Questions tagged [performance]
The performance tag has no usage guidance.
51
questions
1
vote
0answers
28 views
Optimizing texture fetches with higher mip levels
Let's say I have some shader program in DirectX or OpenGL rendering a full screen quad. And in a pixel/fragment shader I sample some huge textures at random texture coordinates. That is one same ...
1
vote
1answer
60 views
Tessellation Speed in terms of interpolated points per second
For a research project, I have written a Tessellation Shader to interpolate solution points of a 3-Dimensional mathematical equation. Therefore I don't use any techniques for displacement, I merely ...
0
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0answers
29 views
Software Rendering Display Latency
I've been doing some reading as to how to reduce input delay on modern computing devices. A lot of my understanding from this comes from the VR research paper by Carmack explaining the numerous ...
0
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0answers
32 views
Where to store a very small set of shading constants in D3D12?
My rendering engine heavily uses implicit rendering techniques, so I have relatively little constant data to upload every frame (just 240 bytes of rendering settings; surface parameters are passed ...
3
votes
1answer
114 views
Compute shader textures compared 2D float4 arrays
I am wondering is there a difference in performance between using floating point textures as my 2D float4 array vs just passing in 2D float4 arrays?
2D float arrays eliminate the need to do texture ...
4
votes
2answers
138 views
Should you measure mesh complexity in triangles or vertices?
I have seen people using either vertices or triangles as a quick heuristic to estimate mesh memory usage and mesh rendering time.
I always thought vertices were better, because the number of vertices ...
-1
votes
1answer
76 views
Are MMORPGs, specifically WoW, limited by their latency in terms of FPS?
It sounds crazy, but I've been doing a lot of reading on exactly why WoW performs very poorly, even on a 1080Ti / 8700k OC'd and overall, a high-end machine.
Overclocking the CPU yielded great ...
6
votes
1answer
826 views
Why are tessellation shaders disliked?
I often hear that tessellation shaders aren't great for performance reasons. Something along the lines that if you try to use a tessellation shader, you'll find that the data you get out isn't ...
0
votes
0answers
206 views
Is a smaller local-size/threadgroup-size better for compute shader performance?
A compute shader defines the number of threads it requires to be executed.
This number can be called "local size" or "threadgroup size" according to the API, and be factored into 3 separate dimensions ...
2
votes
0answers
180 views
Using GPU instead of CPU in Scala
I wrote a program that displays points expressed in 3D in a 2D canvas, using perspective projection. The aim is to display a cube. Each face of the cube is drawn by linearly interpolating the points ...
4
votes
1answer
896 views
How does MSAA performance scale?
I'm finding myself increasingly interested in rendering techniques utilizing multisampling for anti-aliasing (obviously), out-of-order transparency, volumes etc.
Searching the web for performance ...
9
votes
2answers
399 views
The most performant way to organize vertex data on modern GPUs
Say I have a model made up of vertices, each with position, normal, tangent, and ...
4
votes
3answers
160 views
Dealing with wasted space when using SIMD on CPU for vector maths
I've been getting interested in SIMD programming on CPU using SSE recently, but I'm a complete noob on the subject. I found this article describing how to make an efficient float3 type using the ...
1
vote
3answers
113 views
How can an OpenGL visualization run for weeks?
For an art project, I need to make an OpenGL visualization run for at least 4 weeks. Is this possible? I can pretty much choose the rest of the hardware and software.
5
votes
0answers
276 views
In Metal, what performance advantages are there, if any, to using vertex descriptors and the [[stage_in]] qualifier?
Metal seems to provide two very different ways to access vertex data in your vertex shader. You can:
Create an MTLVertexDescriptor object, which describes vertex ...
4
votes
1answer
238 views
Tasks of a professional graphics programmer?
Currently I'm 16 and in high school and I love graphics programming and I'm seriously considering it as a career path. I was wondering what a day as a graphics programmer looks like for offline ...
1
vote
0answers
127 views
Can I voxelize 3D set of points without reconstructing surface first?
I have huge point cloud data I want to render them at interactive frame frate. Process I know is
1.point cloud data
2.triangulate it using delnauy or other triangulation algo
3.surface ...
5
votes
1answer
431 views
Performance impact during texture layer loading
Recently I have been having a rather confusing performance drop with loading in layers of a 2D texture array, but only in one case from what I can tell, leaving me to speculate on why it is happening ...
3
votes
1answer
367 views
GPU not reaching 100% usage when frame rate is dropping
I am making an iOS game using Unity. I am testing some shaders that I have made for the game, and in some cases the device will run at under 30 FPS but not have 100% device utilization.
Sometimes a ...
1
vote
2answers
450 views
Challenges of Offline Rendering
What are some of the challenges of Offline Rendering? I know one problem that is faced is performance and rendering times, are there any more issues?
Path Traced photos seem to have reached the ...
2
votes
1answer
349 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 ...
4
votes
1answer
574 views
Register pressure in Compute Shader
I'm in the process of writing a Ray Tracer using DirectCompute / HLSL. First, eye rays are generated (one per pixel). Then, rays are traced, shaded and reflected in a loop. Also, shadow rays for each ...
6
votes
2answers
381 views
How can I improve the performance of my custom Global Illumination approach?
I want to experiment with some new stuff about modern rendering techniques and in that way I'm trying to implement a custom GI (somewhere between pathtracing and instant radiosity).
My scene is a bit ...
