// DemoSceneGraph.cpp
// NKU CSC 480/580  - Kirby
// --------------------------------------------
// A demo of our first attempt at a scene graph. 
// --------------------------------------------

#include "SceneGraph.h"
#include <GL/glut.h>

// The root of the scene graph.
Node* G_scene= NULL ;



void viewProjection()
// Set up a viewpoint (external to scene graph, in this version).
{
    glMatrixMode( GL_PROJECTION ) ;
    glOrtho( -7, 7, -7, 7, -7, 7 ) ;

    glMatrixMode( GL_MODELVIEW ) ;
    glLoadIdentity() ;
}


void display()
// Display the scene graph.
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ) ;
    G_scene->render() ;
    glutSwapBuffers() ;
}


Node* buildScene()
// Build the scene graph.
{
    // One primitive artifact: a sphere.
    Node* sphere= new GlutSphere() ;

    // Place two solid red spheres on the scene.

        TransformationNode* west= new TransformationNode() ;
        west->set( Vector3(1,0,0), 0, 1, Vector3( -2,0,0 ) ) ;
        west->addChild( sphere ) ;

        TransformationNode* east= new TransformationNode() ;
        east->set( Vector3(1,0,0), 0, 1, Vector3( 2,0,0 ) ) ;
        east->addChild( sphere ) ;

    MaterialNode* redMaterial= new MaterialNode() ;
    redMaterial->setColor( 1,0,0 ) ;
    redMaterial->addChild( west ) ;
    redMaterial->addChild( east ) ;

    // Place a solid blue sphere on the scene.

        TransformationNode* above= new TransformationNode() ;
        above->set( Vector3(1,0,0), 0, 2, Vector3( 0,4,0 ) ) ;
        above->addChild( sphere ) ;

    MaterialNode* blueMaterial= new MaterialNode() ;
    blueMaterial->setColor( 0,0,1 ) ;
    blueMaterial->addChild( above ) ;

    // Light these red and blue spheres with a white light at (1,1,1).

    LightNode* light= new LightNode() ;
    light->setPosition( Point3( 1,1,1 ) ) ;
    light->setDiffuseColor( 1,1,1 ) ;
    light->lightsOn( true ) ;
    light->addChild( blueMaterial ) ;
    light->addChild( redMaterial ) ;

    // Put a green sphere in the center and use a different light to light it.

        TransformationNode* center= new TransformationNode() ;
        center->set( Vector3(1,0,0), 0, 0.5, Vector3(0,0,0) ) ;
        center->addChild( sphere ) ;

    MaterialNode* greenMaterial= new MaterialNode() ;
    greenMaterial->setColor( 0,1,0 ) ;
    greenMaterial->addChild( center ) ;

    LightNode* light2= new LightNode() ;
    light2->setPosition( Point3( -1,0,1 ) ) ;
    light2->setDiffuseColor( 1,1,1 ) ;
    light2->lightsOn( true ) ;
    light2->addChild( greenMaterial ) ;

    // The scene graph consists of both lit sub-scenes.

    Node* scene= new Node() ;
    scene->addChild( light ) ;
    scene->addChild( light2 ) ;

    return scene ;
}


int main( int argc, char** argv )
{
    // Initialize OpenGL. 
    glutInit( &argc, argv ) ;
    glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH ) ; 
    glutInitWindowSize( 600, 600 ) ;
    glutInitWindowPosition( 100, 100 ) ;
    glutCreateWindow( "Scene Graph - Demo" ) ;
    glutDisplayFunc( display ) ;  

    // Initialize lighting mechanisms.
    glEnable( GL_DEPTH_TEST ) ;
    glPolygonMode( GL_FRONT_AND_BACK, GL_FILL ) ;
    glEnable( GL_NORMALIZE ) ; 
    glEnable( GL_LIGHTING ) ;
    
    // Build scene and viewer.
    G_scene= buildScene() ;
    viewProjection() ;

    // Go.
    glutMainLoop() ;

    return 0 ;
}