GPUImage API文档之GPUImageContext类

　　GPUImageContext类，提供OpenGL ES基本环境，我们一般不会用到，所以讲的很简单。

　　属性

　　@property(readonly, nonatomic) dispatch_queue_t contextQueue

　　说明：创建一个context线程

　　描述：_contextQueue = dispatch_queue_create("com.sunsetlakesoftware.GPUImage.openGLESContextQueue", NULL);

 

　　@property(readwrite, retain, nonatomic) GLProgram *currentShaderProgram

　　说明：当前着色器program

 

　　@property(readonly, retain, nonatomic) EAGLContext *context

　　说明：opengl es绘制环境，管理上下文

 

　　方法

　　　　+ (void *)contextKey

　　　　说明：设置当前context的线程标识符，全局静态变量。

　　

　　　　+ (GPUImageContext *)sharedImageProcessingContext

　　　　说明：创建一个全局的GPUImageContext对象的单例。

 

　　　　+ (dispatch_queue_t)sharedContextQueue

　　　　说明：创建一个context queue单例

 

　　　　+ (GPUImageFramebufferCache *)sharedFramebufferCache

　　　　说明：创建一个GPUFramebufferCache单例

　　　　　

　　　　- (void)useAsCurrentContext

　　　　说明：使用当前context

 

　　　　+ (void)setActiveShaderProgram:(GLProgram *)shaderProgram;

　　　　- (void)setContextShaderProgram:(GLProgram *)shaderProgram;

　　　　+ (GLint)maximumTextureSizeForThisDevice;

　　　　+ (GLint)maximumTextureUnitsForThisDevice;

　　　　+ (GLint)maximumVaryingVectorsForThisDevice;

　　　　+ (BOOL)deviceSupportsOpenGLESExtension:(NSString *)extension;

　　　　+ (BOOL)deviceSupportsRedTextures;

　　　　+ (BOOL)deviceSupportsFramebufferReads;

　　　　+ (CGSize)sizeThatFitsWithinATextureForSize:(CGSize)inputSize;

　　　　- (void)presentBufferForDisplay;

　　　　- (GLProgram *)programForVertexShaderString:(NSString *)vertexShaderString fragmentShaderString:(NSString *)fragmentShaderString;

　　　　- (void)useSharegroup:(EAGLSharegroup *)sharegroup;

　　　　+ (BOOL)supportsFastTextureUpload;

 

完整代码

#import "GLProgram.h"
#import "GPUImageFramebuffer.h"
#import "GPUImageFramebufferCache.h"

#define GPUImageRotationSwapsWidthAndHeight(rotation) ((rotation) == kGPUImageRotateLeft || (rotation) == kGPUImageRotateRight || (rotation) == kGPUImageRotateRightFlipVertical || (rotation) == kGPUImageRotateRightFlipHorizontal)

typedef enum { kGPUImageNoRotation, kGPUImageRotateLeft, kGPUImageRotateRight, kGPUImageFlipVertical, kGPUImageFlipHorizonal, kGPUImageRotateRightFlipVertical, kGPUImageRotateRightFlipHorizontal, kGPUImageRotate180 } GPUImageRotationMode;

@interface GPUImageContext : NSObject

@property(readonly, nonatomic) dispatch_queue_t contextQueue;
@property(readwrite, retain, nonatomic) GLProgram *currentShaderProgram;
@property(readonly, retain, nonatomic) EAGLContext *context;
@property(readonly) CVOpenGLESTextureCacheRef coreVideoTextureCache;
@property(readonly) GPUImageFramebufferCache *framebufferCache;

+ (void *)contextKey;
+ (GPUImageContext *)sharedImageProcessingContext;
+ (dispatch_queue_t)sharedContextQueue;
+ (GPUImageFramebufferCache *)sharedFramebufferCache;
+ (void)useImageProcessingContext;
- (void)useAsCurrentContext;
+ (void)setActiveShaderProgram:(GLProgram *)shaderProgram;
- (void)setContextShaderProgram:(GLProgram *)shaderProgram;
+ (GLint)maximumTextureSizeForThisDevice;
+ (GLint)maximumTextureUnitsForThisDevice;
+ (GLint)maximumVaryingVectorsForThisDevice;
+ (BOOL)deviceSupportsOpenGLESExtension:(NSString *)extension;
+ (BOOL)deviceSupportsRedTextures;
+ (BOOL)deviceSupportsFramebufferReads;
+ (CGSize)sizeThatFitsWithinATextureForSize:(CGSize)inputSize;

- (void)presentBufferForDisplay;
- (GLProgram *)programForVertexShaderString:(NSString *)vertexShaderString fragmentShaderString:(NSString *)fragmentShaderString;

- (void)useSharegroup:(EAGLSharegroup *)sharegroup;

// Manage fast texture upload
+ (BOOL)supportsFastTextureUpload;

@end

@protocol GPUImageInput <NSObject>
- (void)newFrameReadyAtTime:(CMTime)frameTime atIndex:(NSInteger)textureIndex;
- (void)setInputFramebuffer:(GPUImageFramebuffer *)newInputFramebuffer atIndex:(NSInteger)textureIndex;
- (NSInteger)nextAvailableTextureIndex;
- (void)setInputSize:(CGSize)newSize atIndex:(NSInteger)textureIndex;
- (void)setInputRotation:(GPUImageRotationMode)newInputRotation atIndex:(NSInteger)textureIndex;
- (CGSize)maximumOutputSize;
- (void)endProcessing;
- (BOOL)shouldIgnoreUpdatesToThisTarget;
- (BOOL)enabled;
- (BOOL)wantsMonochromeInput;
- (void)setCurrentlyReceivingMonochromeInput:(BOOL)newValue;
@end

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