[Bf-committers] [Bf-blender-cvs] SVN commit: /data/svn/bf-blender [18203] trunk/blender/source/gameengine: BGE API cleanup: introduction of a generic framework to link Python attributes to logic brick class member.

[Benoit Bolsee]

Hi Campbell,

Thanks for these advices, you are the Python master.
I will change as you suggest. 
Regarding value clamping versus error, it seems a better thing to do but
I will keep both options as in some cases clamping doesn't make sense.

Benoit

> Hey Benoit,
> best not use PyFloat_Check() - it almost always isnt what you 
> want. Since that means giving func(1) to a function will 
> raise an error where func(1.0) wont.
> 
> Running PyFloat_AsDouble and then checking for errors is 
> better, since it will run the PyTypes float conversion 
> function if it exists.
> 
> Another thing, Id prefer the API clamp the input rather then 
> raising an error (especially for floats), This forces the 
> python scripter to work out range for some attribute and add 
> the clamping to the python script, worse, the errors could 
> only happen in rare cases (possibly float precision), it 
> would be possible to overlook before releasing a game.
> 
> example of float conversion...
> +                                                       float *var =
> reinterpret_cast<float*>(ptr);
> +                                                       double val =
> PyFloat_AsDouble(item);
> +                                                       ptr 
> += sizeof(float);
> +                                                       if ((val==-1.0
> && PyErr_Occurred()) == 0)
> +                                                       {
> +                                                               if
> (val < attrdef->m_fmin || val > attrdef->m_fmax)
> +                                                               {
> +
>  PyErr_SetString(PyExc_ValueError, "item value out of range");
> +
>  goto UNDO_AND_ERROR;
> +                                                               }
> +                                                               *var =
> (float)val;
> +                                                       }
> +                                                       else
> +                                                       {
> +
> PyErr_SetString(PyExc_TypeError, "expected a float");
> +                                                               goto
> UNDO_AND_ERROR;
> +                                                       }
> +                                                       break;
>