CODEWITHSUNDEEP
opengl
Tara
Tara

Reputation: 1796

Back-face Culling Performance

I've always been wondering about this:

Is is there a performance impact if I render only front facing polygons, while back-face culling is enabled?
Should I rather disable it in such a situation?
Or is this something that depends on the OpenGL implementation? I can imagine that rendering polygons with disabled back-face culling will be faster on software implementations. But on hardware?

EDIT
To clear things up: There will never be any back facing polygons in my scene. Back-face culling will never cull anything.

Upvotes: 1

Views: 1743

Answers (1)

datenwolf
datenwolf

Reputation: 162164

Since the winding of a primitive must be determined (for the rasterization process) regardless of culling being enabled or not, back face culling comes practically for free. So you can leave it on. Switching culling state itself is a no-brainer for a OpenGL implementation. It doesn't affect any caches, pipeline state or other things which can have a huge performance impact.

Upvotes: 8

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