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Erik Rufelt

Member Since 17 Apr 2002
Offline Last Active Today, 07:52 AM

Posts I've Made

In Topic: Trilinear texture filtering

01 August 2015 - 02:32 PM

Because of texturecoord-swizzling (Morton order) it will hopefully be 2 cache-lines, one per mip-level, not counting anisotropic filtering, + fetching will probably be done in parallel. Cache etc. is certainly optimized to match common usage as well.

For GPUs latency is also very well hidden by multiple pixels being shaded at once (like hyperthreading). Just as a simplified example, say the shader is run 25 times per core, and there are 4 cycles of calculations setting up texture-coords and start a texture-read, followed by 100 cycles latency waiting for the texture data. That would allow the first instance to do its 4 cycles and start a texture-fetch, at which point the scheduler would interrupt that instance and tell a second instance to run and do its 4 cycles followed by its fetch, etc.. until all the 25 instances are done with their first 4 cycles and 100 cycles have passed.

At that point the results from the texture-fetches have started coming in, and the first instance is allowed to resume, now with its texture data readily available in a register, and each instance is run in sequence again doing what they need to do once the texture color is available. So the entire 100 cycle latency is hidden in this case.

Most of the 25 instances will also probably fetch texture-data from shared cache-lines so not all 25 fetches have to result in actual texture reads (which may matter more or less in real scenarios).

There are often a very large amount of registers in total per core, and each of the 25 instances may have for example 10 registers each (if there are 250 per core), which makes switching between them possible without wasting any cycles.

If each shader-instance would only require 5 registers for example when 250 are available, 50 instances could be run instead on one core, which would allow 200 cycles of latency to be completely hidden instead of just 100, for the same 4 cycles of calculations per texture-fetch. Exactly how this works probably differs by GPU.


EDIT: Edited for clarity (I hope :) )

In Topic: Can't run GL_NV_path_rendering extension demos

01 August 2015 - 12:55 PM

Strange. Perhaps the demos are run on Intel graphics by default, if you have auto-switching graphics on your laptop. Try setting the default to the NVidia.


Or print all available extensions to see if everything looks right.

#include <fstream>
#include <string>
#include <algorithm>
#include <gl/gl.h>


wglMakeCurrent(hDC, hGLRC);
	std::ofstream file("extensions.txt", std::ios::trunc);
	file << glGetString(GL_VENDOR) << '\n' << glGetString(GL_VERSION) << "\n\n";
	std::string str(reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS)));
	std::replace(str.begin(), str.end(), ' ', '\n');
	file << str;

And if it's still missing make sure you have the latest drivers (nvidia.com).

In Topic: Windows 10 is hideously ugly, any tips on how to fix?

31 July 2015 - 03:38 PM

I can't install Siri or AirPlay from my Mac either. And I never use either of those features.

But somehow, the lack of an ability to uninstall this is not making me take up arms against Apple.


I've used a Mac regularly since 2012 and updated reasonably often.. never seen anything like that auto-start, except for iTunes when connecting an iPhone. I don't even get update notifications unless I open the App Store app. Not sure if I disabled something back when I got it...


The real problem with Microsoft is that they seem to be trying to leverage all their users that came on board for something completely different and route us into something we never signed up for. It's like they see Apple and Google making money from something new and just want to move all their old supporters into their new brands, that are completely unrelated to what a desktop OS was ever for.

Regular Windows is not even the worst of it... in Microsoft's standard installed Skype I get ads like "I made $4971 in one week ONLINE!" ... and their app store is ridiculously riddled with scams. I can get pretty seriously ad-ware infested on Win7 and see less crap than on the Windows Store.

It's sad really, considering they were in the perfect situation to actually build something good by looking at Apple and Google and avoiding the mistakes, but instead they created something completely amateurish and rushed. I've always liked Microsoft and I even got a Windows Phone a few years ago, and a Surface too, but I certainly won't be getting another one.

In Topic: Windows 10 is hideously ugly, any tips on how to fix?

31 July 2015 - 06:37 AM

very crazy! WTF do you mean luny?



In Topic: Windows 10 is hideously ugly, any tips on how to fix?

31 July 2015 - 05:26 AM

Had enough! Can't read this thread anymore, least i die of "laugh-mania"

I've made up my mind, Going ahead now to CLICK RESTART!!!


Please share your experience when internet access is working again (so.. once you've reverted the update again I guess..)