kicad-developers team mailing list archive

[Maciej Sumiński <maciej.suminski@xxxxxxx>]

On 09/06/2013 09:26 AM, Lorenzo Marcantonio wrote:
> On Fri, Sep 06, 2013 at 08:53:12AM +0200, Maciej Sumiński wrote:
> Other than being a technique listen even in '80 computer graphics books,
> I suppose that's needed also for 1) culling the primitives using the
> rtree and 2) sorting the draw operation by layers to achieve correct
> blending.
>
> IIRC even using the z-buffer and checking blending only works correcly
> when drawing from bottom up, in opengl (and probably everywhere else
> too)
About culling - you are right, only things that are visible in the 
current viewport are drawn. The order of drawing is a matter only for 
the Cairo backend, in OpenGL it works fine without such requirement.

Regards,
Orson