Shows how to setup a camera, render a grid and control the camera using a mouse.

CamAndGridApp.cpp

#include "cinder/app/AppNative.h"
#include "cinder/gl/gl.h"

#include "cinder/Camera.h"
#include "cinder/MayaCamUI.h"

using namespace ci;
using namespace ci::app;
using namespace std;

class CamAndGridApp : public AppNative {
public:
	void setup();
	void update();
	void draw();

	void resize();

	void mouseDown( MouseEvent event );	
	void mouseDrag( MouseEvent event );	

	void keyDown( KeyEvent event );

private:
	CameraPersp		mCamera;
	MayaCamUI		mMayaCam;
};

void CamAndGridApp::setup()
{
	// initialize the camera
	//  (note: setting the center of interest last will make
	//         sure the camera stays focused on that point)
	mCamera.setEyePoint( Vec3f(0.0f, 200.0f, -500.0f) );
	mCamera.setCenterOfInterestPoint( Vec3f::zero() );
}

void CamAndGridApp::update()
{
	// nothing to update in this sample application
}

void CamAndGridApp::draw()
{
	// clear the window
	gl::clear(); 

	// enable 3D rendering
	gl::enableDepthRead();
	gl::enableDepthWrite();

	// push the matrices, so we can restore them later
	gl::pushMatrices();

	// apply our camera
	gl::setMatrices( mCamera );

	// draw a coordinate frame
	gl::drawCoordinateFrame( 100.0f, 5.0f, 2.5f );

	// draw our grid	
	const int size = 100;
	const int step = 10;

	gl::color( Color::white() );
	for(int i=-size;i<=size;i+=step) {
		gl::drawLine( Vec3f(i, 0.0f, -size), Vec3f(i, 0.0f, size) );
		gl::drawLine( Vec3f(-size, 0.0f, i), Vec3f(size, 0.0f, i) );
	}

	// restore our matrices
	gl::popMatrices();

	// disable 3D rendering
	gl::disableDepthWrite();
	gl::disableDepthRead();
}

void CamAndGridApp::resize()
{
	// make sure the camera has the correct aspect ratio
	mCamera.setAspectRatio( getWindowAspectRatio() );
}

void CamAndGridApp::mouseDown( MouseEvent event )
{
	// start interacting with the camera, by telling MayaCam
	// where our camera is at this moment, then passing the mouse position
	mMayaCam.setCurrentCam( mCamera );
	mMayaCam.mouseDown( event.getPos() );
}

void CamAndGridApp::mouseDrag( MouseEvent event )
{
	// interact with the camera
	mMayaCam.mouseDrag( event.getPos(), event.isLeftDown(), event.isMiddleDown(), event.isRightDown() );

	// update our camera
	mCamera = mMayaCam.getCamera();
}

void CamAndGridApp::keyDown( KeyEvent event )
{
	switch( event.getCode() )
	{
	case KeyEvent::KEY_SPACE:
		// point the camera at the origin again
		mCamera.setCenterOfInterestPoint( Vec3f::zero() );
		break;
	}
}

CINDER_APP_NATIVE( CamAndGridApp, RendererGl )