context.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
 *                                                                           *
 * All rights reserved.                                                      *
 *                                                                           *
 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
 *                                                                           *
 * This program is distributed in the hope that it will be useful,           *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_BGFX_CONTEXT_H
#define VCL_BGFX_CONTEXT_H
 
#include "context/callback.h"
#include "context/font_manager.h"
#include "context/program_manager.h"
 
#include <bgfx/bgfx.h>
#include <bgfx/platform.h>
 
#include <mutex>
#include <stack>
 
#define BGFX_INVALID_VIEW 65535
 
namespace vcl {
 
class Context
{
    // when initialization is done with a window handle
    // this will become the main window handle (withe the *special* framebuffer)
    // otherwise (null window handle) means that the context is headless (no UI)
    void* mWindowHandle  = nullptr;
    void* mDisplayHandle = nullptr;
 
    std::stack<bgfx::ViewId> mViewStack;
 
    Callback        mCallBack;
    FontManager*    mFontManager    = nullptr;
    ProgramManager* mProgramManager = nullptr;
 
    inline static bgfx::RendererType::Enum sRenderType =
        bgfx::RendererType::Count;
 
    inline static uint sResetFlags = BGFX_RESET_VSYNC;
 
    // singleton
    inline static Context*   sInstancePtr = nullptr;
    inline static std::mutex sMutex;
 
public:
    // default values, used for optional parameters
    static constexpr uint32_t                  DEFAULT_CLEAR_COLOR = 0x000000ff;
    static constexpr float                     DEFAULT_CLEAR_DEPTH = 1.0f;
    static constexpr uint8_t                   DEFAULT_CLEAR_STENCIL = 0;
    static constexpr bgfx::TextureFormat::Enum DEFAULT_COLOR_FORMAT =
        bgfx::TextureFormat::RGBA8;
    static constexpr bgfx::TextureFormat::Enum DEFAULT_DEPTH_FORMAT =
        bgfx::TextureFormat::D24S8;
 
    static Context& instance(
        void* windowHandle  = nullptr,
        void* displayHandle = nullptr);
 
    static void init(
        void* windowHandle  = nullptr,
        void* displayHandle = nullptr);
 
    static void initHeadless();
 
    static bool isInitialized();
 
    static void shutdown();
 
    static bgfx::RendererType::Enum renderType();
 
    static void setRenderType(bgfx::RendererType::Enum renderType);
 
    static void setResetFlags(uint flags);
 
    static void setDebugVerbosity(bool verbose);
 
    bool isHeadless() const;
 
    const bgfx::Caps& capabilites() const;
 
    bool supportsReadback() const;
 
    bool isDefaultWindow(void* windowHandle) const;
 
    bool isValidViewId(bgfx::ViewId viewId) const;
 
    bgfx::ViewId requestViewId();
 
    void releaseViewId(bgfx::ViewId viewId);
 
    bgfx::FrameBufferHandle createOffscreenFramebuffer(
        uint16_t                  width,
        uint16_t                  height,
        bgfx::TextureFormat::Enum colorFormat = DEFAULT_COLOR_FORMAT,
        bgfx::TextureFormat::Enum depthFormat = DEFAULT_DEPTH_FORMAT);
 
    void resetDefaultFramebuffer(
        uint16_t                  width,
        uint16_t                  height,
        bgfx::TextureFormat::Enum colorFormat = DEFAULT_COLOR_FORMAT);
 
    bgfx::FrameBufferHandle createFramebufferAndInitView(
        void*                     winId,
        bgfx::ViewId              view,
        uint16_t                  width,
        uint16_t                  height,
        bool                      clear        = false,
        uint32_t                  clearColor   = DEFAULT_CLEAR_COLOR,
        float                     clearDepth   = DEFAULT_CLEAR_DEPTH,
        uint8_t                   clearStencil = DEFAULT_CLEAR_STENCIL,
        bgfx::TextureFormat::Enum colorFormat  = DEFAULT_COLOR_FORMAT,
        bgfx::TextureFormat::Enum depthFormat  = DEFAULT_DEPTH_FORMAT);
 
    bgfx::FrameBufferHandle createOffscreenFramebufferAndInitView(
        bgfx::ViewId              view,
        uint16_t                  width,
        uint16_t                  height,
        bool                      clear        = false,
        uint32_t                  clearColor   = DEFAULT_CLEAR_COLOR,
        float                     clearDepth   = DEFAULT_CLEAR_DEPTH,
        uint8_t                   clearStencil = DEFAULT_CLEAR_STENCIL,
        bgfx::TextureFormat::Enum colorFormat  = DEFAULT_COLOR_FORMAT,
        bgfx::TextureFormat::Enum depthFormat  = DEFAULT_DEPTH_FORMAT);
 
    FontManager& fontManager();
 
    ProgramManager& programManager();
 
private:
    Context(void* windowHandle, void* displayHandle);
 
    ~Context();
 
public:
    Context(const Context&)            = delete;
    Context& operator=(const Context&) = delete;
    Context(Context&&)                 = delete;
    Context& operator=(Context&&)      = delete;
};
 
} // namespace vcl
 
#endif // VCL_BGFX_CONTEXT_H