// ===========================================================================
//	Matrix2D.java	1996 Yushin Hozumi All rights reserved.
//					Author:Yushin Hozumi
// ===========================================================================

package	StudioRAIN.geometry;

import	StudioRAIN.geometry.*;

public class Matrix2D
{
	private Vector2D mXBase = null;
	private Vector2D mYBase = null;

	public Matrix2D()
	{
		mXBase = new Vector2D( 1.0F, 0.0F );
		mYBase = new Vector2D( 0.0F, 1.0F );
	}

	public Matrix2D( Vector2D inXBase, Vector2D inYBase )
	{
		mXBase = new Vector2D( inXBase );
		mYBase = new Vector2D( inYBase );
	}

	public Matrix2D( float in00, float in01, float in10, float in11 )
	{
		mXBase = new Vector2D( in00, in10 );
		mYBase = new Vector2D( in01, in11 );
	}

	public Matrix2D( float inRadian )
	{
		float theSin = ( float )Math.sin( ( double )inRadian );
		float theCos = ( float )Math.cos( ( double )inRadian );

		mXBase = new Vector2D( theCos, theSin );
		mYBase = new Vector2D( -theSin, theCos );
	}

	// query
	public float get00() { return mXBase.getX(); }
	public float get01() { return mYBase.getX(); }
	public float get10() { return mXBase.getY(); }
	public float get11() { return mYBase.getY(); }
	public Vector2D getRow0() { return new Vector2D( mXBase.getX(), mYBase.getX() ); }
	public Vector2D getRow1() { return new Vector2D( mXBase.getY(), mYBase.getY() ); }
	public Vector2D getColumn0() { return new Vector2D( mXBase ); }
	public Vector2D getColumn1() { return new Vector2D( mYBase ); }
	
	public Matrix2D add( Matrix2D inMatrix )
	{
		mXBase.add( inMatrix.mXBase );
		mYBase.add( inMatrix.mYBase );
		return this;
	}

	public Matrix2D sub( Matrix2D inMatrix )
	{
		mXBase.sub( inMatrix.mXBase );
		mYBase.sub( inMatrix.mYBase );
		return this;
	}

	public Matrix2D product( Matrix2D inMatrix )
	{
		Vector2D theXBase = new Vector2D( getRow0().innerProduct( inMatrix.getColumn0() ), getRow1().innerProduct( inMatrix.getColumn0() ) ); 
		Vector2D theYBase = new Vector2D( getRow0().innerProduct( inMatrix.getColumn1() ), getRow1().innerProduct( inMatrix.getColumn1() ) ); 

		mXBase = theXBase;
		mYBase = theYBase;

		return this;
	}

	public Vector2D linearTransform( Vector2D inVector )
	{
		return new Vector2D( getRow0().innerProduct( inVector ), getRow1().innerProduct( inVector ) );
	}

	public float determinant()
	{
		return mXBase.outerProduct( mYBase );
	}

	public Matrix2D inverse()
	{
		float theDeterminant = determinant();
		
		return new Matrix2D( mYBase.getY() / theDeterminant, -mYBase.getX() /  theDeterminant, -mXBase.getY() / theDeterminant, mXBase.getX() / theDeterminant );
	}
}