nehewidget.cpp

一些OpenGL的开发实例

/*

    Qt OpenGL Tutorial - Lesson 12

    nehewidget.cpp
    v 1.00
    2002/12/20

    Copyright (C) 2002 Cavendish
                       [e-mail]
                       http://www.qiliang.net/nehe_qt

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

*/

#include <math.h>
#include <qimage.h>

#include "nehewidget.h"

static GLfloat boxcol[5][3] =
{
  { 1.0, 0.0, 0.0 },
  { 1.0, 0.5, 0.0 },
  { 1.0, 1.0, 0.0 },
  { 0.0, 1.0, 0.0 },
  { 0.0, 1.0, 1.0 }
};

static GLfloat topcol[5][3] =
{
  { 0.5, 0.0, 0.0 },
  { 0.5, 0.25, 0.0 },
  { 0.5, 0.5, 0.0 },
  { 0.0, 0.5, 0.0 },
  { 0.0, 0.5, 0.5 }
};

NeHeWidget::NeHeWidget( QWidget* parent, const char* name, bool fs )
    : QGLWidget( parent, name )
{
  xRot = yRot = zRot = 0.0;
  box = top = 0;
  
  xLoop = yLoop = 0;

  fullscreen = fs;
  setGeometry( 0, 0, 640, 480 );
  setCaption( "NeHe's Display List Tutorial" );

  if ( fullscreen )
    showFullScreen();
}

NeHeWidget::~NeHeWidget()
{
  glDeleteLists( box, 2 );
}

void NeHeWidget::initializeGL()
{
  loadGLTextures();
  buildLists();

  glEnable( GL_TEXTURE_2D );
  glShadeModel( GL_SMOOTH );
  glClearColor( 0.0, 0.0, 0.0, 0.5 );
  glClearDepth( 1.0 );
  glEnable( GL_DEPTH_TEST );
  glDepthFunc( GL_LEQUAL );
  glEnable( GL_LIGHT0 );
  glEnable( GL_LIGHTING );
  glEnable( GL_COLOR_MATERIAL );
  glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
}

void NeHeWidget::paintGL()
{
  glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  glBindTexture( GL_TEXTURE_2D, texture[0] );
  
  for ( yLoop = 1; yLoop < 6; yLoop++ )
  {
    for ( xLoop = 0; xLoop < yLoop; xLoop++ )
    {
      glLoadIdentity();
      glTranslatef( 1.4 + (float(xLoop) * 2.8) - (float(yLoop) * 1.4),
          ( (6.0 - (float(yLoop)) ) * 2.4 ) - 7.0, -20.0 );
      glRotatef( 45.0 - (2.0 * yLoop) + xRot, 1.0, 0.0, 0.0 );
      glRotatef( 45.0 + yRot, 0.0, 1.0, 0.0 );
      glColor3fv( boxcol[yLoop-1] );
      glCallList( box );
      glColor3fv( topcol[yLoop-1] );
      glCallList( top );
    }
  }
}

void NeHeWidget::resizeGL( int width, int height )
{
  if ( height == 0 )
  {
    height = 1;
  }
  glViewport( 0, 0, (GLint)width, (GLint)height );
  glMatrixMode( GL_PROJECTION );
  glLoadIdentity();
  gluPerspective( 45.0, (GLfloat)width/(GLfloat)height, 0.1, 100.0 );
  glMatrixMode( GL_MODELVIEW );
  glLoadIdentity();
}

void NeHeWidget::keyPressEvent( QKeyEvent *e )
{
  switch ( e->key() )
  {
  case Qt::Key_Up:
    xRot -= 0.2;
    updateGL();
    break;
  case Qt::Key_Down:
    xRot += 0.2;
    updateGL();
    break;
  case Qt::Key_Left:
    yRot -= 0.2;
    updateGL();
    break;
  case Qt::Key_Right:
    yRot += 0.2;
    updateGL();
    break;
  case Qt::Key_F2:
    fullscreen = !fullscreen;
    if ( fullscreen )
    {
      showFullScreen();
    }
    else
    {
      showNormal();
      setGeometry( 0, 0, 640, 480 );
    }
    update();
    break;
  case Qt::Key_Escape:
    close();
  }
}

