Texture Size Query not working

[GoogleCodeExporter]

texturesize() doesn't seem to be working correctly, all related dEQP test are 
failing:
dEQP-GLES3.functional.shaders.texture_functions.texturesize.*

Looks like there are multiple issues, some tests are failing because of 
unexpected texture size and some are failing to compile.

Original issue reported on code.google.com by apat...@nvidia.com on 27 Feb 2015 at 12:28

[GoogleCodeExporter]

There are two issues because of which all the texturesize() tests are failing:
1. Wrong variant of GetDimension function is being used in some cases and 
because of which following tests are failing (this is the reason 1 of 2 errors):
dEQP-GLES3.functional.shaders.texture_functions.texturesize.usamplercube_*
dEQP-GLES3.functional.shaders.texture_functions.texturesize.isamplercube_*
I will push a patch fixing this soon.

2. All the tests are failing because of texturesize() returning unexpected 
value when LOD base is non zero. texturesize() gets the size using DirectX's 
GetDiamensions which is capable of returning texture dimensions for different 
mip levels but it doesn't look to be considering non-zero LOD base.

Original comment by apat...@nvidia.com on 2 Mar 2015 at 1:35

[GoogleCodeExporter]

Just did a quick search on GL_TEXTURE_BASE_LEVEL in angle issues and found a 
old bug related to #2 in last comment:
https://code.google.com/p/angleproject/issues/detail?id=596

Original comment by apat...@nvidia.com on 2 Mar 2015 at 1:43