Tag Archives: billboards

More videos – DoF, sun shafts, water caustics, pixel-accurate water surfaces.

Here’s a bunch of new videos. Take a look at:

1) Dynamic depth of field on the GPU and sun shafts:

2) More of the same, but at sunrise:

3) Probably the most technically interesting clip, and a rumination on whether the trees were a mistake and we should never have left the oceans. This one demonstrates per pixel water effects (i.e. only affects parts of the screen below the surface of the water) and also shadow mapping the water surface to give underwater light shafts and caustics:

(Note also: the clouds are rendered as billboarded impostors, ray traced in the fragment shader to give perfect spheres. As you’ve probably noticed they are a bit rubbish at the moment.)

Simple billboard orientation in world space

I had a great deal of difficulty in working out how to do billboards properly, simply because I don’t have the mental agility to handle the descriptions usually given in 3D programming tutorials. The method I’ve managed to figure out is related to gluLookAt: and uses a similar method to work out the rotation matrix needed to map one vector to another.

Here’s how the process works:
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