
            m_pData = nullptr;
            m_Used = 0;
            m_Size = 0;
        }
 
        void Reset()
        {
            m_Used = 0;
        }
 
        void *Alloc(unsigned Requested, unsigned Alignment = alignof(std::max_align_t))
        {
            size_t Offset = reinterpret_cast<uintptr_t>(m_pData + m_Used) % Alignment;
            if(Offset)
                Offset = Alignment - Offset;
 
            if(Requested + Offset + m_Used > m_Size)
                return nullptr;
 
            void *pPtr = &m_pData[m_Used + Offset];
            m_Used += Requested + Offset;
            return pPtr;
        }
 
        unsigned char *DataPtr() { return m_pData; }
        unsigned DataSize() const { return m_Size; }
        unsigned DataUsed() const { return m_Used; }
    };
 
public:
    CBuffer m_CmdBuffer;
    size_t m_CommandCount = 0;
    size_t m_RenderCallCount = 0;
 
    CBuffer m_DataBuffer;
 
    enum
    {
        MAX_TEXTURES = 1024 * 8,
        MAX_VERTICES = 32 * 1024,
    };
 
    enum
    {
        // command groups
        CMDGROUP_CORE = 0, // commands that everyone has to implement
        CMDGROUP_PLATFORM_GL = 10000, // commands specific to a platform
        CMDGROUP_PLATFORM_SDL = 20000,
 
        CMD_FIRST = CMDGROUP_CORE,
    };
 
    enum ECommandBufferCMD
    {
        // synchronization
        CMD_SIGNAL = CMD_FIRST,
 
        // texture commands
        CMD_TEXTURE_CREATE,
        CMD_TEXTURE_DESTROY,
        CMD_TEXT_TEXTURES_CREATE,
        CMD_TEXT_TEXTURES_DESTROY,
        CMD_TEXT_TEXTURE_UPDATE,
 
        // rendering
        CMD_CLEAR,
        CMD_RENDER,
        CMD_RENDER_TEX3D,
 
        // opengl 2.0+ commands (some are just emulated and only exist in opengl 3.3+)
        CMD_CREATE_BUFFER_OBJECT, // create vbo
        CMD_RECREATE_BUFFER_OBJECT, // recreate vbo
        CMD_UPDATE_BUFFER_OBJECT, // update vbo
        CMD_COPY_BUFFER_OBJECT, // copy vbo to another
        CMD_DELETE_BUFFER_OBJECT, // delete vbo
 
        CMD_CREATE_BUFFER_CONTAINER, // create vao
        CMD_DELETE_BUFFER_CONTAINER, // delete vao
        CMD_UPDATE_BUFFER_CONTAINER, // update vao
 
        CMD_INDICES_REQUIRED_NUM_NOTIFY, // create indices that are required
 
        CMD_RENDER_TILE_LAYER, // render a tilelayer
        CMD_RENDER_BORDER_TILE, // render one tile multiple times
        CMD_RENDER_QUAD_LAYER, // render a quad layer
        CMD_RENDER_QUAD_LAYER_GROUPED, // render a quad layer in groups meaning they all share the same envelope and offset (which can be none)
        CMD_RENDER_TEXT, // render text
        CMD_RENDER_QUAD_CONTAINER, // render a quad buffer container
        CMD_RENDER_QUAD_CONTAINER_EX, // render a quad buffer container with extended parameters
        CMD_RENDER_QUAD_CONTAINER_SPRITE_MULTIPLE, // render a quad buffer container as sprite multiple times
 
        // swap
        CMD_SWAP,
 
        // misc
        CMD_MULTISAMPLING,
        CMD_VSYNC,
        CMD_TRY_SWAP_AND_READ_PIXEL,
        CMD_TRY_SWAP_AND_SCREENSHOT,
        CMD_UPDATE_VIEWPORT,
 
        // in Android a window that minimizes gets destroyed
        CMD_WINDOW_CREATE_NTF,
        CMD_WINDOW_DESTROY_NTF,
 
        CMD_COUNT,
    };
 
    typedef vec2 SPoint;
    typedef vec2 STexCoord;
    typedef GL_SColorf SColorf;
    typedef GL_SColor SColor;
    typedef GL_SVertex SVertex;
    typedef GL_SVertexTex3D SVertexTex3D;
    typedef GL_SVertexTex3DStream SVertexTex3DStream;
 
    struct SCommand
    {
    public:
        SCommand(unsigned Cmd) :
            m_Cmd(Cmd), m_pNext(nullptr) {}
        unsigned m_Cmd;
        SCommand *m_pNext;
    };
 
    struct SState
    {
        EBlendMode m_BlendMode;
        EWrapMode m_WrapMode;
        int m_Texture;
        SPoint m_ScreenTL;
        SPoint m_ScreenBR;
 
        // clip
        bool m_ClipEnable;
        int m_ClipX;
        int m_ClipY;
        int m_ClipW;
        int m_ClipH;
    };
 
    struct SCommand_Clear : public SCommand
    {
        SCommand_Clear() :
            SCommand(CMD_CLEAR) {}
        SColorf m_Color;
        bool m_ForceClear;
    };
 
    struct SCommand_Signal : public SCommand
    {
        SCommand_Signal() :
            SCommand(CMD_SIGNAL) {}
        CSemaphore *m_pSemaphore;
    };
 
    struct SCommand_Render : public SCommand
    {
        SCommand_Render() :
            SCommand(CMD_RENDER) {}
        SState m_State;
        EPrimitiveType m_PrimType;
        unsigned m_PrimCount;
        SVertex *m_pVertices; // you should use the command buffer data to allocate vertices for this command
    };
 
    struct SCommand_RenderTex3D : public SCommand
    {
        SCommand_RenderTex3D() :
            SCommand(CMD_RENDER_TEX3D) {}
        SState m_State;
        EPrimitiveType m_PrimType;
        unsigned m_PrimCount;
        SVertexTex3DStream *m_pVertices; // you should use the command buffer data to allocate vertices for this command
    };
 
    struct SCommand_CreateBufferObject : public SCommand
    {
        SCommand_CreateBufferObject() :
            SCommand(CMD_CREATE_BUFFER_OBJECT) {}
 
        int m_BufferIndex;
 
        bool m_DeletePointer;
        void *m_pUploadData;
        size_t m_DataSize;
 
        int m_Flags; // @see EBufferObjectCreateFlags
    };
 
