Polymost

Wireframe mode.

Solid colors mode.

Polymost is a software and OpenGL renderer developed by Ken Silverman as a replacement for the Build engine. From December 2004 to February 2005, Randy worked on adding the software rendering parts of Polymost to ZDoom. If the polymost code were to be finished one day, it would bring true 3D renderer (without Y-shearing when looking up and down) to ZDoom.

In its current state, the Polymost renderer in ZDoom can only render world geometry, either in wireframe or in solid colors. It can be tested by setting r_polymost to 1 (wireframe), 2 (solid colors with wireframe) or 3 (solid colors without wireframe) in the console.

Note that:

1. It is overlaid on the software renderer output. In wireframe mode, it is still playable; but in solid colors mode, the polygons mask the normal view entirely, rendering actors invisible.
2. Since it is part of the software renderer, if you use the OpenGL renderer from GZDoom or Skulltag, this will have no effect.

The two screenshots illustrate the difference between Doom's horizontal projection and the true 3D perspective of polymost.

Global tilt angle.

One other console variable affects the polymost rendering: gtang. It corresponds to the global tilt angle, in radians. Positive values tilt the angle clockwise, negative values tilt it counter-clockwise. With an approximation of π (positive or negative), the projection is upside-down.