org.proteinshader.gui.viewing
Class Camera

java.lang.Object
  org.proteinshader.gui.viewing.Camera

public class Camera
extends Object

Used to store and manipulate camera information.

Field Summary

static double	FOVY The fovy (field of view on y-axis) for the camera is 60 degrees.
static double	HALF_FOVY Half the fovy is useful for some calculations.
static double	HALF_FOVY_RADIANS Half the fovy needs to be in radians for Java trig functions.
static int	MIN_INITIAL_CAMERA_DISTANCE The minimum initial camera distance is 20.
static double	SIN_HALF_FOVY The sine of HALF_FOVY_RADIANS is used in pixel-angstrom conversions.
static double	TAN_HALF_FOVY The tangent of HALF_FOVY_RADIANS is used in pixel-angstrom conversions.

Constructor Summary

Camera()
Constructs a Renderer.

Method Summary

void	aim(GL gl) Uses gluLookAt() to position and aim the camera.
double	calculateDepth(double x, double y, double z) Calculates the depth (z-coordinate in camera space) of the xyz-center of the Drawable object.
double	calculateDepth(Drawable d) Calculates the depth (z-coordinate in camera space) of the xyz-center of the Drawable object.
double	calculateDistance(double x, double y, double z) Calculates the distance between the camera and the xyz-center of the Drawable object by using the Pythagorean theorem.
double	calculateDistance(Drawable d) Calculates the distance between the camera and the xyz-center of the Drawable object by using the Pythagorean theorem.
double	convertToAngstroms(double pixels, double cameraDepth) Converts pixels to angstroms based on depth in camera space.
void	initializeViewport(GLAutoDrawable canvas, GL gl) Sets the viewport so that the origin (0, 0, 0) is in its center.
void	moveX(int x) Add to the camera x position.
void	moveY(int y) Add to the camera y position.
void	moveZ(int z) Add to the camera z position.
void	printModelViewMatrix() This debugging method prints the copy of the ModelViewMatrix stored n m_modelViewMatrix.
void	printXYZ() Prints the xyz-coordinates for the camera.
void	resetDistance() Sets the camera position based on the initial camera distance calculated when a new Structure is loaded.
void	reshape(GL gl, int x, int y, int width, int height) Called on when the GLAutoDrawable object has changed its size so that the perspective and viewport can be recalculated.
void	setAccPerspective(GLAutoDrawable canvas, GL gl, double dxPixels, double dyPixels) Sets the projection matrix by using the glFrustrum() method of OpenGL.
void	setGluPerspective(GLAutoDrawable canvas, GL gl) Sets the projection matrix by using the gluPerspective() method of OpenGL.
void	setInitialCameraDistance(int z) Sets the initial camera distance on the z-axis.
void	updateModelViewMatrix(GL gl) Updates a copy of the OpenGL model view matrix.

Methods inherited from class java.lang.Object

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

Field Detail

FOVY

public static final double FOVY

The fovy (field of view on y-axis) for the camera is 60 degrees.

See Also:

Constant Field Values

HALF_FOVY

public static final double HALF_FOVY

Half the fovy is useful for some calculations.

See Also:

Constant Field Values

HALF_FOVY_RADIANS

public static final double HALF_FOVY_RADIANS

Half the fovy needs to be in radians for Java trig functions.

See Also:

Constant Field Values

SIN_HALF_FOVY

public static final double SIN_HALF_FOVY

The sine of HALF_FOVY_RADIANS is used in pixel-angstrom conversions.

TAN_HALF_FOVY

public static final double TAN_HALF_FOVY

The tangent of HALF_FOVY_RADIANS is used in pixel-angstrom conversions.

MIN_INITIAL_CAMERA_DISTANCE

public static final int MIN_INITIAL_CAMERA_DISTANCE

The minimum initial camera distance is 20.

See Also:

Constant Field Values

Constructor Detail

Camera

public Camera()

Constructs a Renderer.

Method Detail

updateModelViewMatrix

public void updateModelViewMatrix(GL gl)

Updates a copy of the OpenGL model view matrix. This method should be called before using the calculateCameraDistance() method.

Parameters:

gl - the current GL object.

calculateDistance

public double calculateDistance(Drawable d)

Calculates the distance between the camera and the xyz-center of the Drawable object by using the Pythagorean theorem.

A simple z-depth calculation is not as good as Pythagorean distance because of the accuracy in sorting needed before any blending operations.

