GPUImage API文档之GPUImageFramebuffer类

　　GPUImageFramebuffer类用于管理帧缓冲对象，负责帧缓冲对象的创建和销毁，读取帧缓冲内容

　　属性

　　@property(readonly) CGSize size

　　说明：只读属性，在实现中，设置缓冲区的size

　　@property(readonly) GPUTextureOptions textureOptions

　　说明：纹理的选项

　　@property(readonly) GLuint texture

　　说明：管理纹理

　　@property(readonly) BOOL missingFramebuffer

　　说明：指示是否丢失帧缓冲对象

　　方法

　　　- (id)initWithSize:(CGSize)framebufferSize

　　　　说明：创建一个size为framebufferSize大小的帧缓冲对象

　　　　参数：framebuffer的size。

　　　　返回：创建成功的帧缓冲对象。

　　　　实现

- (id)initWithSize:(CGSize)framebufferSize;{  GPUTextureOptions defaultTextureOptions;  defaultTextureOptions.minFilter = GL_LINEAR;  defaultTextureOptions.magFilter = GL_LINEAR;  defaultTextureOptions.wrapS = GL_CLAMP_TO_EDGE;  defaultTextureOptions.wrapT = GL_CLAMP_TO_EDGE;  defaultTextureOptions.internalFormat = GL_RGBA;  defaultTextureOptions.format = GL_BGRA;  defaultTextureOptions.type = GL_UNSIGNED_BYTE;  if (!(self = [self initWithSize:framebufferSize textureOptions:defaultTextureOptions onlyTexture:NO]))  {    return nil;  }  return self;}

　　   - (id)initWithSize:(CGSize)framebufferSize textureOptions:(GPUTextureOptions)fboTextureOptions onlyTexture:(BOOL)onlyGenerateTexture

　　　　说明：创建一个size为framebufferSize大小的帧缓冲对象

　　　　参数：framebufferSize为framebuffer的size。fboTextureOptions是纹理的详细配置。onlyGenerateTexture说明是否只创建纹理而不创建陈帧缓冲对象。

　　　　返回：创建成功的帧缓冲对象。

　　　　实现

- (id)initWithSize:(CGSize)framebufferSize textureOptions:(GPUTextureOptions)fboTextureOptions onlyTexture:(BOOL)onlyGenerateTexture;{  if (!(self = [super init]))  {    return nil;  }    _textureOptions = fboTextureOptions;  _size = framebufferSize;  framebufferReferenceCount = 0;  referenceCountingDisabled = NO;  _missingFramebuffer = onlyGenerateTexture;  if (_missingFramebuffer)  {    runSynchronouslyOnVideoProcessingQueue(^{      [GPUImageContext useImageProcessingContext];      [self generateTexture];      framebuffer = 0;    });  }  else  {    [self generateFramebuffer];  }  return self;}

　　　- (id)initWithSize:(CGSize)framebufferSize overriddenTexture:(GLuint)inputTexture

　　　　说明：创建一个size为framebufferSize大小的帧缓冲对象

　　　　参数：inputTexture为输入的纹理，用于渲染图片。

　　　　返回：创建成功的帧缓冲对象。

　　　　实现

- (id)initWithSize:(CGSize)framebufferSize overriddenTexture:(GLuint)inputTexture;{  if (!(self = [super init]))  {    return nil;  }  GPUTextureOptions defaultTextureOptions;  defaultTextureOptions.minFilter = GL_LINEAR;  defaultTextureOptions.magFilter = GL_LINEAR;  defaultTextureOptions.wrapS = GL_CLAMP_TO_EDGE;  defaultTextureOptions.wrapT = GL_CLAMP_TO_EDGE;  defaultTextureOptions.internalFormat = GL_RGBA;  defaultTextureOptions.format = GL_BGRA;  defaultTextureOptions.type = GL_UNSIGNED_BYTE;  _textureOptions = defaultTextureOptions;  _size = framebufferSize;  framebufferReferenceCount = 0;  referenceCountingDisabled = YES;    _texture = inputTexture;    return self;}

　　　- (void)activateFramebuffer

　　　　说明：激活刚创建的framebuffer对象。只有调用它后，才会起作用。

　　　　实现　

- (void)activateFramebuffer;{  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);  glViewport(0, 0, (int)_size.width, (int)_size.height);}

