OpenGL mipmapping: level outside the range?

0
votes

I'm going deeper on OpenGL texture mipmapping.

I noticed in the specification that mipmap levels less than zero and greater than log2(maxSize) + 1 are allowed.

Effectively TexImage2D doesn't specify errors for level parameter. So... Probably those mipmaps are not accessed automatically using the standard texture access routines...

How could be effectively used this feature?

1
opengltexturesmipmaps

1 Answers

1
votes

For the negative case, the glTexImage2D's man page says:

GL_INVALID_VALUE is generated if level is less than 0.

For the greater than log2(maxsize) case, the specification says what happens to those levels in Raterization/Texturing/Texture Completeness. The short of it is that, yes, they are ignored.