Parameters:

d - the Drawable object.

Returns:

The distance to the camera as a double.

calculateDistance

public double calculateDistance(double x,
                                double y,
                                double z)

Calculates the distance between the camera and the xyz-center of the Drawable object by using the Pythagorean theorem.

A simple z-depth calculation is not as good as Pythagorean distance because of the accuracy in sorting needed before any blending operations.

Parameters:

x - the x-coordinate of a drawable object in world space.

y - the y-coordinate of a drawable object in world space.

z - the z-coordinate of a drawable object in world space.

Returns:

The distance to the camera as a double.

calculateDepth

public double calculateDepth(Drawable d)

Calculates the depth (z-coordinate in camera space) of the xyz-center of the Drawable object.

Pythagorean distance is better for sorting objects, but pixel-angstrom conversions should be based on z-value.

Parameters:

d - the Drawable object.

Returns:

The depth of the Drawable object in camera space.

calculateDepth

public double calculateDepth(double x,
                             double y,
                             double z)

Calculates the depth (z-coordinate in camera space) of the xyz-center of the Drawable object.

Pythagorean distance is better for sorting objects, but pixel-angstrom conversions should be based on z-value.

Parameters:

x - the x-coordinate of a drawable object in world space.

y - the y-coordinate of a drawable object in world space.

z - the z-coordinate of a drawable object in world space.

Returns:

The distance to the camera as a double.

convertToAngstroms

public double convertToAngstroms(double pixels,
                                 double cameraDepth)

Converts pixels to angstroms based on depth in camera space.

Parameters:

pixels - the number of pixels to convert to angstroms.

cameraDepth - the z-value of an object in camera space.

Returns:

The equivalent number of angstroms.

initializeViewport

public void initializeViewport(GLAutoDrawable canvas,
                               GL gl)

Sets the viewport so that the origin (0, 0, 0) is in its center.

Parameters:

canvas - the canvas to draw on.

gl - the current GL object.

setGluPerspective

public void setGluPerspective(GLAutoDrawable canvas,
                              GL gl)

Sets the projection matrix by using the gluPerspective() method of OpenGL.

Parameters:

canvas - the canvas to draw on.

gl - the current GL object.

setAccPerspective

public void setAccPerspective(GLAutoDrawable canvas,
                              GL gl,
                              double dxPixels,
                              double dyPixels)

Sets the projection matrix by using the glFrustrum() method of OpenGL.

The jitter (xy-offset) given in pixels will be converted to world coordinates in angstroms before being added to the values given to glFrustum().

Parameters:

canvas - the canvas to draw on.

gl - the current GL object.

dxPixels - the x-coordinate jitter in pixels.

dyPixels - the y-coordinate jitter in pixels.

aim

public void aim(GL gl)

Uses gluLookAt() to position and aim the camera.

The modelview matrix is initialized to the identity matrix before aiming the camera.

resetDistance

public void resetDistance()

Sets the camera position based on the initial camera distance calculated when a new Structure is loaded. The Model is always placed centered on the origin, and the camera is placed looking down the z-axis at the origin.

setInitialCameraDistance

public void setInitialCameraDistance(int z)

Sets the initial camera distance on the z-axis.
A number greater than the maximum dimension of the model is recommended. If the distance is less than MIN_INITIAL_CAMERA_DISTANCE, the z-coordinate of the camera will be set to MIN_INITIAL_CAMERA_DISTANCE instead.

Parameters:

z - the distance in anstroms along the z axis.

reshape

public void reshape(GL gl,
                    int x,
                    int y,
                    int width,
                    int height)

Called on when the GLAutoDrawable object has changed its size so that the perspective and viewport can be recalculated.

Parameters:

gl - the current GL object.

x - the x-coordinate of the canvas.

y - the y-coordinate of the canvas.

width - the width of the canvas.

height - the height of the canvas.

moveX

public void moveX(int x)

Add to the camera x position.

Parameters:

x - value to add to camera x-coordinate.

moveY

public void moveY(int y)

Add to the camera y position.

Parameters:

y - value to add to camera y-coordinate.

moveZ

public void moveZ(int z)

Add to the camera z position.

Parameters:

z - value to add to camera z-coordinate.

printXYZ

public void printXYZ()

Prints the xyz-coordinates for the camera.

printModelViewMatrix

public void printModelViewMatrix()

This debugging method prints the copy of the ModelViewMatrix stored n m_modelViewMatrix.