SDL结合QWidget的简单使用说明(2)

#ifndef _SDL_RENDER_WND_H__
#define _SDL_RENDER_WND_H__
/********************************************************************
文件名  :    SDLRenderWnd
作者    :    @Kaiming
创建时间:    2018/3/26 11:27
版本    :     1.0
文件描述:    SDL YUV420流输出窗口
*********************************************************************/

#include <QWidget>
struct SDL_Renderer;
struct SDL_Texture;
struct SDL_Window;
struct _TTF_Font;

class SDLRenderWnd : public QWidget
{
    Q_OBJECT

public:
    SDLRenderWnd(QWidget *parent = 0);
    ~SDLRenderWnd();

    void Clear();
    QImage Grab();
    //当前窗口是否为空
    bool IsEmpty() const;

    void UpdateUserHeader(const QImage& header);
    void UpdateUserName(const QString& strName);protected:
    virtual void resizeEvent(QResizeEvent *event);private:
    static void SDL_Related_Init();
    static void SDL_Related_Uninit();

public slots:
//根据传入数据流显示视频
    void PresentFrame(const unsigned char* pBuffer, int nImageWidth, int nImageHeight);
private:
    SDL_Renderer*        　m_pRender;
    SDL_Texture*        　 m_pTexture;
    SDL_Window*            m_pWindow;
    
    bool                　　m_bEmpty;
    QString                m_strUserName;
    QByteArray             m_userHeaderData;

    static int            m_nRef;        //引用计数来确定SDL全局资源的创建和回收
    static _TTF_Font*     m_pFont;
};

#endif // _SDL_RENDER_H__

#include "SDLRenderWnd.h
#include <QBuffer>
#include <QResizeEvent>

extern "C" {
#include "sdl\SDL.h"
#include "sdl\SDL_ttf.h"
#include "sdl\SDL_image.h"
}
#pragma comment(lib, "SDL2.lib")
#pragma comment(lib, "SDL2_ttf.lib")
#pragma comment(lib, "SDL2_image.lib")

int SDLRenderWnd::m_nRef = 0;
_TTF_Font* SDLRenderWnd::m_pFont = nullptr;
SDLRenderWnd::SDLRenderWnd(QWidget *parent)
    : QWidget(parent),
      m_pTexture(nullptr)
{
    setUpdatesEnabled(false);  
    SDL_Related_Init();
    m_pWindow = SDL_CreateWindowFrom((void*)winId());
    m_pRender = SDL_CreateRenderer(m_pWindow, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "best");
}

SDLRenderWnd::~SDLRenderWnd()
{
    if (m_pWindow)
        SDL_DestroyWindow(m_pWindow);
    if (m_pRender)
        SDL_DestroyRenderer(m_pRender);
    if (m_pTexture)
        SDL_DestroyTexture(m_pTexture);
    SDL_Related_Uninit();
}

void SDLRenderWnd::PresentFrame(const unsigned char* pBuffer, int nImageWidth, int nImageHeight)
{
    if (!m_pRender) {
        printf("Render not Create\n");
    }
    else {
        int nTextureWidth = 0, nTextureHeight = 0;
        SDL_QueryTexture(m_pTexture, nullptr, nullptr, &nTextureWidth, &nTextureHeight);
        if (nTextureWidth != nImageWidth || nTextureHeight != nImageHeight) {
            if (m_pTexture)
                SDL_DestroyTexture(m_pTexture);
            m_pTexture = SDL_CreateTexture(m_pRender, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING,
                nImageWidth, nImageHeight);
        }
    }
    
    if (!m_pTexture) {
        printf("YUV Texture Create Failed\n");
    }
    else {
        SDL_UpdateTexture(m_pTexture, nullptr, pBuffer, nImageWidth);
        SDL_RenderClear(m_pRender);
        //Copy YUV Stream
        SDL_RenderCopy(m_pRender, m_pTexture, nullptr, nullptr);
        //Draw UserHeader
        if (SDL_RWops* ops = SDL_RWFromMem((void*)(m_userHeaderData.constData()), m_userHeaderData.size())) {
            if (SDL_Surface* pHeaderSurface = IMG_LoadPNG_RW(ops)) {
                SDL_FreeRW(ops);
                if (SDL_Texture* pHeaderTexture = SDL_CreateTextureFromSurface(m_pRender, pHeaderSurface)) {
                    SDL_Rect dstRect{ 6, height() - 42, 42, 42 };
                    SDL_FreeSurface(pHeaderSurface);
                    SDL_RenderCopy(m_pRender, pHeaderTexture, nullptr, &dstRect);
                    SDL_DestroyTexture(pHeaderTexture);
                }
            }
        }
    }

    //Draw UserName
    if (!m_pFont) {
        printf("Open System Font Failed\n");
    }
    else
    {
        SDL_Color color{ 255, 255, 255 };
        if (SDL_Surface* pTextSurface = TTF_RenderUTF8_Blended(m_pFont, m_strUserName.toUtf8(), color)) {
            SDL_Rect dstRect{ 60, height() - pTextSurface->h, pTextSurface->w, pTextSurface->h };
            if (SDL_Texture* pTextTexture = SDL_CreateTextureFromSurface(m_pRender, pTextSurface)) {
                SDL_FreeSurface(pTextSurface);
                SDL_RenderCopy(m_pRender, pTextTexture, nullptr, &dstRect);
                SDL_DestroyTexture(pTextTexture);
            }
        }
    }
    
    SDL_RenderPresent(m_pRender);
}

void SDLRenderWnd::Clear()
{
    SDL_RenderClear(m_pRender);
}


void SDLRenderWnd::UpdateUserHeader(const QImage& header)
{
    QBuffer buffer(&m_userHeaderData);
    header.save(&buffer, "PNG");
}

void SDLRenderWnd::UpdateUserName(const QString& strName)
{
    m_strUserName = strName;
}

void SDLRenderWnd::resizeEvent(QResizeEvent *event)
{
    QWidget::resizeEvent(event);
}

void SDLRenderWnd::SDL_Related_Init()
{
    if (0 == m_nRef++)
    {
        SDL_Init(SDL_INIT_VIDEO);
        TTF_Init();
        IMG_Init(IMG_INIT_PNG);
        m_pFont = TTF_OpenFont("C:/Windows/Fonts/simfang.ttf", 18);
    }
}

void SDLRenderWnd::SDL_Related_Uninit()
{
    if (0 == --m_nRef)
    {
        if (m_pFont)
            TTF_CloseFont(m_pFont);
        SDL_Quit();
        TTF_Quit();
        IMG_Quit();
    }
}