backend_sdl.h

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#ifndef ENGINE_CLIENT_BACKEND_SDL_H
#define ENGINE_CLIENT_BACKEND_SDL_H
 
#include <base/detect.h>
 
#include <engine/client/backend/backend_base.h>
#include <engine/client/graphics_threaded.h>
#include <engine/graphics.h>
 
#include <SDL_video.h>
 
#include <atomic>
#include <condition_variable>
#include <cstddef>
#include <cstdint>
#include <mutex>
#include <vector>
 
#if defined(CONF_PLATFORM_MACOS)
#include <objc/objc-runtime.h>
 
class CAutoreleasePool
{
private:
    id m_Pool;
 
public:
    CAutoreleasePool()
    {
        Class NSAutoreleasePoolClass = (Class)objc_getClass("NSAutoreleasePool");
        m_Pool = class_createInstance(NSAutoreleasePoolClass, 0);
        SEL selector = sel_registerName("init");
        ((id (*)(id, SEL))objc_msgSend)(m_Pool, selector);
    }
 
    ~CAutoreleasePool()
    {
        SEL selector = sel_registerName("drain");
        ((id (*)(id, SEL))objc_msgSend)(m_Pool, selector);
    }
};
#endif
 
// basic threaded backend, abstract, missing init and shutdown functions
class CGraphicsBackend_Threaded : public IGraphicsBackend
{
private:
    TTranslateFunc m_TranslateFunc;
    std::string m_FatalError;
    SGfxWarningContainer m_Warning;
 
public:
    // constructed on the main thread, the rest of the functions is run on the render thread
    class ICommandProcessor
    {
    public:
        virtual ~ICommandProcessor() = default;
        virtual void RunBuffer(CCommandBuffer *pBuffer) = 0;
 
        virtual const SGfxErrorContainer &GetError() const = 0;
        virtual void ErroneousCleanup() = 0;
 
        virtual const SGfxWarningContainer &GetWarning() const = 0;
    };
 
    CGraphicsBackend_Threaded(TTranslateFunc &&TranslateFunc);
 
    void RunBuffer(CCommandBuffer *pBuffer) override;
    void RunBufferSingleThreadedUnsafe(CCommandBuffer *pBuffer) override;
    bool IsIdle() const override;
    void WaitForIdle() override;
 
    void ProcessError(const SGfxErrorContainer &Error);
 
protected:
    void StartProcessor(ICommandProcessor *pProcessor);
    void StopProcessor();
 
    bool HasWarning() const
    {
        return m_Warning.m_WarningType != GFX_WARNING_TYPE_NONE;
    }
 
private:
    ICommandProcessor *m_pProcessor;
    std::atomic_bool m_Shutdown;
#if !defined(CONF_PLATFORM_EMSCRIPTEN)
    std::mutex m_BufferSwapMutex;
    std::condition_variable m_BufferSwapCond;
    CCommandBuffer *m_pBuffer;
    bool m_Started = false;
    std::atomic_bool m_BufferInProcess;
    void *m_pThread;
    static void ThreadFunc(void *pUser);
#endif
 
public:
    const char *GetFatalError() const override;
    bool GetWarning(std::vector<std::string> &WarningStrings) override;
};
 
// takes care of implementation independent operations
class CCommandProcessorFragment_General
{
    void Cmd_Signal(const CCommandBuffer::SCommand_Signal *pCommand);
 
public:
    bool RunCommand(const CCommandBuffer::SCommand *pBaseCommand);
};
 
struct SBackendCapabilities
{
    bool m_TileBuffering;
    bool m_QuadBuffering;
    bool m_TextBuffering;
    bool m_QuadContainerBuffering;
 
    bool m_MipMapping;
    bool m_NPOTTextures;
    bool m_3DTextures;
    bool m_2DArrayTextures;
    bool m_2DArrayTexturesAsExtension;
    bool m_ShaderSupport;
 
    // use quads as much as possible, even if the user config says otherwise
    bool m_TrianglesAsQuads;
 
    int m_ContextMajor;
    int m_ContextMinor;
    int m_ContextPatch;
};
 
// takes care of sdl related commands
class CCommandProcessorFragment_SDL
{
    // SDL stuff
    SDL_Window *m_pWindow = nullptr;
    SDL_GLContext m_GLContext = nullptr;
 
public:
    enum
    {
        CMD_INIT = CCommandBuffer::CMDGROUP_PLATFORM_SDL,
        CMD_SHUTDOWN,
    };
 
    struct SCommand_Init : public CCommandBuffer::SCommand
    {
        SCommand_Init() :
            SCommand(CMD_INIT) {}
        SDL_Window *m_pWindow;
        SDL_GLContext m_GLContext;
    };
 
    struct SCommand_Shutdown : public CCommandBuffer::SCommand
    {
        SCommand_Shutdown() :
            SCommand(CMD_SHUTDOWN) {}
    };
 
private:
    void Cmd_Init(const SCommand_Init *pCommand);
    void Cmd_Shutdown(const SCommand_Shutdown *pCommand);
    void Cmd_Swap(const CCommandBuffer::SCommand_Swap *pCommand);
    void Cmd_VSync(const CCommandBuffer::SCommand_VSync *pCommand);
    void Cmd_WindowCreateNtf(const CCommandBuffer::SCommand_WindowCreateNtf *pCommand);
    void Cmd_WindowDestroyNtf(const CCommandBuffer::SCommand_WindowDestroyNtf *pCommand);
 
public:
    CCommandProcessorFragment_SDL();
 
    bool RunCommand(const CCommandBuffer::SCommand *pBaseCommand);
};
 
