graphicslib3D

Class MatrixStack

java.lang.Object

graphicslib3D.MatrixStack

public class MatrixStack
extends java.lang.Object

This class defines a Stack for managing hierarchical collections of Matrix3D transformations. It allows pushing and popping Matrix3Ds in a manner analogous to the deprecated OpenGL matrix stacks (e.g. ModelView, Projection, and Texture matrix stacks). The class is modeled after the GLMatrixStack class in the GLTools package of the text "OpenGL SuperBible, 5th Edition", by Richard Wright.

Author:

John Clevenger

Constructor Summary

Constructors

Constructor and Description
MatrixStack(int maxSize) Creates a MatrixStack with the specified maximum depth.

Method Summary

Modifier and Type	Method and Description
void	loadIdentity() Sets the Matrix3D at the top of the stack to be the Identity matrix, discarding the previous contents of the top of the stack.
void	loadMatrix(Matrix3D mat) Sets the Matrix3D at the top of the stack to be a copy of the specified matrix, discarding the previous contents of the top of the stack.
void	multMatrix(Matrix3D mat) Concatenates the specified matrix with the matrix currently at the top of the stack, replacing the top of the stack with the resulting product matrix.
Matrix3D	peek() Returns a copy of the Matrix3D at the top of the stack without affecting the stack.
void	popMatrix() Pops the top element off the stack and discards it, or throws a RuntimeException if the stack is empty.
void	pushMatrix() Makes a copy of the Matrix3D currently at the top of the stack and pushes that copy onto the stack (i.e., duplicates the top of the stack).
void	rotate(double degrees, double x, double y, double z) Applies the specified rotation by angle degrees about the specified axis x,y,z to the Matrix3D at the top of the stack.
void	scale(double x, double y, double z) Applies the specified scale factors to the Matrix3D at the top of the stack.
void	translate(double x, double y, double z) Applies the specified translation factors to the Matrix3D at the top of the stack.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MatrixStack

public MatrixStack(int maxSize)

Creates a MatrixStack with the specified maximum depth. Each entry in the MatrixStack is a single Matrix3D. A newly-created MatrixStack is automatically initialized with an Identity Matrix3D at the top of the stack.

Parameters:

maxSize - - the maximum size (depth) of the stack before a stack overflow exception occurs

Method Detail

loadIdentity

public void loadIdentity()

Sets the Matrix3D at the top of the stack to be the Identity matrix, discarding the previous contents of the top of the stack.

loadMatrix

public void loadMatrix(Matrix3D mat)

Sets the Matrix3D at the top of the stack to be a copy of the specified matrix, discarding the previous contents of the top of the stack.

Parameters:

mat - - the matrix to be copied onto the top of the stack, replacing the current top of the stack

multMatrix

public void multMatrix(Matrix3D mat)

Concatenates the specified matrix with the matrix currently at the top of the stack, replacing the top of the stack with the resulting product matrix. The specified matrix is multiplied "on the right", such that the result is

   stack[top] = stack[top] * mat ;
 

Parameters:

mat - - the matrix to be concatenated onto the matrix at the top of the stack

pushMatrix

public void pushMatrix()

Makes a copy of the Matrix3D currently at the top of the stack and pushes that copy onto the stack (i.e., duplicates the top of the stack). Analogous to OpenGL routine glPushMatrix(). Throws a RuntimeException if there is not room on the stack to push another matrix onto the stack.

popMatrix

public void popMatrix()

Pops the top element off the stack and discards it, or throws a RuntimeException if the stack is empty.

scale

public void scale(double x,
                  double y,
                  double z)

Applies the specified scale factors to the Matrix3D at the top of the stack. This is done by creating a new Matrix3D representing the specified scaling and then concatenating the new matrix with the matrix at the top of the stack using multMatrix(Matrix3D). Analogous to OpenGL method glScaled().

Parameters:

x - - the scale factor in X

y - - the scale factor in Y

z - - the scale factor in Z

rotate

public void rotate(double degrees,
                   double x,
                   double y,
                   double z)

Applies the specified rotation by angle degrees about the specified axis x,y,z to the Matrix3D at the top of the stack. This is done by creating a new Matrix3D representing the specified rotation and then concatenating the new matrix with the matrix at the top of the stack using multMatrix(Matrix3D). Analogous to OpenGL method glRotated().

Parameters:

degrees - - the angle of rotation in degrees

x - - the X component of the rotation axis

y - - the Y component of the rotation axis

z - - the Z component of the rotation axis

translate

public void translate(double x,
                      double y,
                      double z)

Applies the specified translation factors to the Matrix3D at the top of the stack. This is done by creating a new Matrix3D representing the specified translation and then concatenating the new matrix with the matrix at the top of the stack using multMatrix(Matrix3D). Analogous to OpenGL method glTranslated().

Parameters:

x - - the translation in X

y - - the translation in Y

z - - the translation in Z

peek

public Matrix3D peek()

Returns a copy of the Matrix3D at the top of the stack without affecting the stack.

Returns:

a copy of the matrix at the top of the stack