    struct SCommand_RecreateBufferObject : public SCommand
    {
        SCommand_RecreateBufferObject() :
            SCommand(CMD_RECREATE_BUFFER_OBJECT) {}
 
        int m_BufferIndex;
 
        bool m_DeletePointer;
        void *m_pUploadData;
        size_t m_DataSize;
 
        int m_Flags; // @see EBufferObjectCreateFlags
    };
 
    struct SCommand_UpdateBufferObject : public SCommand
    {
        SCommand_UpdateBufferObject() :
            SCommand(CMD_UPDATE_BUFFER_OBJECT) {}
 
        int m_BufferIndex;
 
        bool m_DeletePointer;
        void *m_pOffset;
        void *m_pUploadData;
        size_t m_DataSize;
    };
 
    struct SCommand_CopyBufferObject : public SCommand
    {
        SCommand_CopyBufferObject() :
            SCommand(CMD_COPY_BUFFER_OBJECT) {}
 
        int m_WriteBufferIndex;
        int m_ReadBufferIndex;
 
        size_t m_ReadOffset;
        size_t m_WriteOffset;
        size_t m_CopySize;
    };
 
    struct SCommand_DeleteBufferObject : public SCommand
    {
        SCommand_DeleteBufferObject() :
            SCommand(CMD_DELETE_BUFFER_OBJECT) {}
 
        int m_BufferIndex;
    };
 
    struct SCommand_CreateBufferContainer : public SCommand
    {
        SCommand_CreateBufferContainer() :
            SCommand(CMD_CREATE_BUFFER_CONTAINER) {}
 
        int m_BufferContainerIndex;
 
        int m_Stride;
        int m_VertBufferBindingIndex;
 
        size_t m_AttrCount;
        SBufferContainerInfo::SAttribute *m_pAttributes;
    };
 
    struct SCommand_UpdateBufferContainer : public SCommand
    {
        SCommand_UpdateBufferContainer() :
            SCommand(CMD_UPDATE_BUFFER_CONTAINER) {}
 
        int m_BufferContainerIndex;
 
        int m_Stride;
        int m_VertBufferBindingIndex;
 
        size_t m_AttrCount;
        SBufferContainerInfo::SAttribute *m_pAttributes;
    };
 
    struct SCommand_DeleteBufferContainer : public SCommand
    {
        SCommand_DeleteBufferContainer() :
            SCommand(CMD_DELETE_BUFFER_CONTAINER) {}
 
        int m_BufferContainerIndex;
        bool m_DestroyAllBO;
    };
 
    struct SCommand_IndicesRequiredNumNotify : public SCommand
    {
        SCommand_IndicesRequiredNumNotify() :
            SCommand(CMD_INDICES_REQUIRED_NUM_NOTIFY) {}
 
        unsigned int m_RequiredIndicesNum;
    };
 
    struct SCommand_RenderTileLayer : public SCommand
    {
        SCommand_RenderTileLayer() :
            SCommand(CMD_RENDER_TILE_LAYER) {}
        SState m_State;
        SColorf m_Color; // the color of the whole tilelayer -- already enveloped
 
        // the char offset of all indices that should be rendered, and the amount of renders
        char **m_pIndicesOffsets;
        unsigned int *m_pDrawCount;
 
        int m_IndicesDrawNum;
        int m_BufferContainerIndex;
    };
 
    struct SCommand_RenderBorderTile : public SCommand
    {
        SCommand_RenderBorderTile() :
            SCommand(CMD_RENDER_BORDER_TILE) {}
        SState m_State;
        SColorf m_Color; // the color of the whole tilelayer -- already enveloped
        char *m_pIndicesOffset;
        uint32_t m_DrawNum;
        int m_BufferContainerIndex;
 
        vec2 m_Offset;
        vec2 m_Scale;
    };
 
    struct SCommand_RenderQuadLayer : public SCommand
    {
        SCommand_RenderQuadLayer(bool Grouped) :
            SCommand(Grouped ? CMD_RENDER_QUAD_LAYER_GROUPED : CMD_RENDER_QUAD_LAYER) {}
        SState m_State;
 
        int m_BufferContainerIndex;
        SQuadRenderInfo *m_pQuadInfo;
        size_t m_QuadNum;
        int m_QuadOffset;
    };
 
    struct SCommand_RenderText : public SCommand
    {
        SCommand_RenderText() :
            SCommand(CMD_RENDER_TEXT) {}
        SState m_State;
 
        int m_BufferContainerIndex;
        int m_TextureSize;
 
        int m_TextTextureIndex;
        int m_TextOutlineTextureIndex;
 
        int m_DrawNum;
        ColorRGBA m_TextColor;
        ColorRGBA m_TextOutlineColor;
    };
 
    struct SCommand_RenderQuadContainer : public SCommand
    {
        SCommand_RenderQuadContainer() :
            SCommand(CMD_RENDER_QUAD_CONTAINER) {}
        SState m_State;
 
        int m_BufferContainerIndex;
 
        unsigned int m_DrawNum;
        void *m_pOffset;
    };
 
    struct SCommand_RenderQuadContainerEx : public SCommand
    {
        SCommand_RenderQuadContainerEx() :
            SCommand(CMD_RENDER_QUAD_CONTAINER_EX) {}
        SState m_State;
 
        int m_BufferContainerIndex;
 
        float m_Rotation;
        SPoint m_Center;
 
        SColorf m_VertexColor;
 
        unsigned int m_DrawNum;
        void *m_pOffset;
    };
 
    struct SCommand_RenderQuadContainerAsSpriteMultiple : public SCommand
    {
        SCommand_RenderQuadContainerAsSpriteMultiple() :
            SCommand(CMD_RENDER_QUAD_CONTAINER_SPRITE_MULTIPLE) {}
        SState m_State;
 
        int m_BufferContainerIndex;
 
        IGraphics::SRenderSpriteInfo *m_pRenderInfo;
 
