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ADDITIVE BLENDING TUTORIAL AND GUIDE 08.07.2003


It was with dismay that developers learnt that one of the simplest and most powerful effects that of additive blending (AB) wasn't built into SW3D. However it was soon established that with cunning use of texture layers and certain 3d API's it was possible to achieve the effect. Further effort helped to ascertain a better understanding of the workaround, but until now there had not been a guide that really explained it in detail, nor the extensive testing to ensure the greatest compatibility between 3D cards.

This guide outlines first what is additive blending then the methodology behind accomplishing the effect in SW3D. It goes on to describe the Additive Blending Test Demo, results from a wide selection of 3D cards, systems and API's, a conclusion to the results, questions and answers to help understand the conclusions, and finally how to let Director determine by itself the settings required for additive blending (self diagnosis).

Included with the guide is the open source version of the Additive Blending Test Demo, along with an example of how to implement the feature within a project.

The first four images illustrate realtime glow effects augmented through additive blending.
The fifth has the same glow effect, but with trails, and the sixth is just additive blending.