Scale up non-multiple-of-4 dxt textures

Scale up non-multiple-of-4 dxt textures

D3D doesn't support DXT textures that aren't a multiple of 4 in size, so multiply the sizes by 2 or 4 so they work. Then ensure sampler parameters are set up correctly so they don't sample the unuploaded miplevels.


BUG=https://code.google.com/p/angleproject/issues/detail?id=237
TEST=

Committed: https://code.google.com/p/angleproject/source/detail?r=1222

[dgkoch, 2012-06-07 03:53:55]

Subject to my elsewhere noted concerns, this seems ok.  However it is based on
old source and it needs to be updated to apply to Head.

[John Bauman, 2012-06-07 07:33:58]

On 2012/06/07 03:53:55, dgkoch wrote:
> Subject to my elsewhere noted concerns, this seems ok.  However it is based on
> old source and it needs to be updated to apply to Head.

Oops, I didn't realize the version in Chromium was so out of date. Updated.

[John Bauman, 2012-07-11 00:13:18]

Ok, here's a new version that's restricted to textures that have one dimension
less than 4. I'm not sure if that's exactly how we would want to do the
restriction, or if we want to do something subtly different.

[dgkoch, 2012-07-12 02:53:25]

LGTM.

We'll also need to validate the sizes in libGLESv2, but I can handle that when I
update the extension (unless you beat me to it!).