Hello.
When using
DirectX mode and
PerfectPerspective.fx
shader with
Vertical distortion = 0 and
K > 0 there is an error, not present in
OpenGL.
...a vertical distortion in the middle.
When you look at the
univPerspective function (line 191), there are inputs
l = 0 and
k > 0, which make variable
R ≈ 0 when at the middle of the screen.
Later
R is in denominator. I suppose there is some difference at compilation time between DirecX and OpenGL or maybe different implementation of trigonometric functions.
Does anyone have some clue what's causing the issue? OpenGL doesn't have one.