OpenGL ES到iOS中的视频(使用iOS 5纹理缓存渲染到纹理)

您知道具有 CameraRipple效果的Apple示例代码吗？好吧,我试图在openGL完成水的所有冷却效果之后将相机输出记录在文件中.

我用glReadPixels完成了它,在那里我读取了void *缓冲区中的所有像素,创建了CVPixelBufferRef并将其附加到AVAssetWriterInputPixelBufferAdaptor,但它太慢了,因为readPixels占用了大量的时间.我发现使用FBO和纹理现金你可以做同样的事情,但速度更快.这是Apple使用的drawInRect方法中的代码：

CVReturn err = CVOpenGLESTextureCachecreate(kcfAllocatorDefault,NULL,(__bridge void *)_context,&coreVideoTextureCashE);
if (err) 
{
    NSAssert(NO,@"Error at CVOpenGLESTextureCachecreate %d");
}


CFDictionaryRef empty; // empty value for attr value.
CFMutableDictionaryRef attrs2;
empty = CFDictionaryCreate(kcfAllocatorDefault,// our empty IOSurface properties Dictionary
                           NULL,&kcfTypeDictionaryKeyCallBACks,&kcfTypeDictionaryValueCallBACks);
attrs2 = CFDictionaryCreateMutable(kcfAllocatorDefault,1,&kcfTypeDictionaryValueCallBACks);

CFDictionarySETVALue(attrs2,kCVPixelBufferIOSurfacePropertiesKey,empty);

//CVPixelBufferPoolCreatePixelBuffer (NULL,[assetWriterPixelBufferInput pixelBufferPool],&renderTarget);
CVPixelBufferRef pixiel_bufer4e = NULL;

CVPixelBufferCreate(kcfAllocatorDefault,(int)_screenWidth,(int)_screenHeight,kCVPixelFormatType_32BGRA,attrs2,&pixiel_bufer4E);
CVOpenGLESTextureRef renderTexture;
CVOpenGLESTextureCachecreateTextureFromImage (kcfAllocatorDefault,coreVideoTextureCashe,pixiel_bufer4e,// texture attributes
                                              GL_TEXTURE_2D,GL_RGBA,// opengl format
                                              (int)_screenWidth,GL_BGRA,// native iOS format
                                              GL_UNSIGNED_BYTE,&renderTexturE);
CFRelease(attrs2);
CFRelease(empty);
glBindTexture(CVOpenGLESTextureGetTarget(renderTexturE),CVOpenGLESTextureGetName(renderTexturE));
glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);

glFramebufferTexture2D(GL_FRAMEBUFFER,GL_COLOR_ATTACHMENT0,GL_TEXTURE_2D,CVOpenGLESTextureGetName(renderTexturE),0);

CVPixelBufferLockBaseAddress(pixiel_bufer4e,0);

if([pixelAdapter appendPixelBuffer:pixiel_bufer4e withPresentationTime:currentTime]) {
                float result = currentTime.value;
            NSLog(@"\n\n\4eta dAnni i current time e : %f \n\n",result);
                currentTime = CMTimeAdd(currentTime,frameLength);
        }

CVPixelBufferUnlockBaseAddress(pixiel_bufer4e,0);
CVPixelBufferRelease(pixiel_bufer4E);
CFRelease(renderTexturE);
CFRelease(coreVideoTextureCashE);

它录制了一个视频并且它非常快,但视频只是黑色我认为textureCasheRef不是正确的,或者我填错了.