　　　- (void)lock

　　　　说明：引用计数管理 +1

　　　　实现

- (void)lock;{  if (referenceCountingDisabled)  {    return;  }    framebufferReferenceCount++;}

　　　- (void)unlock

　　　　说明：引用计数管理 -1

　　　　实现

- (void)unlock;{  if (referenceCountingDisabled)  {    return;  }  NSAssert(framebufferReferenceCount > 0, @"Tried to overrelease a framebuffer, did you forget to call -useNextFrameForImageCapture before using -imageFromCurrentFramebuffer?");  framebufferReferenceCount--;  if (framebufferReferenceCount < 1)  {    [[GPUImageContext sharedFramebufferCache] returnFramebufferToCache:self];  }}

　　　- (void)clearAllLocks

　　　　说明：引用计数管理 设置为0

　　　　实现

- (void)clearAllLocks;{  framebufferReferenceCount = 0;}

　　　- (void)disableReferenceCounting

　　　　说明：引用计数管理 禁用引用计数

　　　　实现

- (void)disableReferenceCounting;{  referenceCountingDisabled = YES;}

　　　- (void)enableReferenceCounting

　　　　说明：引用计数管理 启用引用计数

　　　　实现

- (void)enableReferenceCounting;{  referenceCountingDisabled = NO;}

　　　- (CGImageRef)newCGImageFromFramebufferContents

　　　　说明：输出帧缓冲内容。【说明待更新......】

　　　　实现

- (CGImageRef)newCGImageFromFramebufferContents;{  // a CGImage can only be created from a 'normal' color texture  NSAssert(self.textureOptions.internalFormat == GL_RGBA, @"For conversion to a CGImage the output texture format for this filter must be GL_RGBA.");  NSAssert(self.textureOptions.type == GL_UNSIGNED_BYTE, @"For conversion to a CGImage the type of the output texture of this filter must be GL_UNSIGNED_BYTE.");    __block CGImageRef cgImageFromBytes;    runSynchronouslyOnVideoProcessingQueue(^{    [GPUImageContext useImageProcessingContext];        NSUInteger totalBytesForImage = (int)_size.width * (int)_size.height * 4;    // It appears that the width of a texture must be padded out to be a multiple of 8 (32 bytes) if reading from it using a texture cache        GLubyte *rawImagePixels;        CGDataProviderRef dataProvider = NULL;    if ([GPUImageContext supportsFastTextureUpload])    {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE      NSUInteger paddedWidthOfImage = CVPixelBufferGetBytesPerRow(renderTarget) / 4.0;      NSUInteger paddedBytesForImage = paddedWidthOfImage * (int)_size.height * 4;            glFinish();      CFRetain(renderTarget); // I need to retain the pixel buffer here and release in the data source callback to prevent its bytes from being prematurely deallocated during a photo write operation      [self lockForReading];      rawImagePixels = (GLubyte *)CVPixelBufferGetBaseAddress(renderTarget);      dataProvider = CGDataProviderCreateWithData((__bridge_retained void*)self, rawImagePixels, paddedBytesForImage, dataProviderUnlockCallback);      [[GPUImageContext sharedFramebufferCache] addFramebufferToActiveImageCaptureList:self]; // In case the framebuffer is swapped out on the filter, need to have a strong reference to it somewhere for it to hang on while the image is in existence#else#endif    }    else    {      [self activateFramebuffer];      rawImagePixels = (GLubyte *)malloc(totalBytesForImage);      glReadPixels(0, 0, (int)_size.width, (int)_size.height, GL_RGBA, GL_UNSIGNED_BYTE, rawImagePixels);      dataProvider = CGDataProviderCreateWithData(NULL, rawImagePixels, totalBytesForImage, dataProviderReleaseCallback);      [self unlock]; // Don't need to keep this around anymore    }        CGColorSpaceRef defaultRGBColorSpace = CGColorSpaceCreateDeviceRGB();        if ([GPUImageContext supportsFastTextureUpload])    {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE      cgImageFromBytes = CGImageCreate((int)_size.width, (int)_size.height, 8, 32, CVPixelBufferGetBytesPerRow(renderTarget), defaultRGBColorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst, dataProvider, NULL, NO, kCGRenderingIntentDefault);#else#endif    }    else    {      cgImageFromBytes = CGImageCreate((int)_size.width, (int)_size.height, 8, 32, 4 * (int)_size.width, defaultRGBColorSpace, kCGBitmapByteOrderDefault | kCGImageAlphaLast, dataProvider, NULL, NO, kCGRenderingIntentDefault);    }        // Capture image with current device orientation    CGDataProviderRelease(dataProvider);    CGColorSpaceRelease(defaultRGBColorSpace);      });    return cgImageFromBytes;}

