3dpcp/.svn/pristine/98/98f4447cdcf31c3735470baa48f804142aa02671.svn-base
2012-09-16 14:33:11 +02:00

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/**********************************************************************
Arcball.h
A C++ class that implements the Arcball, as described by Ken
Shoemake in Graphics Gems IV.
This class takes as input mouse events (mouse down, mouse drag,
mouse up), and creates the appropriate quaternions and 4x4 matrices
to represent the rotation given by the mouse.
This class is used as follows:
- initialize [either in the constructor or with set_params()], the
center position (x,y) of the arcball on the screen, and the radius
- on mouse down, call mouse_down(x,y) with the mouse position
- as the mouse is dragged, repeatedly call mouse_motion() with the
current x and y positions. One can optionally pass in the current
state of the SHIFT, ALT, and CONTROL keys (passing zero if keys
are not pressed, non-zero otherwise), which constrains
the rotation to certain axes (X for CONTROL, Y for ALT).
- when the mouse button is released, call mouse_up()
Axis constraints can also be explicitly set with the
set_constraints() function.
The current rotation is stored in the 4x4 float matrix 'rot'.
It is also stored in the quaternion 'q_now'.
------------------------------------------------------------------
Feb 25, 1998 - Paul Rademacher (rademach@cs.unc.edu)
**********************************************************************/
#ifndef _ARCBALL_H_
#define _ARCBALL_H_
#include "stdinc.h"
#include "algebra3.h"
#include "quaternion.h"
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
class Arcball {
public:
Bool constraint_x, constraint_y;
vec2 center;
float radius, damp_factor;
int zero_increment;
vec3 constrain_vector( vec3 vector, vec3 axis );
vec3 mouse_to_sphere( vec2 p );
//public:
int is_mouse_down; /* true for down, false for up */
int is_spinning;
quat q_now, q_down, q_drag, q_increment;
vec2 down_pt;
mat4 rot, rot_increment;
mat4 *rot_ptr;
void set_damping( float d );
void idle( void );
void mouse_down( int x, int y );
void mouse_up( void );
void mouse_motion( int x, int y, int shift, int ctrl, int alt );
void mouse_motion( int x, int y );
void set_constraints( Bool constrain_x, Bool constrain_y );
void set_params( vec2 center, float radius );
void reset_mouse( void );
void init( void );
Arcball( void );
Arcball( mat4 *mtx );
Arcball( vec2 center, float radius );
};
#endif