ptitseb i looked at this source at one time and if I remember there were shaders being used for effects. Im curious did you disable/remove these and just convert the basic GL code?
The shaders are optionnal, and only vertex shader are really used, to avoid some intermediary calculation and use vertex buffer (comming from DirectX, you have a x, y,z, rhw quad, you have to take w=1/rhw, and do x*=w; y*=w and z*=w before drawing the triangles). So I used the non-shader version, but no effects where removed in the process.