用Cocos2d-x和libvlc寫一個跨平台播放器

簡介：本文使用cocos2d-x和libvlc兩大免費開源的跨平台框架，實現一個視頻播放器。開發工具使用Visual Studio 2010，測試運行平台為Windows（之前只測了windows，現在mac和linux下也測試通過，ios和android還未測試，很多看了這篇博客的朋友都問過ios和android下能不能用，這點我也無法確定，如果有高手一這兩平台下任一平台測試通過麻煩通知一聲）。cocos2d-x版本2.0.3，VLC版本2.0.5。

    目前游戲程序開發者大部分在以下幾個平台上開發游戲：Windows、Mac OS X、IOS和Android。開發2D游戲且跨平台，cocos2d-x是個非常不錯的選擇，而libvlc也提供了各大平台的支持，因此使用這兩大框架理論上可以做到一次編寫，全平台運行的目的。

    打開Visual Studio 2010，新建一個Cocos2d-win32 Application項目，我這里叫Cocos2dPlayer，配置好整個項目，直到可以編譯通過且能運行（如何配置可以參考網上很多帖子教程，在此就不多說，見諒）。另外還要加上vlc頭文件、庫文件和動態鏈接庫文件，我是直接下載vlc播放器的安裝版本然后在sdk目錄中把vlc文件夾拷貝到Visual Studio 2010的VC\include目錄下，庫文件和動態鏈接庫文件則放在本項目的Debug.win32和Release.win32目錄下。

    接下來進入正題：

    創建文件MoviePlayer.h和MoviePlayer.cpp

MoviePlayer.h

#ifndef __MOVIEPLAYER_H__
#define __MOVIEPLAYER_H__

/****************************************************************************
http://www.cnblogs.com/evan-cai/

Author: Evan-Cai
Date: 2013-01-25
****************************************************************************/

#include <vlc\vlc.h>
#include "sprite_nodes\CCSprite.h"

NS_CC_BEGIN

class MoviePlayer : public CCSprite
{
public:
    ~MoviePlayer();

    static MoviePlayer * instance(void);

    bool init(void);
    void play(char *path);
    void stop(void);
    void pause(void);
    void draw(void);
protected:
    MoviePlayer();

private:

    libvlc_instance_t *vlc;
    libvlc_media_player_t *vlc_player;

    unsigned int width;
    unsigned int height;

    static MoviePlayer * _instance; 
};

NS_CC_END

#endif

MoviePlayer.cpp

#include "MoviePlayer.h"
#include "CCDirector.h"

NS_CC_BEGIN

MoviePlayer * MoviePlayer::_instance = 0;

static char * videobuf = 0;

static void *lock(void *data, void **p_pixels)
{
    *p_pixels = videobuf;
    return NULL;
}

static void unlock(void *data, void *id, void *const *p_pixels)
{
    assert(id == NULL);
}

static void display(void *data, void *id)
{
    (void) data;
    assert(id == NULL);
}

MoviePlayer::MoviePlayer():
vlc(0), vlc_player(0)
{
    init();
}

MoviePlayer::~MoviePlayer()
{
    CCSprite::~CCSprite();
    free(videobuf);

    libvlc_media_player_stop(vlc_player);
    libvlc_media_player_release(vlc_player);
    libvlc_release(vlc);
}

bool MoviePlayer::init(void)
{
    vlc = libvlc_new(0, NULL);
    vlc_player = libvlc_media_player_new(vlc);

    CCSize size = CCDirector::sharedDirector()->getWinSize();
    width = size.width;
    height = size.height;
    videobuf = (char *)malloc((width * height) << 2);
    memset(videobuf, 0, (width * height) << 2);
    libvlc_video_set_callbacks(vlc_player, lock, unlock, display, NULL);
    libvlc_video_set_format(vlc_player, "RGBA", width, height, width << 2);
    
    CCTexture2D *texture = new CCTexture2D();
    texture->initWithData(videobuf, kCCTexture2DPixelFormat_RGBA8888, width, height, size);
    return initWithTexture(texture);
}

void MoviePlayer::play(char *path)
{
    libvlc_media_t *media = libvlc_media_new_path(vlc, path);
    libvlc_media_player_set_media(vlc_player, media);
    libvlc_media_release(media);
    libvlc_media_player_play(vlc_player);
}

void MoviePlayer::stop(void)
{
    libvlc_media_player_stop(vlc_player);
}

void MoviePlayer::pause(void)
{
    libvlc_media_player_pause(vlc_player);
}

void MoviePlayer::draw(void)
{

    CC_PROFILER_START_CATEGORY(kCCProfilerCategorySprite, "CCSprite - draw");

