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Member Since 01 Sep 2007
Offline Last Active Oct 23 2013 12:59 PM

Topics I've Started

Getting GPU vendor ID

03 September 2013 - 12:36 PM



I'm trying to use this code for getting the vendor ID:

    IDXGIDevice *dxgiDevice;
    V(device->QueryInterface(__uuidof(IDXGIDevice), (void **) &dxgiDevice));

    IDXGIAdapter *dxgiAdapter;

    DXGI_ADAPTER_DESC adapterDesc;


    return adapterDesc.VendorId;
And is working well in most cases, but it's failing on my multi-GPU laptop. It always return the vendor ID of the integrated Intel GPU, even if the NVIDIA one is being currently used.
Someone knows where can be the problem?

DXUT and Windows 8, application hanging on first run

23 August 2013 - 11:27 AM



I'm having troubles with old DXUT-based demos in my new Windows 8 system (I believe that is the cause, still not sure).


It seems the first time they are run, they hang for about one minute or two. Subsequent runs are fine. But if I change the executable file name or move them around the filesystem, then they will hang again the first run (so it seems to be something related with the path; note that I've the antivirus turned off).


This didn't happened to me before, so it seems it's either a problem with Windows 8 and DXUT, or with my system (I've tried it on a system with the same GPU and drivers but with Windows 7, and no problems).


The same happens with any DX SDK sample that is using DXUT. In particular, one of my projects that are having this problem is this one:

Code: https://github.com/iryoku/smaa/zipball/v2.8

Binary: http://iryoku.com/smaa/downloads/SMAA-DX10-v2.8.exe


If someone can also test this in Windows 8, and see if it hangs as well I'd really appreciate it (just to know if it's a Windows 8 problem, or something specific to my machine).




Calculate bitangent in vertex vs pixel shader

23 May 2013 - 08:22 AM

Hey guys,


I'm wondering what is the best approach to create the tangent frame:


- Pass normal, tangent and bitangent, and normalize all three in pixel shader [9 instructions]


- Pass normal, tangent and handedness, and do handedness * cross(normal, tangent) [9 instructions]


From the performance side you save two float slots in the interpolators if you use the second approach.


From the quality side, I wonder. I suppose there is no correct approach, and it all depends on how the normal map was baked: if using a orthogonalization before or after interpolation (per vertex or per pixel). If that is true, I wonder what approach popular tools like Maya, xNormal or Zbrush uses.


I'd love to have some input on the topic!




Shadow mapping with orthogonal projection matrices

29 February 2012 - 12:10 PM

Hey guys,

I'm trying to setup a orthogonal projection matrix for a directional light, but it's giving me problems. I just implemented regular spotlight shadow mapping, then switched the projection matrix to an orthogonal one. But as soon as I did that, shadow mapping stopped working (getting really weird non-informative results, so it's probably not very useful to post images). Looking at the shadow map itself, it looks good, the scene is being rendered there properly.

Any general hints about what I can be doing wrongly?


Render to next backbuffer in the chain, possible?

13 May 2011 - 01:46 PM

Hey guys,

To put this in context: imagine I'm rendering to backbuffer 0. Then, without presenting, I want to copy current backbuffer 0 contents to backbuffer 1. Then, continue rendering in backbuffer 0. Is that possible?

From what I have read here:

It seems to be not possible on MSAAed buffers, if someone can confirm, I would really appreciate that! =)