View Full Version : mipmap level selection

11-12-2000, 07:28 PM
How does OpenGL know which mipmap level to use? Asked another way, given the three vertices of a triangle (including texture coordinates), the mipmap dimensions, the modelview and projection matricies (and whatever else you might need), how would I figure out which mipmap level to use?

Is it standardized in any way, or is it implementation dependent? Does it matter how much of the texture subimage is used?


11-13-2000, 12:16 AM
There is a formula given in the spec. It's a function of the derivatives of the texture coordinates in screen space.

However, implementations can choose to approximate the formula. There are certain bounds on this approximation.

- Matt