flipCode - Tech File - Jacco Bikker [an error occurred while processing this directive]
 Jacco Bikker (aka The Phantom) Click the name for some bio info E-Mail: phantom@goright.to http://www.flipcode.com/focus

 11/27/2000, Tech File Update

Here's a bit of info about what I've been doing lately. First the Davilex stuff: The octree is fine now (never mentioned it in my techfile, but I did post an image of the day). I used VTune to find some obsolete debugging code that was eating 20% of my processor time, and I found that the c-buffer span inserter actually wasn't the bottleneck as I suspected. The bottleneck actually was the code that traced occluder polygon outlines, so I added stuff to lower the number of inserted edges (using a winged edge structure). O yeah, about winged edges: That's a structure that contains, for each polygon edge, a pointer to the 'neighbour' polygon. You can use this information to determine the outline of a shape: An edge contributes to the outline if it's neighbour is invisible (not facing the camera). You can also do lots of other stuff with it, but you get the basic idea now. A dude from 3DS Max (forgot the name of the company) once sent me an e-mail about this structure. Calculating the winged edge structure for a 1000 polygon mesh can be quite a lot of work: It involves checking every polygon against every polygon. Well, not if you do it right, and that's exactly what this dude told me: For each vertex, make a list of polygons that use it. That's O(n) code. Now, if you want to determine the neighbouring polygon, you know that it must be in the combined set of polygons of the two vertices that make up the edge. So, now you determine the winged edge structure fast. :)

I've been doing other cool things as well, like programming my Nino (a WinCE 2.01 device). The thing has a 4 color greyscale LCD display, but it now displays 32 shades. Actually, it runs the bilinear interpolated voxel landscape demo that comes with the OpenPTC package. :) I couldn't believe my eyes when I saw that running on such a small (and old!) device... The thing is very fast, and it's a lot of fun to program it. So, if you own one, let me know, I'll send you sources right away. :) I promised Jaap to do Lemmings for it too, does anyone have a set of Lemmings animations for me? Otherwise I'll be busy capturing screenshots from WinLemmings all day... :) Greets - Phantom.

• 11/27/2000 - Tech File Update
• 09/30/2000 - Tech File Update
• 07/05/2000 - Tech File Update
• 06/26/2000 - Tech File Update
• 01/05/2000 - A Little Update For The Techfile
• 11/04/1999 - No Subject
• 07/26/1999 - No Subject
• 06/22/1999 - No Subject
• 06/15/1999 - No Subject
• 05/06/1999 - No Subject
• 05/05/1999 - No Subject
• 04/28/1999 - No Subject
• 04/26/1999 - Introduction

• This document may not be reproduced in any way without explicit permission from the author and flipCode. All Rights Reserved. Best viewed at a high resolution. The views expressed in this document are the views of the author and NOT neccesarily of anyone else associated with flipCode.

[an error occurred while processing this directive]