Image-Space Particle Emission (sap0542)

Particle systems are visualized by rendering some fixed number of particles per frame, where particle information is sampled from emitters represented by a location, and a range of potential initial particle parameters, such as origin, size, etc. For some complicated effects, especially for such effects where there are many potential emitters, where the location of the emitter is not well-defined, or when particle origins or other parameters can not be easily defined by an analytic boundary, the problem of generating new particle samples becomes difficult. One concrete example of such a scenario is the modelling of rain or hail splattering from visible objects as particles, where every point on a surface that can receive rain is a potential emitter. Another example comes in the form of a largescale detailed forest fire simulation, where each leaf (or portion of leaf) that is burning is an emitter of flame particles, and there are potentially thousands of leaves visible at any given time.