Additive blending with particles

beginners
#1

Hello,
I have a particles system and the idea is that where there is a higher density of particles their color is brighter. My particles are stored in a vbo and I thought of drawing them with additive blending mode but the blending mode doesn’t seem to work, I’m certainly missing something. Here is how I draw my particles (I’m using ofxFX):

void testApp::update(){
    particlesSystem.update();

    FXObject.begin();
        ofEnableBlendMode(OF_BLENDMODE_ADD);
            particlesSystem.draw();
        ofDisableBlendMode();
    FXObject.end();

    FXObject.update();
}

void testApp::draw(){
    FXObject.draw(0,0);
}

void ParticlesSystem::draw(){
    vbo.draw(GL_POINTS, 0, NUM_PARTICLES);
}
#2

Usually enableblendmode works if you call it right before you draw your object and disable after everything has been drawn. Try putting it in the draw function.

#3

As far as I know you have to call “ofEnableBlendMode(OF_BLENDMODE_AD)” before
“FXObject.begin()” and “ofDisableBlendMode()” after “FXObject.end()”.

#4

I already tried both and it doesn’t work. Here is an example of the effect I’d like to realize :

#5

And what are you getting now? Does blending example in the sample work for you?

#6

Problem solved. It appeared that I was calling ofEnableAlphaBlending() after ofEnableBlendMode(OF_BLENDMODE_ADD) and that’s why it didn’t work. Thanks for the help!