GPUImageOutput类将静态图像纹理上传到OpenGL ES中，然后使用这些纹理去处理进程链中的下一个对象。它的子类可以获得滤镜处理后的图片功能。［本文讲的很少，由于有许多地方不清楚，以后会更新］
方法
- (void)setInputFramebufferForTarget:(id<GPUImageInput>)target atIndex:(NSInteger)inputTextureIndex
说明：用于设置指定纹理的输入帧缓冲区的尺寸
参数：target是具体的对象，它接受了GPUImageInput的协议，例如：当我们使用［GPUImageLookupFilter］滤镜时，target就是一个GPUImageLookupFilter的实例。
- (void)addTarget:(id<GPUImageInput>)newTarget atTextureLocation:(NSInteger)textureLocation
说明：添加target
- (void)removeTarget:(id<GPUImageInput>)targetToRemove
说明：删除指定的target
- (void)removeAllTargets
说明：删除所有target
- (UIImage *)imageFromCurrentFramebufferWithOrientation:(UIImageOrientation)imageOrientation
说明：从帧缓冲区中取回对象，打印在屏幕中。
参数：imageOrientation时当前设备的手持方向
- (CGImageRef)newCGImageByFilteringCGImage:(CGImageRef)imageToFilter
说明：使用一张静态图片做滤镜纹理
完整代码
#import "GPUImageContext.h"
#import "GPUImageFramebuffer.h" #if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
#import <UIKit/UIKit.h>
#else
// For now, just redefine this on the Mac
typedef NS_ENUM(NSInteger, UIImageOrientation) {
UIImageOrientationUp, // default orientation
UIImageOrientationDown, // 180 deg rotation
UIImageOrientationLeft, // 90 deg CCW
UIImageOrientationRight, // 90 deg CW
UIImageOrientationUpMirrored, // as above but image mirrored along other axis. horizontal flip
UIImageOrientationDownMirrored, // horizontal flip
UIImageOrientationLeftMirrored, // vertical flip
UIImageOrientationRightMirrored, // vertical flip
};
#endif void runOnMainQueueWithoutDeadlocking(void (^block)(void));
void runSynchronouslyOnVideoProcessingQueue(void (^block)(void));
void runAsynchronouslyOnVideoProcessingQueue(void (^block)(void));
void runSynchronouslyOnContextQueue(GPUImageContext *context, void (^block)(void));
void runAsynchronouslyOnContextQueue(GPUImageContext *context, void (^block)(void));
void reportAvailableMemoryForGPUImage(NSString *tag); @class GPUImageMovieWriter; /** GPUImage's base source object Images or frames of video are uploaded from source objects, which are subclasses of GPUImageOutput. These include: - GPUImageVideoCamera (for live video from an iOS camera)
- GPUImageStillCamera (for taking photos with the camera)
- GPUImagePicture (for still images)
- GPUImageMovie (for movies) Source objects upload still image frames to OpenGL ES as textures, then hand those textures off to the next objects in the processing chain.
*/
@interface GPUImageOutput : NSObject
{
GPUImageFramebuffer *outputFramebuffer; NSMutableArray *targets, *targetTextureIndices; CGSize inputTextureSize, cachedMaximumOutputSize, forcedMaximumSize; BOOL overrideInputSize; BOOL allTargetsWantMonochromeData;
BOOL usingNextFrameForImageCapture;
} @property(readwrite, nonatomic) BOOL shouldSmoothlyScaleOutput;
@property(readwrite, nonatomic) BOOL shouldIgnoreUpdatesToThisTarget;
@property(readwrite, nonatomic, retain) GPUImageMovieWriter *audioEncodingTarget;
@property(readwrite, nonatomic, unsafe_unretained) id<GPUImageInput> targetToIgnoreForUpdates;
@property(nonatomic, copy) void(^frameProcessingCompletionBlock)(GPUImageOutput*, CMTime);
@property(nonatomic) BOOL enabled;
@property(readwrite, nonatomic) GPUTextureOptions outputTextureOptions; /// @name Managing targets
- (void)setInputFramebufferForTarget:(id<GPUImageInput>)target atIndex:(NSInteger)inputTextureIndex;
- (GPUImageFramebuffer *)framebufferForOutput;
- (void)removeOutputFramebuffer;
- (void)notifyTargetsAboutNewOutputTexture; /** Returns an array of the current targets.
