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18 views

What modern C++ Unit Testing Framework do you use for highly parallel image, 3D and higher dimensional matrix processing workloads?

Most of the existing open-source libraries such as OpenCV, Tensorflow, and Pytorch use Google Test. I would like to know about strong alternative testing frameworks that thrive under a similar ...
2
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2answers
14 views

BC7 texture with alpha has the same size as BC7 without alpha

So i've a made a texture. I've saved the RGB one with BC7 compression, then added alpha channel[specular map] with varying levels of grayscale, and saved the file again as RGBA with BC7 compression. ...
0
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0answers
14 views

How to transform x-y-z red-green-blue arrows and draw them on 2D screen?

I'm making a raytracer and want to print debug arrows Blender example: Old version of 3d max: How do I do the same having camera forward, up and right vector? I think I need some kind of matrix ...
2
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0answers
27 views

Implementing monte carlo path traced refractions problem

I am writing a forward monte carlo path tracer with the added feature of specular refractions for transparent materials, I have managed to come this far but something is not quite right and I am ...
3
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0answers
35 views

Best practice for managing many shaders and merging multiple shaders into one?

I have managed to greatly minimize draw calls on my recent project, but as I'm adding more shaders, I see that I have to switch more times and that is causing a lot of draw calls. What is the best ...
2
votes
2answers
68 views

Why does the red color channel lose the most details during jpeg compression

I have an e-commerce website dealing with flowers and cakes. We get our photoshoot done inhouse and also the post-shoot editing of images. While we upload them on the website all images go through the ...
0
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0answers
32 views

An equation about PDFs and differentials in the book of pbrt-v3

Why does the equation at the bottom of the following page hold? http://www.pbr-book.org/3ed-2018/Monte_Carlo_Integration/Transforming_between_Distributions.html $p(\theta,\phi)d\theta d\phi=p(\omega)...
1
vote
0answers
27 views

HSI color space and RGB color space relationship in Steganography

I need to embed text in an image, research papers say HSI produces better mse and psnr therefore are better for steganography. I have RGB values(69,223,90) and its corresponding HSI is (127.223,0.458 ,...
2
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0answers
45 views

Groupshared memory and parallel reduction over multiple kernel dispatch

I am doing some parallel reduction and mostly following these nVidia slides. However they are not very detailed in places or I might be missing/misunderstanding something. Edit 2: While I figured ...
3
votes
1answer
33 views

Operator associativity and 4x4 matrices - performance question

During vertex processing with 4x4 matrices, we might stack multiple transformations like projection, model-world, world-camera, etc. by doing something like this: $$v_{final} = T_N \cdot ... \cdot ...
3
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0answers
34 views

How do I make sure my cosine-weighted sampling works fine?

I'm working on a pathtracer and while it's working mostly fine, I'm getting different outputs with cosine-weighted sampling and uniform sampling : Uniform sampling is on the left, cosine-weighted is ...
2
votes
0answers
30 views

Normalization technique to increase spread of data in rgb space

I am visualizing a dataset. My technique is to encode the data into a rgb image with the channel range [0, 255]. The data clusters in a narrow range relative to [0, 255], however, so I'm not getting ...
3
votes
0answers
58 views

volume raymarching - aligning sample coords with the 3d texture

I'm implementing a volume raymarcher and the unlit basic version seems to be working fine. This article helped a ton grokking the view-to-volume-space transform: http://www.lebarba.com However, it ...
1
vote
1answer
77 views

Problem on understanding gamma correction

I am struggling understanding gamma encoding/decoding. So the colors I see and the values I get from a color picker application(like MS Paint) are already in sRGB space(correct?). Assume the color ...
2
votes
1answer
34 views

With vsync enabled where does the wait happen in OpenGL?

When having vsync enabled I'm imagining that OpenGL has an explicit wait function to try and keep the frame rate constant. If so where is this function implemented exactly? After running some tests <...
0
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0answers
20 views

Can you use OpenCV Stereo 3D Reconstruction with iPhone cameras to approximate LiDAR?

If the iPhone had LiDAR sensors, it would be possible to generate a 3D point cloud that you could theoretically use to furnish a 3D AR reconstruction of your surroundings. E.g. you could create an AR ...
1
vote
2answers
53 views

What's more optimal - sampling one channel at a time or all channels at once?

