OpenGL Point Sprites question

[Morpheus011]

I'm writing a particle engine and want to use point sprites...i have a few examples but they don't really let me understand everything that's going on behind the scenes with point sprites. for example i see the lines


glPointParameterfARB(GL_POINT_FADE_THRESHOLD_SIZE_ ARB, 80.0f);
glPointParameterfARB(GL_POINT_SIZE_MIN_ARB, 1.0f);
glPointParameterfARB(GL_POINT_SIZE_MAX_ARB, 30);
glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATIO N_ARB, attenuation); but don't really know what i'm doing by setting these environment settins. I'm just wondering if anyone knows where i can find out more info about point sprites, are they detailed in the language spec? Or is there a good reference someone can point me to online? Any help is greatly appreciated, thanks :)

Point sprites are detailed nicely in the OpenGL spec , starting on page 95 ;)

To be honest, though, I'm not too crazy about them. There's the max point size (usually around 64), and they're notoriously buggy in ATI implementations (don't know if that's true anymore). And, you can achieve the same thing using vertex shaders, with much greater flexibility. If you're able to use shaders/programs, I suggest that you do so as soon as possible.