SDL2：封装媒体显示播放Csdl2

Github

https://github.com/gongluck/SDL2-study/tree/master/Csdl2

Csdl2.h

#ifndef __CSDL2_H__
#define __CSDL2_H__

#include <SDL.h>
#include <string>
#include <mutex>

class Csdl2
{
public:
    // 状态
    enum STATUS { STOP = 0b00, LOCKEDV = 0b01, LOCKEDA = 0b10, LOCKEDBOTH = 0b11 };

    // 全局的初始化
    bool global_init(Uint32 flags, std::string& err);
    // 全局的反初始化
    bool global_uninit(std::string& err);

    // 设置(windows)窗口
    bool set_window(const void* hwnd, std::string& err);
    // 设置图像格式(SDL_PIXELFORMAT_???)
    bool set_pix_fmt(Uint32 fmt, int w, int h, std::string& err);
    // 渲染数据，pitch是图像一行的字节大小，rect是渲染目标矩形，angle旋转角度，center旋转中心(在rect，{0,0}为左上)，flip翻转
    bool render(const void* data, int pitch, const SDL_Rect* rect, 
        const double angle, const SDL_Point* center, const SDL_RendererFlip flip, std::string& err);
    // 清理图像格式资源
    bool clear_pix_fmt(std::string& err);
    // 销毁关联资源
    bool detach_window(std::string& err);

    // 设置音频格式和处理回调
    bool set_audio_fmt(int freq, SDL_AudioFormat fmt, Uint8 channels, Uint16 samples, SDL_AudioCallback callback, void* userdata, std::string& err);
    // 开始音频播放
    bool start_audio(std::string& err);
    // 停止音频播放
    bool stop_audio(std::string& err);

private:
    STATUS status_ = STOP;
    std::recursive_mutex mutex_;

    SDL_Window* win_ = nullptr;
    SDL_Renderer* renderer_ = nullptr;
    SDL_Texture* texture_ = nullptr;

    SDL_AudioSpec reqspec_ = { 0 };
    SDL_AudioSpec recspec_ = { 0 };
};

#endif//__CSDL2_H__

Csdl2.cpp

#include "Csdl2.h"

// 递归锁
#define LOCKCSDL2() std::lock_guard<std::recursive_mutex> _lock(this->mutex_)

// 检查停止状态
#define CHECKCSDL2STOP(err) if(this->status_ != STOP){    err = "status is not stop.";    return false;}
// 检查视频停止
#define CHECKCSDL2STOPV(err) if(this->status_ & 1 != 0){    err = "statusv is not stop.";    return false;}
// 检查音频停止
#define CHECKCSDL2STOPA(err) if((this->status_ >> 1) & 1 != 0){    err = "statusa is not stop.";    return false;}
// 检查视频未停止
#define CHECKCSDL2NSTOPV(err) if(this->status_ & 1 == 0){    err = "statusv is stop.";    return false;}
// 检查音频未停止
#define CHECKCSDL2NSTOPA(err) if((this->status_ >> 1) & 1 == 0){    err = "statusa is stop.";    return false;}

// 返回成功
#define OPTSUCCEED(){    err = "opt succeed.";    return true;}

// 返回失败
#define OPTFAILED(){    err = SDL_GetError();    return false; }

// 判断结果，并返回(必定退出函数!!!)
#define CHECKSDLRET(ret)if(ret == 0){    OPTSUCCEED();}else{    OPTFAILED();}

bool Csdl2::global_init(Uint32 flags, std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2STOP(err);
    if (SDL_Init(flags) < 0)
    {
        OPTFAILED();
    }
    else
    {
        OPTSUCCEED();
    }
}

bool Csdl2::global_uninit(std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2STOP(err);
    SDL_Quit();
    OPTSUCCEED();
}

bool Csdl2::set_window(const void* hwnd, std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2STOPV(err);
    detach_window(err);
    win_ = SDL_CreateWindowFrom(hwnd);
    if (win_ != nullptr)
    {
        renderer_ = SDL_CreateRenderer(win_, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
        if (renderer_ != nullptr)
        {
            OPTSUCCEED();
        }
        else
        {
            std::string e;
            detach_window(e);
            OPTFAILED();
        }
    }
    else
    {
        OPTFAILED();
    }
}

bool Csdl2::set_pix_fmt(Uint32 fmt, int w, int h, std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2STOPV(err);
    clear_pix_fmt(err);
    if (renderer_ == nullptr)
    {
        err = "renderer is nullptr.";
        return false;
    }
    texture_ = SDL_CreateTexture(renderer_, fmt, SDL_TEXTUREACCESS_STREAMING, w, h);
    if (texture_ != nullptr)
    {
        status_ = static_cast<STATUS>(static_cast<unsigned int>(status_) | LOCKEDV);
        OPTSUCCEED();
    }
    else
    {
        OPTFAILED();
    }
}

bool Csdl2::render(const void* data, int pitch, const SDL_Rect* rect, 
    const double angle, const SDL_Point* center, const SDL_RendererFlip flip, 
    std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2NSTOPV(err);
    if (texture_ == nullptr || renderer_ == nullptr)
    {
        err = texture_ == nullptr ? "texture is nullptr." : "renderer is nullptr.";
        return false;
    }
    if (SDL_UpdateTexture(texture_, nullptr, data, pitch) != 0)
    {
        OPTFAILED();
    }
    else
    {
        if (SDL_RenderClear(renderer_) != 0)
        {
            OPTFAILED();
        }
        else
        {
            if (SDL_RenderCopyEx(renderer_, texture_, nullptr, rect, angle, center, flip) != 0)
            {
                OPTFAILED();
            }
            else
            {
                SDL_RenderPresent(renderer_);
                OPTSUCCEED();
            }
        }
    }
}