I'm going through and optimizing some of my glsl code for a project, and have come across a scenario several times that I am not sure how best to optimize. In summary - Is it faster to sample a ...
3
votes
1answer
84 views

Shader that transforms a mercator projection to equirectangular?

I am new in the OpenGL - GLSL and trying to make a shader that taking a mercator projection texture as a source and converting it to an equirectangular projection texture. Sample input: (1024x1024) ...
0
votes
0answers
14 views

How Quantum works exactly in MagickCore?

It's been long I have been trying but I guess I will give up now, I am not able to understand some stuffs + documentations seem wrong. For example, In Magick++, the QuantumRange equations they ...
0
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0answers
29 views

C++ code to subdivide skinny 3D triangles into more regular triangles

I am currently in the search for a C++ function that takes a triangle and some input control data (e.g. max area) and returns a list of triangles that are as equilateral as possible. I know there are ...
1
vote
1answer
58 views

Help me understand the voronoi shader

I am trying to understand the voronoi shader implemented in the Book of Shaders in the Tiling and iteration section: https://thebookofshaders.com/12/ Specifically how do these lines calculate the ...
0
votes
0answers
12 views

Custom Create Maps in OpenGL

I am trying to create some procedurally created terrains for which i need to create noise maps. How do I create a texture of noise map in OpenGL and then pass that in my vertex shader as a heightMap? ...
1
vote
0answers
27 views

How to properly combine diffuse and rough specular BRDFs in a path tracer

Looking around here on various sources (including related questions on this site), if my understanding is correct, when implementing a path tracer with a material which has both a diffuse term and a ...
2
votes
1answer
64 views

Creating glsl library

I have different functions for example normalmapping which I use all the time... Now I thought about making a small glsl library. My problem: I don't want to have all functions within the same "...
-1
votes
0answers
8 views

Debugging Python OpenGL apps

how do I debug OpenGL apps written in python? I tried but I was unable to use standard tools like nvidia nsight or glsl-debugger or renderDoc on python code. Are there any specialized tools for ...
1
vote
0answers
30 views

How to find the BRDF of a rough specular surface

So I know that the BRDF for a diffuse material is `albedo/π', and I know that the BRDF for a perfectly specular surface is only non-zero on the reflected direction. How would I find the BRDF for a ...
3
votes
0answers
23 views

Analytical derivative of a 3D Simplex Noise field

I am using Simplex Noise to generate a 3D field. The specific implementation is FastNoise-SIMD. Assume I want to have a gradient (or derivative) for a sample at Sx, Sy, Sz in that field. Do I ...
0
votes
0answers
30 views

What are some uses for the vector triple product in computer graphics?

I have just learned about the vector triple product (Lagrange formula) from a math for computer graphics textbook, however the book does not mention any use cases for it beyond the fact that it's a ...
1
vote
0answers
30 views

What is the projection matrix of reverse (Byzantine) perspective?

I would like to construct a projection matrix for reverse perspective. I'm using OpenGL and tried to modify concepts from this excelent tutorial. I came up with: $$ \begin{bmatrix} 2\frac{(near-M)}{...
0
votes
1answer
40 views

Is it viable to create computer graphics via terrain scanning?

Couldn't find any resources on this, so I'll ask here. For example, I want to create a game model of a mountain peak. I took lots and lots of drone footage, almost from every side, photography ...
0
votes
0answers
48 views

UE 5 - How does Nanite work?

From the UE5 revelation video: There are over a billion triangles of source geometry in each frame, that Nanite cruches down losslessly to around 20 million drawn triangles. How does this work? ...
0
votes
0answers
22 views

What technique should I use to animate a summer picture to its winter version: linear interpolation, or opacity?