*/
- (NSArray*)targets; /** Adds a target to receive notifications when new frames are available. The target will be asked for its next available texture. See [GPUImageInput newFrameReadyAtTime:] @param newTarget Target to be added
*/
- (void)addTarget:(id<GPUImageInput>)newTarget; /** Adds a target to receive notifications when new frames are available. See [GPUImageInput newFrameReadyAtTime:] @param newTarget Target to be added
*/
- (void)addTarget:(id<GPUImageInput>)newTarget atTextureLocation:(NSInteger)textureLocation; /** Removes a target. The target will no longer receive notifications when new frames are available. @param targetToRemove Target to be removed
*/
- (void)removeTarget:(id<GPUImageInput>)targetToRemove; /** Removes all targets.
*/
- (void)removeAllTargets; /// @name Manage the output texture - (void)forceProcessingAtSize:(CGSize)frameSize;
- (void)forceProcessingAtSizeRespectingAspectRatio:(CGSize)frameSize; /// @name Still image processing - (void)useNextFrameForImageCapture;
- (CGImageRef)newCGImageFromCurrentlyProcessedOutput;
- (CGImageRef)newCGImageByFilteringCGImage:(CGImageRef)imageToFilter; // Platform-specific image output methods
// If you're trying to use these methods, remember that you need to set -useNextFrameForImageCapture before running -processImage or running video and calling any of these methods, or you will get a nil image
#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
- (UIImage *)imageFromCurrentFramebuffer;
- (UIImage *)imageFromCurrentFramebufferWithOrientation:(UIImageOrientation)imageOrientation;
- (UIImage *)imageByFilteringImage:(UIImage *)imageToFilter;
- (CGImageRef)newCGImageByFilteringImage:(UIImage *)imageToFilter;
#else
- (NSImage *)imageFromCurrentFramebuffer;
- (NSImage *)imageFromCurrentFramebufferWithOrientation:(UIImageOrientation)imageOrientation;
- (NSImage *)imageByFilteringImage:(NSImage *)imageToFilter;
- (CGImageRef)newCGImageByFilteringImage:(NSImage *)imageToFilter;
#endif - (BOOL)providesMonochromeOutput; @end
#import "GPUImageOutput.h"
#import "GPUImageMovieWriter.h"
#import "GPUImagePicture.h"
#import <mach/mach.h> void runOnMainQueueWithoutDeadlocking(void (^block)(void))
{
if ([NSThread isMainThread])
{
block();
}
else
{
dispatch_sync(dispatch_get_main_queue(), block);
}
} void runSynchronouslyOnVideoProcessingQueue(void (^block)(void))
{
dispatch_queue_t videoProcessingQueue = [GPUImageContext sharedContextQueue];
#if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
{
block();
}else
{
dispatch_sync(videoProcessingQueue, block);
}
} void runAsynchronouslyOnVideoProcessingQueue(void (^block)(void))
{
dispatch_queue_t videoProcessingQueue = [GPUImageContext sharedContextQueue]; #if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
{
block();
}else
{
dispatch_async(videoProcessingQueue, block);
}
} void runSynchronouslyOnContextQueue(GPUImageContext *context, void (^block)(void))
{
dispatch_queue_t videoProcessingQueue = [context contextQueue];
#if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
{
block();
}else
{
dispatch_sync(videoProcessingQueue, block);
}
} void runAsynchronouslyOnContextQueue(GPUImageContext *context, void (^block)(void))
{
dispatch_queue_t videoProcessingQueue = [context contextQueue]; #if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
{
block();
}else
{
dispatch_async(videoProcessingQueue, block);
}
} void reportAvailableMemoryForGPUImage(NSString *tag)
{
if (!tag)
tag = @"Default"; struct task_basic_info info; mach_msg_type_number_t size = sizeof(info); kern_return_t kerr = task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)&info, &size);
if( kerr == KERN_SUCCESS ) {
NSLog(@"%@ - Memory used: %u", tag, (unsigned int)info.resident_size); //in bytes
} else {
NSLog(@"%@ - Error: %s", tag, mach_error_string(kerr));
}
} @implementation GPUImageOutput @synthesize shouldSmoothlyScaleOutput = _shouldSmoothlyScaleOutput;
@synthesize shouldIgnoreUpdatesToThisTarget = _shouldIgnoreUpdatesToThisTarget;
@synthesize audioEncodingTarget = _audioEncodingTarget;
