A quick (and dirty?) image averager in Cinder. Uses a 32 bit (floating point) Fbo to accumulate frames.

CaptureTest.cpp

#include "cinder/Cinder.h"
#include "cinder/app/AppBasic.h"

#include "cinder/ImageIo.h"
#include "cinder/Utilities.h"

#include "cinder/gl/Texture.h"
#include "cinder/Capture.h"
#include "cinder/gl/Fbo.h"

using namespace ci;
using namespace ci::app;

class CaptureApp : public AppBasic {
 public:	
	void setup();
	void keyDown( KeyEvent event );
	
	void update();
	void draw();

	void clearImage();
	void saveImage();
	void saveBuffer();

	Capture				mCapture;
	gl::Texture			mTexture;
	gl::Fbo				mRenderBuffer;

	unsigned int		mFrames;
	bool				mLive;
	bool				mCapturing;
};

void CaptureApp::setup()
{	
	try {
		mCapture = Capture( 1920, 1080 );
		mCapture.start();
	}
	catch( ... ) {
		console() << "Failed to initialize capture" << std::endl;
	}

	gl::Fbo::Format fmt;
	fmt.setColorInternalFormat( GL_RGB32F_ARB );

	mRenderBuffer = gl::Fbo( mCapture.getWidth(), mCapture.getHeight(), fmt );
	mFrames = 0;

	mLive = false;
	mCapturing = true;
}

void CaptureApp::keyDown( KeyEvent event )
{
	switch( event.getCode() ) {
	case KeyEvent::KEY_f:
		// toggle fullscreen
		setFullScreen( ! isFullScreen() );
		break;

	case KeyEvent::KEY_SPACE:
		// pause/resume
		mCapturing = !mCapturing;
		break;

	case KeyEvent::KEY_l:
		// toggle live preview/accumulated result
		mLive = !mLive;
		break;

	case KeyEvent::KEY_c:
		// clear renderbuffer
		clearImage();
		break;

	case KeyEvent::KEY_s:
		// save result
		saveImage();
		break;

	case KeyEvent::KEY_b:
		// save buffer
		saveBuffer();
		break;
	}
}

void CaptureApp::update()
{
	if( mCapture && mCapture.checkNewFrame() ) {
		mTexture = gl::Texture( mCapture.getSurface() );

		if( mCapturing ) {
			// bind the FBO, so we can draw on it
			mRenderBuffer.bindFramebuffer();
	
			// set the correct viewport and matrices
			glPushAttrib( GL_VIEWPORT_BIT );
			gl::setViewport( mRenderBuffer.getBounds() );
	
			gl::pushMatrices();
			gl::setMatricesWindow( mRenderBuffer.getSize() );

			// enable additive blending
			gl::enableAdditiveBlending();
	
			// draw Fbo upsidedown, because...
			Rectf bufferRect = Rectf( 0, (float)mRenderBuffer.getHeight(), (float)mRenderBuffer.getWidth(), 0 );

			gl::draw( mTexture, mTexture.getBounds(), bufferRect );

			gl::disableAlphaBlending();

			// restore matrices and viewport
			gl::popMatrices();
			glPopAttrib();

			// unbind the FBO to stop drawing on it
			mRenderBuffer.unbindFramebuffer();

			// Increase frame count
			mFrames++;
		}
	}
}

void CaptureApp::draw()
{
	gl::clear( Color( 0.0f, 0.0f, 0.0f ));

	if( !mLive ) {
		if( mFrames > 0 ) {
			float factor = 1.0f / (float)mFrames;

			gl::color( Color( factor, factor, factor ));
			gl::draw( mRenderBuffer.getTexture(), Rectf( mRenderBuffer.getBounds() ).getCenteredFit( getWindowBounds(), true ));
			gl::color( Color( 1.0f, 1.0f, 1.0f ));	
		}
	} else {
		gl::draw( mTexture, Rectf( mTexture.getBounds() ).getCenteredFit( getWindowBounds(), true ));
	}
}

void CaptureApp::clearImage()
{
	mRenderBuffer.bindFramebuffer();
	gl::clear( Color( 0.0f, 0.0f, 0.0f ) );
	mRenderBuffer.unbindFramebuffer();
	mFrames = 0;
}

void CaptureApp::saveImage()
{
	fs::path pngPath = getSaveFilePath( getHomeDirectory() );
	if( pngPath.empty() ) {
		return;
	}

	gl::Fbo	exportBuffer;
	exportBuffer = gl::Fbo( mCapture.getWidth(), mCapture.getHeight() );

	// bind the FBO, so we can draw on it
	exportBuffer.bindFramebuffer();
	
	// set the correct viewport and matrices
	glPushAttrib( GL_VIEWPORT_BIT );
	gl::setViewport( exportBuffer.getBounds() );
	
	gl::pushMatrices();
	gl::setMatricesWindow( exportBuffer.getSize() );

	
	// draw Fbo upsidedown, because...
	Rectf bufferRect = Rectf( 0, (float)exportBuffer.getHeight(), (float)exportBuffer.getWidth(), 0 );

	if( mFrames > 0 ) {
		float factor = 1.0f / (float)mFrames;

		gl::color( Color( factor, factor, factor ));
		gl::draw( mRenderBuffer.getTexture(), bufferRect );
		gl::color( Color( 1.0f, 1.0f, 1.0f ));	
	}
	
	// restore matrices and viewport
	gl::popMatrices();
	glPopAttrib();

	// unbind the FBO to stop drawing on it
	mRenderBuffer.unbindFramebuffer();

	writeImage( pngPath, Surface32f( exportBuffer.getTexture() ), ImageTarget::Options(), "png" );
}

void CaptureApp::saveBuffer()
{
	fs::path pngPath = getSaveFilePath( getHomeDirectory() );
	if( pngPath.empty() ) {
		return;
	}
	writeImage( pngPath, Surface32f( mRenderBuffer.getTexture() ), ImageTarget::Options(), "png" );
}

CINDER_APP_BASIC( CaptureApp, RendererGl )