Questions tagged [gpu]

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3
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1answer
154 views

If I have more than enough memory, can it still be beneficial to use compressed textures?

I'm wondering whether some of you would have tested and seen quite a difference in using a compressed texture even when the OpenGL environment does not need saving any memory (i.e. the card has more ...
13
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1answer
715 views

Why is work-efficiency desired in GPU programming?

I've been reading the following article on how to do a parallel scan in CUDA: https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch39.html In the article, there is an emphasis on making the scan ...
3
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1answer
174 views

What are the most efficient ways to convert between f32 and smaller float formats on the CPU?

Open GL and other graphics APIs support floating point formats smaller than 32 bits (e.g. see https://www.opengl.org/wiki/Small_Float_Formats). While GPUs seem to handle these formats natively, CPUs ...
3
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2answers
6k views

What are the differences between GPU instancing and standard instancing?

I have been reading a lot of debate on a new feature that will be available in the new version of the game engine Unity 5.4 - called GPU instancing. I understand the importance of instancing in ...
3
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0answers
110 views

What techniques are used to build ray intersection acceleration structures on the GPU?

What improvements and alternatives have been developed since HLBVH was introduced in the 2010 paper HLBVH: Hierarcihcal LBVH Construction for Real-Time Ray Tracing of Dynamic Geometry by J. Pantaleoni ...
9
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1answer
489 views

Creating shared vertex normals on GPU

I've mostly succeeded at porting an implementation of Marching Cubes from CPU over to OpenGL compute shaders, but I haven't tackled normals yet and wondering the best way to go about it. My ...
4
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1answer
584 views

Clipping for perspective projection

In the following two graphs, the red lines are borders of the perspective-projection frustum, the blue lines are to be rasterized, the green lines are perspective-projection lines, which are wrong. ...
1
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0answers
95 views

Efficient operations on polyhedra

I currently perform several operations on polyhedra with cgal. These operations include Union of two or more polyhedra Difference of two or more polyhedra Intersection of two or more polyhedra ...
0
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0answers
1k views

YUV (NV12) Chroma subsampling while converting from RGB image

I convert RGB input to YUV 420 semi-planar output using compute shader.Luma plane is straightforward as it maps 1:1 with RGB dimensions. As we know, NV12 packs Cb and Cr into one plane, which means ...
2
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1answer
119 views

Handling GPU resource management

I recently finished the base implementation of a DX12 rederer and I started to think in ways of improving the performance. I think that one problem that my implementation has, is memory fragmentation, ...
5
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2answers
357 views

How did the hard, accurate shadows, work in early 3d (2000 - 2004) games?

I've been hunting around the internet for a while now, and I can't find anything about the specific shadow technique that I'm looking for. I can only recall one game in particular that used it, and I ...
1
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1answer
1k views

How many GPUs can you simultaneously output from using a single PC?

I'm aware that it's technically possible to connect a large number of GPUs to a PC for mining purposes https://www.pcgamer.com/asus-has-a-motherboard-that-supports-up-to-19-gpus/, but how many of ...
-5
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1answer
125 views
5
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1answer
555 views

Why sending data from gpu to cpu is slower than cpu to gpu?

Why sending data from gpu to cpu is slower than cpu to gpu? I heard the relation is similar to network situation, in detail, the upload is slower than download. However, I could not understand the ...
3
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0answers
296 views

Is Nvidia's delta color compression supported in CUDA, or with DirectX UAVs?

Nvidia discusses their lossless delta color compression is on its fourth generation in Pascal, and that it transparently saves bandwidth behind the scenes for rendering workloads. AMD has a similar ...
3
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1answer
145 views

What mechanisms are being used by Directx12 and Vulkan APIs in order to communicate with graphic card drivers internally?

I am trying and learning to develop a low level graphics API. I want to know, how do modern graphics APIs manage to communicate with graphic card drivers (to tackle GPU) so efficiently and in an ...
0
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1answer
179 views

Process of compute shader in OpenGL

I'am curious about compute shader in OpenGL. Let's assume the number of points (vec4) is 900 and the work group size(= the number of work items) is 256 Then, We would have four work groups because ...
5
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1answer
1k views

The mathematics of two dimensional interpolation on a quad

I am trying to wrap my head around how exactly the GPU interpolates texture coords on a quad. I realize to the GPU a quad is two triangles but I find thinking in terms of the whole quad to be easiest. ...
0
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1answer
319 views

Should I prefer an AMD or Nvidia GPU for studying graphics programming, especially with respect to vendor specific debugging tools and ecosystem?

