gl_box Class Reference

A class to enable GL drawing in an FLTK window. More...

#include <gl_box.h>

List of all members.

Public Member Functions
void	set_limits (double min_coords[3], double max_coords[3])
	Function to set the x, y and z limits of the data to display.
void	reset_view ()
	Function to reset the viewing parameters for the gl_box.
void	set_stereo (int option)
	Function to select between 4 stereo/fullscreen options.
void	draw_axes ()
	Function to draw arrows for the x, y and z axes.
void	draw_box ()
	Function to draw a single pixel wide box surrounding the data.
void	copy_image_to_ppm ()
	Function to copy the current image to a ppm file.
void	add_to_color (int i, int amount)
	Function to add or subtract 1 (or more) from a color component.
void	set_movie (movie *m)
	Function to tell gl_box the current movie object.
void	draw ()
	Function called by FLTK to draw the Fl_Gl_Window.
void	draw_frame (bool left)
	Function to draw a frame.
void	gl_init ()
	Function to set some initial values for OpenGL.
template<class T, class S> void	draw (sphere< T, S > *s)
	Function to draw one sphere.
template<class T, class S> void	draw (gl_cylinder< T, S > *c)
	Function to draw one cylinder.
int	handle (int event)
	Function to handle keyboard and mouse events.
	gl_box (int x, int y, int w, int h, const char *label=0)
	Constructor which sets the location and size of the gl_box.
Public Attributes
movie *	m
	Pointer to the current movie object.
double	eye [3]
	Current x, y, and z coordinates of the viewing point.
double	focus [3]
	This is the x, y and z value for focusing the camera.
double	min_coords [3]
	Minimum coordinates for all objects in all frames.
double	max_coords [3]
	Maximum coordinates for all objects in all frames.
double	max_diff
	Maximum difference over x, y and z dimensions between min_coords and max_coords.
ap_array< drawable > *	objects
	Array of objects to draw.
ap_array< gl_cylinder_f > *	gl_cylinders
	Array of gl_cylinders with float coordinates.
ap_array< gl_cylinder_s > *	short_gl_cylinders
	Array of gl_cylinders with short int coordinates.
ap_array< byte > *	pixels
	Array of bytes used when reading pixels from display memory to save a frame in a ppm file.
double	distance
	Current distance from the view point to the origin.
double	near_percent
	Percentage of the original far clipping distance to use as the front clipping distance.
double	far_percent
	Percentage to add to the near_percent to compute the far clipping distance.
bool	rotating
	Whether the image is being rotated.
int	wobble
	Whether the image is wobbling.
double	wobble_theta
	Angle of wobble.
timeval	wobble_start
	Time when wobble was started.
timeval	now
	Current time.
bool	full
	Whether in fullscreen mode or not.
bool	stereo
	Whether in stereo mode.
bool	cross_eyed
	Whether in cross-eyed stereo mode.
double	eye_separation
int	spin_rate
	Rate of spin.
double	spin
	Amount of spin (spin_rate * theta).
timeval	last_spin
	Time of last spin calculation.
int	save_detail
	Level of detail to save while rotating.
double	save_delay
	Delay value to save while rotating.
int	mouse_start_x
	Starting mouse x position for rotations.
int	mouse_start_y
	Starting mouse y position for rotations.
int	mouse_x
	Current mouse x for rotations.
int	mouse_y
	Current mouse y for rotations.
Arcball *	a
	Glui rotation control class.
Arcball *	light_arcball
	Glui rotation control class for light.
ap_color	bg_color
bool	stop
	Whether frames are advancing or not.
bool	lights
	Whether lighting is enabled.
bool	blend
	Whether blending is enabled.
bool	axes
	Whether axes should be drawn.
bool	box
	Whether a box should be drawn.
bool	save_frame
	Whether the next frame should be saved.
int	save_movie
	Whether all the frames should be saved.
char *	ppm_file
	File name for saving the frame.
const char *	ppm_prefix
	File name prefix for saving frames.
int	detail
	Level of detail for rendering.
GLUquadricObj *	qobj
	Used to build OpenGL display lists.
int	sphere_lists
	Starting value for sphere display lists.
int	cylinder_lists
	Starting value for cylinder display lists.
int	highlight
	Highlight index.
bool	quash
	Whether the image motion is quashed.
bool	need_to_copy
	Whether new spheres and cylinders need to be copied to the objects array before sorting.
Static Public Attributes
const double	theta = 0.00025
	A small angle to multiply by spin to determine the current rotation angle.

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Detailed Description

A class to enable GL drawing in an FLTK window.

FLTK uses an Fl_Gl_Window widget to provide access to OpenGL from an FLTK application. The simplest way to use Fl_Gl_Window is to derive your own class from it and over-ride the draw and handle functions.

