cocos2dx学习笔记：CCShaderCache

CCShaderCache是CCGLProgram的管理类，单例形式。这里备注下代码：

CCShaderCache.cpp

NS_CC_BEGIN

//==>>cocos2dx自带的几个shader
enum {
    kCCShaderType_PositionTextureColor,
    kCCShaderType_PositionTextureColorAlphaTest,
    kCCShaderType_PositionColor,
    kCCShaderType_PositionTexture,
    kCCShaderType_PositionTexture_uColor,
    kCCShaderType_PositionTextureA8Color,
    kCCShaderType_Position_uColor,
    kCCShaderType_PositionLengthTexureColor,
    kCCShaderType_ControlSwitch,
    
    kCCShaderType_MAX,
};

//单例相关
static CCShaderCache *_sharedShaderCache = 0;
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//==>>载入cocos2dx自带的几个shader，并将其放入字典中。
void CCShaderCache::loadDefaultShaders()
{
    // Position Texture Color shader
    CCGLProgram *p = new CCGLProgram();
    loadDefaultShader(p, kCCShaderType_PositionTextureColor);

    m_pPrograms->setObject(p, kCCShader_PositionTextureColor);
    p->release();

    // Position Texture Color alpha test
    p = new CCGLProgram();
    loadDefaultShader(p, kCCShaderType_PositionTextureColorAlphaTest);

    m_pPrograms->setObject(p, kCCShader_PositionTextureColorAlphaTest);
    p->release();
。。。。。
。。。。。
}

//==>>重置shaders，可参考CCGLProgram的reset方法。
void CCShaderCache::reloadDefaultShaders()
{
    // reset all programs and reload them
    
    // Position Texture Color shader
    CCGLProgram *p = programForKey(kCCShader_PositionTextureColor);    
    p->reset();
    loadDefaultShader(p, kCCShaderType_PositionTextureColor);

    // Position Texture Color alpha test
    p = programForKey(kCCShader_PositionTextureColorAlphaTest);
    p->reset();    
    loadDefaultShader(p, kCCShaderType_PositionTextureColorAlphaTest);
}

//==>>载入cocos2dx自带的shader，根据不同的type，读入不同的shader内容，并且绑定变量。
void CCShaderCache::loadDefaultShader(CCGLProgram *p, int type)
{
    switch (type) {
        case kCCShaderType_PositionTextureColor:
            p->initWithVertexShaderByteArray(ccPositionTextureColor_vert, ccPositionTextureColor_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);
            
            break;
        case kCCShaderType_PositionTextureColorAlphaTest:
            p->initWithVertexShaderByteArray(ccPositionTextureColor_vert, ccPositionTextureColorAlphaTest_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);

            break;
        case kCCShaderType_PositionColor:  
            p->initWithVertexShaderByteArray(ccPositionColor_vert ,ccPositionColor_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);

            break;
        case kCCShaderType_PositionTexture:
            p->initWithVertexShaderByteArray(ccPositionTexture_vert ,ccPositionTexture_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);

            break;
        case kCCShaderType_PositionTexture_uColor:
            p->initWithVertexShaderByteArray(ccPositionTexture_uColor_vert, ccPositionTexture_uColor_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);

            break;
        case kCCShaderType_PositionTextureA8Color:
            p->initWithVertexShaderByteArray(ccPositionTextureA8Color_vert, ccPositionTextureA8Color_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);

            break;
        case kCCShaderType_Position_uColor:
            p->initWithVertexShaderByteArray(ccPosition_uColor_vert, ccPosition_uColor_frag);    
            
            p->addAttribute("aVertex", kCCVertexAttrib_Position);    
            
            break;
        case kCCShaderType_PositionLengthTexureColor:
            p->initWithVertexShaderByteArray(ccPositionColorLengthTexture_vert, ccPositionColorLengthTexture_frag);
            
            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);
            p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);
            
            break;

       case kCCShaderType_ControlSwitch:
            p->initWithVertexShaderByteArray(ccPositionTextureColor_vert, ccExSwitchMask_frag);

            p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
            p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);
            p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);

            break;

        default:
            CCLOG("cocos2d: %s:%d, error shader type", __FUNCTION__, __LINE__);
            return;
    }
//==>>连接program，更新常量值  
    p->link();
    p->updateUniforms();
    
    CHECK_GL_ERROR_DEBUG();
}

//==>>根据名称获取CCGLProgram
CCGLProgram* CCShaderCache::programForKey(const char* key)
{
    return (CCGLProgram*)m_pPrograms->objectForKey(key);
}

//==>>添加一个program到单例中
void CCShaderCache::addProgram(CCGLProgram* program, const char* key)
{
    m_pPrograms->setObject(program, key);
}

NS_CC_END