289 - Rotation Matrix Y

//
//  RotationMatrixY.java
//  Easel
//
//  Created by Philip Rhodes on 7/29/05.
//  Copyright 2005 __MyCompanyName__. All rights reserved.
//

/** This class represents matrices that rotate vertices around the y axis.
  * according to the "right hand rule".
  */
public class RotationMatrixY extends RotationMatrix{

   /** Constructs a rotation matrix with rotation angle 0. */
   public RotationMatrixY(){
      // The default constructor will set this matrix
      // equal to the identity, so do nothing here.

   }


   /** Construct a matrix that will rotate vertices around the y axis by the
    *  angle theta, expressed in radians."
    */
   RotationMatrixY(double theta){
      // Write me!
      float  [][] rotationx_matrix =
              {{(float)Math.cos(theta), 0.0f, (float)Math.sin(theta), 0.0f},
              {0.0f,                    1.0f,    0.0f,                 0.0f},
              {-(float)Math.sin(theta),  0.0f, (float)Math.cos(theta),  0.0f},
              {0.0f,                    0.0f,    0.0f,                 1.0f}
      };

      matrix = rotationx_matrix;
   }

   /** Set the angle of rotation to theta, expressed in radians.  */
   public void setAngle(double theta){
     // Write me!
      matrix[0][0] = (float)Math.cos(theta);
      matrix[0][2] = (float)Math.sin(theta);
      matrix[2][0] = -(float)Math.sin(theta);
      matrix[2][2] = (float)Math.cos(theta);
   }

}