Adventures in engine land, part 2

jal: knew you'd notice this minor change! To be honest, I have no idea what might have caused it, despite spending a considerable amount of time investigating. The best idea I came up with was a change in vertex normals due to SKM -> IQM convertion, not necessarily a bug..

Or maybe it was color clamping due to multipass rendering, dunno..

2jal: turned out to be a bug in the IQM compiler tool, it has been fixed by eihrul.

Very interesting informations.
I love to get some details behind a game it gets some better understanding whats going on, while playing.
Thx for all the hours you spend on this !!! ;)

For the GPU skinning dual quaternions technique could be used

Hi Vic!

You implemented dual quat skinning? I'm interested in that but my math background is too weak to translate the formulaes from the pdf into code. Also i never found some existing source code about it. I guess i could wait until source for 0.7 comes out, but maybe you have time to give a little preudo code on a basic example, say transforming a single vertex by two influences? Would be great! ...if that fits in a single post :)

My background:
I've implemented matrix skinning on both CPU and GPU, understand that process completely.
I use quaternions for both physics and graphics, mostly for orientation interpolation, but i don't really understand how they work :)
Also, i don't really grasp what complex or dual numbers are, but mostly complete understandung of the basics is not required to use things like quaternions, spherical harmonics...

appreciate your help!

Hi quaternion (nice nickname),

the first google search result for 'dual quaternion skinning' brings us here. The page also links to implementation source code, which I think is exactly what eihrul's work was based on.

Anyway, here's part of the vertex shader which I'm using in 0.7

Ah yes, i can remember... when i first saw the paper years ago, that referenced university homepage always was down.
I've got it working now. Thanks for your help! I came to this place by googeling docs about quake live mouse accel, but found something much more useful :D

Needed to read twice to understand it ;D
Awesome work :)