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Techniques for Working with Texture Data

Textures add realism to OpenGL objects. They are what makes the objects defined by vertex data take on the material properties of real-world objects, such as wood, brick, metal, and fur. Texture data can originate from many sources, including images. As with vertex data, there are a variety of techniques you can use to minimize the number of times texture data is copied and converted as it's moved throughout the system.

Textures start as pixel data that flows through an OpenGL program, as shown in Figure 9-2. As with vertex data you can supply pixel data in two ways. The first way, from pixel data to per-pixel operations, is as part of an OpenGL command sequence that is issued by the application and executed immediately (immediate mode). The second is packaged as a named display list that can be preprocessed ahead of time and used later in the program.

The precise route that texture data takes from your application to its final destination can impact the performance of your application. The purpose of this chapter is to provide techniques you can use to ensure optimal processing of texture data in your application. This chapter

• shows how to use OpenGL extensions to optimize performance

• lists optimal data formats and types

• provides information on working with textures whose dimensions are not a power of two

• describes creating textures from image data

• shows how to download textures

• discusses using double buffers for texture data

Contents:

Using Extensions to Optimize
Optimal Data Formats and Types
Working with Non–Power-of-Two Textures
Creating Textures from Image Data
Downloading Texture Data
Double Buffering Texture Data
See Also

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