223 lines
4.6 KiB
C++
223 lines
4.6 KiB
C++
/**********************************************************************
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arcball.cpp
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--------------------------------------------------
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Copyright (c) 1998 Paul Rademacher
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This program is freely distributable without licensing fees and is
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provided without guarantee or warrantee expressed or implied. This
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program is -not- in the public domain.
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**********************************************************************/
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#include "arcball.h"
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#include <stdio.h>
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/**************************************** Arcball::Arcball() ****/
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/* Default (void) constructor for Arcball */
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Arcball::Arcball( void )
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{
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rot_ptr = &rot;
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init();
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}
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/**************************************** Arcball::Arcball() ****/
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/* Takes as argument a mat4 to use instead of the internal rot */
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Arcball::Arcball( mat4 *mtx )
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{
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rot_ptr = mtx;
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}
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/**************************************** Arcball::Arcball() ****/
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/* A constructor that accepts the screen center and arcball radius*/
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Arcball::Arcball( vec2 _center, float _radius )
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{
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rot_ptr = &rot;
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init();
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set_params( _center, _radius );
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}
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/************************************** Arcball::set_params() ****/
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void Arcball::set_params( vec2 _center, float _radius )
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{
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center = _center;
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radius = _radius;
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}
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/*************************************** Arcball::init() **********/
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void Arcball::init( void )
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{
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center.set( 0.0, 0.0 );
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radius = 1.0;
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q_now = quat_identity();
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*rot_ptr = identity3D();
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q_increment = quat_identity();
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rot_increment = identity3D();
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is_mouse_down = false;
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is_spinning = false;
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damp_factor = 0.0;
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zero_increment = true;
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}
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/*********************************** Arcball::mouse_to_sphere() ****/
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vec3 Arcball::mouse_to_sphere( vec2 p )
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{
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float mag;
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vec2 v2 = (p - center) / radius;
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vec3 v3( v2[0], v2[1], 0.0 );
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mag = v2*v2;
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if ( mag > 1.0 ) {
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v3.normalize();
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}
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else {
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v3[VZ] = sqrt( 1.0 - mag );
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}
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/* Now we add constraints - X takes precedence over Y */
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if ( constraint_x ) {
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v3 = constrain_vector( v3, vec3( 1.0, 0.0, 0.0 ));
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} else if ( constraint_y ) {
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v3 = constrain_vector( v3, vec3( 0.0, 1.0, 0.0 ));
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}
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return v3;
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}
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/************************************ Arcball::constrain_vector() ****/
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vec3 Arcball::constrain_vector( vec3 vector, vec3 axis )
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{
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return (vector-(vector*axis)*axis).normalize();
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}
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/************************************ Arcball::mouse_down() **********/
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void Arcball::mouse_down( int x, int y )
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{
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down_pt.set( (float)x, (float) y );
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is_mouse_down = true;
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q_increment = quat_identity();
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rot_increment = identity3D();
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zero_increment = true;
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}
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/************************************ Arcball::mouse_up() **********/
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void Arcball::mouse_up( void )
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{
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q_now = q_drag * q_now;
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is_mouse_down = false;
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}
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/********************************** Arcball::mouse_motion() **********/
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void Arcball::mouse_motion( int x, int y, int shift, int ctrl, int alt )
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{
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/* Set the X constraint if CONTROL key is pressed, Y if ALT key */
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set_constraints( ctrl != 0, alt != 0 );
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vec2 new_pt( (float)x, (float) y );
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vec3 v0 = mouse_to_sphere( down_pt );
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vec3 v1 = mouse_to_sphere( new_pt );
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vec3 cross = v0^v1;
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q_drag.set( cross, v0 * v1 );
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// *rot_ptr = (q_drag * q_now).to_mat4();
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mat4 temp = q_drag.to_mat4();
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*rot_ptr = *rot_ptr * temp;
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down_pt = new_pt;
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/* We keep a copy of the current incremental rotation (= q_drag) */
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q_increment = q_drag;
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rot_increment = q_increment.to_mat4();
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set_constraints( false, false );
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if ( q_increment.s < .999999 ) {
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is_spinning = true;
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zero_increment = false;
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}
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else {
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is_spinning = false;
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zero_increment = true;
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}
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}
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/********************************** Arcball::mouse_motion() **********/
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void Arcball::mouse_motion( int x, int y )
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{
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mouse_motion( x, y, 0, 0, 0 );
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}
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/***************************** Arcball::set_constraints() **********/
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void Arcball::set_constraints( Bool _constraint_x, Bool _constraint_y )
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{
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constraint_x = _constraint_x;
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constraint_y = _constraint_y;
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}
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/***************************** Arcball::idle() *********************/
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void Arcball::idle( void )
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{
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if ( is_mouse_down ) {
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is_spinning = false;
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zero_increment = true;
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}
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if ( damp_factor < 1.0 ) {
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q_increment.scale_angle( 1.0 - damp_factor );
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}
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rot_increment = q_increment.to_mat4();
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if ( q_increment.s >= .999999 ) {
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is_spinning = false;
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zero_increment = true;
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}
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}
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/************************ Arcball::set_damping() *********************/
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void Arcball::set_damping( float d )
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{
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damp_factor = d;
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}
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