　　　- (void)restoreRenderTarget

　　　　说明：还原渲染目标对象

　　　　实现

- (void)restoreRenderTarget;{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  [self unlockAfterReading];  CFRelease(renderTarget);#else#endif}

　　　- (void)lockForReading

　　　　说明：锁定PixelBuffer

　　　　实现：

- (void)lockForReading{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  if ([GPUImageContext supportsFastTextureUpload])  {    if (readLockCount == 0)    {      CVPixelBufferLockBaseAddress(renderTarget, 0);    }    readLockCount++;  }#endif}

　　　- (void)unlockAfterReading

　　　　说明：解锁PixelBuffer

- (void)unlockAfterReading{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  if ([GPUImageContext supportsFastTextureUpload])  {    NSAssert(readLockCount > 0, @"Unbalanced call to -[GPUImageFramebuffer unlockAfterReading]");    readLockCount--;    if (readLockCount == 0)    {      CVPixelBufferUnlockBaseAddress(renderTarget, 0);    }  }#endif}

　　　- (NSUInteger)bytesPerRow

　　　　说明：获取pixel buffer的行字节数

　　　　实现

- (NSUInteger)bytesPerRow;{  if ([GPUImageContext supportsFastTextureUpload])  {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE    return CVPixelBufferGetBytesPerRow(renderTarget);#else    return _size.width * 4; // TODO: do more with this on the non-texture-cache side#endif  }  else  {    return _size.width * 4;  }}

　　　- (GLubyte *)byteBuffer

　　　　说明：获取pixel buffer的基地址

　　　　实现

- (GLubyte *)byteBuffer;{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  [self lockForReading];  GLubyte * bufferBytes = CVPixelBufferGetBaseAddress(renderTarget);  [self unlockAfterReading];  return bufferBytes;#else  return NULL; // TODO: do more with this on the non-texture-cache side#endif}

完整代码

#import <Foundation/Foundation.h>#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE#import <OpenGLES/EAGL.h>#import <OpenGLES/ES2/gl.h>#import <OpenGLES/ES2/glext.h>#else#import <OpenGL/OpenGL.h>#import <OpenGL/gl.h>#endif#import <QuartzCore/QuartzCore.h>#import <CoreMedia/CoreMedia.h>typedef struct GPUTextureOptions {  GLenum minFilter;  GLenum magFilter;  GLenum wrapS;  GLenum wrapT;  GLenum internalFormat;  GLenum format;  GLenum type;} GPUTextureOptions;@interface GPUImageFramebuffer : NSObject@property(readonly) CGSize size;@property(readonly) GPUTextureOptions textureOptions;@property(readonly) GLuint texture;@property(readonly) BOOL missingFramebuffer;// Initialization and teardown- (id)initWithSize:(CGSize)framebufferSize;- (id)initWithSize:(CGSize)framebufferSize textureOptions:(GPUTextureOptions)fboTextureOptions onlyTexture:(BOOL)onlyGenerateTexture;- (id)initWithSize:(CGSize)framebufferSize overriddenTexture:(GLuint)inputTexture;// Usage- (void)activateFramebuffer;// Reference counting- (void)lock;- (void)unlock;- (void)clearAllLocks;- (void)disableReferenceCounting;- (void)enableReferenceCounting;// Image capture- (CGImageRef)newCGImageFromFramebufferContents;- (void)restoreRenderTarget;// Raw data bytes- (void)lockForReading;- (void)unlockAfterReading;- (NSUInteger)bytesPerRow;- (GLubyte *)byteBuffer;@end