My current laptop has a fairly old Intel integrated GPU which was good enough for following simple tutorials. I am now keen on getting to grips with advanced techniques and newer APIs, and so I am ...
5
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2answers
326 views

In a shader, how to store fragment coordinates in a spatial partitioning from one pass to the next?

I have a post-effect camera-shader in which I want to implement a simple spatial partitioning of the screen between two passes of the fragment shader. The first pass should divide the screen into ...
6
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1answer
3k views

What is the difference in overlay and framebuffer?

I have been trying to understand display and graphics. I feel that it's hard to make a logical image of the terms. I understand this: Frame buffer is a dedicated memory that has the image/video/...
3
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0answers
186 views

What aspects of GPU architecture are computer graphics programmers expected to be intimately familiar with? [closed]

I am an aspiring CG programmer and would like to know what some of the more nuanced aspects of computer architecture are. I have already taken several introductory arch courses where we've covered ...
4
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2answers
427 views

Can a scene graph be stored in the GPU?

I am starting to learn WebGL. Can a scene graph be stored in the GPU? Or is that type of thing more for the main thread (or webworker)? For example, I want to calculate some layout, and apply it as a ...
6
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2answers
15k views

OpenCL doesn't detect GPU

I installed AMD APP SDK and here my problem. The OpenCL samples do not detect the GPU. HelloWorld give me this: ...
2
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1answer
464 views

Can I use QueryPerformanceCounter to measure single draw or compute call performance?

I know I can use QueryPerformanceCounter for measure time for whole single frame. But can I when it comes to OpenGL draw or compute call? I always assumed that, as ...
1
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1answer
260 views

Is it Possible to send data directly to the GPU via a custom hardware interface?

Is it possible to directly bypass the CPU while transferring data to the GPU? could there be hardware which gives the GPU direct memory access to a data stream for real-time GPU processing and ...
5
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1answer
1k views

Do GPU performance improve when rendering at native or half resolution, compared to fixed scaling?

This might be an odd question, but I was wondering if you could improve GPU performance with games, comparatively, when using doubles/halves of the native resolution, instead of an odd ratio of that. ...
4
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1answer
741 views

What is the difference and/or relationship between the OpenGL SDK and the OpenGL GPU driver?

I'm brand new to OpenGL and graphics programming in general, and I'm trying to figure out what software I need to program a GPU. I saw an NVidia OpenGL driver, and I've also seen reference to the ...
14
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1answer
2k views

Why do GPUs still have rasterizers?

Despite advancements modern GPUs still have fixed rasterizers. Highly customizable, with programmable shaders but nevertheless not fully programmable. Why is that? Why can't GPUs be simply massively ...
4
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1answer
371 views

Where is the best place for Tangent-bitangent calculation, in shader or in C/CPP code?

I have two methods of calculating tangent and cotengent (needed for normalMap lighting calculation). The one is doing it from CPP code (with assimp library for example) The second is doing it ...
0
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0answers
83 views

Image cleaning - removing all regular shapes ( circles, squares, text, icons etc. )

I'd like an automatic method to clean images. I've been looking at the GIMP, and its command line (cli) interface, in scheme / lisp. It looks very promising, but I'm a complete novice, so I'd be ...
3
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0answers
83 views

What is a good algorithm, and framework, to calculate centres of gravity or mass (cog)?

I'd like to take an photograph, subdivide it into a tesselation, either of squares, or (ideally), hexagons, and then find the centre of gravity (or, if you prefer, centre of mass) of each cell of the ...
14
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2answers
5k views

How is anisotropic filtering typically implemented in modern GPUs?

Anisotropic filtering "retains the sharpness of a texture normally lost by MIP map texture's attempts to avoid aliasing". The Wikipedia article gives hints about how it can be implemented ("probe the ...
10
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1answer
236 views

Why did AMD's putting an SSD on a GPU board reduce latency so much?

