这里暂时作为记录我写程序的日志

我的想法：利用高通的Vuforia，写一个可以把scenekit代替OpenGL，并把UserDF和Image合并，如果还可以，就把扫码融入识别的场景中（我同事用Unity实现此功能，非常地耗Cpu，iPhone 5 ，5s，6都发热得非常严重），把整个识别的VC独立出来，app其他的界面就可以分别作为TableView，或者一些瀑布流，不用局限于此app只是用来识别。

感谢博客http://qiita.com/akira108/items/a743138fca532ee193fe 帮我完成了最难的一部分，就是用Scenekit代替OpenGL在Vuforia上面显示，目前有日文和英文版。理解得还不是很完全，大体是知道把识别的摄像头位置赋值给Scenekit场景中，摄像头的位置。

The AR in this context means reconstructing the marker's relative 3D position towards a camera from the 2D image which taken by the camera.

@protocol UserDefinedTargetsEAGLViewSceneSoure

• (SCNScene *)sceneForEAGLView:(UIView *)view; @end

@property (nonatomic, strong) SCNRenderer *renderer; // renderer ， @property (nonatomic, strong) SCNNode *cameraNode; // node which holds camera ， @property (nonatomic, assign) CFAbsoluteTime startTime; // elapsed time in 3D scene

• (void)setupRenderer { self.renderer = [SCNRenderer rendererWithContext:context options:nil]; self.renderer.autoenablesDefaultLighting = YES; self.renderer.playing = YES;

  if (self.sceneSource != nil) { self.renderer.scene = [self.sceneSource sceneForEAGLView:self];

    SCNCamera *camera = [SCNCamera camera];
    self.cameraNode = [SCNNode node];
    self.cameraNode.camera = camera;
    [self.renderer.scene.rootNode addChildNode:self.cameraNode];
    self.renderer.pointOfView = self.cameraNode;
  

  }

}

• (SCNMatrix4)SCNMatrix4FromQCARMatrix44:(QCAR::Matrix44F)matrix { GLKMatrix4 glkMatrix;

  for(int i=0; i<16; i++) { glkMatrix.m[i] = matrix.data[i]; } return SCNMatrix4FromGLKMatrix4(glkMatrix); }

• (void)setCameraMatrix:(QCAR::Matrix44F)matrix { SCNMatrix4 extrinsic = [self SCNMatrix4FromQCARMatrix44:matrix]; SCNMatrix4 inverted = SCNMatrix4Invert(extrinsic); // inverse matrix! self.cameraNode.transform = inverted; // assign it to the camera node's transform property. }

• (void)setProjectionMatrix:(QCAR::Matrix44F)matrix { self.cameraNode.camera.projectionTransform = [self SCNMatrix4FromQCARMatrix44:matrix]; }

// *** QCAR will call this method periodically on a background thread ***

• (void)renderFrameQCAR { [self setFramebuffer];

  // Clear colour and depth buffers glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  // Render video background and retrieve tracking state QCAR::State state = QCAR::Renderer::getInstance().begin(); QCAR::Renderer::getInstance().drawVideoBackground();

  glEnable(GL_DEPTH_TEST); // We must detect if background reflection is active and adjust the culling direction. // If the reflection is active, this means the pose matrix has been reflected as well, // therefore standard counter clockwise face culling will result in "inside out" models. glEnable(GL_CULL_FACE); glCullFace(GL_BACK); if(QCAR::Renderer::getInstance().getVideoBackgroundConfig().mReflection == QCAR::VIDEO_BACKGROUND_REFLECTION_ON) glFrontFace(GL_CW); //Front camera else glFrontFace(GL_CCW); //Back camera

  // Render the RefFree UI elements depending on the current state refFreeFrame->render();

  [self setProjectionMatrix:vapp.projectionMatrix]; // Actually you don't have to call that every frame. Because projection matrix does not change.

  for (int i = 0; i < state.getNumTrackableResults(); ++i) { // Get the trackable const QCAR::TrackableResult* result = state.getTrackableResult(i); //const QCAR::Trackable& trackable = result->getTrackable(); QCAR::Matrix44F modelViewMatrix = QCAR::Tool::convertPose2GLMatrix(result->getPose()); // Obtain model view matrix

    ApplicationUtils::translatePoseMatrix(0.0f, 0.0f, kObjectScale, &modelViewMatrix.data[0]);
    ApplicationUtils::scalePoseMatrix(kObjectScale, kObjectScale, kObjectScale, &modelViewMatrix.data[0]);
  
    [self setCameraMatrix:modelViewMatrix]; // SCNCameraにセット
    [self.renderer renderAtTime:CFAbsoluteTimeGetCurrent() - self.startTime]; // Render objects into OpenGL context
  
    ApplicationUtils::checkGlError("EAGLView renderFrameQCAR");
  

  }

  glDisable(GL_DEPTH_TEST); glDisable(GL_CULL_FACE);

  QCAR::Renderer::getInstance().end(); [self presentFramebuffer];

}

以上以下是日志 4.11:修改结果，ImageTarget 与UserDefined 的 renderFrameQCAR方法一致，使用教程修改过后的，两个都可以使用SceneKit展现模型。

未实现功能：把UserDefined 与 ImageTarget 合并到同一个场景； 失去识别图时，把模型用动画过渡到中间，增加触摸手势旋转（参考以前写的项目）； 把扫码功能与识别场景融合（考虑是否实用）； AR能用到什么地方