Painter's Algorithm

[jrygeorge]

https://en.wikipedia.org/wiki/Painter%27s_algorithm

Would be nice to see a video on Painter's Algorithm, one of the ways in which we determine which surfaces are visible and which are hidden to the user when drawing a 3D object.

[shiffman]

I like this idea!! Maybe I could even show a parallax effect along with it? What would be a very simple way to demonstrate the algorithm without getting into 3D rendering I wonder?

[jrygeorge]

@shiffman Easiest way I think would just be to take all the vertices we need, do all the affine transformations, pass it through the perspective projection matrix for the parallax effect, order the faces, then just chop off the Z coordinate and draw the polygons (Actually now, that seems like a lot).

I tried it like that myself and it mostly works.
The code is kind of a mish mash of things I wrote sometime ago, so might be a bit difficult to read.

Also after, you could talk about things like frustum culling and face culling too, would be nice :)