android - 使用 OpenGl 和触摸屏功能视觉校正旋转

Question

我一直在尝试为 android 做 Cube of Rubik。我有一个关于轮换的问题。我想在视觉上正确地旋转一个图形。这意味着如果用户触摸屏幕并将手指向右移动后，图形会从观察点的一侧向右旋转。但是当我进行一些旋转时，图形开始朝不正确的方向移动。我知道这取决于那个轴正在改变他们的情况。但是我尝试使用逆模型矩阵来获得必要的坐标，但我还没有结果。任何人都可以给我示例或在鼠标或触摸屏的帮助下视觉上正确旋转 3D 图形的链接吗？

   //get vector 3D of touch
   Vector3f touchVector = getRubikSystemCoordinates(mTouchX,mTouchY,square.rubikRotationMatrix);
   //Get vector 3D of move     
   Vector3f moveVector = getRubikSystemCoordinates(mMoveX,mMoveY,square.rubikRotationMatrix);
        //get direction of motion
        float direction = touchVector.substractFrom(moveVector); 
        //get axis for rotation
        Vector3f axis = touchVector.vectorProductTo(moveVector);
        //normalize axis
        axis.normalize();
        //get angle of rotation
        float angle = direction.length;
        //make identity Quad
        Quaternion quad = new Quaternion();
        //make rotation quad
        quad.makeRotationKvaternion(angle,axis);
        //from quad recieve matrix
        Matrix4f matrix = quad.toMatrix();
        //multiply to current modelview matrix
        gl.glMultMatrixf(matrix.returnArray(),0);
        //save rotation matrix
        square.rotationMatrix = square.rotationMatrix.multiply(matrix);
        //save modelView matrix
        square.saveModelView(square.initMatrix.returnArray()); 


      // touch coords to current modelView coords
      private Vector3f getRubikSystemCoordinates(float x, float y, Matrix4f matrix){
       // touch coords to normal coords of screen 
       Vector2f normalCoords = (new Vector2f(x,y)).toNormalScreenCoordinates(Settings.viewPort[2],Settings.viewPort[3]);
        // to sphere coords in 3D
        Vector3f sphereVector = new Vector3f(normalCoords.x,normalCoords.y, FloatMath.sqrt(2-normalCoords.x*normalCoords.x-normalCoords.y*normalCoords.y));
        //Get inverse matrix from ModelView Matrix
        Matrix4f m = matrix.inverseMatrix();
        //Get vector for current modelView 3D coords
        Vector3f vector = m.multiplyToVector(vector);
        // make normalize vector
        vector.normalize();
        return vector;
        }

Answer 1

您正在寻找的是名为 arcball 的旋转。您会在互联网上找到大量有关 Java 的资源。