Using Strips

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4 comments, last by MaxPoly 24 years, 2 months ago
I''m using D3D. I want to use the draw primitive sending triangle strips. I don''t have a problem emplementing the api call or conceptualizing the data. However, when dealing with actual models (not just small primitives for testing) it''s much to dificult to setup the strips manually (text editor). Is there a tool or modeler that helps arrange vertex data into strips? Is anyone using strips? If so how do you do it? Thanks very much. MaXPoly
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Usually the strips are setup automatically be analysing a set of triangles and connecting the into strips.

But I''m going to save you the trouble and tell you not to use triangle strips. Triangle strips are only useful if you can put many triangles together in one long strip. With many I mean more than 20. (Not an exact figure here as I haven''t done any benchmarking on it)

What you should use instead is VertexBuffers and indexed Triangle Strips. If you read the DirectX Developer FAQ on vertex buffers, it says that the best way to draw models is this, where you try to put as many triangles in one call at once.

Hi Spellbound.

Thanks for your reply. It''s my intention to implement vertex buffers and indexed triangle strips. It''s easy to make a strip longer than twenty triangles. You just pop a degenerate triangle here and there and viola!

Are you using strips?

What modeler automatically generates them?

Thanks again for the reply

MaxPoly
I''m not using strips, I prefer triangle lists as it is easier to do progressive LOD on the meshes with those.

I don''t know of any modellers that save with triangle strips. But it is not that hard to build a little program that analyzes the mesh and build the strips for you.

The first thing the program needs to do is to find all triangle connections so that it knows which triangles are neighboring each other. Then the strips can easily be build with a recursive algorithm.
I used tristrips / indexed vertices in OpenGL with my old engine. They helped improving performance quite a lot. The average strip was not so long (smaller than 10 tris), but that is already quite efficient.

I used a package called Stripe V2 to generate the strips. It works well, but it is not entirely bug-free.

DaBit.

DaBit,

Where can I find this package?
Is it expensive?

Thanks for your reply

MaxPoly

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