@synthesize targetToIgnoreForUpdates = _targetToIgnoreForUpdates;
@synthesize frameProcessingCompletionBlock = _frameProcessingCompletionBlock;
@synthesize enabled = _enabled;
@synthesize outputTextureOptions = _outputTextureOptions; #pragma mark -
#pragma mark Initialization and teardown - (id)init;
{
if (!(self = [super init]))
{
return nil;
} targets = [[NSMutableArray alloc] init];
targetTextureIndices = [[NSMutableArray alloc] init];
_enabled = YES;
allTargetsWantMonochromeData = YES;
usingNextFrameForImageCapture = NO; // set default texture options
_outputTextureOptions.minFilter = GL_LINEAR;
_outputTextureOptions.magFilter = GL_LINEAR;
_outputTextureOptions.wrapS = GL_CLAMP_TO_EDGE;
_outputTextureOptions.wrapT = GL_CLAMP_TO_EDGE;
_outputTextureOptions.internalFormat = GL_RGBA;
_outputTextureOptions.format = GL_BGRA;
_outputTextureOptions.type = GL_UNSIGNED_BYTE; return self;
} - (void)dealloc
{
[self removeAllTargets];
} #pragma mark -
#pragma mark Managing targets - (void)setInputFramebufferForTarget:(id<GPUImageInput>)target atIndex:(NSInteger)inputTextureIndex;
{
[target setInputFramebuffer:[self framebufferForOutput] atIndex:inputTextureIndex];
} - (GPUImageFramebuffer *)framebufferForOutput;
{
return outputFramebuffer;
} - (void)removeOutputFramebuffer;
{
outputFramebuffer = nil;
} - (void)notifyTargetsAboutNewOutputTexture;
{
for (id<GPUImageInput> currentTarget in targets)
{
NSInteger indexOfObject = [targets indexOfObject:currentTarget];
NSInteger textureIndex = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue]; [self setInputFramebufferForTarget:currentTarget atIndex:textureIndex];
}
} - (NSArray*)targets;
{
return [NSArray arrayWithArray:targets];
} - (void)addTarget:(id<GPUImageInput>)newTarget;
{
NSInteger nextAvailableTextureIndex = [newTarget nextAvailableTextureIndex];
[self addTarget:newTarget atTextureLocation:nextAvailableTextureIndex]; if ([newTarget shouldIgnoreUpdatesToThisTarget])
{
_targetToIgnoreForUpdates = newTarget;
}
} - (void)addTarget:(id<GPUImageInput>)newTarget atTextureLocation:(NSInteger)textureLocation;
{
if([targets containsObject:newTarget])
{
return;
} cachedMaximumOutputSize = CGSizeZero;
runSynchronouslyOnVideoProcessingQueue(^{
[self setInputFramebufferForTarget:newTarget atIndex:textureLocation];
[targets addObject:newTarget];
[targetTextureIndices addObject:[NSNumber numberWithInteger:textureLocation]]; allTargetsWantMonochromeData = allTargetsWantMonochromeData && [newTarget wantsMonochromeInput];
});
} - (void)removeTarget:(id<GPUImageInput>)targetToRemove;
{
if(![targets containsObject:targetToRemove])
{
return;
} if (_targetToIgnoreForUpdates == targetToRemove)
{
_targetToIgnoreForUpdates = nil;
} cachedMaximumOutputSize = CGSizeZero; NSInteger indexOfObject = [targets indexOfObject:targetToRemove];
NSInteger textureIndexOfTarget = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue]; runSynchronouslyOnVideoProcessingQueue(^{
[targetToRemove setInputSize:CGSizeZero atIndex:textureIndexOfTarget];
[targetToRemove setInputRotation:kGPUImageNoRotation atIndex:textureIndexOfTarget]; [targetTextureIndices removeObjectAtIndex:indexOfObject];
[targets removeObject:targetToRemove];
[targetToRemove endProcessing];
});
} - (void)removeAllTargets;
{
cachedMaximumOutputSize = CGSizeZero;
runSynchronouslyOnVideoProcessingQueue(^{
for (id<GPUImageInput> targetToRemove in targets)
{
NSInteger indexOfObject = [targets indexOfObject:targetToRemove];
NSInteger textureIndexOfTarget = [[targetTextureIndices objectAtIndex:indexOfObject] integerValue]; [targetToRemove setInputSize:CGSizeZero atIndex:textureIndexOfTarget];
[targetToRemove setInputRotation:kGPUImageNoRotation atIndex:textureIndexOfTarget];
}
[targets removeAllObjects];
[targetTextureIndices removeAllObjects]; allTargetsWantMonochromeData = YES;
});
} #pragma mark -
#pragma mark Manage the output texture - (void)forceProcessingAtSize:(CGSize)frameSize;
{ } - (void)forceProcessingAtSizeRespectingAspectRatio:(CGSize)frameSize;
{
} #pragma mark -