#import "GPUImageFramebuffer.h"#import "GPUImageOutput.h"@interface GPUImageFramebuffer(){  GLuint framebuffer;#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  CVPixelBufferRef renderTarget;  CVOpenGLESTextureRef renderTexture;  NSUInteger readLockCount;#else#endif  NSUInteger framebufferReferenceCount;  BOOL referenceCountingDisabled;}- (void)generateFramebuffer;- (void)generateTexture;- (void)destroyFramebuffer;@endvoid dataProviderReleaseCallback (void *info, const void *data, size_t size);void dataProviderUnlockCallback (void *info, const void *data, size_t size);@implementation GPUImageFramebuffer@synthesize size = _size;@synthesize textureOptions = _textureOptions;@synthesize texture = _texture;@synthesize missingFramebuffer = _missingFramebuffer;#pragma mark -#pragma mark Initialization and teardown- (id)initWithSize:(CGSize)framebufferSize textureOptions:(GPUTextureOptions)fboTextureOptions onlyTexture:(BOOL)onlyGenerateTexture;{  if (!(self = [super init]))  {    return nil;  }    _textureOptions = fboTextureOptions;  _size = framebufferSize;  framebufferReferenceCount = 0;  referenceCountingDisabled = NO;  _missingFramebuffer = onlyGenerateTexture;  if (_missingFramebuffer)  {    runSynchronouslyOnVideoProcessingQueue(^{      [GPUImageContext useImageProcessingContext];      [self generateTexture];      framebuffer = 0;    });  }  else  {    [self generateFramebuffer];  }  return self;}- (id)initWithSize:(CGSize)framebufferSize overriddenTexture:(GLuint)inputTexture;{  if (!(self = [super init]))  {    return nil;  }  GPUTextureOptions defaultTextureOptions;  defaultTextureOptions.minFilter = GL_LINEAR;  defaultTextureOptions.magFilter = GL_LINEAR;  defaultTextureOptions.wrapS = GL_CLAMP_TO_EDGE;  defaultTextureOptions.wrapT = GL_CLAMP_TO_EDGE;  defaultTextureOptions.internalFormat = GL_RGBA;  defaultTextureOptions.format = GL_BGRA;  defaultTextureOptions.type = GL_UNSIGNED_BYTE;  _textureOptions = defaultTextureOptions;  _size = framebufferSize;  framebufferReferenceCount = 0;  referenceCountingDisabled = YES;    _texture = inputTexture;    return self;}- (id)initWithSize:(CGSize)framebufferSize;{  GPUTextureOptions defaultTextureOptions;  defaultTextureOptions.minFilter = GL_LINEAR;  defaultTextureOptions.magFilter = GL_LINEAR;  defaultTextureOptions.wrapS = GL_CLAMP_TO_EDGE;  defaultTextureOptions.wrapT = GL_CLAMP_TO_EDGE;  defaultTextureOptions.internalFormat = GL_RGBA;  defaultTextureOptions.format = GL_BGRA;  defaultTextureOptions.type = GL_UNSIGNED_BYTE;  if (!(self = [self initWithSize:framebufferSize textureOptions:defaultTextureOptions onlyTexture:NO]))  {    return nil;  }  return self;}- (void)dealloc{  [self destroyFramebuffer];}#pragma mark -#pragma mark Internal- (void)generateTexture;{  glActiveTexture(GL_TEXTURE1);  glGenTextures(1, &_texture);  glBindTexture(GL_TEXTURE_2D, _texture);  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, _textureOptions.minFilter);  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, _textureOptions.magFilter);  // This is necessary for non-power-of-two textures  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, _textureOptions.wrapS);  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, _textureOptions.wrapT);    // TODO: Handle mipmaps}- (void)generateFramebuffer;{  runSynchronouslyOnVideoProcessingQueue(^{    [GPUImageContext useImageProcessingContext];      glGenFramebuffers(1, &framebuffer);    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);        // By default, all framebuffers on iOS 5.0+ devices are backed by texture caches, using one shared cache    if ([GPUImageContext supportsFastTextureUpload])    {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE      CVOpenGLESTextureCacheRef coreVideoTextureCache = [[GPUImageContext sharedImageProcessingContext] coreVideoTextureCache];      // Code originally sourced from http://allmybrain.com/2011/12/08/rendering-to-a-texture-with-ios-5-texture-cache-api/            CFDictionaryRef empty; // empty value for attr value.      