void NeHeWidget::loadGLTextures()
{
  QImage tex, buf;
  if ( !buf.load( "./data/Cube.bmp" ) )
  {
    qWarning( "Could not read image file, using single-color instead." );
    QImage dummy( 128, 128, 32 );
    dummy.fill( Qt::green.rgb() );
    buf = dummy;
  }
  tex = QGLWidget::convertToGLFormat( buf );
  
  glGenTextures( 1, &texture[0] );
  
  glBindTexture( GL_TEXTURE_2D, texture[0] );
  glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  glTexImage2D( GL_TEXTURE_2D, 0, 3, tex.width(), tex.height(), 0,
      GL_RGBA, GL_UNSIGNED_BYTE, tex.bits() );
}

void NeHeWidget::buildLists()
{
  box = glGenLists( 2 );
  
  glNewList( box, GL_COMPILE );
  
  glBegin( GL_QUADS );
    glNormal3f( 0.0, -1.0, 0.0 );
    glTexCoord2f( 1.0, 1.0 ); glVertex3f( -1.0, -1.0, -1.0 );
    glTexCoord2f( 0.0, 1.0 ); glVertex3f(  1.0, -1.0, -1.0 );
    glTexCoord2f( 0.0, 0.0 ); glVertex3f(  1.0, -1.0,  1.0 );
    glTexCoord2f( 1.0, 0.0 ); glVertex3f( -1.0, -1.0,  1.0 );

    glNormal3f( 0.0, 0.0, 1.0 );
    glTexCoord2f( 0.0, 0.0 ); glVertex3f( -1.0, -1.0,  1.0 );
    glTexCoord2f( 1.0, 0.0 ); glVertex3f(  1.0, -1.0,  1.0 );
    glTexCoord2f( 1.0, 1.0 ); glVertex3f(  1.0,  1.0,  1.0 );
    glTexCoord2f( 0.0, 1.0 ); glVertex3f( -1.0,  1.0,  1.0 );

    glNormal3f( 0.0, 0.0, -1.0 );
    glTexCoord2f( 1.0, 0.0 ); glVertex3f( -1.0, -1.0, -1.0 );
    glTexCoord2f( 1.0, 1.0 ); glVertex3f( -1.0,  1.0, -1.0 );
    glTexCoord2f( 0.0, 1.0 ); glVertex3f(  1.0,  1.0, -1.0 );
    glTexCoord2f( 0.0, 0.0 ); glVertex3f(  1.0, -1.0, -1.0 );

    glNormal3f( 1.0, 0.0, 0.0 );
    glTexCoord2f( 1.0, 0.0 ); glVertex3f(  1.0, -1.0, -1.0 );
    glTexCoord2f( 1.0, 1.0 ); glVertex3f(  1.0,  1.0, -1.0 );
    glTexCoord2f( 0.0, 1.0 ); glVertex3f(  1.0,  1.0,  1.0 );
    glTexCoord2f( 0.0, 0.0 ); glVertex3f(  1.0, -1.0,  1.0 );

    glNormal3f( -1.0, 0.0, 0.0 );
    glTexCoord2f( 0.0, 0.0 ); glVertex3f( -1.0, -1.0, -1.0 );
    glTexCoord2f( 1.0, 0.0 ); glVertex3f( -1.0, -1.0,  1.0 );
    glTexCoord2f( 1.0, 1.0 ); glVertex3f( -1.0,  1.0,  1.0 );
    glTexCoord2f( 0.0, 1.0 ); glVertex3f( -1.0,  1.0, -1.0 );
  glEnd();
  
  glEndList();
  
  top = box + 1;

  glNewList( top, GL_COMPILE );
  
  glBegin( GL_QUADS );
    glNormal3f( 0.0, 1.0, 0.0 );
    glTexCoord2f( 0.0, 1.0 ); glVertex3f( -1.0,  1.0, -1.0 );
    glTexCoord2f( 0.0, 0.0 ); glVertex3f( -1.0,  1.0,  1.0 );
    glTexCoord2f( 1.0, 0.0 ); glVertex3f(  1.0,  1.0,  1.0 );
    glTexCoord2f( 1.0, 1.0 ); glVertex3f(  1.0,  1.0, -1.0 );
  glEnd();
  
  glEndList();
}