CODEWITHSUNDEEP
openglculling
Bartvbl
Bartvbl

Reputation: 2928

Is there a significant performance difference between using GL_CW in favour of GL_CCW with backface culling?

Let's say I enable backface culling using:

glEnable(GL_CULL_FACE);

I can configure which side faces are culled on using either of these:

glFrontFace(GL_CW);
glFrontFace(GL_CCW);

Is there a significant performance difference if I choose one over the other?

My hunch says it doesn't matter because this should only involve checking against a different sign when taking the scalar product. Though perhaps this is hardware dependent too?

Upvotes: 2

Views: 725

Answers (2)

datenwolf
datenwolf

Reputation: 162164

As far as the OpenGL specification is concerned, there's nothing defined about exact runtime behavior, which included performance. Behaviour like this always depends on the implementation at hand. However I know of no implementation in particular where there would be a measureable difference.

Upvotes: 0

codetiger
codetiger

Reputation: 2779

These functions are not linked to performance directly. It depends on how you define your mesh and these function are only information to culling functions to decide which winding to ignore. So it should not matter performance in anyway.

Upvotes: 1

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