289 - Rotation Matrix X

//
//  RotationMatrixX.java
//  Easel
//
//  Created by Philip Rhodes on 7/28/05.
//  Copyright 2005 __MyCompanyName__. All rights reserved.
//

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

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

   }

   /** Construct a matrix that will rotate vertices around the x axis by the
    *  angle theta, expressed in radians."
    */
   public RotationMatrixX(double theta){
          float  [][] rotationx_matrix = {{1.0f, 0.0f, 0.0f, 0.0f},
                                          {0.0f, (float)Math.cos(theta), -(float)Math.sin(theta), 0.0f},
                                          {0.0f, (float)Math.sin(theta), (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){
       matrix[1][1] = (float)Math.cos(theta);
       matrix[1][2] = -(float)Math.sin(theta);
       matrix[2][1] = (float)Math.sin(theta);
       matrix[2][2] = (float)Math.cos(theta);
   }


}