Polygon order on a single surface

Blitz3D Forums/Blitz3D Programming/Polygon order on a single surface

Stevie G (Posted 2004) [#1]

What I'm trying to do is add quads to a surface so that certain quads specifically appear in front or behind others. I understood that this could be acheived by building the quads in the order you want them displayed - first quad created is behind all the others etc... This doesn't seem to be working for me - is my understanding of this wrong?

Damien Sturdy (Posted 2004) [#2]

Now it doesnt work like this in blitz3d, but, theres a bug(feature???) in the new version with alpha vertices if you force alpha onto a mesh it seems to screw up the meshes... then you can rearrange the triangles like you want...... Well, im not at a position to try atm as im at work, but im sure someone else can explain that im right or wrong :)

Stevie G (Posted 2004) [#3]

Gygnus, Thanks but I'm not using vertex alpha so this is not the reason .. I'm pretty sure about that. Any one else able to explain how it works?

Damien Sturdy (Posted 2004) [#4]

Il have a play when i get home, ive come across it before and the only way i could fix it was to manually rearrange my triangles.. Interesting Il get back to you on that later...

Stevie G (Posted 2004) [#5]

That's what I'm doing at the moment ... a kind of entityorder but at quad level. This must be possible?! I've heard of people actually creating the triangles on a mesh in a specific order to enable the polys to look correct when using alpha.

Damien Sturdy (Posted 2004) [#6]

Yes, ive had to use the tehcnique because when i used alpha and it messed up the way it drew the triangles and i had to rearrange them all :/ search arund i think there was code posted somewhere....

Ross C (Posted 2004) [#7]

To reorder them, just choose the order they appear in and rebuild them, using the lower vertex numbers for the closer triangles. Is that what you mean? There's some single surface grass in the code archives which does this. Modified by Beaker i believe. :o)

Stevie G (Posted 2004) [#8]

Sussed it now. It was just as I originally thought .. just didn't set up the order array correctly. Thanks for the help and sorry for wasting anyones time!!

Ross C (Posted 2004) [#9]

Never a waste of time man :)