@arturo any help would be greatly appreciated!
so I’m getting some mixed results with a program I’m trying to write where a shape is used as an alpha mask for incoming video via webcam that then gets painted onto the screen through a second FBO that will ultimately run as a standalone on the raspberry Pi (3b,3b+)
I’m doing my main programming on my macbook and then transferring over the files to run on the RPI
in the main.cpp in wanting to run at SD as I will be outputting via the composite output
ofSetupOpenGL( 640,480, OF_FULLSCREEN);
ofapp.cpp
#include "ofApp.h"
//--------------------------------------------------------------
void ofApp::setup(){
vidGrabber.setDeviceID(0);
vidGrabber.setDesiredFrameRate(30);
ofSetVerticalSync(true);
ofBackground(0,0,0);
vidGrabber.initGrabber(ofGetWidth(), ofGetHeight());
paint.allocate(ofGetWidth(), ofGetHeight());
fbo.allocate(ofGetWidth(), ofGetHeight());
vidGrabber.getTexture().setAlphaMask(fbo.getTexture());
paint.begin();
ofClear(255);
paint.end();
ofSetCircleResolution(100);
}
//--------------------------------------------------------------
void ofApp::update(){
vidGrabber.update();
if(ofGetMousePressed(OF_MOUSE_BUTTON_RIGHT))
{
paint.begin();
ofClear(255);
paint.end();
}
}
//--------------------------------------------------------------
void ofApp::draw(){
fbo.begin();
ofClear(0,0,0,0);
ofSetColor(255,255);
ofDrawCircle(mouseX, mouseY, 55);
fbo.end();
paint.begin();
vidGrabber.draw(0, 0);
paint.end();
paint.draw(0,0);
}
these are declared in .h
ofFbo fbo;
ofFbo paint;
ofVideoGrabber vidGrabber;
so in this picture you can see when I’m running at fullscreen
the bottom right corner is not set all the way to the edge of the screen in both the X and Y directions
![]()
however if I change
vidGrabber.draw(0, 0);
to
vidGrabber.draw(0, 0,ofGetScreenWidth(),ofGetScreenHeight());
![]()
I get this result
the camera image now fills the screen
but there are artifacts at the edge of the shape that show through to the background
in addition the mouse now acts strangely as when in the top left corner the circle is centered on the mouse cursor but in the bottom right corner it is no longer in alignment. I think this has to do with the ofgetW&H being set by the 640,480 in the main.cpp but then getting stretched in the final paint.draw to the screen W&H. I’m less worried about the mouse (although it is a bit annoying)
the first image has the look I want as you don’t see the edges of the shapes but the second allows for actual full screen (all of this has been when using mac so far)
now when I load this onto the raspberry Pi
it gives me the same edge artifacts that I’m getting in the second picture no matter what I change
and when in full screen it only shows black with the mouse cursor unless
vidGrabber.initGrabber(ofGetWidth(), ofGetHeight());
is changed to
vidGrabber.initGrabber(640,480);
I’m testing on a projector right now with the RPI and I believe it is not actually filling the screen too
I’m feeling kind of stuck here
I feel like there is a solution to instead of paint.draw add a third FBO to mix paint and the original image in some way I tried that on the computer with ofblendmode ADD and got feedback that turned the screen white eventually
something like if you comment out the paint.draw(); gives a neat effects but is not what I’m looking for I’m sure I’m just not familiar enough with all this to understand what I’m doing wrong
bucket.begin();
vidGrabber.draw(0,0,ofGetScreenWidth(),ofGetScreenHeight());
ofEnableBlendMode(OF_BLENDMODE_ADD);
//paint.draw(0, 0,ofGetScreenWidth(),ofGetScreenHeight());
paint.draw(0, 0,ofGetScreenWidth(),ofGetScreenHeight());
ofDisableBlendMode();
bucket.end();
bucket.draw(0,0);
help on any front would be greatly appreciated again I really just want a full screen version of what is happening in the first picture nice clean edges
After the initial fade-in setup the code runs smoothly as it doesn’t need to fade in that many at a time. Now I was thinking, maybe I can do these fading-operations in a shader, though I don’t actually need the visuals, would just be nice to do the computation on the GPU over some textures.