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/****************************************************************************
**
** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
**
** This file is part of an example program for Qt. This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/
//
// Draws a gear.
//
// Portions of this code have been borrowed from Brian Paul's Mesa
// distribution.
//
#include <qgl.h>
#include <qapplication.h>
#include <math.h>
#if defined(Q_CC_MSVC)
#pragma warning(disable:4305) // init: truncation from const double to float
#endif
/*
* Draw a gear wheel. You'll probably want to call this function when
* building a display list since we do a lot of trig here.
*
* Input: inner_radius - radius of hole at center
* outer_radius - radius at center of teeth
* width - width of gear
* teeth - number of teeth
* tooth_depth - depth of tooth
*/
static void gear( GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
GLint teeth, GLfloat tooth_depth )
{
GLint i;
GLfloat r0, r1, r2;
GLfloat angle, da;
GLfloat u, v, len;
r0 = inner_radius;
r1 = outer_radius - tooth_depth/2.0;
r2 = outer_radius + tooth_depth/2.0;
const double pi = 3.14159264;
da = 2.0*pi / teeth / 4.0;
glShadeModel( GL_FLAT );
glNormal3f( 0.0, 0.0, 1.0 );
/* draw front face */
glBegin( GL_QUAD_STRIP );
for (i=0;i<=teeth;i++) {
angle = i * 2.0*pi / teeth;
glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
glVertex3f( r1*cos(angle), r1*sin(angle), width*0.5 );
glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
}
glEnd();
/* draw front sides of teeth */
glBegin( GL_QUADS );
da = 2.0*pi / teeth / 4.0;
for (i=0;i<teeth;i++) {
angle = i * 2.0*pi / teeth;
glVertex3f( r1*cos(angle), r1*sin(angle), width*0.5 );
glVertex3f( r2*cos(angle+da), r2*sin(angle+da), width*0.5 );
glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), width*0.5 );
glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
}
glEnd();
glNormal3f( 0.0, 0.0, -1.0 );
/* draw back face */
glBegin( GL_QUAD_STRIP );
for (i=0;i<=teeth;i++) {
angle = i * 2.0*pi / teeth;
glVertex3f( r1*cos(angle), r1*sin(angle), -width*0.5 );
glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
}
glEnd();
/* draw back sides of teeth */
glBegin( GL_QUADS );
da = 2.0*pi / teeth / 4.0;
for (i=0;i<teeth;i++) {
angle = i * 2.0*pi / teeth;
glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), -width*0.5 );
glVertex3f( r2*cos(angle+da), r2*sin(angle+da), -width*0.5 );
glVertex3f( r1*cos(angle), r1*sin(angle), -width*0.5 );
}
glEnd();
/* draw outward faces of teeth */
glBegin( GL_QUAD_STRIP );
for (i=0;i<teeth;i++) {
angle = i * 2.0*pi / teeth;
glVertex3f( r1*cos(angle), r1*sin(angle), width*0.5 );
glVertex3f( r1*cos(angle), r1*sin(angle), -width*0.5 );
u = r2*cos(angle+da) - r1*cos(angle);
v = r2*sin(angle+da) - r1*sin(angle);
len = sqrt( u*u + v*v );
u /= len;
v /= len;
glNormal3f( v, -u, 0.0 );
glVertex3f( r2*cos(angle+da), r2*sin(angle+da), width*0.5 );
glVertex3f( r2*cos(angle+da), r2*sin(angle+da), -width*0.5 );
glNormal3f( cos(angle), sin(angle), 0.0 );
glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), width*0.5 );
glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), -width*0.5 );
u = r1*cos(angle+3*da) - r2*cos(angle+2*da);
v = r1*sin(angle+3*da) - r2*sin(angle+2*da);
glNormal3f( v, -u, 0.0 );
glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
