Transparency

Stain · Post by **Stain** » Tue Oct 11, 2005 1:33 pm

Hi guys!

I'm new to Irrlicht (actually I'm using Irrlicht.Net) and I came across a problem with making a model transparent. I add 3ds textured model, a camera and one or several lights to the scene: everything renders fine. But when I change material type for that model to TRANSPARENT_VERTEX_ALPHA the model is rendered incorrectly: far faces are sometimes rendered on top of nearer ones. It looks like no alpa-sorting is performed.
What shall I do to get a single model rendered correctly with transparency?

Ishtm · Post by **Ishtm** » Tue Oct 11, 2005 6:12 pm

May by you can't setting correct flags for material,
try put true on these material flags:

ZwriteEnable
ZBuffer
BackFaceCulling

that makes zorder work, but another thing is needed to use TransparentVertexAlpha:

when you create mesh you have to set the alpha value of vertex color less than 1.0 to get some transparency

Stain · Post by **Stain** » Sun Oct 16, 2005 3:51 pm

Thanks for advice, but it didn't work.

TRANSPARENT_VERTEX_ALPHA doesn't work properly with any combination of material flags (zbuffer, zwritesenabled, backfaceculling, lighting, and all others). I spent two days playing with all these options and material colors with no result.

I've managed to get transparent model by using TRANSPARENT_ADD_COLOR material type. It works fine but this option mixes material color with texture color and I need pure texture color. I guess, TRANSPARENT_VERTEX_ALPHA should do this but it doesn't work for me. So the question is still open: how can I render model with alpha but without material color blended to texture?

(I use Irrlicht 0.12 with DX9 driver on DirectX 9.0c from Aug 2005 DX SDK update.)

squisher · Post by **squisher** » Wed Sep 10, 2008 9:49 pm

bump. help.

dlangdev · Post by **dlangdev** » Thu Sep 11, 2008 1:46 am

screenshots please. just because...

jontan6 · Post by **jontan6** » Thu Sep 11, 2008 3:40 am

quickfix: use opengl not d3d

Bear_130278 · Post by **Bear_130278** » Thu Sep 11, 2008 8:16 am

Flip normals

JP · Post by JP » Thu Sep 11, 2008 8:21 am

Normals have nothing to do with this problem

Bear_130278 · Post by **Bear_130278** » Thu Sep 11, 2008 11:40 am

Just wanted to say something

JP · Post by JP » Thu Sep 11, 2008 11:50 am

Best not to if you don't know what you're talking about because you'll just confuse people... it's not a contest to see who can post most!

Bear_130278 · Post by **Bear_130278** » Thu Sep 11, 2008 12:25 pm

JP, you are not in the mood today?
My idea based on own experience.
Sometimes when exporting meshes in .x format i received very similar problems with incorrect polygon placement, but it was only visual illusion because of incorrect normal directions.

JP · Post by JP » Thu Sep 11, 2008 12:53 pm

Normals are only used for lighting so they're not going to affect z-order at all.