CODEWITHSUNDEEP
openglnvidia
Mortennobel
Mortennobel

Reputation: 3481

Strict nVidia OpenGL support (OpenGL 3.2)

While AMD is following the OpenGL specification very strict, nVidia often works even when the specification is not followed. One example is that nVidia supports element incides (used in glDrawElements) on the CPU memory, whereas AMD only supports element indices from a element array buffer.

My question is: Is there a way to enforce strict OpenGL behaviour using a nVidia driver? Currently I'm interested in a solution for a Windows/OpenGL 3.2/FreeGlut/GLEW setup.

Edit: If it is not possible to enforce strict behaviour on the driver itself - is there some OpenGL proxy that guarantees strict behaviour (such as GLIntercept)

Upvotes: 4

Views: 732

Answers (2)

fintelia
fintelia

Reputation: 1211

Unfortunately, the only way you can be sure that your OpenGL code will work on your target hardware is to test it. In theory simply writing standard compliant code should work everywhere, but sadly this isn't always the case.

Upvotes: 0

Andon M. Coleman
Andon M. Coleman

Reputation: 43319

No vendor enforces the specification strictly. Be it AMD, nVidia, Intel, PowerVR, ... they all have their idiosyncrasies and you have to learn to live with them, sadly. That is one of the annoying things about having each vendor implement their own GLSL compiler, as opposed to Microsoft implementing the one and only HLSL compiler in D3D.

The ANGLE project tries to mitigate this to a certain extent by providing a single shader validator shared across many of the major web browsers, but it is an uphill battle and this only applies to WebGL for the most part. You will always have implementation differences when every vendor implements the entire API themselves.

Now that Khronos group has seriously taken on the task of establishing a set of conformance tests for desktop OpenGL like they have for WebGL / OpenGL ES, things might start to get a little bit better. But forcing a driver to operate in a strict conformance mode is not really a standard thing - there may be #pragmas and such that hint the compiler to behave more strictly, but these are all vendor specific.

By the way, I realize this question has nothing to do with GLSL per-se, but it was the best example I could give.

Upvotes: 4

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