        SPoint m_Center;
        SColorf m_VertexColor;
 
        unsigned int m_DrawNum;
        unsigned int m_DrawCount;
        void *m_pOffset;
    };
 
    struct SCommand_TrySwapAndReadPixel : public SCommand
    {
        SCommand_TrySwapAndReadPixel() :
            SCommand(CMD_TRY_SWAP_AND_READ_PIXEL) {}
        ivec2 m_Position;
        SColorf *m_pColor; // processor will fill this out
        bool *m_pSwapped; // processor may set this to true, must be initialized to false by the caller
    };
 
    struct SCommand_TrySwapAndScreenshot : public SCommand
    {
        SCommand_TrySwapAndScreenshot() :
            SCommand(CMD_TRY_SWAP_AND_SCREENSHOT) {}
        CImageInfo *m_pImage; // processor will fill this out, the one who adds this command must free the data as well
        bool *m_pSwapped; // processor may set this to true, must be initialized to false by the caller
    };
 
    struct SCommand_Swap : public SCommand
    {
        SCommand_Swap() :
            SCommand(CMD_SWAP) {}
    };
 
    struct SCommand_VSync : public SCommand
    {
        SCommand_VSync() :
            SCommand(CMD_VSYNC) {}
 
        int m_VSync;
        bool *m_pRetOk;
    };
 
    struct SCommand_MultiSampling : public SCommand
    {
        SCommand_MultiSampling() :
            SCommand(CMD_MULTISAMPLING) {}
 
        uint32_t m_RequestedMultiSamplingCount;
        uint32_t *m_pRetMultiSamplingCount;
        bool *m_pRetOk;
    };
 
    struct SCommand_Update_Viewport : public SCommand
    {
        SCommand_Update_Viewport() :
            SCommand(CMD_UPDATE_VIEWPORT) {}
 
        // Viewport rectangle, relative to the top left of the drawable area.
        int m_X;
        int m_Y;
        int m_Width;
        int m_Height;
        // Size of the whole drawable area, which the viewport can be smaller than.
        int m_DrawableWidth;
        int m_DrawableHeight;
        bool m_ByResize; // resized by an resize event.. a hint to make clear that the viewport update can be deferred if wanted
    };
 
    struct SCommand_Texture_Create : public SCommand
    {
        SCommand_Texture_Create() :
            SCommand(CMD_TEXTURE_CREATE) {}
 
        // texture information
        int m_Slot;
 
        size_t m_Width;
        size_t m_Height;
        int m_Flags;
        // data must be in RGBA format
        uint8_t *m_pData; // will be freed by the command processor
    };
 
    struct SCommand_Texture_Destroy : public SCommand
    {
        SCommand_Texture_Destroy() :
            SCommand(CMD_TEXTURE_DESTROY) {}
 
        // texture information
        int m_Slot;
    };
 
    struct SCommand_TextTextures_Create : public SCommand
    {
        SCommand_TextTextures_Create() :
            SCommand(CMD_TEXT_TEXTURES_CREATE) {}
 
        // texture information
        int m_Slot;
        int m_SlotOutline;
 
        size_t m_Width;
        size_t m_Height;
 
        uint8_t *m_pTextData; // will be freed by the command processor
        uint8_t *m_pTextOutlineData; // will be freed by the command processor
    };
 
    struct SCommand_TextTextures_Destroy : public SCommand
    {
        SCommand_TextTextures_Destroy() :
            SCommand(CMD_TEXT_TEXTURES_DESTROY) {}
 
        // texture information
        int m_Slot;
        int m_SlotOutline;
    };
 
    struct SCommand_TextTexture_Update : public SCommand
    {
        SCommand_TextTexture_Update() :
            SCommand(CMD_TEXT_TEXTURE_UPDATE) {}
 
        // texture information
        int m_Slot;
 
        int m_X;
        int m_Y;
        size_t m_Width;
        size_t m_Height;
        uint8_t *m_pData; // will be freed by the command processor
    };
 
    struct SCommand_WindowCreateNtf : public CCommandBuffer::SCommand
    {
        SCommand_WindowCreateNtf() :
            SCommand(CMD_WINDOW_CREATE_NTF) {}
 
        uint32_t m_WindowId;
    };
 
    struct SCommand_WindowDestroyNtf : public CCommandBuffer::SCommand
    {
        SCommand_WindowDestroyNtf() :
            SCommand(CMD_WINDOW_DESTROY_NTF) {}
 
        uint32_t m_WindowId;
    };
 
    //
    CCommandBuffer(unsigned CmdBufferSize, unsigned DataBufferSize) :
        m_CmdBuffer(CmdBufferSize), m_DataBuffer(DataBufferSize), m_pCmdBufferHead(nullptr), m_pCmdBufferTail(nullptr)
    {
    }
 
    void *AllocData(unsigned WantedSize)
    {
        return m_DataBuffer.Alloc(WantedSize);
    }
 
    template<class T>
    bool AddCommandUnsafe(const T &Command)
    {
        // make sure that we don't do something stupid like ->AddCommand(&Cmd);
        (void)static_cast<const SCommand *>(&Command);
 
        // allocate and copy the command into the buffer
        T *pCmd = (T *)m_CmdBuffer.Alloc(sizeof(*pCmd), alignof(T));
        if(!pCmd)
            return false;
        *pCmd = Command;
        pCmd->m_pNext = nullptr;
 
        if(m_pCmdBufferTail)
            m_pCmdBufferTail->m_pNext = pCmd;
        if(!m_pCmdBufferHead)
            m_pCmdBufferHead = pCmd;
        m_pCmdBufferTail = pCmd;
 
        ++m_CommandCount;
 
        return true;
    }
 
    const SCommand *Head() const { return m_pCmdBufferHead; }
    SCommand *Head() { return m_pCmdBufferHead; }
 
    void Reset()
    {
        m_pCmdBufferHead = m_pCmdBufferTail = nullptr;
        m_CmdBuffer.Reset();
        m_DataBuffer.Reset();
 
        m_CommandCount = 0;
        m_RenderCallCount = 0;
    }
 
    void AddRenderCalls(size_t RenderCallCountToAdd)
    {
        m_RenderCallCount += RenderCallCountToAdd;
    }
 
private:
    SCommand *m_pCmdBufferHead;
    SCommand *m_pCmdBufferTail;
};
 
enum EGraphicsBackendErrorCodes
{
    GRAPHICS_BACKEND_ERROR_CODE_NONE = 0,
    GRAPHICS_BACKEND_ERROR_CODE_GL_CONTEXT_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_GL_VERSION_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_GLEW_INIT_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_SDL_INIT_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_SDL_SCREEN_REQUEST_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_SDL_SCREEN_INFO_REQUEST_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_SDL_SCREEN_RESOLUTION_REQUEST_FAILED,
    GRAPHICS_BACKEND_ERROR_CODE_SDL_WINDOW_CREATE_FAILED,
};
 
