The Texture LOD Extension

The Texture LOD Extension

The texture LOD extension, SGIS_texture_lod, imposes constraints on the texture LOD parameter. Together these constraints allow a large texture to be loaded and used initially at low resolution, and to have its resolution raised gradually as more resolution is desired or available. By providing separate, continuous clamping of the LOD parameter, the extension makes it possible to avoid "popping" artifacts when higher-resolution images are provided.

To achieve this, the extension imposes the following constraints:

It clamps LOD to a specific floating point range.
It limits the selection of mipmap image arrays to a subset of the arrays that would otherwise be considered.

To understand the issues discussed in this section, you should be familiar with the issues discussed in the sections "Multiple Levels of Detail" and "Controlling Filtering" in Chapter 9, "Texture Mapping," of the OpenGL Programming Guide.

Specifying a Minimum or Maximum Level of Detail
Specifying Image Array Availability