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12:14 AM
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Q: When creating a JPEG, how can I minimize the occurence of artifacts?

ArmfootThere are 2 main factors that seem to lead to digital artifacts when creating JPEG images: Aliasing and Compression. Example: Converting a PNG with characters on it to a JPEG or placing vector images over a photograph, will result in pixelization on their edges. The antialiasing generally cr...

 
 
1 hour later…
1:21 AM
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Q: Why do Vertex Buffer Objects improve performance?

Ethan BierleinFrom my basic understanding, a Vertex Buffer Object works something like this (psuedo code): Normally, if one wanted to say, draw a square, one could issue line drawing commands. line (0, 0) -> (1, 0) line (1, 0) -> (1, 1) line (1, 1) -> (0, 1) line (0, 1) -> (0, 0) Using a Vertex Buff...

 
1:53 AM
Man all those questions take a ton of space!
 
2:09 AM
hi
I'm trying to see if there are any users who might want to join the private beta
 
 
1 hour later…
3:25 AM
0
Q: What is the cost of changing state?

Julien GuertaultProgrammers are supposed to have a fairly good idea of the cost of certain operations: for example the cost of an instruction on CPU, the cost of a L1, L2, or L3 cache miss, the cost of a LHS. When it comes to graphics, I realize I have little to no idea what they are. I have in mind that if we ...

 
3:59 AM
2
Q: Data structures for tile-based (deferred) rendering

warrenmTiled rendering is used in modern mobile GPU architectures to increase the coherency of memory access by subdividing image space into a regular grid of small (e.g., 32x32 pixel) tiles. Information is scarce on the types of data structures used to track the primitives that are associated with each...

 
@NoviceInDisguise Martin did offer to set the feeds up in "overlay" mode, but, people who spoke up thought it was unsightly.
 
0
Q: How is Gaussian Blur Implemented?

Alan WolfeI've read that blur is done in real time graphics by doing it on one axis and then the other. I've done a bit of convolution in 1d in the past but am not super comfortable with it, nor know what to convolve in this case exactly. Can anyone explain in plain terms how a 2d Gaussian Blur of an ima...

 
 
2 hours later…
5:48 AM
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Q: What is "Scanline Racing"

MokoshaI've heard a lot of people working on VR talk about scanline racing and that it's supposed to help improve latency for motion-to-photon. However, it isn't clear to me how this can be done with OpenGL. Could someone explain how scanline racing works, and how it can be implemented on modern GPUs.

 
6:26 AM
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Q: Using a DirectX renderer into a game

Uri PopovFor my bachelor thesis I have written my own DirectX11 renderer . It can render water , terrain , dynamic lights and so on. Right now it runs as its own application. My question is what is a good design idea to implement the c++ DirectX code I have written into a actual game. Is building the rend...

 
 
2 hours later…
8:01 AM
posted on August 05, 2015 by Michael IV

GPGPU is not always about graphics.But CUDA and OpenCL are also used for Graphics interop with graphics libs like OpenGL and D3D.So is it ok asking CUDA/OpenCL related questions here?

 
Huh. I was expecting an IRC channel
"We're trying to build a system better and easier to use than IRC, that is native to modern web browsers." Interesting
I didn't know browsers could do something like this!
 
8:30 AM
2
Q: Asset creation for signed distance field rendering?

MokoshaIn traditional computer graphics, most 3D models are rendered by rasterizing or ray tracing against a subdivided mesh of primitives, usually triangles or quads. More recently, some real-time techniques have been predicated on ray-tracing against signed distance fields (SDFs). Intuitively, these d...

2
Q: How can I generate procedural noise on a sphere?

Martin BüttnerI would like to generate procedural noise on the surface of a sphere (e.g. to procedurally generate planets or marble-textured balls). Of course, I could just take a standard noise algorithm and map it onto the sphere, but this has all the issues of projecting a plane onto a sphere, like distorti...

 
 
1 hour later…
9:41 AM
1
Q: When is a compute shader more efficient than a pixel shader for image filtering?

Nathan ReedImage filtering operations such as blurs, SSAO, bloom and so forth are usually done using pixel shaders and "gather" operations, where each pixel shader invocation issues a number of texture fetches to access the neighboring pixel values, and computes a single pixel's worth of the result. This a...

 
 
1 hour later…
11:06 AM
0
Q: When to disable perspective correct interpolation ( noperspective )

gemseIn GLSL, perspective correct interpolation of vertex attributes is the default setting - one can disable it for specific vertex attributes by using the noperspective qualifier. Other than in post-processing shaders, I've never seen the perspective correct interpolation disabled - are there any ot...

 
11:40 AM
0
Q: How can I concentrate points in areas of higher curvature?

trichoplaxHow can I distribute points unevenly over an implicit surface, to concentrate points more densely in areas of higher curvature? I've considered adding points randomly and rejecting points not required based on the curvature, but I'd like to know if there is a better approach giving a more even d...

0
Q: What are the side effects of biasing brightness in continuous spectrum raytracing?

trichoplaxI want to model rays with a continuous range of frequencies so that I can get raytraced images with colour separation on refraction. I can model a light source with a specified frequency distribution by using the distribution to affect the probability of a random ray lying in a given frequency ra...

 
12:35 PM
I'm much more confident about this private beta going well now. The comments on my question have already left me out of my depth :)
 
 
1 hour later…
2:04 PM
Yeah . . . hopefully I can glean some of the knowledge
 
2:57 PM
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Q: What is fwidth and how does it work?

ApoorvaJThe OpenGL documentation states that fwidth returns the sum of the absolute value of derivatives in x and y. What does this mean in less mathematical terms, and is there a way to visualize it? Based on my understanding of the function, fwidth(p) has access to the value of p in neighboring pixel...

