Cocos3d和增强现实

Question

我想在iPhone应用程序中添加来自cocos3d的3D对象作为增强现实的相机覆盖。我有一些型号的CC3Scene。我创建了motionManager捕获来获取有关设备相机方向的信息，然后在-（void）更新：（ccTime）dt中，我正在尝试更新场景相机位置中的cocos3d（场景的向上方向是Z轴）：

-(void) update:(ccTime)dt
{
    CMDeviceMotion *currentDeviceMotion = motionManager.deviceMotion;
    CMAttitude *currentAttitude = currentDeviceMotion.attitude;
    CC3Camera *cam = (CC3Camera*)[cc3Scene getNodeNamed:@"Camera"];
    static double lastY = 0;
    static double lastP = 0;
    static double lastR = 0;
    double yaw = CC_RADIANS_TO_DEGREES(currentAttitude.yaw-lastY);
    double pitch = CC_RADIANS_TO_DEGREES(currentAttitude.pitch-lastP);
    double roll = CC_RADIANS_TO_DEGREES(currentAttitude.roll-lastR);
    CC3Vector fd = cc3v(0,1,0);
    [cam rotateByAngle:roll aroundAxis:fd];
    CC3Vector rp = cc3v(1,0,0);
    [cam rotateByAngle:pitch aroundAxis:rp];
    CC3Vector up = cc3v(0,0,1);
    [cam rotateByAngle:yaw aroundAxis:up];
lastY = currentAttitude.yaw;
lastP = currentAttitude.pitch;
lastR = currentAttitude.roll;
[super update:dt];
}

我不能直接使用cam.rrotation=cc3v（俯仰、滚转、偏航），因为椰子中的旋转顺序（与我当前的轴）与设备中的不匹配。但我的代码也不正确。手动旋转相机时出现错误，我不知道该如何旋转才能使其正确（我几乎尝试了所有顺序和轴的组合）。

所以问题是，我如何才能匹配cocos的相机旋转和设备的旋转？我是不是错过了什么？或者你可以提供这样主题的代码或教程项目吗？我知道这是一个很简单的问题，因为只有三角法，但我试着去做它时已经疯了

谢谢！

Answer 1

完成了该代码，运行良好

-(CC3Vector4)multiplyQuaternion:(CC3Vector4)q2 onAxis:(CC3Vector4)axis byDegress:(float)degrees{
  CC3Vector4 q1;
  q1.x = axis.x;
  q1.y = axis.y;
  q1.z = axis.z;
  // Converts the angle in degrees to radians.
  float radians = CC_DEGREES_TO_RADIANS(degrees);
  // Finds the sin and cosine for the half angle.
  float sin = sinf(radians * 0.5);
  float cos = cosf(radians * 0.5);
  // Formula to construct a new Quaternion based on direction and angle.
  q1.w = cos;
  q1.x = q1.x * sin;
  q1.y = q1.y * sin;
  q1.z = q1.z * sin;
  // Multiply quaternion, q1 x q2 is not equal to q2 x q1
  CC3Vector4 newQ;
  newQ.w = q1.w * q2.w - q1.x * q2.x - q1.y * q2.y - q1.z * q2.z;
  newQ.x = q1.w * q2.x + q1.x * q2.w + q1.y * q2.z - q1.z * q2.y;
  newQ.y = q1.w * q2.y - q1.x * q2.z + q1.y * q2.w + q1.z * q2.x;
  newQ.z = q1.w * q2.z + q1.x * q2.y - q1.y * q2.x + q1.z * q2.w;
  return  newQ;
}
-(void)updateCameraFromMotion:(CMDeviceMotion *)deviceMotion {
  CMAttitude  * attitude    = deviceMotion.attitude;
  CMQuaternion  quaternion  = attitude.quaternion;
  CC3Vector4    camQuaternion;
  camQuaternion.w =  quaternion.w;
  camQuaternion.x = -quaternion.x;
  camQuaternion.y = -quaternion.z;
  camQuaternion.z =  quaternion.y;
  camQuaternion   = [self multiplyQuaternion:camQuaternion onAxis:CC3Vector4Make(1, 0, 0, 0) byDegress:90];
  self.activeCamera.quaternion = camQuaternion;  
}

注意，相机启动时的正向确实很重要，我将其设置为（1,0,0）