In all that impenetrable voodoo math from Polymost it picked the wrong vector to calculate the depth of the scene and since I apparently removed the compensation math for the broken shader on the C++ side the calculated value was no longer correct.
That Polymost renderer really needs to go away. :(
Not only is this a deprecated feature - it also does not work right when complex lighting is at play, it must be done in the shader to get proper results.
For Duke Nukem and its direct offspring (Nam, WW2GI and Redneck Rampage) the ramp is not a linear fade from 0 to 1, it needs to be a little darker than that.
Unfortunately the proper factor needed here must be set manually, this cannot really be calculated from the lookup tables.
Something about their data preparation is not right, their depth looks totally off and causes fog to become to dense.
One more reason to reconstruct the renderer in a sane fashion.
The only compatibility mode feature left is the main drawer function using glBegin/glEnd but changing that is not as urgent as the rest.
This also cleans up the fog application and adds the exponential fog mode again that somehow got lost over time.
The builtin matrices are no longer available in modern GLSL, preventing an upgrade of the shader.
Also perform better reporting of shader compilation errors.
This is one unbelievable piece of weird coding based on the 15 year old concept to avoid conditionals at all costs.
As a result the code is totally unreadable and no longer really portable to modern OpenGL.
This has to be done in small pieces.
Currently this only contains the main Polymost shaders and the resources from nblood.pk3.
The latter cannot be used yet because the Build resource management system is too stubborn to add the newly added file without some changes.
It's better to refactor the entire system instead.