// command processor implementation, uses the fragments to combine into one processor
class CCommandProcessor_SDL_GL : public CGraphicsBackend_Threaded::ICommandProcessor
{
    CCommandProcessorFragment_GLBase *m_pGLBackend;
    CCommandProcessorFragment_SDL m_SDL;
    CCommandProcessorFragment_General m_General;
 
    EBackendType m_BackendType;
 
    SGfxErrorContainer m_Error;
    SGfxWarningContainer m_Warning;
 
public:
    CCommandProcessor_SDL_GL(EBackendType BackendType, int GLMajor, int GLMinor, int GLPatch);
    ~CCommandProcessor_SDL_GL() override;
    void RunBuffer(CCommandBuffer *pBuffer) override;
 
    const SGfxErrorContainer &GetError() const override;
    void ErroneousCleanup() override;
 
    const SGfxWarningContainer &GetWarning() const override;
 
    void HandleError();
    void HandleWarning();
};
 
static constexpr size_t GPU_INFO_STRING_SIZE = 256;
 
// graphics backend implemented with SDL and the graphics library @see EBackendType
class CGraphicsBackend_SDL_GL : public CGraphicsBackend_Threaded
{
    SDL_Window *m_pWindow = nullptr;
    SDL_GLContext m_GLContext = nullptr;
    ICommandProcessor *m_pProcessor = nullptr;
    std::atomic<uint64_t> m_TextureMemoryUsage{0};
    std::atomic<uint64_t> m_BufferMemoryUsage{0};
    std::atomic<uint64_t> m_StreamMemoryUsage{0};
    std::atomic<uint64_t> m_StagingMemoryUsage{0};
 
    TTwGraphicsGpuList m_GpuList;
 
    TGLBackendReadPresentedImageData m_ReadPresentedImageDataFunc;
 
    int m_NumScreens;
 
    SBackendCapabilities m_Capabilities;
 
    char m_aVendorString[GPU_INFO_STRING_SIZE] = {};
    char m_aVersionString[GPU_INFO_STRING_SIZE] = {};
    char m_aRendererString[GPU_INFO_STRING_SIZE] = {};
 
    EBackendType m_BackendType = BACKEND_TYPE_AUTO;
 
    char m_aErrorString[256];
 
    static EBackendType DetectBackend();
    static void ClampDriverVersion(EBackendType BackendType);
 
public:
    CGraphicsBackend_SDL_GL(TTranslateFunc &&TranslateFunc);
    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) override;
    int Shutdown() 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;
 
    int GetNumScreens() const override { return m_NumScreens; }
    const char *GetScreenName(int Screen) const override;
 
    void GetVideoModes(CVideoMode *pModes, int MaxModes, int *pNumModes, float HiDPIScale, int MaxWindowWidth, int MaxWindowHeight, int ScreenId) override;
    void GetCurrentVideoMode(CVideoMode &CurMode, float HiDPIScale, int MaxWindowWidth, int MaxWindowHeight, int ScreenId) override;
 
    void Minimize() override;
    void SetWindowParams(int FullscreenMode, bool IsBorderless) override;
    bool SetWindowScreen(int Index, bool MoveToCenter) override;
    bool UpdateDisplayMode(int Index) override;
    int GetWindowScreen() override;
    int WindowActive() override;
    int WindowOpen() override;
    void SetWindowGrab(bool Grab) override;
    bool ResizeWindow(int w, int h, int RefreshRate) override;
    void GetViewportSize(int &w, int &h) override;
    void NotifyWindow() override;
    bool IsScreenKeyboardShown() override;
 
    void WindowDestroyNtf(uint32_t WindowId) override;
    void WindowCreateNtf(uint32_t WindowId) override;
 
    bool GetDriverVersion(EGraphicsDriverAgeType DriverAgeType, int &Major, int &Minor, int &Patch, const char *&pName, EBackendType BackendType) override;
    bool IsConfigModernAPI() override { return IsModernAPI(m_BackendType); }
    bool UseTrianglesAsQuad() override { return m_Capabilities.m_TrianglesAsQuads; }
    bool HasTileBuffering() override { return m_Capabilities.m_TileBuffering; }
    bool HasQuadBuffering() override { return m_Capabilities.m_QuadBuffering; }
    bool HasTextBuffering() override { return m_Capabilities.m_TextBuffering; }
    bool HasQuadContainerBuffering() override { return m_Capabilities.m_QuadContainerBuffering; }
    bool Uses2DTextureArrays() override { return m_Capabilities.m_2DArrayTextures; }
    bool HasTextureArraysSupport() override { return m_Capabilities.m_2DArrayTextures || m_Capabilities.m_3DTextures; }
 
    const char *GetErrorString() override
    {
        if(m_aErrorString[0] != '\0')
            return m_aErrorString;
 
        return nullptr;
    }
 
    const char *GetVendorString() override
    {
        return m_aVendorString;
    }
 
    const char *GetVersionString() override
    {
        return m_aVersionString;
    }
 
    const char *GetRendererString() override
    {
        return m_aRendererString;
    }
 
    TGLBackendReadPresentedImageData &GetReadPresentedImageDataFuncUnsafe() override;
 
    std::optional<int> ShowMessageBox(const IGraphics::CMessageBox &MessageBox) override;
 
    static bool IsModernAPI(EBackendType BackendType);
};
 
#endif // ENGINE_CLIENT_BACKEND_SDL_H