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SIIYA

Pure device question

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Hi all,

DirectX documentation says that GetRenderState() and some other functions don't work when device is created as pure. It also says that pure device doesn't filter redundant states. But it seems that all GetRendersState functions work correctly when I create device as pure. I don't get any errors in debbug output when using these functions on pure device. Also I get warnings of dx ignoring setting redundant states. Why is this so? I use ATI Radeon HD 5770.

Thanks!

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It is fairly common for a set of illegal API calls to actually be supported by the D3D9 drivers - even if you aren't technically supposed to be able to do some things, it is often allowed by the driver anyway.  You could try creating a reference device and see if you get the same behavior.  The ref device is typically the 'law' when it comes to ensuring that your program is running correctly.

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It works on reference device too. So what does this mean? Is it driver specific and I can't count on it to work on other drivers? I don't use these illegal functions anyway, I just wanted to know. Edited by SIIYA

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The docs say it's not supposed to work, so I wouldn't rely on it (make a non-pure device if you need this functionality).

 

Out of curiosity, does it work only because you've set D3D9 to debug mode in the Direct3D control panel? Or does it work even when you set it back to regular mode?

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It works in regular mode also...I was curious about why I'm getting D3D9 warnings in debbug mode about ignoring setting redundant states when using pure device. And then I saw that these illigal functions also worked so I thought maybe pure device functionality was obsolete on new drivers. But like I said, i don't really use any of these functions...just wanted to see difference in performance between pure and non-pure device and as far as I can see there isn't one (in my case instancing helps a lot). Edited by SIIYA

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It's possible something else has hooked the device creation and not passed through the pure flag. Obvious candidates are programs like FRAPS, and Steam which draw on top of the rendered image.

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It works in regular mode also...I was curious about why I'm getting D3D9 warnings in debbug mode about ignoring setting redundant states when using pure device. And then I saw that these illigal functions also worked so I thought maybe pure device functionality was obsolete on new drivers. But like I said, i don't really use any of these functions...just wanted to see difference in performance between pure and non-pure device and as far as I can see there isn't one (in my case instancing helps a lot).

Those warnings about redundant states can be related to the debug runtimes, maybe with debug runtimes redundant states are checked even for pure device. And as you don't get any debug output in the release version, you won't be able to see whether it does the checking with release pure device or not :)

 

And the second part - are the GetXxxx just working in the meaning that they are not giving you warnings or errors, or are they really actually returning valid data? Did you verify this thoroughly? What I mean is that maybe the functions are returning wrong values (random / cached / default / whatever).

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<blockquote class="ipsBlockquote" data-author="mhagain" data-cid="5022477"><p>&nbsp;<br />Is this on a Vista/7/8 machine?&nbsp; On these a pure device <em>may</em> be disabled - see: <a data-cke-saved-href="http://msdn.microsoft.com/en-us/library/windows/hardware/ff539634(v=vs.85).aspx" href="http://msdn.microsoft.com/en-us/library/windows/hardware/ff539634(v=vs.85).aspx">http://msdn.microsoft.com/en-us/library/windows/hardware/ff539634(v=vs.85).aspx</a><br /><br /></p><blockquote class="ipsBlockquote"><p>When the fixed-function vertex or pixel shader converter is used, the pure device is disabled. When an application requests the pure device, the Direct3D runtime creates a HAL device.</p></blockquote>&nbsp;<br /><p><br /></p></blockquote><br /><br />This is it. Thank you very much for this link, I didn't know this.<br /><br />And thank you all guys<br />

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Is this on a Vista/7/8 machine? On these a pure device may be disabled - see: <a data-cke-saved-href="" href="" "="">http://msdn.microsof...4(v=vs.85).aspx

Quote
When the fixed-function vertex or pixel shader converter is used, the pure device is disabled. When an application requests the pure device, the Direct3D runtime creates a HAL device.
 
This is it. Thank you very much for this link, I didn't know this.

And thank you all guys

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