| OCR Text |
Show 21 vary in size and shape. In addition the user can select color from th availabl palette. The images produced by a paint program can easily be converted into a color texture map and applied to an object during rendering. A large number of stochastic models have been explored that are useful for generating color texture maps. Dithering, cell growth, bombing, particle systems, Markov fields, Brownian motion, and Martingales are among the many stochastic models used to generate texture. A digitizer allows the computer to capture real world images and textures. Photographs, drawings, and paintings are just a few of the things that can be digitized into an image. Any image synthesis program can be used to create images which are easily converted into color texture maps. 3.1.3 Rendering with Color Maps Rendering with a color texture map is performed by ray tracing until the closest intersection is found. The intersection coordinate and surface normal are calcu-lated. The object is then checked to see if it refers to a color texture map. If there is no color map reference, the color field of the surface attributes is placed into the ray intersection. If there is a color map reference, the intersection coordinate is transformed into a map coordinate, which is then used to retrieve a value from the color map to be placed into the ray intersection record. This process paints the surface of the object with the patterns stored in the color texture map. The code that implements the color texture mapping algorithm is shown in Figure 9. |
