Test failure on Nvidia Quadro card

This is a bit of a corner case but worth documenting. The test Scene/Primitive shader validation fails with Expected function to throw DeveloperError. only when running with the Quadro M1200/PCIe/SSE2 card. It works fine whens witching to the embedded Intel renderer.

The expected error is:

Appearance/Geometry mismatch.  The appearance requires vertex shader attribute input 
'tangent', which was not computed as part of the Geometry.  
Use the appearance's vertexFormat property when constructing the geometry

The difference comes right here:

https://github.com/AnalyticalGraphicsInc/cesium/blob/64cc4dca3db7f460b420cdaaef6d10947ea2ca8b/Source/Renderer/ShaderProgram.js#L450-L454

It correctly passes a shader program with a vertex shader that has a tangent attribute, and on Intel it correctly returns 9 attributes, but on Nvidia it returns only 6 (potentially stripping away unused attributes?) which then causes the test to fail.

[likangning93]

Also this was Linux

[IanLilleyT]

Basically I think that function is the problem code. The vertex format mismatch could be detected much sooner (I think!) and then you don’t have to go so far as to compile the shader and rely on the vendor’s shader compiler to preserve unused attributes in order to detect a mismatch.