Let's say that I want to render something like Dimmadome's hat, a hat which has the height of infinity.
A quick answer to this would be to place the top side of the hat high enough for the crown(cylinder) to be cropped(like y=9999999...) half way in the view. I don't like this idea. So what I came up with is using IEEE 754 infinity in vertices.
(-0.5, INF, -0.5) (0.5, INF, -0.5) (0.5, INF, 0.5) (-0.5, INF, 0.5)
(assuming the crown is a cube)
The problem is that after multiplying with the transform matrix, the vertices end up being all
(INF, INF, INF), making them unrenderable. I just wrote this to give you an idea.
Is there any technique that can be used to achieve this? rather than using huge number? I wonder how they implemented this.