[Mesa-dev] [PATCH 2/4] st/mesa: implement AllocTextureImageBuffer() driver hook

[Brian Paul]

On 09/29/2011 08:37 PM, Eric Anholt wrote:
> On Thu, 29 Sep 2011 14:24:46 -0600, Brian Paul<brian.e.paul at gmail.com>  wrote:
>> From: Brian Paul<brianp at vmware.com>
>>
>> This hasn't been needed so far since none of the core Mesa code paths
>> that call ctx->Driver.AllocTextureImageBuffer() are used with the
>> state tracker.  That will change in upcoming patches.
>> Note that this function duplicates some code seen in the st_TexImage()
>> function.  That can be cleaned up later.
>
> I'll note that I found it useful within our driver to have
> AllocTextureImageBuffer succeed even if there was data that hadn't been
> Free()d.
>
> If in general Alloc just freed existing memory (or reused it if it was
> well-sized already), we wouldn't need to be so careful about
> FreeTextureImageBuffer()ing in mipmap gen or teximage.  Just a thought.

I'd rather leave it as-is for now.  I'll revisit this in the future, 
no doubt.

BTW, one thing I have in the back of my mind is to someday try to 
remove the Alloc/FreeTextureImageBuffer() hooks and instead use a 
(de)allocator system based on complete mipmaps (see 
GL_EXT_texture_storage).  I have a patch for that extension that I'm 
sitting on until after the current batch of changes is finished.

-Brian