Re: [Mesa3d-dev] Hacking GLU for more flexibility

[Brian P. <br...@vm...>]

arthur m wrote:
> Hello guys,
>  
> I have been playing a bit with GLU library in context of 2d graphics. I
> found that GLU tessellator
> can be improved in regards of the interface with very little code added.
> As of standard gluTessVertex
> accepts only arrays of double[3] values, which is a bit annoying when
> one has arrays of type float[2]
> or int[2]. It is quite easy to add more flexible interface in style of:
>  
> 
> GLAPI void GLAPIENTRY gluTessVertex2i (GLUtesselator* tess, GLint
> *location, GLvoid* data);
> 
> GLAPI void GLAPIENTRY gluTessVertex2f (GLUtesselator* tess, GLfloat
> *location, GLvoid* data);
> 
> GLAPI void GLAPIENTRY gluTessVertex2d (GLUtesselator* tess, GLdouble
> *location,GLvoid* data);
> 
>  
> 
> GLAPI void GLAPIENTRY gluTessVertex3i (GLUtesselator* tess, GLint
> *location, GLvoid* data);
> 
> GLAPI void GLAPIENTRY gluTessVertex3f (GLUtesselator* tess, GLfloat
> *location,GLvoid* data);
> 
> GLAPI void GLAPIENTRY gluTessVertex3d (GLUtesselator* tess, GLdouble
> *location,GLvoid* data);
> 
>  
> I also found by looking at the tessellation algorithm and docs, that one
> can make it more effectively when working
> in 2d. Originally the algorithm will project all vertices of a polygon
> into same plane. When working in 2d we can skipp
> this projection, since we anyway have all vertices in same plane, say Z
> = 0. Furthermore it is quite easy to hack GLU
> to incorporate this by simply adding new boolean property (say
> GLU_TESS_DONT_PROJECT) which can be set by programmer and checked
> by algorithm before projection. 
>  
> Those two addons does not break any previous functionality of GLU so one
> can use new library as a drop-in repl.
>  
> I have used mesa code for my own GLU dll and if this can be of interest
> to more people than me,
> I can post patches to this list or maybe entire project code somewhere
> on the net.

It sounds like these two features are orthogonal.  I'd suggest you write up a couple of GLU extensions using the usual OpenGL extension template.  I think there's a couple GLU extensions in the OpenGL extension registry which you could use as examples.

If you could then post the specs and your patches for review, that'd be great.

-Brian