// interface for the graphics backend
// all these functions are called on the main thread
class IGraphicsBackend
{
public:
    enum
    {
        INITFLAG_FULLSCREEN = 1 << 0,
        INITFLAG_VSYNC = 1 << 1,
        INITFLAG_RESIZABLE = 1 << 2,
        INITFLAG_BORDERLESS = 1 << 3,
        INITFLAG_DESKTOP_FULLSCREEN = 1 << 4,
    };
 
    virtual ~IGraphicsBackend() = default;
 
    virtual int Init(const char *pName, int *pScreen, int *pWidth, int *pHeight, int *pRefreshRate, int *pFsaaSamples, int Flags, int *pDesktopWidth, int *pDesktopHeight, int *pCurrentWidth, int *pCurrentHeight, class IStorage *pStorage) = 0;
    virtual int Shutdown() = 0;
 
    virtual uint64_t TextureMemoryUsage() const = 0;
    virtual uint64_t BufferMemoryUsage() const = 0;
    virtual uint64_t StreamedMemoryUsage() const = 0;
    virtual uint64_t StagingMemoryUsage() const = 0;
 
    virtual const TTwGraphicsGpuList &GetGpus() const = 0;
 
    virtual void GetVideoModes(CVideoMode *pModes, int MaxModes, int *pNumModes, float HiDPIScale, int MaxWindowWidth, int MaxWindowHeight, int Screen) = 0;
    virtual void GetCurrentVideoMode(CVideoMode &CurMode, float HiDPIScale, int MaxWindowWidth, int MaxWindowHeight, int Screen) = 0;
 
    virtual int GetNumScreens() const = 0;
    virtual const char *GetScreenName(int Screen) const = 0;
 
    virtual void Minimize() = 0;
    virtual void SetWindowParams(int FullscreenMode, bool IsBorderless) = 0;
    virtual bool SetWindowScreen(int Index, bool MoveToCenter, ivec2 *pDesktopSize) = 0;
    virtual bool UpdateDisplayMode(int Index, ivec2 *pDesktopSize) = 0;
    virtual int GetWindowScreen() = 0;
    virtual int WindowActive() = 0;
    virtual int WindowOpen() = 0;
    virtual void SetWindowGrab(bool Grab) = 0;
    // returns true, if the video mode changed
    virtual bool ResizeWindow(int w, int h, int RefreshRate) = 0;
    virtual void GetViewportSize(int &w, int &h) = 0;
    // Insets of the drawable area which are covered by the cutout of the display,
    // in pixels. Only determined on iOS, zero on all other platforms.
    virtual void GetDisplayCutoutInsets(int &Left, int &Right) = 0;
    virtual void NotifyWindow() = 0;
    virtual bool IsScreenKeyboardShown() = 0;
 
    virtual void WindowDestroyNtf(uint32_t WindowId) = 0;
    virtual void WindowCreateNtf(uint32_t WindowId) = 0;
 
    virtual void RunBuffer(CCommandBuffer *pBuffer) = 0;
    virtual void RunBufferSingleThreadedUnsafe(CCommandBuffer *pBuffer) = 0;
    virtual bool IsIdle() const = 0;
    virtual void WaitForIdle() = 0;
 
    virtual bool GetDriverVersion(EGraphicsDriverAgeType DriverAgeType, int &Major, int &Minor, int &Patch, const char *&pName, EBackendType BackendType) = 0;
    // checks if the current values of the config are a graphics modern API
    virtual bool IsConfigModernAPI() { return false; }
    virtual bool UseTrianglesAsQuad() { return false; }
    virtual bool HasTileBuffering() { return false; }
    virtual bool HasQuadBuffering() { return false; }
    virtual bool HasTextBuffering() { return false; }
    virtual bool HasQuadContainerBuffering() { return false; }
    virtual bool Uses2DTextureArrays() { return false; }
    virtual bool HasTextureArraysSupport() { return false; }
    virtual const char *GetErrorString() { return nullptr; }
 
    virtual const char *GetVendorString() = 0;
    virtual const char *GetVersionString() = 0;
    virtual const char *GetRendererString() = 0;
 
    // be aware that this function should only be called from the graphics thread, and even then you should really know what you are doing
    virtual TGLBackendReadPresentedImageData &GetReadPresentedImageDataFuncUnsafe() = 0;
 
    virtual const char *GetFatalError() const = 0;
    virtual bool GetWarning(std::vector<std::string> &WarningStrings) = 0;

    virtual std::optional<int> ShowMessageBox(const IGraphics::CMessageBox &MessageBox) = 0;
};
 
class CGraphics_Threaded : public IEngineGraphics
{
    enum class EDrawing
    {
        NONE,
        QUADS,
        LINES,
        TRIANGLES,
    };
 
    CCommandBuffer::SState m_State;
    IGraphicsBackend *m_pBackend;
    bool m_GLTileBufferingEnabled;
    bool m_GLQuadBufferingEnabled;
    bool m_GLTextBufferingEnabled;
    bool m_GLQuadContainerBufferingEnabled;
    bool m_GLUses2DTextureArrays;
    bool m_GLHasTextureArraysSupport;
    bool m_GLUseTrianglesAsQuad;
 
    CCommandBuffer *m_apCommandBuffers[2];
    CCommandBuffer *m_pCommandBuffer;
    unsigned m_CurrentCommandBuffer;
 
    //
    class IStorage *m_pStorage;
    class IEngine *m_pEngine;
 
    int m_CurIndex;
 
    CCommandBuffer::SVertex m_aVertices[CCommandBuffer::MAX_VERTICES];
    CCommandBuffer::SVertexTex3DStream m_aVerticesTex3D[CCommandBuffer::MAX_VERTICES];
    int m_NumVertices;
 
    CCommandBuffer::SColor m_aColor[4];
    CCommandBuffer::STexCoord m_aTexture[4];
 
    bool m_RenderEnable;
 
    float m_Rotation;
    EDrawing m_Drawing;
    bool m_DoScreenshot;
    char m_aScreenshotName[IO_MAX_PATH_LENGTH];
 
    CTextureHandle m_NullTexture;
 
    std::vector<int> m_vTextureIndices;
    size_t m_FirstFreeTexture;
    int m_TextureMemoryUsage;
 
    std::atomic<bool> m_WarnPngliteIncompatibleImages = false;
 
    std::mutex m_WarningsMutex;
    std::vector<SWarning> m_vWarnings;
 
