Bloom using the geometry shader

Is it possible to use a geometry shader to create a bloom effect? If I understand them right, you could create circles for each point and then have the fragment shader apply a blur.

it’s easier to use an image of a circle as a point texture, you just create a mesh with all your points and apply the texture to each in the fragment shader.

How could I do that if my mesh is being drawn as triangle strips?

I did a lot of reading on what you mentioned, but that seems to work only when you draw as a point (I’ve read about point sprites here and here).

if you are drawing faces the tipical thing to do is render to an fbo and on a second pass do a gaussian blur on a fragment shader

Hi, is there any reason not to do the bloom effect in image space?

Otherwise this explains pretty well how it works in image space:

There are a few different shader blur addons to help you create the blurred version of the scene.

Try to look at this example:

maybe it’s not what you need, but it can be useful to understand what they mean the boys over.


@arturo, yes, I’ve read about that technique at several places. I was wondering if there was an easier way.

@hahakid, I’ve come across Phillip’s page a couple of times, and went through it. Thanks for it :slight_smile:
Regarding blur addons, I want to build a simple blur oF app myself, without using any addons (to learn how it’s done)

@kashim, great example. I need to learn a bit more about the GLSL language before I understand those shaders.