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