    // is a non full windowed (in a sense that the viewport won't include the whole window),
    // forced viewport, so that it justifies our UI ratio needs
    bool m_IsForcedViewport = false;
 
    struct SVertexArrayInfo
    {
        SVertexArrayInfo() :
            m_FreeIndex(-1) {}
        // keep a reference to it, so we can free the ID
        int m_AssociatedBufferObjectIndex;
 
        int m_FreeIndex;
    };
    std::vector<SVertexArrayInfo> m_vVertexArrayInfo;
    int m_FirstFreeVertexArrayInfo;
 
    std::vector<int> m_vBufferObjectIndices;
    int m_FirstFreeBufferObjectIndex;
 
    struct SQuadContainer
    {
        SQuadContainer(bool AutomaticUpload = true)
        {
            m_vQuads.clear();
            m_QuadBufferObjectIndex = m_QuadBufferContainerIndex = -1;
            m_FreeIndex = -1;
 
            m_AutomaticUpload = AutomaticUpload;
        }
 
        struct SQuad
        {
            CCommandBuffer::SVertex m_aVertices[4];
        };
 
        std::vector<SQuad> m_vQuads;
 
        int m_QuadBufferObjectIndex;
        int m_QuadBufferContainerIndex;
 
        int m_FreeIndex;
 
        bool m_AutomaticUpload;
    };
    std::vector<SQuadContainer> m_vQuadContainers;
    int m_FirstFreeQuadContainer;
 
    std::vector<WINDOW_RESIZE_FUNC> m_vResizeListeners;
    std::vector<WINDOW_PROPS_CHANGED_FUNC> m_vPropChangeListeners;
 
    void *AllocCommandBufferData(size_t AllocSize);
 
    void AddVertices(int Count);
    void AddVertices(int Count, CCommandBuffer::SVertex *pVertices);
    void AddVertices(int Count, CCommandBuffer::SVertexTex3DStream *pVertices);
 
    template<typename TName>
    void Rotate(const CCommandBuffer::SPoint &Center, TName *pPoints, int NumPoints)
    {
        float c = std::cos(m_Rotation);
        float s = std::sin(m_Rotation);
        float x, y;
        int i;
 
        TName *pVertices = pPoints;
        for(i = 0; i < NumPoints; i++)
        {
            x = pVertices[i].m_Pos.x - Center.x;
            y = pVertices[i].m_Pos.y - Center.y;
            pVertices[i].m_Pos.x = x * c - y * s + Center.x;
            pVertices[i].m_Pos.y = x * s + y * c + Center.y;
        }
    }
 
    template<typename TName>
    void AddCmd(
        TName &Cmd, const std::function<bool()> &FailFunc = [] { return true; })
    {
        if(m_pCommandBuffer->AddCommandUnsafe(Cmd))
            return;
 
        // kick command buffer and try again
        KickCommandBuffer();
 
        dbg_assert(FailFunc(), "graphics: failed to run fail handler for command '%s'", typeid(TName).name());
        dbg_assert(m_pCommandBuffer->AddCommandUnsafe(Cmd), "graphics: failed to add command '%s' to command buffer", typeid(TName).name());
    }
 
    void KickCommandBuffer();
 
    void AddBackEndWarningIfExists();
 
    void AdjustViewport(bool SendViewportChangeToBackend);
 
    ivec2 m_ReadPixelPosition = ivec2(0, 0);
    ColorRGBA *m_pReadPixelColor = nullptr;
    void ReadPixelDirect(bool *pSwapped);
    void ScreenshotDirect(bool *pSwapped);
 
    int IssueInit();
    int InitWindow();
 
public:
    CGraphics_Threaded();
 
    void ClipEnable(int x, int y, int w, int h) override;
    void ClipDisable() override;
 
    void BlendNone() override;
    void BlendNormal() override;
    void BlendAdditive() override;
 
    void WrapNormal() override;
    void WrapClamp() override;
 
    uint64_t TextureMemoryUsage() const override;
    uint64_t BufferMemoryUsage() const override;
    uint64_t StreamedMemoryUsage() const override;
    uint64_t StagingMemoryUsage() const override;
 
    const TTwGraphicsGpuList &GetGpus() const override;
 
    void MapScreen(const CScreenRect &ScreenRect) override;
    CScreenRect GetScreen() const override;
 
    void LinesBegin() override;
    void LinesEnd() override;
    void LinesDraw(const CLineItem *pArray, size_t Num) override;
 
    void LinesBatchBegin(CLineItemBatch *pBatch) override;
    void LinesBatchEnd(CLineItemBatch *pBatch) override;
    void LinesBatchDraw(CLineItemBatch *pBatch, const CLineItem *pArray, size_t Num) override;
 
    IGraphics::CTextureHandle FindFreeTextureIndex();
    void FreeTextureIndex(CTextureHandle *pIndex);
    void UnloadTexture(IGraphics::CTextureHandle *pIndex) override;
    void LoadTextureAddWarning(size_t Width, size_t Height, int Flags, const char *pTexName);
    IGraphics::CTextureHandle LoadTextureRaw(const CImageInfo &Image, int Flags, const char *pTexName = nullptr) override;
    IGraphics::CTextureHandle LoadTextureRawMove(CImageInfo &Image, int Flags, const char *pTexName = nullptr) override;
 
    bool LoadTextTextures(size_t Width, size_t Height, CTextureHandle &TextTexture, CTextureHandle &TextOutlineTexture, uint8_t *pTextData, uint8_t *pTextOutlineData) override;
    bool UnloadTextTextures(CTextureHandle &TextTexture, CTextureHandle &TextOutlineTexture) override;
    bool UpdateTextTexture(CTextureHandle TextureId, int x, int y, size_t Width, size_t Height, uint8_t *pData, bool IsMovedPointer) override;
 
    CTextureHandle LoadSpriteTexture(const CImageInfo &FromImageInfo, const std::optional<CImageInfo> &FallbackImageInfo, const struct CDataSprite *pSprite) override;
 
    bool IsImageSubFullyTransparent(const CImageInfo &FromImageInfo, int x, int y, int w, int h) override;
    bool IsSpriteTextureFullyTransparent(const CImageInfo &FromImageInfo, const struct CDataSprite *pSprite) override;
 
