ExampleSimpleGLApp1.cpp

Very simple GL application with a single scene

Author

Jan Woetzel

/*
This file is part of the BIAS library (Basic ImageAlgorithmS).

Copyright (C) 2003, 2004    (see file CONTACTS for details)
  Multimediale Systeme der Informationsverarbeitung
  Institut fuer Informatik
  Christian-Albrechts-Universitaet Kiel


BIAS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

BIAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with BIAS; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/** 
 * @example ExampleSimpleGLApp1.cpp
 * @ingroup g_examples
 * @brief Very simple GL application with a single scene
 * @author Jan Woetzel  
 */

#include <Gui/SimpleGLApp.hh>
#include <Gui/SceneGL.hh>


// global helpers
GLfloat light_position0[]     = {1.0f, 1.0, 3.0f, 1.0f}; // w=0: direction
void SetMaterial();


// your simple wrapper for a (possibly global) display function
/** \cond HIDDEN_SYMBOLS */
class MyScene : public BIAS::SceneGL {
public:
  void Display(){
    BIASASSERT(this->pc!=NULL); // should be set in ctor

    // clear scene, either with canvas' function 
    // this->pc->DisplayClear();
    // or optionally by hand- may be more efficient by tighter buffer mask: 
    glClearColor(0.2,0,0,0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // set MODELVIEW_PROJECTION 
    // internal+external virtual camera parameters 
    // with mouse interaction
    this->pc->DisplayCameraView();

    // 
    // more of your fancy GL calls, here: 
    //
    this->pc->DisplayCoordCross();

    // a lit geometry that depnds on mode:
    glPushMatrix();
    glTranslatef(0, 0. ,-1.);
    SetMaterial();
    glColor4f( 0.9f, 0.2f, 0.5f, 1.0f ); // paintcolor
    // select geometry based on mode
    const int geoMode = BIAS::SimpleGLFrame::mode %4;
    switch(geoMode){
      case 0: 
        glFrontFace(GL_CW);
        glutSolidTeapot(1);
        glFrontFace(GL_CCW);
        break;
      case 1: glutSolidSphere(1,20,20);break;
      case 2: glutSolidCube(1); break;
      case 3: glutSolidCone(1, 1, 20, 20); break;
    }

    glPopMatrix();

    // the light position:
    glPushMatrix();
    glTranslatef(light_position0[0], light_position0[1], light_position0[2] );
    glColor3f(1, 1, 0);
    glDisable(GL_LIGHTING);
    glutSolidSphere(0.2,32,32);
    glPopMatrix();

    // ...

  }
};

// your simple application
class MyApp : public BIAS::SimpleGLApp {
public:
  MyApp() : SimpleGLApp(){
    this->scene = new MyScene();
  }
};

IMPLEMENT_APP(MyApp)


// helper
void SetMaterial(){
    // light source proeprties for enabled lighting:  
    // specified pos by w=1, direction by w=0:
    GLfloat light_maincolor0[]    = {1.0f, 1.0, 1.0f, 1.0f};
    GLfloat light_ambientcolor0[] = {0.4f, 0.2f, 0.2f, 1.0f};

    // GL create light 0
    glLightfv(GL_LIGHT0, GL_POSITION, light_position0);
    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_maincolor0);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_maincolor0);
    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambientcolor0);

    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHTING); // may be switched on/off for every object
    glEnable(GL_DEPTH_TEST); // depth buffer occlusions of objects

    // material properties for enabled lighting: 
    GLfloat paintcolor0[]    = { 0.9f, 0.2f, 0.5f, 1.0f};
    GLfloat specularcolor0[] = { 1.0f, 1.0f, 1.0f, 1.0f};
    GLfloat shininess0[]     = { 70.0f }; // 1..128, large values make smaller specular highlights

    // activate material properties: 
    glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, specularcolor0);
    glMaterialfv( GL_FRONT_AND_BACK, GL_SHININESS, shininess0);
    glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, paintcolor0);
    
    glColor4fv(&paintcolor0[0]);
}
/** \endcond */