Particle effects is a common technique used in many 3D applications and games. A particle effect is a generic term for any special effect created by rendering groups of particles (displayed as points, textured quads, or repeated geometry), typically with some simple physics simulation acting on the individual particles. They can be used for simulating smoke, fire, bullets, explosions, water, sparks, and many other effects that are difficult to represent by a single geometric model.
One very efficient way of rendering particles is to use point sprites. Throughout this book, we've been rendering triangle primitives, but if you render vertices with the POINTS primitive type, then each vertex will be rendered as a single pixel on the screen. A point sprite is an extension of the POINTS primitive rendering, where each point is provided a size and is textured in the...
