# Frustum culling techniques

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Hello! I've came across two different frustum culling solutions. The first one involves extracting clipping planes from the 'clip matrix'. Then, points are tested using a plane equation. The second approach is to transform a vertex by a clip matrix. After that we check if coordinates of the transformed vertex stay in range -W to W (where W is the clip coordinate value). Does the second method make sense at all? If so, which solution is better? I warn you I could have messed something up. ;) Thanks in advance!

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 I've came across two different frustum culling solutions. The first one involves extracting clipping planes from the 'clip matrix'. Then, points are tested using a plane equation. The second approach is to transform a vertex by a clip matrix. After that we check if coordinates of the transformed vertex stay in range -W to W (where W is the clip coordinate value).Does the second method make sense at all? If so, which solution is better
The first method is very common; although the second makes sense, I don't think I've seen it used in practice, for what it's worth.

I'd prefer the first because:

1. It operates in world rather than clip space, which is a little more intuitive

2. You only have to extract the planes once at the beginning of the frame, and from then on the culling tests are inexpensive and relatively straightforward

Take this with a grain of salt though - there may be some advantages to the second method that I'm not aware of.

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 Take this with a grain of salt though - there may be some advantages to the second method that I'm not aware of.

Well, actually the author stated that it's not the proper way to do frustum culling. Frankly speaking, it's tough to find advantages of this solution. I was just curious. ;)

Anyway, it's good to know there is some alternative.

Thanks!

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