作为更新,这是我尝试过的另一种方式.我肯定错过了什么.在viewDidLoad中,在我设置openGL上下文后,我这样做：

CVOpenGLESTextureCachecreate(kcfAllocatorDefault,(__bridge   void *)_context,&coreVideoTextureCashE);

    if (err) 
    {
        NSAssert(NO,@"Error at CVOpenGLESTextureCachecreate %d");
    }

    //creats the pixel buffer

    pixel_buffer = NULL;
    CVPixelBufferPoolCreatePixelBuffer (NULL,[pixelAdapter pixelBufferPool],&pixel_buffer);

    CVOpenGLESTextureRef renderTexture;
    CVOpenGLESTextureCachecreateTextureFromImage (kcfAllocatorDefault,pixel_buffer,// texture attributes
                                                  GL_TEXTURE_2D,//  opengl format
                                                   (int)screenWidth,(int)screenHeight,// native iOS format
                                                  GL_UNSIGNED_BYTE,&renderTexturE);

    glBindTexture(CVOpenGLESTextureGetTarget(renderTexturE),CVOpenGLESTextureGetName(renderTexturE));
    glTexParameterf(GL_TEXTURE_2D,GL_CLAMP_TO_EDGE);
    glTexParameterf(GL_TEXTURE_2D,GL_CLAMP_TO_EDGE);

    glFramebufferTexture2D(GL_FRAMEBUFFER,0);

然后在drawInRect中：我这样做：

if(isRecording&&writerInput.readyForMoreMediaData) {
    CVPixelBufferLockBaseAddress(pixel_buffer,0);

    if([pixelAdapter appendPixelBuffer:pixel_buffer withPresentationTime:currentTime]) {
        currentTime = CMTimeAdd(currentTime,frameLength);
    }
    CVPixelBufferLockBaseAddress(pixel_buffer,0);
    CVPixelBufferRelease(pixel_buffer);
}

然而它在renderTexture上崩溃了bad_acsess,它不是nil而是0x000000001.

updatE

通过下面的代码,我实际设法拉出视频文件,但有一些绿色和红色闪烁.我使用BGRA pixelFormatType.

在这里我创建纹理Cache：

CVReturn err2 = CVOpenGLESTextureCachecreate(kcfAllocatorDefault,&coreVideoTextureCashE);
if (err2) 
{
    NSLog(@"Error at CVOpenGLESTextureCachecreate %d",err);
    return;
}

然后在drawInRect中我称之为：

if(isRecording&&writerInput.readyForMoreMediaData) {
    [self cleanUpTextures];



    CFDictionaryRef empty; // empty value for attr value.
    CFMutableDictionaryRef attrs2;
    empty = CFDictionaryCreate(kcfAllocatorDefault,&kcfTypeDictionaryValueCallBACks);
    attrs2 = CFDictionaryCreateMutable(kcfAllocatorDefault,&kcfTypeDictionaryValueCallBACks);

    CFDictionarySETVALue(attrs2,&renderTarget);
    CVPixelBufferRef pixiel_bufer4e = NULL;

    CVPixelBufferCreate(kcfAllocatorDefault,&pixiel_bufer4E);
    CVOpenGLESTextureRef renderTexture;
    CVOpenGLESTextureCachecreateTextureFromImage (kcfAllocatorDefault,&renderTexturE);
    CFRelease(attrs2);
    CFRelease(empty);
    glBindTexture(CVOpenGLESTextureGetTarget(renderTexturE),0);

    CVPixelBufferLockBaseAddress(pixiel_bufer4e,0);

    if([pixelAdapter appendPixelBuffer:pixiel_bufer4e withPresentationTime:currentTime]) {
        float result = currentTime.value;
        NSLog(@"\n\n\4eta dAnni i current time e : %f \n\n",result);
        currentTime = CMTimeAdd(currentTime,frameLength);
    }

    CVPixelBufferUnlockBaseAddress(pixiel_bufer4e,0);
    CVPixelBufferRelease(pixiel_bufer4E);
    CFRelease(renderTexturE);
  //  CFRelease(coreVideoTextureCashE);
}

我知道我可以通过不在这里做所有这些事情来优化这一点,但我想用它来使它工作.在cleanUpTextures中,我用以下方法刷新textureCache：

CVOpenGLESTextureCacheFlush(coreVideoTextureCashe,0);

RGBA的东西可能有问题,或者我不知道,但似乎它仍然有点错误的Cache.