OpenCV for Ios 學習筆記(8)－用OPENGL渲染AR情境1

本文原始地址：OpenCV for Ios 學習筆記(8)－用OPENGL渲染AR情境1

 建立OpenGL渲染層

為了在你的應用中使用opengl函數，你必須為你的應用添加一個圖形畫板，它給使用者呈現被渲染的情境。

為了封裝opengl畫板初始化邏輯，我們介紹EAGLView類：

////  EAGLView.h//  OpenCvDemo////  Created by apple on 13-4-24.//  Copyright (c) 2013年 hxy. All rights reserved.//#import <UIKit/UIKit.h>#import <OpenGLES/ES1/gl.h>#import <OpenGLES/ES1/glext.h>#import <OpenGLES/ES2/gl.h>#import <OpenGLES/ES2/glext.h>@class EAGLContext;@interface EAGLView : UIView{    @private    GLuint defaultFrameBuffer,colorRenderBuffer,depthRenderBuffer;}@property (nonatomic, retain) EAGLContext *context;@property (readonly) GLint frameBufferWidth,frameBufferHeight;//初始化畫板- (void)initContext;//設定幀緩衝- (void)setFrameBuffer;//呈現幀緩衝- (void)presentFrameBuffer;@end

////  EAGLView.m//  OpenCvDemo////  Created by apple on 13-4-24.//  Copyright (c) 2013年 hxy. All rights reserved.//#import "EAGLView.h"@interface EAGLView (Private)//建立幀緩衝- (void)createFrameBuffer;//刪除所有的緩衝- (void)deleteFrameBuffer;@end@implementation EAGLView@synthesize context,frameBufferHeight,frameBufferWidth;- (void)dealloc{    [self deleteFrameBuffer];    if ([EAGLContext currentContext] == context)    {        [EAGLContext setCurrentContext:nil];    }    [super dealloc];}+ (Class)layerClass{    return [CAEAGLLayer class];}- (void)layoutSubviews{    //在下一次設定幀緩衝時，幀緩衝將會重新建立    [self deleteFrameBuffer];}- (void)initContext{    if (!context)    {        EAGLRenderingAPI api = kEAGLRenderingAPIOpenGLES2;        context = [[EAGLContext alloc] initWithAPI:api];        if (!context)        {            NSLog(@"畫布都建立失敗，還運行個闖闖！");            exit(1);            return;        }        if (![EAGLContext setCurrentContext:context])        {            NSLog(@"悲劇了塞！");            exit(1);            return;        }    }}- (void)setContext:(EAGLContext *)newcontext{    if (context != newcontext)    {        [self deleteFrameBuffer];        context = newcontext;        [EAGLContext setCurrentContext:nil];    }}- (CAEAGLLayer *)myLayer{    return (CAEAGLLayer *)self.layer;}- (id)initWithCoder:(NSCoder *)aDecoder{    if (self = [super initWithCoder:aDecoder])    {        CAEAGLLayer *layer = [self myLayer];        layer.opaque = TRUE;        layer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:FALSE],kEAGLDrawablePropertyRetainedBacking,kEAGLColorFormatRGBA8,kEAGLDrawablePropertyColorFormat, nil];        [self initContext];    }    return self;}- (void)setFrameBuffer{    if (context)    {        [EAGLContext setCurrentContext:context];        if (!depthRenderBuffer)        {            [self createFrameBuffer];        }                glBindFramebuffer(GL_FRAMEBUFFER, defaultFrameBuffer);        glViewport(0, 0, frameBufferWidth, frameBufferHeight);        glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);    }}- (void)presentFrameBuffer{    BOOL success = FALSE;    if (context)    {        [EAGLContext setCurrentContext:context];                glBindRenderbuffer(1, colorRenderBuffer);        success = [context presentRenderbuffer:GL_RENDERBUFFER];    }}- (void)createFrameBuffer{    //還未設定預設幀緩衝    if (context && !defaultFrameBuffer)    {        [EAGLContext setCurrentContext:context];                //建立預設幀緩衝對象        glGenFramebuffers(1, &(defaultFrameBuffer));        glBindFramebuffer(GL_FRAMEBUFFER, defaultFrameBuffer);                //建立顏色緩衝，分配記憶體        glGenRenderbuffers(1, &colorRenderBuffer);        glBindRenderbuffer(GL_RENDERBUFFER, colorRenderBuffer);                [context renderbufferStorage:GL_RENDERBUFFER fromDrawable:[self myLayer]];                glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &frameBufferWidth);        glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &frameBufferHeight);                glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderBuffer);        //產生深度緩衝        glGenRenderbuffers(1, &depthRenderBuffer);        glBindRenderbuffer(GL_RENDERBUFFER, depthRenderBuffer);                glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, frameBufferWidth, frameBufferHeight);        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderBuffer);                //檢查狀態        if (glCheckFramebufferStatus(GL_FRAMEBUFFER)!= GL_FRAMEBUFFER_COMPLETE)        {            NSLog(@"Failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER));        }    }}- (void)deleteFrameBuffer{    if (context)    {        [EAGLContext setCurrentContext:context];                if (defaultFrameBuffer)        {            glDeleteFramebuffers(1, &defaultFrameBuffer);            defaultFrameBuffer = 0;        }                if (colorRenderBuffer)        {            glDeleteRenderbuffers(1, &colorRenderBuffer);            colorRenderBuffer = 0;        }                if (depthRenderBuffer)        {            glDeleteRenderbuffers(1, &depthRenderBuffer);            depthRenderBuffer = 0;        }    }}@end

渲染AR情境

在上面的EAGLView並不包括任何的3維物體虛擬化的方法，當然，我們是故意的。EAGLView的任務是提供渲染的畫板，將各個類的職責區別開有利於我們在接下來改變虛擬化過程的邏輯。

為了實現增強現實的虛擬化，我們將會建立一個單獨的類VisualizationController：

@interface SimpleVisualizationController : NSObject{  EAGLView * m_glview;  GLuint m_backgroundTextureId;  std::vector<Transformation> m_transformations;  CameraCalibration m_calibration;  CGSize m_frameSize;}-(id) initWithGLView:(EAGLView*)view calibration:(CameraCalibration) calibration frameSize:(CGSize) size;//把ar渲染到EAGLView目標視圖上去-(void) drawFrame;-(void) updateBackground:(BGRAVideoFrame) frame;-(void) setTransformationList:(const std::vector<Transformation>&) transformations;@end

未完