Alain Martel <kua### [at] videotronca> wrote:
> The actual problem was a negative right vector.

Alain, yes - the primary difference between the OpenGL and POV-Ray coordinate
systems is their handedness. OpenGL traditionally defaults to a right-handed
coordinate system, whereas POV-Ray strictly uses a left-handed coordinate
system.

Changing POV-Ray to a right-handed system requires manually modifying the

macro libraries. 10 years ago I changed the right vector in BPP POV-Ray export
to be negative:

https://github.com/bullet-physics-playground/bpp/commit/a01a071a31fc4f263225aa05eb7de655d9c5e37f#diff-0944863e432aaa433
80d43497ccbe58cd8a099832772b0a5ffb9271385e0ddd1R903

But I don't know if this is the correct way of doing the OpenGL to POV-Ray
export or if there is a better solution; the cleaner, more standard solution is
to keep POV-Ray's camera completely default (left-handed) and convert the OpenGL
coordinate data (positions, rotations, and matrices) directly during the export
phase.

I think I need to rewrite the rotation or positioning routines inside BPP:
 1. Transform Positions and Direction Vectors
 2. Transform Rotations
 3. Transforming Full 4x4 Matrices

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