Glass like in HalfLife 2

OpenGL Development JOGL Development
#1

Hi,

I’m looking for information on how glass wall effects are done in video games that make the glass look bumpy or textured.

I’ve seen special effects done with glass in both HalfLife 2, and Rainbow Six on the XBox.

In both cases there is a glass wall which you the player can walk up to, and see threw. You can see other characters behind the glass wall in great detail, except that the glass is bumpy like glass bricks or an office door.

How is this effect done?

From what I can tell. It sure does look like they render the scene, and then the glass is a second pass. They shader appears to be sampling the image buffer from the first pass.

Is it possible to sample the buffer from a shader? I thought this couldn’t be done.

Anyone know how to do this, or know what I’m talking about?

#2

Are you talking about refraction?
If so I guess (not tried it) you could render the view to a texture (render target) and then distort the texture in a pixel shader the second time around. Check out the bunny example in the JOGL demos as they do refraction.