Indexed vs Non-indexed primitives

wh1sp3rik · 2013-01-19T20:04:55

Hello, I am trying to choose the right way for me. I am rewriting some parts of my engine and now i stand before this question. I will use these indexed/nonindexed primitives only for imported models ( characters or objects ), not for terrains, particles. Let's say the advantages and disadvantages. Advantages of indexed primitives: Primitive can take less memory They are rendered faster ( because of first point ? ) Disadvantages of indexed primitives: More complex models needs normals/bitangents/tangents/uvs/colours per vertex We have to bind two buffers, vertex and index cache miss, if indexes not ordered propertly and nonindexed are opposite of these. Is indexed primitives really faster to render for medium complex objects ( even, 50% of vertices needs different normals/tangents/.... so they are reperating actually ). Perhaps it's easy to answer, i would like to hear opinions from more experienced users. Thank you very much.

Graphics and GPU Programming Programming

Started by wh1sp3rik January 17, 2013 12:38 PM

10 comments, last by 21st Century Moose 11 years, 3 months ago

Brother Bob

10,350

January 19, 2013 06:57 PM

Ok, bad example if you draw it with triangles. Take a tetrahedron instead for an example with no shared vertices.

21st Century Moose

13,459

January 19, 2013 08:04 PM

This is one case where the GS stage is genuinely useful; you have access to all of the position data on a per-face basis, so you could use that to generate normals and texcoords for a cube (which tend to be pretty standard) while still keeping the vertex count down.

Direct3D has need of instancing, but we do not. We have plenty of glVertexAttrib calls.

Indexed vs Non-indexed primitives

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Indexed vs Non-indexed primitives

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