The draw function is used to do all OpenGL drawing. It is called by the FLTK code whenever the window needs to be drawn. Sometimes when the draw function is called, the window's shape will have changed. This can be detected by calling the valid function. When valid returns false, it is necessary to reset the window size and viewing parameters for OpenGL.

The handle function is called with mouse and keyboard events. This class uses mouse events in the gl_box to control rotation of the data displayed using OpenGL.

The code for rotation is extracted from the <A HREF="http://www.cs.unc.edu/~rademach/glui/> GLUI code by Paul Rademacher. Glui provides a nice set of user interface widgets which are written using OpenGL and glut. The GLUI_Rotation widget provides an excellent tool for rotating an OpenGL object. After a short reading of the GLUI_Rotation code, I decided to try to use the classes below the GLUI_Rotation widget, all of which perform only numerical calculations. The separation of GUI code from the mathematics was perfect and there was not much required in gl_box to achieve the same sort of smooth rotations as in glui.

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Constructor & Destructor Documentation

gl_box::gl_box (  int  x, int  y, int  w, int  h, const char *  label = 0 )

Constructor which sets the location and size of the gl_box. The gl_box is placed in the Fl_Window wherever desired. Care needs to be taken to avoid any overlap between the gl_box and other objects in the main Fl_Window. Parameters: x  The x coordinate for the gl_box relative to the main window. y  The y coordinate for the gl_box relative to the main window. w  The width for the gl_box. h  The height for the gl_box. label  A text string for the gl_box.

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Member Function Documentation

void gl_box::set_limits (  double  min_coords[3], double  max_coords[3] )

Function to set the x, y and z limits of the data to display. For a movie the minimum and maximum coordinates are based on all the frames of the movie file. For a molecule the limits are based on the atoms' coordinates. Parameters: min_coords  Array of x, y, and z minimums max_coords  Array of x, y, and z maximums

void gl_box::reset_view (   )

Function to reset the viewing parameters for the gl_box. It sets the viewing position to the original position on the z axis with the focus being in the middle of the data. It also turns off spinning. Last it sets the size to the default which can be quite useful for molecules when it will result in proper atom/bond sizes.

void gl_box::set_stereo (  int  option  )

Function to select between 4 stereo/fullscreen options. Parameters: option  Which stereo/fullscreen option 0 means not fullscreen or stereo 1 means fullscreen 2 means stereo 3 means cross-eyed stereo

void gl_box::draw_axes (   )

Function to draw arrows for the x, y and z axes. The x axis is red, the y axis is green and the z axis is blue.

void gl_box::draw_box (   )

Function to draw a single pixel wide box surrounding the data.

void gl_box::copy_image_to_ppm (   )

Function to copy the current image to a ppm file. The file name is in ppm_file.

void gl_box::add_to_color (  int  i, int  amount )

Function to add or subtract 1 (or more) from a color component. Animp uses the r, g, b, and a keys to subtract 1 from the red, green, blue and alpha values for the selected color. It uses the capital letters to add to these values. Modifications are limited to the 0-255 range. Parameters: i  Color component to modify (0-3 for r,g,b,a) amount  Amount to add to the component

void gl_box::set_movie (  movie *  m  )

Function to tell gl_box the current movie object.

void gl_box::draw (   )

Function called by FLTK to draw the Fl_Gl_Window. Internally draw calls draw_frame(true) to draw the left frame and, if in stereo or cross-eyed stereo mode, it calls draw_frame(false) to draw the right frame.

void gl_box::draw_frame (  bool  left  )

Function to draw a frame. Parameters: left  True if the frame to be drawn is the left of a stereo pair

void gl_box::gl_init (   )

Function to set some initial values for OpenGL. This function is called the first time the draw function is called. It set some defaults like the light and material parameters and prepares OpenGL display lists to make drawing faster.

template<class T, class S> void gl_box::draw (  sphere< T, S > *  s  )

Function to draw one sphere. This function is called from gl_box::draw() to draw one sphere. It sets the color and draws the sphere at the proper location using an OpenGL display list. There are 10 different display lists used to draw spheres - each with a different setting for the level of detail. Smaller spheres are drawn with less detail to speed up the rendering. This is a template class which allows using the same code to draw spheres with short int coordinates and spheres with float coordinates.

template<class T, class S> void gl_box::draw (  gl_cylinder< T, S > *  c  )

Function to draw one cylinder. This function is called from gl_box::draw() to draw one cylinder. It sets the color and draws the cylinder at the proper location using an OpenGL display list. There are 10 different display lists used to draw cylinders - each with a different setting for the level of detail. Smaller cylinders are drawn with less detail to speed up the rendering. This is a template class which allows using the same code to draw cylinders with short int coordinates and cylinders with float coordinates.

int gl_box::handle (  int  event  )

Function to handle keyboard and mouse events. Keyboard and mouse events are passed into gl_box from FLTK when they are not directed for the GUI objects on the screen. The handle function uses only the mouse events. Mouse events control the rotation using the GLUI Arcball class.

