Is Vulkan cutting edge, or bleeding edge?
Sounds like the programming of it wouldn't be as weird as WebGL/OpenGL is, but there are apparently only two finished games running Vulkan.
freeetard edgy
>>55373782
2016 /g/
>>55373782
Get out >>>/b/
>>55373782
kek'd
>>55373782
what the fuck
>>55373782
>>55373890
I never understood how these images worked, even if I open them in an image editor they show the thumbnail image at full scale.
And now that I look at this one I see that it shows colours that don't even exist in the image, what
I tried to make one from a guess of how these work, but it didn't work.
Made this while experimenting though which is pretty cool.
DotA 2 ran better on my machine before Vulkan. Is it because of Vulkan or did they improve the graphics?
>>55373996
Images like >>55373890 work based on gamma. The basic idea is to make an image that will trick the 4chan thumbnail generation into looking different, right?
For this, there are two facts you can exploit:
1. 4chan's thumbnailer ignores gamma tags (google for “png chunk gAMA”), which means that if you encode your PNG with a very high or very low gamma (using the gAMA tag to instruct the browser on how to view it), then you can use the high-end or low-end of the image to encode the actual image, and the middle range to encode the thumbnail. The “image” bits will look like white dots in the thumbnail due to being encoded with such a high gamma. (Hence why you get this weird checkerboard effect)
This is the effect used in >>55373890 specifically. To easily show this, open it in an image viewer that lets you selectively ignore the colorimetry tags (like sxiv with my color management patches). With the tags ignored, you get the top. With the tags applied (e.g. using IM's [color]convert -gamma 0.05[/code]), you get the bottom.
2. 4chan's thumbnail ignores gamma-correction when downscaling, so you can create an image that will appear darker when downscaled by 4chan. You could potentially use this to hide information the other way around (i.e. have a dark image hidden inside a white checkerboard, and 4chan when downscaling will obscure the dark image in favor of the white checkerboard). This is not as flexible or as aesthetically pleasing as the first method, though. But you could still try experimenting with it.
>>55374261
Wouldn't that mean it's also theoretically possible to not even use a grid to disguise one greyscale image as another?
Since you can turn black pixels white and white pixels black.
>>55373996
>I tried to make one from a guess of how these work, but it didn't work.
You were trying to use a completely different effect: interlaced PNG
This doesn't help for the 4chan thumbnail problem at all because once you fully download an interlaced file, it is completely equivalent to the progressive file. (And since most people have stupid high bandwidth these days, transient effects are lost on them)
To understand why you see colors that seemingly don't exist, it helps to understand that these colors *do* in fact exist in the image. Look at this close-up zoom of it.
When loading an interlaced PNG, you start by loading every Nth pixel first. So for the first pass, you only get all of the green pixels (or whatever). For the second pass, you add a second row of other-colored pixels. (Resulting in an image that always alternates between two different colors, which overall looks like a blend of the two)
And so on. Once you've loaded the full-sized version of the image, you get the entire pattern visible here, and so the overall image looks like some sort of reddish pink.
>>55374350
Of course I know how that works.
You'd have to be a special kind of stupid to precisely exploit those workings despite having no idea what you're doing and following no instructions.
>>55374320
>Wouldn't that mean it's also theoretically possible to not even use a grid to disguise one greyscale image as another?
Yes, sort of. Using a grid has the advantage that it lets you hide any image regardless of what it is. But if you specifically constructed a pattern that could exploit this effect to hide something, you could do away with the grid.
Take this image for example. (Untested, consider this my world premiere)
>>55374320
>Since you can turn black pixels white and white pixels black.
You can't actually do this. The gamma trick just allows you to move all of the colors in one direction - it's an order-preserving map (so you can't have something that is darker in the thumbnail suddenly be brighter in the full image. You can just have something be even darker, or even brighter)
It's also worth noting that the gamma transformation doesn't affect black and white at all. So to generate >>55374420, I made sure to use (250,250,250) for my white, and not (255,255,255) since the latter would be completely unaffected.
To understand why, it helps looking at at what an extreme gamma curve actually looks like: (pic related, here with a relatively mild gamma of 5. In >>55374420, I used a gamma of 200. In >>55374261, the gamma is approximately 30)
In exploiting the image trick, all you're doing is taking an image that's encoded like the red line and making 4chan interpret it like the blue line instead. So what was the middle range (0.4 - 0.6) in the red image, gets treated by 4chan like the high range (0.8 - 0.9) instead.
If you take this to an extreme, you can have an image encoded in the white portions of the image (0.8 - 1.0 on the x axis) get treated as a full range image when decoded correctly (red curve), but which 4chan squishes to pure white pixels (blue curve). Simultaneously, you can have an image encoded in the black region (0.0 - 0.2) in the source image get treated by 4chan as a faux image (0.0 - 0.8) instead.
Combine the two and you get an image that not only looks pure white (or pure black) in the 4chan thumbnail, but in fact conceals a different image.
Also note that when generating these, you want to further gamma-correct to account for the presence of the white (or black) overlaid checkerboard, which this guy's shit program obviously didn't (otherwise they would be the same brightness in >>55374261)
>>55374420
Neat.
Probably can't perfectly disguise one image as another like this though, I just remembered that gamma is a variable and not something that can have its own map.
>>55374519
>In exploiting the image trick, all you're doing is taking an image that's encoded like the red line and making 4chan interpret it like the blue line instead.
To be more precise, it's like taking an image encoded with the blue line and making the browser treat it like the red line instead. 4chan just ignores this color management tag.
Note that some browsers and viewers will also ignore it, so your results can be highly inconsistent among users. Firefox and Safari acknowledge the tag. No idea about chrome.
>>55374519
Also note that you probably want to be using 16-bit PNG for this to prevent precision loss, if you're doing it optimally.
>>55373675
There are currently very few games using Vulkan, but there are also very few games using DX12.
Vulkan is by far better than DX12. It has all the advantages and is cross-platform. I cannot imagine why anyone would use DX12.
Whether or not Vulkan will catch on is another matter. The superior technology often loses.
>>55374567
>I cannot imagine why anyone would use DX12.
Microsoft money, duh
>>55374583
That's what I meant. I can't see why any engineer would choose DX12, but suits make all the decisions and MS can probably convince them.
>>55374567
I didn't think that Vulkan actually replaced DX12.
Is the case that DX12 is by now an inefficient palimpsest and anything using Vulkan will be better?
Also, is it impossible for a game using Vulkan to be lightweight what with all the Vulkan stuff that has to be included?
>>55374632
I'm not sure if you really understand all that much about GPU drivers and graphics APIs.
>>55374632
DX12 isn't really worse. It's just not any better.
Given that they both do pretty much the same things, the fact that Vulkan is cross-platform and more open means it's the better choice.
