A survey of raster-based transparency techniques

Transparency is an important effect for several graphics applications. Correct transparency rendering requires fragment-sorting, which can be more expensive than sorting geometry primitives, and can handle situations that might not be solved in geometry space, such as object interpenetrations. In this paper we survey different transparency techniques and analyze them in terms of processing time, memory consumption, and accuracy. Ideally, the perfect method computes correct transparency in real-time with low memory usage. However, achieving these goals simultaneously is still a challenging task. We describe features and trade-offs adopted by each technique, pointing out pros and cons that can be used to help with the decision of which method to use in a given situation.

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► Transparency is used in several applications, like computer games, scientific visualization, and realistic rendering.
► We survey different transparency techniques in terms of processing time, memory consumption, and accuracy.
► Transparency techniques are summarized by their features and trade-offs, pointing out pros and cons.
► The universe of techniques proposed to solve transparency in raster-based pipelines is vast.
► We hope this survey is comprehensive and motivates new research in the field.