[cowtools]

I've been advised not to use point sprites. Apparently, most GPU inplementations merely convert it into a quad in the backend, and gl_PointSize seems to have a soft maximum that depends on implementation.

I've found a mechanism that uses the "interleaved attribs" feature of transform feedbacks to spit out 4 verts at a time (as six to draw two GL_TRIANGLES) into a buffer that a quad-drawing shader program consumes.

Using GL_POINTS/gl_PointCoord is probably better though just for teaching children fundamentals, I just wish that it actually worked properly in practice.