    // simple uncompressed RGBA loaders
    IGraphics::CTextureHandle LoadTexture(const char *pFilename, int StorageType, int Flags = 0) override;
    bool LoadPng(CImageInfo &Image, const char *pFilename, int StorageType) override;
    bool LoadPng(CImageInfo &Image, const uint8_t *pData, size_t DataSize, const char *pContextName) override;
 
    bool CheckImageDivisibility(const char *pContextName, CImageInfo &Image, int DivX, int DivY, bool AllowResize) override;
    bool IsImageFormatRgba(const char *pContextName, const CImageInfo &Image) override;
 
    void TextureSet(CTextureHandle TextureId) override;
 
    void Clear(float r, float g, float b, bool ForceClearNow = false) override;
 
    void QuadsBegin() override;
    void QuadsEnd() override;
    void QuadsTex3DBegin() override;
    void QuadsTex3DEnd() override;
    void TrianglesBegin() override;
    void TrianglesEnd() override;
    void QuadsEndKeepVertices() override;
    void QuadsDrawCurrentVertices(bool KeepVertices = true) override;
    void QuadsSetRotation(float Angle) override;
 
    void SetColor(float r, float g, float b, float a) override;
    void SetColor(ColorRGBA Color) override;
    void SetColor2(ColorRGBA First, ColorRGBA Second) override;
    void SetColor4(ColorRGBA TopLeft, ColorRGBA TopRight, ColorRGBA BottomLeft, ColorRGBA BottomRight) override;
 
    void ChangeColorOfQuadVertices(size_t QuadOffset, unsigned char r, unsigned char g, unsigned char b, unsigned char a) override;
 
    void QuadsSetSubset(float TlU, float TlV, float BrU, float BrV) override;
    void QuadsSetSubsetFree(
        float x0, float y0, float x1, float y1,
        float x2, float y2, float x3, float y3, int Index = -1) override;
 
    void QuadsDraw(CQuadItem *pArray, int Num) override;
 
    template<typename TName>
    void QuadsDrawTLImpl(TName *pVertices, const CQuadItem *pArray, int Num)
    {
        CCommandBuffer::SPoint Center;
 
        dbg_assert(m_Drawing == EDrawing::QUADS, "called Graphics()->QuadsDrawTL without begin");
 
        if(g_Config.m_GfxQuadAsTriangle && !m_GLUseTrianglesAsQuad)
        {
            for(int i = 0; i < Num; ++i)
            {
                // first triangle
                pVertices[m_NumVertices + 6 * i].m_Pos.x = pArray[i].m_X;
                pVertices[m_NumVertices + 6 * i].m_Pos.y = pArray[i].m_Y;
                pVertices[m_NumVertices + 6 * i].m_Tex = m_aTexture[0];
                pVertices[m_NumVertices + 6 * i].m_Color = m_aColor[0];
 
                pVertices[m_NumVertices + 6 * i + 1].m_Pos.x = pArray[i].m_X + pArray[i].m_Width;
                pVertices[m_NumVertices + 6 * i + 1].m_Pos.y = pArray[i].m_Y;
                pVertices[m_NumVertices + 6 * i + 1].m_Tex = m_aTexture[1];
                pVertices[m_NumVertices + 6 * i + 1].m_Color = m_aColor[1];
 
                pVertices[m_NumVertices + 6 * i + 2].m_Pos.x = pArray[i].m_X + pArray[i].m_Width;
                pVertices[m_NumVertices + 6 * i + 2].m_Pos.y = pArray[i].m_Y + pArray[i].m_Height;
                pVertices[m_NumVertices + 6 * i + 2].m_Tex = m_aTexture[2];
                pVertices[m_NumVertices + 6 * i + 2].m_Color = m_aColor[2];
 
                // second triangle
                pVertices[m_NumVertices + 6 * i + 3].m_Pos.x = pArray[i].m_X;
                pVertices[m_NumVertices + 6 * i + 3].m_Pos.y = pArray[i].m_Y;
                pVertices[m_NumVertices + 6 * i + 3].m_Tex = m_aTexture[0];
                pVertices[m_NumVertices + 6 * i + 3].m_Color = m_aColor[0];
 
                pVertices[m_NumVertices + 6 * i + 4].m_Pos.x = pArray[i].m_X + pArray[i].m_Width;
                pVertices[m_NumVertices + 6 * i + 4].m_Pos.y = pArray[i].m_Y + pArray[i].m_Height;
                pVertices[m_NumVertices + 6 * i + 4].m_Tex = m_aTexture[2];
                pVertices[m_NumVertices + 6 * i + 4].m_Color = m_aColor[2];
 
                pVertices[m_NumVertices + 6 * i + 5].m_Pos.x = pArray[i].m_X;
                pVertices[m_NumVertices + 6 * i + 5].m_Pos.y = pArray[i].m_Y + pArray[i].m_Height;
                pVertices[m_NumVertices + 6 * i + 5].m_Tex = m_aTexture[3];
                pVertices[m_NumVertices + 6 * i + 5].m_Color = m_aColor[3];
 
                if(m_Rotation != 0)
                {
                    Center.x = pArray[i].m_X + pArray[i].m_Width / 2;
                    Center.y = pArray[i].m_Y + pArray[i].m_Height / 2;
 
                    Rotate(Center, &pVertices[m_NumVertices + 6 * i], 6);
                }
            }
 
            AddVertices(3 * 2 * Num, pVertices);
        }
        else
        {
            for(int i = 0; i < Num; ++i)
            {
                pVertices[m_NumVertices + 4 * i].m_Pos.x = pArray[i].m_X;
                pVertices[m_NumVertices + 4 * i].m_Pos.y = pArray[i].m_Y;
                pVertices[m_NumVertices + 4 * i].m_Tex = m_aTexture[0];
                pVertices[m_NumVertices + 4 * i].m_Color = m_aColor[0];
 
                pVertices[m_NumVertices + 4 * i + 1].m_Pos.x = pArray[i].m_X + pArray[i].m_Width;
                pVertices[m_NumVertices + 4 * i + 1].m_Pos.y = pArray[i].m_Y;
                pVertices[m_NumVertices + 4 * i + 1].m_Tex = m_aTexture[1];
                pVertices[m_NumVertices + 4 * i + 1].m_Color = m_aColor[1];
 