I've used a CycleGAN to generate the winter version from a summer picture (https://github.com/junyanz/pytorch-CycleGAN-and-pix2pix). An example of the output can be seen in the top right corner: ...
0
votes
0answers
11 views

UV coordinates along stroke / edge of object

I'd like to write a shader that works like the UV Along Stroke node from Blender. Basically, I need UV coordinates that follow the edge of an object and wrap. For clarity, I know how to do edge ...
2
votes
1answer
25 views

How to convert from XYZ or sRGB to ACEScg/AP1

I'm confused about how to properly convert from sRGB or XYZ color space to ACEScg. Specifically whether I have to account for differences in white point explicitly. The aces github page gives the ...
0
votes
1answer
36 views

Early depth test in WebGL

I understand that in OpenGL early depth test can be performed in the rasterizer (before running the fragment shader), but is it the same case for WebGL? If so, how is early depth test enabled in WebGL?...
1
vote
1answer
48 views

Ray Tracing Bounding Volume Hierarchies nodes

I'm new to computer graphics programming so I apologize in advance if my question is stupid. I'm trying to implement a BVH for my ray tracer and I looked at some lectures explaining BVH. They all ...
0
votes
1answer
29 views

Calculate BRDF and PDF when doing direct light sampling

I learned in PBRT that to sample direct lighting for a surface a integrator usually calculates the sample as $$ Sample = \frac{L_d(p,\omega_r) f(p,\omega_o,\omega_r)|cos\theta_i|}{p(\omega_r)} $$ ...
1
vote
1answer
26 views

Is it possible to decode and play e.g. 60fps video as 30fps, if computer is too slow for 60fps?

I am wondering this, as e.g. YouTube offers some videos 60fps, but computer may be too slow to play them.
0
votes
2answers
48 views

Weird patch on reflective spheres on planes in raytracer

I am writing a small raytracer in python , everything was working fine but when i implemented plane geometry then the reflective spheres are getting weird patches on lower bottom. image below: I ...
0
votes
1answer
20 views

OpenGL Render front and back faces with different shading for 3d modeller

I'm working on a simple 3d modeller and I would like to render the back facing triangles a bit darker, to easier differentiate between front and back faces. Like you can see in most modelling ...
0
votes
1answer
39 views

chess-like rectangles on the mesh

I am new to concepts in CG. What are the red and white rectangles trying to represent in the following screenshot? The image is from the paper "MoSh: Motion and Shape Capture from Sparse Markers".
1
vote
1answer
27 views

Do we have OpenGL shaders write out the intermediate *.o-esque file on first compile so that we can skip compiling them in run-time every single time?

Shaders get compiled during runtime every single time an app starts. I understand the reasoning for this is that there are so many GPU architectures out there that it does not make sense to ship pre-...
0
votes
0answers
21 views

How to filter a photo to look like a cartoon / anime?

I am interested in reverse engineering a video effect, that is composed of different parts. I'll try to split it into different questions as advised on StackExchange Meta. Part 1: TV-Noise effect ...
-1
votes
1answer
85 views

When do people need to work directly with a graphical API (eg: Direct3D) instead of using already made software?

I had this doubt in my head for several months and have been unable to find an answer anywhere on internet. I know what OpenGL, DirectX, Vulkan, Metal, etc... are, I already know what they are used ...
0
votes
0answers
13 views

Create a TV noise effect

I am interested in reverse engineering a video effect, that is composed of different parts. I'll try to split it into different questions as advised on StackExchange Meta. This is the example image: ...
0
votes
0answers
19 views

Generate hardcoded texture data to pass to shaders

I'm trying to manually create a color data to load as a texture with OpenGl for learning purposes. I created an unsigned char array consisting of 4 pixels with 3 ...
0
votes
1answer
96 views

Prove radiance contributions of deeper paths fade away

When ray tracing, I find it intuitively clear that deeper paths have a lower contribution to the overal picture than shorter paths. This is the main reason why it is generally okay to render a picture ...
0
votes
0answers
18 views

Birectional path tracing - connection of paths

I have a few questions about setting up a bidirectional path tracer described by Veach here. I have created both an eye path and a light path. Both are using BRDF for calculating how much light can ...
0
votes
0answers
44 views

What fast algorithms can generate not-realistic but quite handsome animated landscapes?

I was looking for algorithms that quickly compute quite nice realistic, or not realistic, animated landscapes, in video format ("animated" = the camera moves, or the water is animated, etc.) But all I ...
0
votes
0answers
40 views

Why is my ray caster is running much faster as a fragment shader compared to a compute shader

I'm trying to write a simple ray caster in OpenGL with C++. Previously, I have been using the fragment shader of a quad that covers the entire screen to do all the ray calculations. Now, I want to do ...

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