 
3:47 PM
1
Q: What is the optimal radius of gaussian distribution for determining pixel colour?

trichoplaxUsing a gaussian distribution of points on an image plane to calculate a pixel value, what radius will give the most information in the final image? Too large a radius gives a blurred image, and too small a radius neglects information that is smaller than a pixel so that it does not contribute to...

 
4:13 PM
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Q: How is Depth of Field Implemented?

Alan WolfeI know that depth of field involves blurring. There's some great information about how to do a Gaussian blur in the question How is Gaussian Blur Implemented? But, other than that, how is depth of field implemented? What are the rules about how you blur each pixel, and how do you handle the ca...

 
4:38 PM
0
Q: Could a hexgaonal pixel array store an image more efficiently?

trichoplaxMost computer monitors and televisions have a rectangular array of pixels arranged on a square (or nearly square) lattice. Would a hexagonal lattice give better image quality for the same number of pixels? In other words, would the same amount of memory allow storage of more detail? Even if th...

0
Q: Is gamma still important to take into account?

trichoplaxDo different monitors (including mobile screens) still use significantly different gamma functions when displaying colour images? Is there a standardised way to represent colour that can then be translated according to the gamma of the monitor, or are they all sufficiently similar to preclude the...

 
4:55 PM
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Q: Is depth of field incongruous in a 3d still image?

trichoplaxIf rendering an image in 2d, adding depth of field effects (blurring objects further from the focal distance) adds realism and draws the eye to the object of the image. With a 3d image, looking at an object in the image at a given depth will makes objects at all other depths defocused (not blurre...

 
 
3 hours later…
7:43 PM
posted on August 05, 2015 by trichoplax

There are comments on this question suggesting that gamma is off topic due to it being on topic elsewhere. However, I think we need to decide what is on topic here, independently of what is on topic elsewhere. Should questions about gamma be acceptable here?

 
@MartinBüttner are you substituting until we get a room owner? Or can any of us make changes to the feeds? The meta feed seems to have a lot of superfluous text before the question title...
I can't see an option to edit so I'm guessing you used your mod powers?
 
Is this community specifically focused on technical discussion or are general questions like this one also appropriate too? computergraphics.stackexchange.com/questions/3/…
I noticed that the top answer was very technical but it didn't really speak at the level the question was asked.
 
8:03 PM
@ShaneC I believe the vague answer is that questions here should be for graphics programmers or researchers (programming questions rather than art questions) but this private beta is all about defining the scope more explicitly, so if there are any questions that seem borderline go ahead and raise them for discussion on meta
 
Admittedly, the answer to that question is quite complex. My assumption, based on the language in the question, was that the poster was not a graphics programmer. Since this site isn't called "Graphics Programming" it seems that general, and less technical, questions might be okay. Is there a wiki page or some live document that serves as the current thinking about the focus of this site?
 
@ShaneC All of Meta serves as the thinking on this. If we do a good job of defining the scope there with discussion and voting, then the site will be allowed to progress to public beta in a week or two.
This site is literally 1 day old, so the scope will take a week or two to be defined by the current community.
Although programming isn't in the name, the example questions during the planning of this site were mostly programming or algorithm related, so I expect that the scope will lean in that direction. Vote on meta questions and answers if you want a say in it... :)
 
Thanks for the guidance!
 
I hope I'm explaining this reasonably well - there will be others around at some point who can probably put it better...
@ShaneC No problem :)
Thanks for being part of the site...
 
9:03 PM
posted on August 05, 2015 by trichoplax

I'm fairly sure 2D topics are welcome here too, but having seen a comment suggesting this site is specifically oriented towards 3d I'd like to see answers and plenty of voting here so the community consensus can be clear.

 
9:20 PM
@trichoplax I guess I do. I can't really do much about the feeds though except avoid oneboxing them or changing them to overlay feeds.
 
Can we name the feeds something different? Something clever, like teapot, or something
 
@MartinBüttner I like them oneboxed. Is the way posts show on PPCG not a straightforward setting? Does that take a bot?
The main posts here seem to show up succinctly, but the meta posts have metadata after the title and intro before the title
(It isn't important - if there isn't a quick fix it's hardly high priority :) )
 
Qix
@ChrisJester-Young ^ input?
 
@trichoplax There is no setting for that... I think it depends on what the bot gets from the feed. I feel like there's something fishy with private beta meta sites, because I can't access CG meta from the mobile app (but I can access main). This could have the same reason as the difference between how the feeds display.
 
@MartinBüttner Ah. That sounds like a problem during what should be a meta-heavy week...
I hope we don't have too many people restricted to mostly mobile access...
 
9:25 PM
I should check MSE about that
 
posted on August 05, 2015 by Drazick

There's a proposal about Image Processing which is very related. I think it would be great if we could back it up which would divide the number of questions and make a clear line between two communities. What do you think? Anyone who could assist people to spread it up, it would be great.

 
huh, this seems to be specific to meta.CG ... I can access meta.OS
 
OS is in public beta now, right?
 
@trichoplax I meant Open Science, which launched together with CG
 
@MartinBüttner Oops :) Then yes, now that I understand, it is indeed confusing...
 
9:53 PM
posted on August 05, 2015 by Martin Büttner

I seem to be unable to access any content on this meta site from the Android app. I thought this might be because we're in private beta, but I have no trouble accessing the metas of the other current private betas. If I open the site itself, the question list shows empty, and if I try a direct link to any post, I get Loading the question failed. Especially dur

 
10:12 PM
finally found some time to write an extensive argument for youtube embeds:
 
A minute ago I had no opinion. Now, +1
 

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