CFMutableDictionaryRef attrs;      empty = CFDictionaryCreate(kCFAllocatorDefault, NULL, NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); // our empty IOSurface properties dictionary      attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 1, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);      CFDictionarySetValue(attrs, kCVPixelBufferIOSurfacePropertiesKey, empty);            CVReturn err = CVPixelBufferCreate(kCFAllocatorDefault, (int)_size.width, (int)_size.height, kCVPixelFormatType_32BGRA, attrs, &renderTarget);      if (err)      {        NSLog(@"FBO size: %f, %f", _size.width, _size.height);        NSAssert(NO, @"Error at CVPixelBufferCreate %d", err);      }            err = CVOpenGLESTextureCacheCreateTextureFromImage (kCFAllocatorDefault, coreVideoTextureCache, renderTarget,                                NULL, // texture attributes                                GL_TEXTURE_2D,                                _textureOptions.internalFormat, // opengl format                                (int)_size.width,                                (int)_size.height,                                _textureOptions.format, // native iOS format                                _textureOptions.type,                                0,                                &renderTexture);      if (err)      {        NSAssert(NO, @"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);      }            CFRelease(attrs);      CFRelease(empty);            glBindTexture(CVOpenGLESTextureGetTarget(renderTexture), CVOpenGLESTextureGetName(renderTexture));      _texture = CVOpenGLESTextureGetName(renderTexture);      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, _textureOptions.wrapS);      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, _textureOptions.wrapT);            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, CVOpenGLESTextureGetName(renderTexture), 0);#endif    }    else    {      [self generateTexture];      glBindTexture(GL_TEXTURE_2D, _texture);            glTexImage2D(GL_TEXTURE_2D, 0, _textureOptions.internalFormat, (int)_size.width, (int)_size.height, 0, _textureOptions.format, _textureOptions.type, 0);      glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, _texture, 0);    }        #ifndef NS_BLOCK_ASSERTIONS    GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);    NSAssert(status == GL_FRAMEBUFFER_COMPLETE, @"Incomplete filter FBO: %d", status);    #endif        glBindTexture(GL_TEXTURE_2D, 0);  });}- (void)destroyFramebuffer;{  runSynchronouslyOnVideoProcessingQueue(^{    [GPUImageContext useImageProcessingContext];        if (framebuffer)    {      glDeleteFramebuffers(1, &framebuffer);      framebuffer = 0;    }        if ([GPUImageContext supportsFastTextureUpload] && (!_missingFramebuffer))    {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE      if (renderTarget)      {        CFRelease(renderTarget);        renderTarget = NULL;      }            if (renderTexture)      {        CFRelease(renderTexture);        renderTexture = NULL;      }#endif    }    else    {      glDeleteTextures(1, &_texture);    }  });}#pragma mark -#pragma mark Usage- (void)activateFramebuffer;{  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);  glViewport(0, 0, (int)_size.width, (int)_size.height);}#pragma mark -#pragma mark Reference counting- (void)lock;{  if (referenceCountingDisabled)  {    return;  }    framebufferReferenceCount++;}- (void)unlock;{  if (referenceCountingDisabled)  {    return;  }  NSAssert(framebufferReferenceCount > 0, @"Tried to overrelease a framebuffer, did you forget to call -useNextFrameForImageCapture before using -imageFromCurrentFramebuffer?");  framebufferReferenceCount--;  if (framebufferReferenceCount < 1)  {    [[GPUImageContext sharedFramebufferCache] returnFramebufferToCache:self];  }}- (void)clearAllLocks;{  framebufferReferenceCount = 0;}- (void)disableReferenceCounting;{  referenceCountingDisabled = YES;}- (void)enableReferenceCounting;{  referenceCountingDisabled = NO;}#pragma mark -#pragma mark Image capturevoid dataProviderReleaseCallback (void *info, const void *data, size_t size){  free((void *)data);}void dataProviderUnlockCallback (void *info, const void *data, size_t size){  GPUImageFramebuffer *framebuffer = (__bridge_transfer GPUImageFramebuffer*)info;    [framebuffer restoreRenderTarget];  [framebuffer unlock];  [[GPUImageContext sharedFramebufferCache] removeFramebufferFromActiveImageCaptureList:framebuffer];}- (CGImageRef)newCGImageFromFramebufferContents;{  // a CGImage can only be created from a 'normal' color texture  NSAssert(self.textureOptions.internalFormat == GL_RGBA, @"For conversion to a CGImage the output texture format for this filter must be GL_RGBA.");  NSAssert(self.textureOptions.type == GL_UNSIGNED_BYTE, @"For conversion