Chapter 4 - Digital images and image manipulation

Abstract

This chapter reviews the characteristics of a digital image and outlines OpenGL's image manipulation capabilities. These capabilities are traditionally encompassed by the pipeline's “pixel path” and the blend functionality in the “fragment operations” part of the OpenGL pipeline. The OpenGL image pipeline is still undergoing evolution. With the transition to a more programmable pipeline, some image manipulation operations can be readily expressed in fragment processing, but many sophisticated operations still require specialized support or more complex algorithms. Modern rendering techniques combine both geometric and image-based rendering. Image representation and manipulation are essential to the rendering pipeline, not only for generating the final image viewing but as part of the rendering process itself. Even if an application doesn't make use of sophisticated image processing, familiarity with the basics of image representation and sampling theory guides the crafting of good quality images and helps in fixing many problems that are encountered while rendering and texture mapping. All the representation issues and the pipeline mechanisms for manipulating images play an important part in the correct application of texture mapping.