Re: [PyOpenGL-Users] Pyopengl - slow performance using

[Chris B. <Chr...@no...>]

On 1/13/2011 3:17 PM, Ian Mallett wrote:
>      > doing this. Python lists are just linked lists,
>
>     no, they are not -- they are internally regular C arrays.
>
> But they are resizable, which implies they are either linked lists or
> array lists--because I doubt the pointers are copied over to a brand-new
> array just big enough each time a single element is added or removed.

A bit OT, but they handle re-sizing by over allocating when appended to. 
So most of the time you can append to a list without any memory 
allocation or copying, but as it grows, it does need to do that once in 
a while.

linked lists would be great for appending, but horrible for indexing and 
slicing.

But anyway, the original point is correct -- python lists don't store 
the data in a way that is compatible with OpenGL, so a lot of work has 
to be done to create OpenGL objects from lists -- numpy arrays are 
really just wrappers around blocks of memory, so they can efficiently be 
used to move data in and out of OpenGL.

-Chris


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Chr...@no...