glNormal3f( cos(angle), sin(angle), 0.0 );
}
glVertex3f( r1*cos(0.0), r1*sin(0.0), width*0.5 );
glVertex3f( r1*cos(0.0), r1*sin(0.0), -width*0.5 );
glEnd();
glShadeModel( GL_SMOOTH );
/* draw inside radius cylinder */
glBegin( GL_QUAD_STRIP );
for (i=0;i<=teeth;i++) {
angle = i * 2.0*pi / teeth;
glNormal3f( -cos(angle), -sin(angle), 0.0 );
glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
}
glEnd();
}
static GLfloat view_rotx=20.0, view_roty=30.0, view_rotz=0.0;
static GLint gear1, gear2, gear3;
static GLfloat angle = 0.0;
static void draw()
{
angle += 2.0;
view_roty += 1.0;
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
glRotatef( view_rotx, 1.0, 0.0, 0.0 );
glRotatef( view_roty, 0.0, 1.0, 0.0 );
glRotatef( view_rotz, 0.0, 0.0, 1.0 );
glPushMatrix();
glTranslatef( -3.0, -2.0, 0.0 );
glRotatef( angle, 0.0, 0.0, 1.0 );
glCallList(gear1);
glPopMatrix();
glPushMatrix();
glTranslatef( 3.1, -2.0, 0.0 );
glRotatef( -2.0*angle-9.0, 0.0, 0.0, 1.0 );
glCallList(gear2);
glPopMatrix();
glPushMatrix();
glTranslatef( -3.1, 2.2, -1.8 );
glRotatef( 90.0, 1.0, 0.0, 0.0 );
glRotatef( 2.0*angle-2.0, 0.0, 0.0, 1.0 );
glCallList(gear3);
glPopMatrix();
glPopMatrix();
}
static int timer_interval = 10; // timer interval (millisec)
class GearWidget : public QGLWidget
{
public:
GearWidget( QWidget *parent=0, const char *name=0 );
protected:
void initializeGL();
void resizeGL( int, int );
void paintGL();
void timerEvent( QTimerEvent * );
};
GearWidget::GearWidget( QWidget *parent, const char *name )
: QGLWidget( parent, name )
{
startTimer( timer_interval );
}
void GearWidget::initializeGL()
{
static GLfloat pos[4] = {5.0, 5.0, 10.0, 1.0 };
static GLfloat ared[4] = {0.8, 0.1, 0.0, 1.0 };
static GLfloat agreen[4] = {0.0, 0.8, 0.2, 1.0 };
static GLfloat ablue[4] = {0.2, 0.2, 1.0, 1.0 };
glLightfv( GL_LIGHT0, GL_POSITION, pos );
glEnable( GL_CULL_FACE );
glEnable( GL_LIGHTING );
glEnable( GL_LIGHT0 );
glEnable( GL_DEPTH_TEST );
/* make the gears */
gear1 = glGenLists(1);
glNewList(gear1, GL_COMPILE);
glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, ared );
gear( 1.0, 4.0, 1.0, 20, 0.7 );
glEndList();
gear2 = glGenLists(1);
glNewList(gear2, GL_COMPILE);
glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, agreen );
gear( 0.5, 2.0, 2.0, 10, 0.7 );
glEndList();
gear3 = glGenLists(1);
glNewList(gear3, GL_COMPILE);
glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, ablue );
gear( 1.3, 2.0, 0.5, 10, 0.7 );
glEndList();
glEnable( GL_NORMALIZE );
}
void GearWidget::resizeGL( int width, int height )
{
GLfloat w = (float) width / (float) height;
GLfloat h = 1.0;
glViewport( 0, 0, width, height );
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum( -w, w, -h, h, 5.0, 60.0 );
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef( 0.0, 0.0, -40.0 );
}
void GearWidget::paintGL()
{
draw();
}
void GearWidget::timerEvent(QTimerEvent*)
{
updateGL();
}
int main( int argc, char **argv )
{
QApplication::setColorSpec( QApplication::CustomColor );
QApplication a( argc, argv );
if ( !QGLFormat::hasOpenGL() ) {
qWarning( "This system has no OpenGL support. Exiting." );
return -1;
}
if ( argc >= 2 ) {
bool ok = TRUE;
timer_interval = QString::fromLatin1( argv[1] ).toInt( &ok );
if ( !ok )
timer_interval = 10;
}
GearWidget w;
a.setMainWidget( &w );
w.show();
return a.exec();
}
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