    CCAssert(!m_pobBatchNode, "If CCSprite is being rendered by CCSpriteBatchNode, CCSprite#draw SHOULD NOT be called");

    CC_NODE_DRAW_SETUP();

    ccGLBlendFunc( m_sBlendFunc.src, m_sBlendFunc.dst );

    if (m_pobTexture != NULL)
    {
        ccGLBindTexture2D( m_pobTexture->getName() );
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE,(uint8_t *) videobuf);
    }
    else
    {
        ccGLBindTexture2D(0);
    }

    //
    // Attributes
    //

    ccGLEnableVertexAttribs( kCCVertexAttribFlag_PosColorTex );

#define kQuadSize sizeof(m_sQuad.bl)
    long offset = (long)&m_sQuad;

    // vertex
    int diff = offsetof( ccV3F_C4B_T2F, vertices);
    glVertexAttribPointer(kCCVertexAttrib_Position, 3, GL_FLOAT, GL_FALSE, kQuadSize, (void*) (offset + diff));

    // texCoods
    diff = offsetof( ccV3F_C4B_T2F, texCoords);
    glVertexAttribPointer(kCCVertexAttrib_TexCoords, 2, GL_FLOAT, GL_FALSE, kQuadSize, (void*)(offset + diff));

    // color
    diff = offsetof( ccV3F_C4B_T2F, colors);
    glVertexAttribPointer(kCCVertexAttrib_Color, 4, GL_UNSIGNED_BYTE, GL_TRUE, kQuadSize, (void*)(offset + diff));

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    CHECK_GL_ERROR_DEBUG();

    CC_INCREMENT_GL_DRAWS(1);

    CC_PROFILER_STOP_CATEGORY(kCCProfilerCategorySprite, "CCSprite - draw");
}

MoviePlayer * MoviePlayer::instance()
{
    if(_instance == 0)
        _instance = new MoviePlayer();
    return _instance;
}

NS_CC_END

    然后編輯HelloWorldScene.cpp文件的init函數，最后函數如下：
    （說明：我把HelloWorld類改成了Cocos2dPlayer類，所以瀏覽本文章的朋友只要把下面的Cocos2dPlayer::init改成HelloWorld::init就可以編譯運行了，另外Can't Wait.mp4是我在網絡上下載下來的mp4文件，請朋友你自行更改名稱^_^）

bool Cocos2dPlayer::init()
{
    bool bRet = false;
    do 
    {
        //////////////////////////////////////////////////////////////////////////
        // super init first
        //////////////////////////////////////////////////////////////////////////

        CC_BREAK_IF(! CCLayer::init());

        //////////////////////////////////////////////////////////////////////////
        // add your codes below...
        //////////////////////////////////////////////////////////////////////////

        // 1. Add a menu item with "X" image, which is clicked to quit the program.

        // Create a "close" menu item with close icon, it's an auto release object.
        CCMenuItemImage *pCloseItem = CCMenuItemImage::create(
            "CloseNormal.png",
            "CloseSelected.png",
            this,
            menu_selector(Cocos2dPlayer::menuCloseCallback));
        CC_BREAK_IF(! pCloseItem);

        // Place the menu item bottom-right conner.
        pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20));

        // Create a menu with the "close" menu item, it's an auto release object.
        CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);
        pMenu->setPosition(CCPointZero);
        CC_BREAK_IF(! pMenu);

        // Add the menu to Cocos2dPlayer layer as a child layer.
        this->addChild(pMenu, 1);

        // 2. Add a label shows "Hello World".

        // Create a label and initialize with string "Hello World".
        //CCLabelTTF* pLabel = CCLabelTTF::create("Let's PLAY!", "Arial", 24);
        //CC_BREAK_IF(! pLabel);

        // Get window size and place the label upper. 
        CCSize size = CCDirector::sharedDirector()->getWinSize();
        //pLabel->setPosition(ccp(size.width / 2, size.height - 50));

        // Add the label to Cocos2dPlayer layer as a child layer.
        //this->addChild(pLabel, 1);

        // 3. Add add a splash screen, show the cocos2d splash image.
        MoviePlayer* pPlayer = MoviePlayer::instance();

        // Place the sprite on the center of the screen
        pPlayer->setPosition(ccp(size.width/2, size.height/2));

        // Add the sprite to Cocos2dPlayer layer as a child layer.
        this->addChild(pPlayer, 0);

        pPlayer->play("Can't Wait.mp4");

        bRet = true;
    } while (0);

    return bRet;
}

如果您遇到這種情況：release版本程序調用libvlc接口出現異常