6
votes
1answer
332 views
Optimizing performance on hardware
I'm working on a webgl audio visualizer that uses particles, and I want to optimize rendering based on the user's hardware. I'd like to offer a "low quality" and "high quality" setting so that it ...
4
votes
1answer
229 views
How to get unique nearest neighbour?
There's already something called K-nearest neighbour algorithm with gives nearest neighbour to points. But what I want is unique neighbour which is not shared by any other neighbour.
I've implemented ...
1
vote
0answers
463 views
Billboards or impostors when objects' instances are re-scaled [closed]
Billboarding/impostors mean, roughly, representing complex 3D objects in 2D or with simple quadrilaterals, for the sake of LOD systems.
Consider the case of rendering a very numerous asteroid field ...
10
votes
1answer
200 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 ...
7
votes
1answer
464 views
Estimating the area of a triangle-circle intersection
I am trying to implement Ray Tracing with Cones (Amanatides 1984). Instead of rays, cones are shot into the scene and intersected with geometry. Since multiple triangles can occupy the cone's aperture,...
4
votes
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 ...
8
votes
1answer
811 views
How does everyone count “Rays per Second”?
Recently I'm developing a Monte-Carlo path tracer. To measure my tracer's performance, I decided to implement a simple mechanism to count how many rays can it trace in a second. Then here comes the ...
3
votes
1answer
343 views
Data structure and algorithm for clipping triangulation with leaf nodes of an octree
I have an application in which I am using an octree to store a volume mesh of axis-aligned bounding boxes (AABBs).
Given a water-tight manifold triangle mesh, I need to:
find if an AABB is ...
7
votes
2answers
224 views
What methods/technologies to reduce required performance for virtual reality are there?
I'm interested in virtual reality, but according to some sources, less than 1% of computers in use today have the necessary performance to run modern VR games, granted many of them are not intended ...
15
votes
3answers
4k 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 ...
11
votes
1answer
3k views
Loop performance in a shader
I am wondering what's the best way to integrate a dynamic loop function in a shader?
First, it seems that dynamic arrays are not possible. So, is it better to create a maximum size array and only ...
8
votes
1answer
306 views
Do modern GPUs contain barrel shifters?
I'm aware that most modern GPUs, although designed for floating point, are more or less equivalent in integer performance these days, with a few caveats like the lack of a fused multiply add. I'm not ...
2
votes
0answers
238 views
Projecting light shapes
I am wondering how professional light visualizer software (like Capture Argo - WYSIWYG - Realizzer - LightConverse) project the lights on the objects (like stage, floor, people), even projecting the ...
16
votes
3answers
5k views
Difference between rendering in OpenGL and 3D animation software
With OpenGL and such I can render some pretty amazing looking things in "real time" 60 FPS. However, if I try to make a video of that same scene in let's say Maya, or 3ds Max it would take MUCH MUCH ...
10
votes
2answers
372 views
With modern fillrates and deferred rendering, is occlussion culling still relevant?
For example, while it's the current top-of-the-line GPU, the GTX 980 has a staggering 72.1 gigapixels/second fillrate, which with back-to-front rendering and/or Z buffer checks, seems almost ...
2
votes
1answer
125 views
Is there some book about how to design a 3D math lib? [closed]
3D math covers vector algebra and matrix algebra, which are easily calculated on paper, but not so easy when coding them effectively. I only leant some basic algorithms on matrix in my Data Structure ...
8
votes
2answers
164 views
When is it better to upload partial model matrices to the vertex shader?
As of now, when rendering my scene and while iterating through the scene graph, for each node its model matrix is calculated from the parent's model matrix and the scene node's pose. This is quite ...
8
votes
1answer
528 views
Shader uniform performance
I'd like to know if there's any performance impact based on how I struct my shader uniforms. For instance, is passing 4 floats worse than passing a single vec4?
14
votes
1answer
705 views
Is a constant condition more costly than switching shaders?
In general, branching in shaders is not a good idea. But now I have a shader with a condition that is constant with respect to the entire draw call. So the branch that is executed is always the same ...
5
votes
2answers
2k views
How to reduce the number of draw calls when rendering one object multiple times?
Especially when rendering particle effects, the same object needs to be rendered several times with slightly modified properties. But these changes are often limited to properties like pose or ...
11
votes
1answer
6k views
Why is accessing textures much slower when calculating the texture coordinate in the fragment shader?
When using textures in GLSL, it is best to calculate the final texture coordinates in the vertex shader and hand them over to the fragment shader using varyings. ...
19
votes
1answer
2k views
Why is this conditional in my fragment shader so slow?
I have set up some FPS-measuring code in WebGL (based on this SO answer) and have discovered some oddities with the performance of my fragment shader. The code just renders a single quad (or rather ...
9
votes
1answer
2k views
What is the performance tradeoff between forward and deferred rendering?
Forward rendering is the process of computing a radiance value for a surface fragment directly from input geometry and lighting information. Deferred rendering splits that process into two steps: ...
11
votes
1answer
1k views
When to disable perspective correct interpolation ( noperspective )
In 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-...
37
votes
3answers
15k views
When is a compute shader more efficient than a pixel shader for image filtering?
Image 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 ...
25
votes
2answers
6k views
What is the cost of changing state?
Programmers 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 ...
10
votes
3answers
1k views
Why do Vertex Buffer Objects improve performance?
From my basic understanding, a Vertex Buffer Object works something like this (pseudo code):
Normally, if one wanted to say, draw a square, one could issue line drawing commands.
...