to a CGImage the type of the output texture of this filter must be GL_UNSIGNED_BYTE.");    __block CGImageRef cgImageFromBytes;    runSynchronouslyOnVideoProcessingQueue(^{    [GPUImageContext useImageProcessingContext];        NSUInteger totalBytesForImage = (int)_size.width * (int)_size.height * 4;    // It appears that the width of a texture must be padded out to be a multiple of 8 (32 bytes) if reading from it using a texture cache        GLubyte *rawImagePixels;        CGDataProviderRef dataProvider = NULL;    if ([GPUImageContext supportsFastTextureUpload])    {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE      NSUInteger paddedWidthOfImage = CVPixelBufferGetBytesPerRow(renderTarget) / 4.0;      NSUInteger paddedBytesForImage = paddedWidthOfImage * (int)_size.height * 4;            glFinish();      CFRetain(renderTarget); // I need to retain the pixel buffer here and release in the data source callback to prevent its bytes from being prematurely deallocated during a photo write operation      [self lockForReading];      rawImagePixels = (GLubyte *)CVPixelBufferGetBaseAddress(renderTarget);      dataProvider = CGDataProviderCreateWithData((__bridge_retained void*)self, rawImagePixels, paddedBytesForImage, dataProviderUnlockCallback);      [[GPUImageContext sharedFramebufferCache] addFramebufferToActiveImageCaptureList:self]; // In case the framebuffer is swapped out on the filter, need to have a strong reference to it somewhere for it to hang on while the image is in existence#else#endif    }    else    {      [self activateFramebuffer];      rawImagePixels = (GLubyte *)malloc(totalBytesForImage);      glReadPixels(0, 0, (int)_size.width, (int)_size.height, GL_RGBA, GL_UNSIGNED_BYTE, rawImagePixels);      dataProvider = CGDataProviderCreateWithData(NULL, rawImagePixels, totalBytesForImage, dataProviderReleaseCallback);      [self unlock]; // Don't need to keep this around anymore    }        CGColorSpaceRef defaultRGBColorSpace = CGColorSpaceCreateDeviceRGB();        if ([GPUImageContext supportsFastTextureUpload])    {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE      cgImageFromBytes = CGImageCreate((int)_size.width, (int)_size.height, 8, 32, CVPixelBufferGetBytesPerRow(renderTarget), defaultRGBColorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst, dataProvider, NULL, NO, kCGRenderingIntentDefault);#else#endif    }    else    {      cgImageFromBytes = CGImageCreate((int)_size.width, (int)_size.height, 8, 32, 4 * (int)_size.width, defaultRGBColorSpace, kCGBitmapByteOrderDefault | kCGImageAlphaLast, dataProvider, NULL, NO, kCGRenderingIntentDefault);    }        // Capture image with current device orientation    CGDataProviderRelease(dataProvider);    CGColorSpaceRelease(defaultRGBColorSpace);      });    return cgImageFromBytes;}- (void)restoreRenderTarget;{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  [self unlockAfterReading];  CFRelease(renderTarget);#else#endif}#pragma mark -#pragma mark Raw data bytes- (void)lockForReading{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  if ([GPUImageContext supportsFastTextureUpload])  {    if (readLockCount == 0)    {      CVPixelBufferLockBaseAddress(renderTarget, 0);    }    readLockCount++;  }#endif}- (void)unlockAfterReading{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  if ([GPUImageContext supportsFastTextureUpload])  {    NSAssert(readLockCount > 0, @"Unbalanced call to -[GPUImageFramebuffer unlockAfterReading]");    readLockCount--;    if (readLockCount == 0)    {      CVPixelBufferUnlockBaseAddress(renderTarget, 0);    }  }#endif}- (NSUInteger)bytesPerRow;{  if ([GPUImageContext supportsFastTextureUpload])  {#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE    return CVPixelBufferGetBytesPerRow(renderTarget);#else    return _size.width * 4; // TODO: do more with this on the non-texture-cache side#endif  }  else  {    return _size.width * 4;  }}- (GLubyte *)byteBuffer;{#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE  [self lockForReading];  GLubyte * bufferBytes = CVPixelBufferGetBaseAddress(renderTarget);  [self unlockAfterReading];  return bufferBytes;#else  return NULL; // TODO: do more with this on the non-texture-cache side#endif}- (GLuint)texture;{//  NSLog(@"Accessing texture: %d from FB: %@", _texture, self);  return _texture;}@end

原标题：GPUImage API文档之GPUImageFramebuffer类

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