A couple people have tried our game and had issues with the 3d rendering not working. All you see is a purple screen (the clear color for the RT) with all the 2d elements (text & UI) rendering perfectly fine on top of it. We've used the DX11 API in slimdx but, as far as I can tell, haven't used any DX11 specific features. Everything should be DX10.0 compatible. Not having a DX10 card, the only way I've been able to test this is to force the device to use the 10_0 feature level, which runs perfectly fine on my computer.

I don't expect someone to magically know what the specific issue here is, but maybe someone knows a bit more about the quirks of different graphics cards. One of the people who tried the game was running off an i3 370M integrated graphics card. According to wikipedia, it should support DX10.0 with SM4. All of our shaders are SM4. I also had that person run the game with the DX debug layer, but there were no warnings or errors.

Obviously an integrated graphics card isn't the best in the world, but I was under the impression that the majority of features in DX10+ were REQUIRED with only a handful of features being optional. I looked at the MSDN page listing which formats were supported by which versions and whatnot, and it doesn't seem like we're using any unsupported/optional features (though I could easily be wrong). The only iffy one is the BGRA support which MSDN says requires DXGI1.1. I'm not really sure if that is a software requirement or a hardware requirement. Also, the BGRA is used for our font rendering, which is one of the two things that do work, so I doubt that's even the issue.

So, basically what I'm asking is: how can I better track down the source of this issue?

Had something similar with my engine. I was just using DX9 and it was not running on my i7 with nVidia mobility chip but it was all fine on my rather old Radeon HD2600. The problem was not DX itself but the rendertargets I used. I suppose the gui is rendered directly to the backbuffer. The backbuffer is always rgba8 and this is supported by all cards so this could be the reason why they can see the gui but nothing else.

I had the person step through PIX and it turns out the first issue is that filtering on R32 RTs is optional. My question now is... how do we test for support for these optional features? I tried googling it and found absolutely nothing useful

Ah, found it: http://msdn.microsoft.com/en-us/library/windows/desktop/ff476498%28v=vs.85%29.aspx