Method draw

samples/_opengl/PBOReadBack/src/PBOReadBackApp.cpp:98–180

}

void PBOReadBackApp::draw()
{
	mTimer.start();
	
	// Read from old Fbo
	if( mUsePbo ) {
		
		// Read to new Pbo (non-blocking)
		{
			gl::ScopedFramebuffer sFbo( mFbo[mIndexOld] );
			gl::ScopedBuffer sPbo( mPbo[mIndexNew] );
			
			gl::readBuffer( GL_COLOR_ATTACHMENT0 );
			gl::readPixels( 0, 0, WIDTH, HEIGHT, PIXEL_FORMAT, GL_UNSIGNED_BYTE, 0 );
		}
		
		// Receive data from old Pbo (potentially blocking hence the Pbo ping-pong)
		mPbo[mIndexOld]->getBufferSubData( 0, DATA_SIZE, mSurf.getData() );
		
	} else {
		
		// Read directly (blocking)
		gl::ScopedFramebuffer sFbo( mFbo[mIndexOld] );
		
		gl::readBuffer( GL_COLOR_ATTACHMENT0 );
		gl::readPixels( 0, 0, WIDTH, HEIGHT, PIXEL_FORMAT, GL_UNSIGNED_BYTE, mSurf.getData() );
	}

	mTimer.stop();
	
	// Render to new Fbo
	gl::enableDepthRead();
	gl::enableDepthWrite();
	
	{
		gl::ScopedFramebuffer sFbo( mFbo[mIndexNew] );
		gl::ScopedViewport sVp( 0, 0, WIDTH, HEIGHT );
		gl::ScopedMatrices sMat;
		
		gl::setMatrices( mCam );
		
		gl::clear( Color( 0.2, 0.4, 0.8 ) );
		
		gl::rotate( mRotate, vec3( 0.0, 1.0, 0.0 ) );
		gl::drawColorCube( vec3( 0 ) , vec3( 15 ) );
	}
	
	// Render to screen
	gl::disableDepthRead();
	gl::disableDepthWrite();
	
	gl::setMatricesWindow( getWindowSize() );
	gl::clear();
	
	gl::draw( mFbo[mIndexNew]->getColorTexture(), Area( 0, 0, 256, 256 ) );
	
	// Show the change to the data
	mTex->setTopDown( true );