Porting Color, Shading, and Writemask Code
When porting color, shading, and writemask code to OpenGL, keep the following points in mind:
- Though you can set color-map indexes with the OpenGL glIndex function, OpenGL does not have a function for loading color-map indexes.
- Color values are normalized to their data type. (For information about color values, see glColor).
- There is no simple equivalent for cpack.
- You may have to translate code that includes the c or color functions to glClearColor or glClearIndex instead of glColor or glIndex.
- The RGBA writemask applies to each component but not for each bit.
- IRIS GL provides defined color constants: BLACK, BLUE, RED, GREEN, MAGENTA, CYAN, YELLOW, and WHITE. OpenGL does not provide these constants.
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