Indigo2 IMPACT systems render textures quickly: Texturing is only slightly slower than non-textured fill rates and significantly improves image quality for your application. To get the most benefit from textures, use the extensions to OpenGL for texture management as follows:
Use the texture object extension (EXT_texture_object) to keep as many textures resident in texture memory as possible. The extension lets you bind a texture to a name, then use it as needed (similar to the way you define and call a display list). The extension also allows you to specify a set of textures and prioritize which textures should be resident in texture memory. For more information, see "The Texture Object Extension".
Use the texture-LOD extension to minimize the number of mipmap levels you need to have resident while at the same time having the advantage of several levels of detail. For more information, see "The Texture LOD Extension".
Use the subtexture extension to make texture definition more efficient. For example, assume an application uses several large textures, all of the same size and component type. Instead of declaring multiple textures, declare one, then use glTexSubImage2DEXT() to redefine the image as needed. For more information, see "The Subtexture Extension".
This format is especially important if you have a large number of textures. The quality is reduced, but you can fit more textures into memory because they need less space.
Use the GL_RGBA4 internal format and the packed pixels extension to minimize disk space and improve download rate (see "The Packed Pixels Extension").
Use the 3D texture extension for volume rendering. Note, however, that due to the large amount of data, you typically have to tile the texture. You can set up the texture as a volume and slice through it as needed. For more information, see "The 3D Texture Extension".
If you use GL_LUMINANCE and GL_LUMINANCE_ALPHA textures, you can speed up loading by using the texture select extension.
For Indigo2 IMPACT graphics, data coherence enhances performance. If you're drawing texture-mapped points, short lines, or very small triangles, try to draw together the ones that are close together in the image. Don't bounce around, or drawing may slow down.