Jump to content
  • Advertisement
Sign in to follow this  
zurekx

Transform planes

This topic is 3624 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I just tried to use User Clip Planes (XNA) to cull everything below a particular plane. Since the culling is done after the vertex shader, I must transform the plane with the same transform as the vertices. Normally, if I have a plane, I just transform the normal with the inverse-transpose of my transformation-matrix. But now that I got translations and 4-dimensional matrices, I got a little confused. How should I look at it? Cause somehow I need to take the translation into account, and multiply the vector (normalx, normaly, normalz, constant) with the inverse-transpose.

Share this post


Link to post
Share on other sites
Advertisement
Treat your plane as a 4D vector (Nx, Ny, Nz, d) where d = -(N dot P) for any point P in the plane. Then you can transform it by multiplying it by the inverse transpose of the full 4x4 matrix.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!