lod.cpp

Lod example application. This example illustrates how to use gzLod nodes.
The source code can also be found in the examples directory of the Gizmo3D distribution.

// *****************************************************************************
// File         : lod.cpp
// Module       : 
// Description  : Test app for a sample lod
// Author       : Lisa Johansson          
// Product      : Gizmo3D 2.1.1
//              
// Copyright © 2003- Saab Training Systems AB, Sweden   
//                      
// NOTE:    Gizmo3D is a high performance 3D Scene Graph and effect visualisation 
//          C++ toolkit for Linux, Mac OS X, Windows (Win32) and IRIX® for  
//          usage in Game or VisSim development.
//
//
// Revision History...                                                  
//                                                                      
// Who  Date    Description                                             
//                                                                      
// LJH  040322  Created file    
//
// ******************************************************************************

#include "gzGizmo3DLibrary.h"

// *******************************************************************************
// Defines the window class

class MyWin : public gzWindow
{
public:
        
    MyWin();

    virtual ~MyWin(){};

    void onIdle();

    gzRefPointer<gzText>        screenText;

    gzRefPointer<gzPerspCamera> cam;

    gzRefPointer<gzLod>         lod;
};


MyWin::MyWin():gzWindow("Lod Test")
{

    // Create a scene to render
    gzScene * scene=new gzScene();

    scene -> addNode(new gzGeometryAxis(10,1));

    gzEnvironment * env = new gzEnvironment();

    gzState * state=new gzState;
    
    // the state removes the backfaces in the rendering
    state -> setMode(GZ_STATE_POLYGON_MODE,GZ_STATE_ON);
    
    state -> setBackPolygonMode(GZ_POLYGON_MODE_CULL);
    
    state -> setFrontPolygonMode(GZ_POLYGON_MODE_FILL);

    env -> setState(state);

    gzNode * gizmo1 = gzDbManager::loadDB("lodmodel1.3DS",GZ_EVALUATE_EXTENSION,GZ_DB_FLAGS_USE_MIPMAPS);

    gzTransform * gt1 = gzDynamic_Cast<gzTransform>(gizmo1);

    if(gt1)
    {
        gt1 -> unitScale();

        gt1 -> scale((gzReal)(2),(gzReal)(2),(gzReal)(2));

    }

    gzNode * gizmo2 = gzDbManager::loadDB("lodmodel2.3DS",GZ_EVALUATE_EXTENSION,GZ_DB_FLAGS_USE_MIPMAPS);

    gzTransform * gt2 = gzDynamic_Cast<gzTransform>(gizmo2);

    if(gt2)
    {
        gt2 -> unitScale();

        gt2 -> scale((gzReal)(2),(gzReal)(2),(gzReal)(2));

    }

    gzNode * gizmo3 = gzDbManager::loadDB("lodmodel3.3DS",GZ_EVALUATE_EXTENSION,GZ_DB_FLAGS_USE_MIPMAPS);

    gzTransform * gt3 = gzDynamic_Cast<gzTransform>(gizmo3);

    if(gt3)
    {
        gt3 -> unitScale();

        gt3 -> scale((gzReal)(2),(gzReal)(2),(gzReal)(2));

    }

    lod = new gzLod;

    lod -> addNode(gizmo1);

    lod -> addNode(gizmo2);

    lod -> addNode(gizmo3);

    //lod->setLOD(gzULong index , gzBool enable , gzReal min = 0 , gzReal max = 1, gzReal fade = 0);

    lod->setLOD(0, TRUE , 0, 20, 0,30);

    lod->setLOD(1, TRUE, 20, 40, 10,40);

    lod->setLOD(2, TRUE, 40, 100, 20,0);

    env -> addNode(lod);
    
    scene -> addNode (env);

    //
    // Add some text to the scene
    //

    screenText = new gzText("Screen Text");

    screenText -> setColor(gzVec4(1,1,0,0.5));
    
    screenText -> use2DPosition(TRUE);
    
    screenText -> set2DPosition(10, -10);
            
    scene -> addNode(screenText);

    cam = new gzPerspCamera;

    cam -> setPosition(0,0,20);

    cam -> setScene(scene);

    cam -> setNearClipPlane(1);

    cam -> setFarClipPlane(100000);

    setCamera(cam);

    gzSimpleMouseViewControl * myInput = new gzSimpleMouseViewControl( cam );
    
    addInputInterface( myInput );

    refreshWindow();
}


void MyWin::onIdle()
{
    triggerKeyEvaluation();

    refreshWindow();
    
};


// ******************************************************************************
// Definition of a lod application
// The application provides an initialisation and an onIdle loop manager
// to do the refresh of the window


class LodApp : public gzApplication
{
public:
        
    LodApp();

    ~LodApp();

private:

    friend class MyWin;

    gzRefPointer<MyWin> m_win;         // the window   
    
    void onIdle();

};

LodApp::LodApp()
{
        m_win = new MyWin();
}

LodApp::~LodApp()
{
    // When the lod application is deleted the smart pointer for the window is
    // automatically removed
}

void LodApp::onIdle()
{
    if(m_win)
    {
        m_win -> onIdle();

        m_win -> triggerKeyEvaluation();

        gzString outputString;

        outputString = gzString("FrameRate:")+gzString(m_win->getFrameRate());

        outputString = outputString + gzString("\n\nCamera position: ") + gzString(m_win->cam->getPosition().v1) + gzString(", ") + gzString(m_win->cam->getPosition().v2) + gzString(", ") + gzString(m_win->cam->getPosition().v3);
    
        outputString = outputString + gzString("\n\nHeading: ") + gzString(m_win->cam->getHPR().v1) + gzString("\nPitch: ") + gzString(m_win->cam->getHPR().v2) + gzString("\nRoll: ") + gzString(m_win->cam->getHPR().v3);
    
        gzVec3 lodCenter = m_win->lod->getCenter();

        gzDouble lodDistance = sqrt((m_win->cam->getPosition().v1 - lodCenter.v1)*(m_win->cam->getPosition().v1 - lodCenter.v1) + (m_win->cam->getPosition().v2 - lodCenter.v2)*(m_win->cam->getPosition().v2 - lodCenter.v2) + (m_win->cam->getPosition().v3 - lodCenter.v3)*(m_win->cam->getPosition().v3 - lodCenter.v3));
        
        outputString = outputString + gzString("\n\nLodDistance: ") + gzString(lodDistance);

        m_win->screenText->setText(outputString);

    }

}


// ******************************************************************************
// The main method

int main(int argc, char *argv[])
{
    gzStartUpGizmo();   // Needed for some systems to install external graphics engines
    
    try
    {       
        // Set the appropriate graphics engine API
        gzGraphicsEngine::useEngine(GZ_ENGINE_OPENGL);

        gzInitializeDbManagers();

        // Make the application
        LodApp app;

        // run the application
        app.run();

    }
    catch(gzBaseError &error)       // In case of exceptions thrown we want to print the message
    {
                error.reportError();
    }
    
    gzShutDownGizmo();
    
    return 0;
}

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