Chapter 23. High-Speed, Off-Screen Particles

Iain Cantlay NVIDIA Corporation

Particle effects are ubiquitous in games. Large particle systems are common for smoke, fire, explosions, dust, and fog. However, if these effects fill the screen, overdraw can be almost unbounded and frame rate problems are common, even in technically accomplished triple-A titles.

Our solution renders expensive particles to an off-screen render target whose size is a fraction of the frame-buffer size. This can produce huge savings in overdraw, at the expense of some image processing overhead.

Motivation

Particle systems often consume large amounts of overdraw and fill rate, leading to performance issues. There are several common scenarios and associated hazards.

Particle systems ...

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