hey there

Does anyone know any cool special effects for opengl, im just putting together a tech demo for college and finding lots of cool techniques and special effects. I currently am using the stencil buffer for reflections and projected shadows , if anyone wants to know how to do this just ask and if anyone has any ideas of new special effects i could incorporate that would be great currently working on environment mapping

cheers

Parallax mapping

elaborate?

http://www.google.com/search?q=parallax+mapping

I could have done that

Soft shadows would be interesting as well.

And I've always liked the motion blur effect.

do you use the accumulation buffer for motion blur, iv heard something like that. gonna have to research it.

I haven't the slightest clue.

I dont know what your fimiliar with so im just gonna say a few, hopefully some are at least helpful.

a few relatively easy ones that have a nice effect are.

Bloom effect:
basically copy the screen to an image. shrink it to, half or a quarter of the original. place it back over the original image, with a blending effect that only blends the birghter parts. increase the bloom by placing it a few more times a pixel or two away from the last shrunkn images location (i hope you get that).

If your playing around with the stencil buffer. you may want to look into stencil shadows. really cool stuff. I found the nehe tutorials (27) really helpful for this. the code can be tweeked alot, but nun the less the concept is really great.

yeah like tom said parallax bump mapping, but thats more about using the fragment/vertex shaders. really easy to implement as there is heeps of variations of the shaders available. all you need to know is how to use the shaders. and thats simple enough. I personally havnt spent much time with shader language, so i wouldnt know how to create it fresh.

if you want to show a demo, and your playing with light sources. Its fun to dazzle ppl with particle effects as the light source. simple and effective.

thanks for the help guys, im gonna check those things out.

having real trouble with sphere mapping at the minute, for some reason it alters every textured object even tho its only called on one object :s

if anyone can help ill post the code

sphere mapping, as in cube mapping? not tryn 2 be anal just tryn to undestand, because sphere mapping is taking an image and rapping it around a sphere.
If its sphere mapping then it should only be related to texture co-ordinates and not effect any other model.

Cube mapping sounds like what u may be doing. If it is then im guessing u are enabling a client state at some time before drawing the object. I generally enable client state just before drawing the cube mapped model, or group of cube mapped models, then disable it just after.

eg.


hope that helps.

They are spheres so yeah its sphere mapping, opengl has functions that do this

glEnable(GL_S, GL_TEXTURE_2D, &textureId);
glEnable(GL_T, GL_TEXTURE_2D, &textureId);

these are called once u have binded the texture, with a few other parameters

my drawing code is a bit messy so it could just be that, but it looks fine to me and i push and pop matrix :s

really really frustrating