sig
type light_pname =
GL_SPOT_EXPONENT of float
| GL_SPOT_CUTOFF of float
| GL_CONSTANT_ATTENUATION of float
| GL_LINEAR_ATTENUATION of float
| GL_QUADRATIC_ATTENUATION of float
| GL_SPOT_DIRECTION of (float * float * float)
| GL_AMBIENT of (float * float * float * float)
| GL_DIFFUSE of (float * float * float * float)
| GL_SPECULAR of (float * float * float * float)
| GL_POSITION of (float * float * float * float)
end