                pVertices[m_NumVertices + 4 * i + 2].m_Pos.x = pArray[i].m_X + pArray[i].m_Width;
                pVertices[m_NumVertices + 4 * i + 2].m_Pos.y = pArray[i].m_Y + pArray[i].m_Height;
                pVertices[m_NumVertices + 4 * i + 2].m_Tex = m_aTexture[2];
                pVertices[m_NumVertices + 4 * i + 2].m_Color = m_aColor[2];
 
                pVertices[m_NumVertices + 4 * i + 3].m_Pos.x = pArray[i].m_X;
                pVertices[m_NumVertices + 4 * i + 3].m_Pos.y = pArray[i].m_Y + pArray[i].m_Height;
                pVertices[m_NumVertices + 4 * i + 3].m_Tex = m_aTexture[3];
                pVertices[m_NumVertices + 4 * i + 3].m_Color = m_aColor[3];
 
                if(m_Rotation != 0)
                {
                    Center.x = pArray[i].m_X + pArray[i].m_Width / 2;
                    Center.y = pArray[i].m_Y + pArray[i].m_Height / 2;
 
                    Rotate(Center, &pVertices[m_NumVertices + 4 * i], 4);
                }
            }
 
            AddVertices(4 * Num, pVertices);
        }
    }
 
    void QuadsDrawTL(const CQuadItem *pArray, int Num) override;
 
    void QuadsTex3DDrawTL(const CQuadItem *pArray, int Num) override;
 
    void QuadsDrawFreeform(const CFreeformItem *pArray, int Num) override;
    void QuadsText(float x, float y, float Size, const char *pText) override;
 
    void DrawRectExt(float x, float y, float w, float h, float r, int Corners) override;
    void DrawRectExt4(float x, float y, float w, float h, ColorRGBA ColorTopLeft, ColorRGBA ColorTopRight, ColorRGBA ColorBottomLeft, ColorRGBA ColorBottomRight, float r, int Corners) override;
    int CreateRectQuadContainer(float x, float y, float w, float h, float r, int Corners) override;
    void DrawRect(float x, float y, float w, float h, ColorRGBA Color, int Corners, float Rounding) override;
    void DrawRect4(float x, float y, float w, float h, ColorRGBA ColorTopLeft, ColorRGBA ColorTopRight, ColorRGBA ColorBottomLeft, ColorRGBA ColorBottomRight, int Corners, float Rounding) override;
    void DrawCircle(float CenterX, float CenterY, float Radius, int Segments) override;
 
    int CreateQuadContainer(bool AutomaticUpload = true) override;
    void QuadContainerChangeAutomaticUpload(int ContainerIndex, bool AutomaticUpload) override;
    void QuadContainerUpload(int ContainerIndex) override;
    int QuadContainerAddQuads(int ContainerIndex, CQuadItem *pArray, int Num) override;
    int QuadContainerAddQuads(int ContainerIndex, CFreeformItem *pArray, int Num) override;
    void QuadContainerReset(int ContainerIndex) override;
    void DeleteQuadContainer(int &ContainerIndex) override;
    void RenderQuadContainer(int ContainerIndex, int QuadDrawNum) override;
    void RenderQuadContainer(int ContainerIndex, int QuadOffset, int QuadDrawNum, bool ChangeWrapMode = true) override;
    void RenderQuadContainerEx(int ContainerIndex, int QuadOffset, int QuadDrawNum, float X, float Y, float ScaleX = 1.f, float ScaleY = 1.f) override;
    void RenderQuadContainerAsSprite(int ContainerIndex, int QuadOffset, float X, float Y, float ScaleX = 1.f, float ScaleY = 1.f) override;
    void RenderQuadContainerAsSpriteMultiple(int ContainerIndex, int QuadOffset, int DrawCount, SRenderSpriteInfo *pRenderInfo) override;
 
    // sprites
private:
    vec2 m_SpriteScale = vec2(-1.0f, -1.0f);
 
protected:
    void SelectSprite(const CDataSprite *pSprite, int Flags);
 
public:
    void SelectSprite(int Id, int Flags = 0) override;
    void SelectSprite7(int Id, int Flags = 0) override;
 
    void GetSpriteScale(const CDataSprite *pSprite, float &ScaleX, float &ScaleY) const override;
    void GetSpriteScale(int Id, float &ScaleX, float &ScaleY) const override;
    void GetSpriteScaleImpl(int Width, int Height, float &ScaleX, float &ScaleY) const override;
 
    void DrawSprite(float x, float y, float Size) override;
    void DrawSprite(float x, float y, float ScaledWidth, float ScaledHeight) override;
 
    int QuadContainerAddSprite(int QuadContainerIndex, float x, float y, float Size) override;
    int QuadContainerAddSprite(int QuadContainerIndex, float Size) override;
    int QuadContainerAddSprite(int QuadContainerIndex, float Width, float Height) override;
    int QuadContainerAddSprite(int QuadContainerIndex, float X, float Y, float Width, float Height) override;
 
    template<typename TName>
    void FlushVerticesImpl(bool KeepVertices, EPrimitiveType &PrimType, size_t &PrimCount, size_t &NumVerts, TName &Command, size_t VertSize)
    {
        Command.m_pVertices = nullptr;
        if(m_NumVertices == 0)
            return;
 
        NumVerts = m_NumVertices;
 
        if(!KeepVertices)
            m_NumVertices = 0;
 
        if(m_Drawing == EDrawing::QUADS)
        {
            if(g_Config.m_GfxQuadAsTriangle && !m_GLUseTrianglesAsQuad)
            {
                PrimType = EPrimitiveType::TRIANGLES;
                PrimCount = NumVerts / 3;
            }
            else
            {
                PrimType = EPrimitiveType::QUADS;
                PrimCount = NumVerts / 4;
            }
        }
        else if(m_Drawing == EDrawing::LINES)
        {
            PrimType = EPrimitiveType::LINES;
            PrimCount = NumVerts / 2;
        }
        else if(m_Drawing == EDrawing::TRIANGLES)
        {
            PrimType = EPrimitiveType::TRIANGLES;
            PrimCount = NumVerts / 3;
        }
        else
        {
            return;
        }
 
        Command.m_pVertices = (decltype(Command.m_pVertices))AllocCommandBufferData(VertSize * NumVerts);
        Command.m_State = m_State;
 
        Command.m_PrimType = PrimType;
        Command.m_PrimCount = PrimCount;
 
