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qt3/examples/opengl/texture/gltexobj.cpp

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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.
**
*****************************************************************************/
/****************************************************************************
**
** This is a simple QGLWidget demonstrating the use of QImages for textures.
**
** Much of the GL code is inspired by the 'spectex' and 'texcyl'
** public domain demo programs by Brian Paul.
**
****************************************************************************/
#include "gltexobj.h"
#include <qimage.h>
#include <qtimer.h>
const int redrawWait = 50;
/*!
Create a GLTexobj widget
*/
GLTexobj::GLTexobj( QWidget* parent, const char* name )
: QGLWidget( parent, name )
{
xRot = yRot = zRot = 0.0; // default object rotation
scale = 5.0; // default object scale
object = 0;
animation = TRUE;
timer = new QTimer( this );
connect( timer, SIGNAL(timeout()), SLOT(update()) );
timer->start( redrawWait, TRUE );
}
/*!
Release allocated resources
*/
GLTexobj::~GLTexobj()
{
makeCurrent();
glDeleteLists( object, 1 );
}
/*!
Paint the texobj. The actual openGL commands for drawing the texobj are
performed here.
*/
void GLTexobj::paintGL()
{
if ( animation ) {
xRot += 1.0;
yRot += 2.5;
zRot -= 5.0;
}
glClear( GL_COLOR_BUFFER_BIT );
glPushMatrix();
glRotatef( xRot, 1.0, 0.0, 0.0 );
glRotatef( yRot, 0.0, 1.0, 0.0 );
glRotatef( zRot, 0.0, 0.0, 1.0 );
glScalef( scale, scale, scale );
glCallList( object );
glPopMatrix();
if ( animation ) {
glFlush(); // Make sure everything is drawn before restarting timer
timer->start( redrawWait, TRUE ); // Wait this many msecs before redraw
}
}
/*!
Set up the OpenGL rendering state, and define display list
*/
void GLTexobj::initializeGL()
{
// Set up the lights
GLfloat whiteDir[4] = {2.0, 2.0, 2.0, 1.0};
GLfloat whiteAmb[4] = {1.0, 1.0, 1.0, 1.0};
GLfloat lightPos[4] = {30.0, 30.0, 30.0, 1.0};
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_FALSE);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, whiteAmb);
glMaterialfv(GL_FRONT, GL_DIFFUSE, whiteDir);
glMaterialfv(GL_FRONT, GL_SPECULAR, whiteDir);
glMaterialf(GL_FRONT, GL_SHININESS, 20.0);
glLightfv(GL_LIGHT0, GL_DIFFUSE, whiteDir); // enable diffuse
glLightfv(GL_LIGHT0, GL_SPECULAR, whiteDir); // enable specular
glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
// Set up the textures
QImage tex1, tex2, buf;
if ( !buf.load( "gllogo.bmp" ) ) { // Load first image from file
qWarning( "Could not read image file, using single-color instead." );
QImage dummy( 128, 128, 32 );
dummy.fill( Qt::green.rgb() );
buf = dummy;
}
tex1 = QGLWidget::convertToGLFormat( buf ); // flipped 32bit RGBA
if ( !buf.load( "qtlogo.bmp" ) ) { // Load first image from file
qWarning( "Could not read image file, using single-color instead." );
QImage dummy( 128, 128, 32 );
dummy.fill( Qt::red.rgb() );
buf = dummy;
}
tex2 = QGLWidget::convertToGLFormat( buf ); // flipped 32bit RGBA
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
glEnable( GL_TEXTURE_2D );
// Set up various other stuff
glClearColor( 0.0, 0.0, 0.0, 0.0 ); // Let OpenGL clear to black
glEnable( GL_CULL_FACE ); // don't need Z testing for convex objects
glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
// Make the object display list
object = makeObject( tex1, tex2 ); // Generate an OpenGL display list
}
/*!
Set up the OpenGL view port, matrix mode, etc.
*/
void GLTexobj::resizeGL( int w, int h )
{
glViewport( 0, 0, w, h );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -1.0, 1.0, -1.0, 1.0, 10.0, 100.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -70.0 );
}
/*!
Generate an OpenGL display list for the object to be shown, i.e. the texobj
*/
GLuint GLTexobj::makeObject( const QImage& tex1, const QImage& tex2 )
{
GLUquadricObj* q = gluNewQuadric();
GLuint cylinderObj = glGenLists(1);
glNewList( cylinderObj, GL_COMPILE );
glTranslatef( 0.0, 0.0, -1.0 );
// cylinder
glTexImage2D( GL_TEXTURE_2D, 0, 3, tex1.width(), tex1.height(), 0,
GL_RGBA, GL_UNSIGNED_BYTE, tex1.bits() );
gluQuadricTexture( q, GL_TRUE );
gluCylinder(q, 0.6, 0.6, 2.0, 24, 1);
// end cap
glTexImage2D( GL_TEXTURE_2D, 0, 3, tex2.width(), tex2.height(), 0,
GL_RGBA, GL_UNSIGNED_BYTE, tex2.bits() );
glTranslatef( 0.0, 0.0, 2.0 );
gluDisk( q, 0.0, 0.6, 24, 1 );
// other end cap
glTranslatef( 0.0, 0.0, -2.0 );
gluQuadricOrientation( q, (GLenum)GLU_INSIDE );
gluDisk( q, 0.0, 0.6, 24, 1 );
glEndList();
gluDeleteQuadric( q );
return cylinderObj;
}
/*!
Set the rotation angle of the object to \e degrees around the X axis.
*/
void GLTexobj::setXRotation( int degrees )
{
xRot = (GLfloat)(degrees % 360);
updateGL();
}
/*!
Set the rotation angle of the object to \e degrees around the Y axis.
*/
void GLTexobj::setYRotation( int degrees )
{
yRot = (GLfloat)(degrees % 360);
updateGL();
}
/*!
Set the rotation angle of the object to \e degrees around the Z axis.
*/
void GLTexobj::setZRotation( int degrees )
{
zRot = (GLfloat)(degrees % 360);
updateGL();
}
/*!
Turns animation on or off
*/
void GLTexobj::toggleAnimation()
{
animation = !animation;
if ( animation )
updateGL();
else
timer->stop();
}