AMD have recently been in the news with an interesting Radeon Pro board with a couple of M2 SSDs on it. As some of the more detailed stories (here or here, for example) note, the benefits may ...
0
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1answer
481 views

Distributed parallel rendering in Gaming or VR rendering

VR rendering needs a lot of GPU power. VR SLI can help that. But, is it possible for us to use distributed parallel rendering technology to improve the performance dramatically? There is an open ...
7
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1answer
200 views

What modern real-time rendering applications still use fragment shader depth writes / late-Z?

It is pretty well known that writing depth in your fragment shader generally disables "early Z" test/write optimizations that modern GPUs rely on for fastness. Nonetheless, APIs still allow it and ...
7
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1answer
148 views

The generations of Intel's integrated graphics

Which among Intel's integrated GPUs depart from their predecessors in a major way? Which are merely incremental improvements? BACKGROUND Intel integrates GPUs with many of the processors they sell. ...
1
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1answer
173 views

How to ensure a fragment shader only runs once

I am trying to programmatically figure out how many "texture2d " calls the gpu can make before the fps drops below 60fps. My current way of doing this is to have a fragment shader with a for loop ...
4
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2answers
2k views

How does a GPU process a task by using multiple ALUs?

I know the philosophy of how a GPU works {many weak men doing a task (GPU) compared to one strong man doing the same task (CPU)}. How does the GPU manage all the ALUs and schedule the necessary ...
4
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1answer
1k views

Compute shaders: one-time-only versus persistent buffers

When using a Compute Shader, is it possible to keep a buffer in the GPU memory during the whole run-time duration of the application, so whenever the original Compute Shader or other Compute Shaders ...
2
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1answer
334 views

Chromakey Conversion

I have a program I wrote that allows chromakey (green screen) using a web cam. I wrote it using DirectShow - I created a custom filter to blend the web cam video with a graphic. It works fine but ...
3
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1answer
215 views

GPU short circuit when multiply by 0?

So I am trying to make my shader efficient by lowing the amount of texture lookups. If I had a line of code with something like. ...
2
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1answer
133 views

Hlsl - registers type

Is there any difference between registers types in hlsl? For example when using register t0 for UAV will it be somehow precache ...
8
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1answer
875 views

How to get started writing a low-level GPU profiler?

I have been studying hardware corporation GPU profilers in recent days (Qualcomm, PowerVR, Intel). I've noticed that these tools seem to give more low-level details than the GPU profilers I have ...
5
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2answers
523 views

Why did tessellation come to be a prominent feature?

Tessellation has been touted as one of the major features in newer graphics APIs like DirecX 11, and it is shown as a standalone stage in a modern graphics pipeline. Compared to the amount of ...
4
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1answer
665 views

Modern Screen Space Ambient Occlusion Techniques

Down the road, I'm planning to implement one or another GPU based ambient occlusion technique. My goal will be to approximate a physically based offline renderer, so I was pretty happy when Wikipedia ...
0
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1answer
643 views

Can Frameless rendering reduce latency? And, can FPGA do 3D rendering instead of GPU?

In virtual reality, the motion-to-photon time is very important. Oculus says it has to be less than 20ms. Maybe 10~15ms is better. Some people try to introduce Frameless rendering technology into VR. ...
1
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1answer
155 views

Can V-Sync avoid tearing? I think it can't. Am I wrong?

1) Update the front buffer will cause screen tearing, every one knows it. 2) But V-Sync, I think it still get the same issue. Why I get this idea? 2.1) When GPU flips to the back buffer, current ...
4
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1answer
310 views

Gpu derivatives. How it's done across 2x2 boundary?

This question bothers me since the first time I got to know about derivatives in pixel shader. Suppose we have a 2d texture: 5 10 20 30 6 11 50 100 If I ...
16
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3answers
5k views

Why do we have graphics frameworks like OpenGL and DirectX, when games could just draw pixels directly?

Games and other graphically intensive applications use frameworks like OpenGL and DirectX. Also they require features like pixel shader and DX12. But why would we need all these frameworks and GPU ...