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Member Data Documentation

movie* gl_box::m

Pointer to the current movie object. The gl_box code must display the objects in the frames maintained in the movie object. This makes it almost necessary to have access to the movie object in all the gl_box functions.

double gl_box::eye[3]

Current x, y, and z coordinates of the viewing point. When gl_box rotates, it basically moves the eye position around on a sphere centered at the origin of the model space. This is necessary since distances to objects need to be computed. It is much easier to leave the object coordinates fixed and rotate the view point.

double gl_box::focus[3]

This is the x, y and z value for focusing the camera.

double gl_box::min_coords[3]

Minimum coordinates for all objects in all frames.

double gl_box::max_coords[3]

Maximum coordinates for all objects in all frames.

double gl_box::max_diff

Maximum difference over x, y and z dimensions between min_coords and max_coords.

ap_array<drawable>* gl_box::objects

Array of objects to draw. Spheres and cylinders of various types need to be combined in one array to be sorted.

ap_array<gl_cylinder_f>* gl_box::gl_cylinders

Array of gl_cylinders with float coordinates. Cylinders must be converted to gl_cylinders to be displayed. Gl_cylinders have a computed axis of rotation and an angle of rotation to be used when drawn.

ap_array<gl_cylinder_s>* gl_box::short_gl_cylinders

Array of gl_cylinders with short int coordinates.

ap_array<byte>* gl_box::pixels

Array of bytes used when reading pixels from display memory to save a frame in a ppm file.

double gl_box::distance

Current distance from the view point to the origin.

double gl_box::near_percent

Percentage of the original far clipping distance to use as the front clipping distance.

double gl_box::far_percent

Percentage to add to the near_percent to compute the far clipping distance.

bool gl_box::rotating

Whether the image is being rotated.

int gl_box::wobble

Whether the image is wobbling.

double gl_box::wobble_theta

Angle of wobble.

timeval gl_box::wobble_start

Time when wobble was started.

timeval gl_box::now

Current time.

bool gl_box::full

Whether in fullscreen mode or not.

bool gl_box::stereo

Whether in stereo mode.

bool gl_box::cross_eyed

Whether in cross-eyed stereo mode.

double gl_box::eye_separation

int gl_box::spin_rate

Rate of spin. When the image is spinning on its own spin_rate is non-zero. It can spin either clockwise or counter-clockwise and at different rates which are set as integer values of spin_rate.

double gl_box::spin

Amount of spin (spin_rate * theta).

timeval gl_box::last_spin

Time of last spin calculation.

int gl_box::save_detail

Level of detail to save while rotating.

double gl_box::save_delay

Delay value to save while rotating.

int gl_box::mouse_start_x

Starting mouse x position for rotations.

int gl_box::mouse_start_y

Starting mouse y position for rotations.

int gl_box::mouse_x

Current mouse x for rotations.

int gl_box::mouse_y

Current mouse y for rotations.

Arcball* gl_box::a

Glui rotation control class.

Arcball* gl_box::light_arcball

Glui rotation control class for light.

ap_color gl_box::bg_color

bool gl_box::stop

Whether frames are advancing or not.

bool gl_box::lights

Whether lighting is enabled.

bool gl_box::blend

Whether blending is enabled.

bool gl_box::axes

Whether axes should be drawn.

bool gl_box::box

Whether a box should be drawn.

bool gl_box::save_frame

Whether the next frame should be saved.

int gl_box::save_movie

Whether all the frames should be saved.

char* gl_box::ppm_file

File name for saving the frame.

const char* gl_box::ppm_prefix

File name prefix for saving frames.

int gl_box::detail

Level of detail for rendering.

GLUquadricObj* gl_box::qobj

Used to build OpenGL display lists.

int gl_box::sphere_lists

Starting value for sphere display lists.

int gl_box::cylinder_lists

Starting value for cylinder display lists.

int gl_box::highlight

Highlight index. If a color is being selected for modifications, animp will flash all the objects of that color using a sequence of hightlight colors. When highlight is 0, no highlighting is being done. Otherwise highlight is the index into the array of highlight colors to use for the next display.

bool gl_box::quash

Whether the image motion is quashed.

bool gl_box::need_to_copy

Whether new spheres and cylinders need to be copied to the objects array before sorting. When the frame advances new objects must be copied prior to sorting. When the frame number is the same as the last time, there is no need to copy.

const double gl_box::theta = 0.00025 [static]

A small angle to multiply by spin to determine the current rotation angle.

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The documentation for this class was generated from the following files:

• gl_box.h
• gl_box.cpp

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