FBOTest.cpp

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

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

#define IS_LANDSCAPE (getWindowWidth()/1.6f > getWindowHeight())
#define WIDTH 320
#define HEIGHT 200
#define ASPECT 1.6f

class FBOTestApp : public AppNative {
	gl::Fbo _fbo;
	gl::Texture _texture;
	int _x, _y;
	Perlin noise;

public:
	void prepareSettings(App::Settings *settings);
	void setup();
	void update();
	void draw();
	void drawToFbo();
};

void FBOTestApp::prepareSettings(App::Settings *settings) {
//	settings->enableHighDensityDisplay();
}

void FBOTestApp::setup() {
	gl::Fbo::Format format;
	format.setSamples(0);
	format.setTarget(GL_TEXTURE_2D);
	format.enableMipmapping(false);
	format.enableDepthBuffer();
	_fbo = gl::Fbo(WIDTH, HEIGHT, format);
	setWindowSize(HEIGHT*2, WIDTH*2);
	noise = Perlin();

	setFrameRate(30);
}

void FBOTestApp::update() {
	float dx = 100 * noise.fBm((float)_x/WIDTH, 0, getElapsedSeconds()/100.0);
	float dy = 100 * noise.fBm(0, (float)_y/HEIGHT, getElapsedSeconds()/100.0);
	_x = round(dx + WIDTH/2);
	_y = round(dy + HEIGHT/2);
}

void FBOTestApp::drawToFbo() {
	gl::SaveFramebufferBinding bindingSaver;
	_fbo.bindFramebuffer();
	gl::setViewport(_fbo.getBounds());
	gl::setMatricesWindow(_fbo.getSize());
	gl::color(ColorA(0, 0, 0, 0.1f));
	gl::drawSolidRect(_fbo.getBounds());
	gl::color(ColorA(1.0f, 1.0f, 1.0f));
	gl::drawSolidCircle(Vec2f(_x, _y), 20 - 10*cos(2*M_PI * 0.01 * getElapsedSeconds()));
}

void FBOTestApp::draw() {
	gl::clear(Color(0,0,0));
	drawToFbo();

	Area a;
	if(IS_LANDSCAPE) {
		int h = getWindowHeight();
		int w = floor((float)h * ASPECT);
		int d = floor((getWindowWidth() - w)/2.0);
		a = Area(d, 0, d+w, h);
	} else {
		int w = getWindowWidth();
		int h = floor((float)w / ASPECT);
		int d = floor((getWindowHeight() - h)/2.0);
		a = Area(0, d, w, d+h);
	}
	gl::setViewport(a);

	gl::Texture t(_fbo.getTexture());
	t.setMagFilter(GL_NEAREST);
	gl::draw(t);
}

CINDER_APP_NATIVE( FBOTestApp, RendererGl(0) )