#pragma mark Still image processing - (void)useNextFrameForImageCapture;
{ } - (CGImageRef)newCGImageFromCurrentlyProcessedOutput;
{
return nil;
} - (CGImageRef)newCGImageByFilteringCGImage:(CGImageRef)imageToFilter;
{
GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithCGImage:imageToFilter]; [self useNextFrameForImageCapture];
[stillImageSource addTarget:(id<GPUImageInput>)self];
[stillImageSource processImage]; CGImageRef processedImage = [self newCGImageFromCurrentlyProcessedOutput]; [stillImageSource removeTarget:(id<GPUImageInput>)self];
return processedImage;
} - (BOOL)providesMonochromeOutput;
{
return NO;
} #pragma mark -
#pragma mark Platform-specific image output methods #if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE - (UIImage *)imageFromCurrentFramebuffer;
{
UIDeviceOrientation deviceOrientation = [[UIDevice currentDevice] orientation];
UIImageOrientation imageOrientation = UIImageOrientationLeft;
switch (deviceOrientation)
{
case UIDeviceOrientationPortrait:
imageOrientation = UIImageOrientationUp;
break;
case UIDeviceOrientationPortraitUpsideDown:
imageOrientation = UIImageOrientationDown;
break;
case UIDeviceOrientationLandscapeLeft:
imageOrientation = UIImageOrientationLeft;
break;
case UIDeviceOrientationLandscapeRight:
imageOrientation = UIImageOrientationRight;
break;
default:
imageOrientation = UIImageOrientationUp;
break;
} return [self imageFromCurrentFramebufferWithOrientation:imageOrientation];
} - (UIImage *)imageFromCurrentFramebufferWithOrientation:(UIImageOrientation)imageOrientation;
{
CGImageRef cgImageFromBytes = [self newCGImageFromCurrentlyProcessedOutput];
UIImage *finalImage = [UIImage imageWithCGImage:cgImageFromBytes scale:1.0 orientation:imageOrientation];
CGImageRelease(cgImageFromBytes); return finalImage;
} - (UIImage *)imageByFilteringImage:(UIImage *)imageToFilter;
{
CGImageRef image = [self newCGImageByFilteringCGImage:[imageToFilter CGImage]];
UIImage *processedImage = [UIImage imageWithCGImage:image scale:[imageToFilter scale] orientation:[imageToFilter imageOrientation]];
CGImageRelease(image);
return processedImage;
} - (CGImageRef)newCGImageByFilteringImage:(UIImage *)imageToFilter
{
return [self newCGImageByFilteringCGImage:[imageToFilter CGImage]];
} #else - (NSImage *)imageFromCurrentFramebuffer;
{
return [self imageFromCurrentFramebufferWithOrientation:UIImageOrientationLeft];
} - (NSImage *)imageFromCurrentFramebufferWithOrientation:(UIImageOrientation)imageOrientation;
{
CGImageRef cgImageFromBytes = [self newCGImageFromCurrentlyProcessedOutput];
NSImage *finalImage = [[NSImage alloc] initWithCGImage:cgImageFromBytes size:NSZeroSize];
CGImageRelease(cgImageFromBytes); return finalImage;
} - (NSImage *)imageByFilteringImage:(NSImage *)imageToFilter;
{
CGImageRef image = [self newCGImageByFilteringCGImage:[imageToFilter CGImageForProposedRect:NULL context:[NSGraphicsContext currentContext] hints:nil]];
NSImage *processedImage = [[NSImage alloc] initWithCGImage:image size:NSZeroSize];
CGImageRelease(image);
return processedImage;
} - (CGImageRef)newCGImageByFilteringImage:(NSImage *)imageToFilter
{
return [self newCGImageByFilteringCGImage:[imageToFilter CGImageForProposedRect:NULL context:[NSGraphicsContext currentContext] hints:nil]];
} #endif #pragma mark -
#pragma mark Accessors - (void)setAudioEncodingTarget:(GPUImageMovieWriter *)newValue;
{
_audioEncodingTarget = newValue;
if( ! _audioEncodingTarget.hasAudioTrack )
{
_audioEncodingTarget.hasAudioTrack = YES;
}
} -(void)setOutputTextureOptions:(GPUTextureOptions)outputTextureOptions
{
_outputTextureOptions = outputTextureOptions; if( outputFramebuffer.texture )
{
glBindTexture(GL_TEXTURE_2D, outputFramebuffer.texture);
//_outputTextureOptions.format
//_outputTextureOptions.internalFormat
//_outputTextureOptions.magFilter
//_outputTextureOptions.minFilter
//_outputTextureOptions.type
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, _outputTextureOptions.wrapS);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, _outputTextureOptions.wrapT);
glBindTexture(GL_TEXTURE_2D, );
}
} @end