minimal demo app showing camera frustum drawing

main.cpp

#include "ofMain.h"

class ofApp: public ofBaseApp {

	ofEasyCam cam[2];
	size_t activeCam = 1;

public:
	void ofApp::setup() {
		cam[0].setupPerspective( false, 30, 20.f, 500.f );
		cam[0].setDistance( 20 );
		cam[1].setupPerspective( false, 60, 5.f, 2000.f );
		cam[1].setDistance( 50 );
		ofSetBackgroundColor( ofColor::fromHex( 0x333333 ) );
	};

	//--------------------------------------------------------------
	void ofApp::update() {

	};

	//--------------------------------------------------------------
	void ofApp::draw() {
		ofEnableDepthTest();
		glCullFace( GL_CCW );
		glEnable( GL_CULL_FACE );
		cam[activeCam].begin();
		ofSetColor( ofColor::blueSteel, 128 );
		ofDrawSphere( { 0,0,-200 }, 50 );
		ofSetColor( ofColor::white );
		cam[( activeCam + 1 ) % 2].drawFrustum();
		cam[( activeCam + 1 ) % 2].draw();
		cam[activeCam].end();
		glDisable( GL_CULL_FACE );
		ofDisableDepthTest();
	};

	//--------------------------------------------------------------
	void ofApp::keyPressed( int key ) {
	};

	//--------------------------------------------------------------
	void ofApp::keyReleased( int key ) {
		switch ( key ) {
		case 'o':
			( !cam[0].getOrtho() ) ? cam[0].enableOrtho() : cam[0].disableOrtho();
			break;
		case 'c':
			cam[activeCam].disableMouseInput();
			activeCam = ( activeCam + 1 ) % 2;
			cam[activeCam].enableMouseInput();
		default:
			break;
		}
	};

	void mouseMoved( int x, int y ) {};
	void mouseDragged( int x, int y, int button ) {};
	void mousePressed( int x, int y, int button ) {};
	void mouseReleased( int x, int y, int button ) {};
	void mouseEntered( int x, int y ) {};
	void mouseExited( int x, int y ) {};
	void windowResized( int w, int h ) {};
	void dragEvent( ofDragInfo dragInfo ) {};
	void gotMessage( ofMessage msg ) {};

};

//========================================================================
int main( ){
	ofSetupOpenGL(1024,768,OF_WINDOW);			// <-------- setup the GL context

	// this kicks off the running of my app
	// can be OF_WINDOW or OF_FULLSCREEN
	// pass in width and height too:
	ofRunApp(new ofApp());

}