Screen tearing effect

[vooku666]

Hi,

I was wandering about how to implement a screen tearing effect, such as this (photoshop demo):

[ATTACH=CONFIG]1373[/ATTACH]
[ATTACH=CONFIG]1374[/ATTACH]

I imagine the work should be done in the fragment shader, as if I did it in the vertex shader, everything would be just deformed and not cut. I can send the offset in via an input variable or calculate it in the shader, but how to move the fragments? Also, would I have to do it in every fragment shader I’m using (say 3 for different kinds of objects) or is there a way to acces all the fragments below the current one?

Thank you

[PLeLuron]

You have to do post-processing, i.e. rendering your scene to a texture, then use that texture on a full screen quad with the desired effect in the fragment shader. What you called accessing fragments would be fetching texels on that texture.