bool Csdl2::clear_pix_fmt(std::string& err)
{
    LOCKCSDL2();
    if (texture_ != nullptr)
    {
        SDL_DestroyTexture(texture_);
        texture_ = nullptr;
    }
    status_ = static_cast<STATUS>(static_cast<unsigned int>(status_) & ~LOCKEDV);
    OPTSUCCEED();
}

bool Csdl2::detach_window(std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2STOPV(err);
    if (renderer_ != nullptr)
    {
        SDL_DestroyRenderer(renderer_);
        renderer_ = nullptr;
    }
    if (win_ != nullptr)
    {
        SDL_DestroyWindow(win_);
        win_ = nullptr;
    }
    OPTSUCCEED();
}

bool Csdl2::set_audio_fmt(int freq, SDL_AudioFormat fmt, Uint8 channels, Uint16 samples, SDL_AudioCallback callback, void* userdata, std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2STOPA(err);
    reqspec_ = { 0 };
    recspec_ = { 0 };
    reqspec_.freq = freq;
    reqspec_.format = fmt;
    reqspec_.channels = channels;
    reqspec_.samples = samples;
    reqspec_.callback = callback;
    reqspec_.userdata = userdata;
    if (SDL_OpenAudio(&reqspec_, &recspec_) != 0)
    {
        OPTFAILED();
    }
    else
    {
        status_ = static_cast<STATUS>(static_cast<unsigned int>(status_) | LOCKEDA);
        OPTSUCCEED();
    }
}

bool Csdl2::start_audio(std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2NSTOPA(err);
    SDL_PauseAudio(0);
    OPTSUCCEED();
}

bool Csdl2::stop_audio(std::string& err)
{
    LOCKCSDL2();
    CHECKCSDL2NSTOPA(err);
    SDL_PauseAudio(1);
    status_ = static_cast<STATUS>(static_cast<unsigned int>(status_) & ~LOCKEDA);
    OPTSUCCEED();
}

测试

#include "Csdl2.h"
#include <iostream>
#include <fstream>
#include <Windows.h>

#define TESTCHECKRET(ret)if(!ret){    std::cerr << err << std::endl;    std::cout << "input to end." << std::endl;    getchar();    return SDL_Error(SDL_LASTERROR);}

Csdl2 g_test;
void SDLCALL SDL_AudioCB(void* userdata, Uint8* stream, int len)
{
    static std::ifstream f("in.pcm", std::ios::binary);
    SDL_memset(stream, 0, len);
    void* buf = malloc(len);
    f.read((char*)buf, len);
    SDL_MixAudio(stream, (const Uint8*)buf, len, SDL_MIX_MAXVOLUME);
    free(buf);
    if (f.eof())
    {
        std::cout << "end" << std::endl;
        f.close();
        std::string err;
        g_test.stop_audio(err);
    }    
}

int main(int argc, char* argv[])
{
    std::string err;
    RECT rect = { 0 };
    SDL_Point p = { 0, 50 };
    std::ifstream file("in.rgb", std::ios::binary);
    if (!file.is_open())
    {
        std::cerr << "open file failed " << std::endl;
        getchar();
        return 0;
    }
    int size = 320 * 240 * 3;
    void* buf = malloc(size);

    file.read(static_cast<char*>(buf), size);

    TESTCHECKRET(g_test.global_init(SDL_INIT_VIDEO | SDL_INIT_AUDIO, err));

    HWND hwnd = CreateWindow(TEXT("static"), TEXT("test csdl2"), WS_VISIBLE,
        CW_USEDEFAULT, CW_USEDEFAULT, 800, 500, nullptr, nullptr, GetModuleHandle(nullptr), nullptr);
    //SDL_Window* hwnd = SDL_CreateWindow("test csdl2", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 320, 240, SDL_WINDOW_SHOWN);
    if (hwnd == nullptr)
    {
        std::cerr << "create window failed " << GetLastError() << std::endl;
        goto END;
    }
    TESTCHECKRET(g_test.set_window(hwnd, err));
    TESTCHECKRET(g_test.set_pix_fmt(SDL_PIXELFORMAT_RGB24, 320, 240, err));
    TESTCHECKRET(g_test.render(buf, size / 240, nullptr, 2, &p, SDL_FLIP_NONE, err));
    std::cout << "render succeed." << std::endl;

    TESTCHECKRET(g_test.set_audio_fmt(44100, AUDIO_F32, 2, 1024, SDL_AudioCB, nullptr, err));
    TESTCHECKRET(g_test.start_audio(err));
    std::cout << "open audio succeed." << std::endl;

END:
    std::cout << "input to end." << std::endl;
    getchar();
    TESTCHECKRET(g_test.clear_pix_fmt(err));
    TESTCHECKRET(g_test.detach_window(err));
    if (hwnd != nullptr)
    {
        DestroyWindow(hwnd);
        hwnd = nullptr;
    }
    TESTCHECKRET(g_test.stop_audio(err));
    TESTCHECKRET(g_test.global_uninit(err));
    if (buf != nullptr)
    {
        free(buf);
        buf = nullptr;
    }
    return 0;
}