Hi !
Featured games (91)
games approved by the League of Dukes
Games in Showcase (757)
Games in Android Showcase (229)
games submitted by our members
Games in WIP (844)
games currently in development
News: Read the Java Gaming Resources, or peek at the official Java tutorials
    Home     Help   Search   Login   Register   
Pages: [1]
  ignore  |  Print  
  glNormalPointer  (Read 4314 times)
0 Members and 1 Guest are viewing this topic.
Offline Mojomonkey

Senior Devvie

ooh ooh eee eeee

« Posted 2003-10-31 11:09:51 »

Ok, this probably a simple problem, but I'm having trouble wrapping my head around it.

I understand that if I have a complex model I have my vertex array and my normal array (as well as texture, color etc). Each normal entry corresponds to a vertex. That's fine, I understand that....

but, now I have a simple box. 6 vertices. However, each vertex has three possible normals (where the normal depends on which side I'm rendering.)

Is this not doable using pointers? Do I need to seperate my box into 6 seperate sides and render them independantly?

Don't send a man to do a monkey's work.
Offline Orangy Tang

JGO Kernel

Medals: 57
Projects: 11

Monkey for a head

« Reply #1 - Posted 2003-10-31 11:29:01 »

A box is about the worst possible case for vertex arrays since you've got plenty of shared vertices but no shared normals. The only way to do it is to duplicate your vertices so you end up with 4 vertices and 4 associated normals for each face. Theres no pointer magic you can do to get around this, since GL will just read the data in in continuous blocks.

It would be nice to have separate indices for vertex, normal, texture coords etc. but I don't think that'd be as hardware friendly for caching. Plus you'd have so many more indices the actual data to move around would greatly increase.

[ - Play Growth Spurt, Rescue Squad and Snowman Village ] [ Rebirth - game resource library ]
Offline princec

« JGO Spiffy Duke »

Medals: 1033
Projects: 3
Exp: 20 years

Eh? Who? What? ... Me?

« Reply #2 - Posted 2003-10-31 12:10:48 »

And when you delve deeper into 3D rendering you'll gradually realise why there is no sensible way to specify the vertex coordinates just once and the normals separately 3 times.

Cas Smiley

Pages: [1]
  ignore  |  Print  

EgonOlsen (79 views)
2018-06-10 19:43:48

EgonOlsen (59 views)
2018-06-10 19:43:44

EgonOlsen (78 views)
2018-06-10 19:43:20

DesertCoockie (261 views)
2018-05-13 18:23:11

nelsongames (160 views)
2018-04-24 18:15:36

nelsongames (158 views)
2018-04-24 18:14:32

ivj94 (901 views)
2018-03-24 14:47:39

ivj94 (162 views)
2018-03-24 14:46:31

ivj94 (813 views)
2018-03-24 14:43:53

Solater (177 views)
2018-03-17 05:04:08
Java Gaming Resources
by philfrei
2017-12-05 19:38:37

Java Gaming Resources
by philfrei
2017-12-05 19:37:39

Java Gaming Resources
by philfrei
2017-12-05 19:36:10

Java Gaming Resources
by philfrei
2017-12-05 19:33:10

List of Learning Resources
by elect
2017-03-13 14:05:44

List of Learning Resources
by elect
2017-03-13 14:04:45

SF/X Libraries
by philfrei
2017-03-02 08:45:19

SF/X Libraries
by philfrei
2017-03-02 08:44:05 is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑
Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines | Managed by Enhanced Four Valid XHTML 1.0! Valid CSS!