edge detection in 3D-scene's

[Anonymous]

Just found this info at flipcode :

on the news-page @ delphi3d you can find an demo for edge detection.
This demo requires an GF3 or better, so can you try it please?

Is this useful for edgeAA too?

Link : http://www.delphi3d.net/

[Simon F]

Is this useful for edgeAA too?

Unlikely. It just looks as though it's a 'special effect' for showing high rates of change in the rendered image.

[3dcgi]

Ati is presenting a similar program at Siggraph in a couple weeks.

Real-Time Image-Space Outlining for Non-Photorealistic Rendering

An image-space algorithm that uses pixel shaders to render silhouette, crease, shadow, and texture outlines of 3D scenes in real time on consumer-level graphics hardware.

It sounds like a cool effect.

[BoardBonobo]

I would think that most edge detection would be used for toon shading type effects. Most edge detection routines are quite slow (at least they used to seem slow on my old rig), laplacian of gaussian or Roberts for example.

They mostly require the image to be converted into into an intensity map, you lose the hue and saturation values, whilst retaining the luminance (you end up a image made up of values ranging from 0 to 1). Convert this to a black and white image and run your edge detection routine. This is just a 2D[XxX] convolution looking for horizontal or vertical edges. I would presume that is similar to how edge detection in hardware works but with larger matrices.