        AddCmd(Command, [&] {
            Command.m_pVertices = (decltype(Command.m_pVertices))m_pCommandBuffer->AllocData(VertSize * NumVerts);
            return Command.m_pVertices != nullptr;
        });
 
        m_pCommandBuffer->AddRenderCalls(1);
    }
 
    void FlushVertices(bool KeepVertices = false) override;
    void FlushVerticesTex3D() override;
 
    void RenderTileLayer(int BufferContainerIndex, const ColorRGBA &Color, char **pOffsets, unsigned int *pIndicedVertexDrawNum, size_t NumIndicesOffset) override;
    void RenderBorderTiles(int BufferContainerIndex, const ColorRGBA &Color, char *pIndexBufferOffset, const vec2 &Offset, const vec2 &Scale, uint32_t DrawNum) override;
    void RenderQuadLayer(int BufferContainerIndex, SQuadRenderInfo *pQuadInfo, size_t QuadNum, int QuadOffset, bool Grouped = false) override;
    void RenderText(int BufferContainerIndex, int TextQuadNum, int TextureSize, int TextureTextIndex, int TextureTextOutlineIndex, const ColorRGBA &TextColor, const ColorRGBA &TextOutlineColor) override;
 
    // modern GL functions
    int CreateBufferObject(size_t UploadDataSize, void *pUploadData, int CreateFlags, bool IsMovedPointer = false) override;
    void RecreateBufferObject(int BufferIndex, size_t UploadDataSize, void *pUploadData, int CreateFlags, bool IsMovedPointer = false) override;
    void UpdateBufferObjectInternal(int BufferIndex, size_t UploadDataSize, void *pUploadData, void *pOffset, bool IsMovedPointer = false);
    void CopyBufferObjectInternal(int WriteBufferIndex, int ReadBufferIndex, size_t WriteOffset, size_t ReadOffset, size_t CopyDataSize);
    void DeleteBufferObject(int BufferIndex) override;
 
    int CreateBufferContainer(SBufferContainerInfo *pContainerInfo) override;
    // destroying all buffer objects means, that all referenced VBOs are destroyed automatically, so the user does not need to save references to them
    void DeleteBufferContainer(int &ContainerIndex, bool DestroyAllBO = true) override;
    void UpdateBufferContainerInternal(int ContainerIndex, SBufferContainerInfo *pContainerInfo);
    void IndicesNumRequiredNotify(unsigned int RequiredIndicesCount) override;
 
    int GetNumScreens() const override;
    const char *GetScreenName(int Screen) const override;
 
    void Minimize() override;
    void WarnPngliteIncompatibleImages(bool Warn) override;
    void SetWindowParams(int FullscreenMode, bool IsBorderless) override;
    bool SetWindowScreen(int Index, bool MoveToCenter) override;
    bool SwitchWindowScreen(int Index, bool MoveToCenter) override;
    void Move(int x, int y) override;
    bool Resize(int w, int h, int RefreshRate) override;
    void ResizeToScreen() override;
    void GotResized(int w, int h, int RefreshRate) override;
    void UpdateViewport(int X, int Y, int W, int H, bool ByResize) override;
    bool IsScreenKeyboardShown() override;
 
    void AddWindowResizeListener(WINDOW_RESIZE_FUNC pFunc) override;
    void AddWindowPropChangeListener(WINDOW_PROPS_CHANGED_FUNC pFunc) override;
    int GetWindowScreen() override;
 
    void WindowDestroyNtf(uint32_t WindowId) override;
    void WindowCreateNtf(uint32_t WindowId) override;
 
    int WindowActive() override;
    int WindowOpen() override;
 
    void SetWindowGrab(bool Grab) override;
    void NotifyWindow() override;
 
    int Init() override;
    void Shutdown() override;
 
    void ReadPixel(ivec2 Position, ColorRGBA *pColor) override;
    void TakeScreenshot(const char *pFilename) override;
    void TakeCustomScreenshot(const char *pFilename) override;
    void Swap() override;
    bool SetVSync(bool State) override;
    bool SetMultiSampling(uint32_t ReqMultiSamplingCount, uint32_t &MultiSamplingCountBackend) override;
 
    int GetVideoModes(CVideoMode *pModes, int MaxModes, int Screen) override;
    void GetCurrentVideoMode(CVideoMode &CurMode, int Screen) override;
 
    // synchronization
    void InsertSignal(CSemaphore *pSemaphore) override;
    bool IsIdle() const override;
    void WaitForIdle() override;
 
    void AddWarning(const SWarning &Warning);
    std::optional<SWarning> CurrentWarning() override;
 
    std::optional<int> ShowMessageBox(const CMessageBox &MessageBox) override;
 
    bool IsBackendInitialized() override;
 
    bool GetDriverVersion(EGraphicsDriverAgeType DriverAgeType, int &Major, int &Minor, int &Patch, const char *&pName, EBackendType BackendType) override { return m_pBackend->GetDriverVersion(DriverAgeType, Major, Minor, Patch, pName, BackendType); }
    bool IsConfigModernAPI() override { return m_pBackend->IsConfigModernAPI(); }
    bool IsTileBufferingEnabled() override { return m_GLTileBufferingEnabled; }
    bool IsQuadBufferingEnabled() override { return m_GLQuadBufferingEnabled; }
    bool IsTextBufferingEnabled() override { return m_GLTextBufferingEnabled; }
    bool IsQuadContainerBufferingEnabled() override { return m_GLQuadContainerBufferingEnabled; }
    bool Uses2DTextureArrays() override { return m_GLUses2DTextureArrays; }
    int TextureLoadFlags() override { return Uses2DTextureArrays() ? IGraphics::TEXLOAD_TO_2D_ARRAY_TEXTURE : IGraphics::TEXLOAD_TO_3D_TEXTURE; }
    bool HasTextureArraysSupport() override { return m_GLHasTextureArraysSupport; }
 
    const char *GetVendorString() override;
    const char *GetVersionString() override;
    const char *GetRendererString() override;
    const char *GetFatalError() const override;
 
    TGLBackendReadPresentedImageData &GetReadPresentedImageDataFuncUnsafe() override;
};
 
typedef std::function<const char *(const char *, const char *)> TTranslateFunc;
extern IGraphicsBackend *CreateGraphicsBackend(TTranslateFunc &&TranslateFunc);
 
#endif // ENGINE_CLIENT_GRAPHICS_THREADED_H