# All Questions

3,015 questions
Filter by
Sorted by
Tagged with
10 views

### Algorithm for thinning a thick line

I'm trying to reduce a thick line, in raster space, down to a thin line, preferably one pixel wide (or thick). Does anybody know of an algorithm that can do this? Imagine you draw with a marker on a ...
9 views

### Wrapping a point cloud skeleton with a mesh

Using Unity I've been producing sculptural forms that look like this. It's made of patterns of cubes that twist around each other. I'm trying to get it into a 3D printable format. From unity I export ...
9 views

### problem: Visualization shape showing up on Visualization shape in python

I am working on showing a correlation matrix for dataset features using this code ...
40 views

### Rendering a volume that might be completely clipped in OpenGL

Suppose that I have some world-space volume (which we may assume is a convex polyhedron with a small number of vertices), and I want to render its intersection with the view frustum, such that every ...
29 views

### OpenGL pipeline stages, when is the primitive assembly executed?

The question is simple, I have this diagram from the Khronos page: And this diagram from the Learn OpenGL page In the first picture the Primitive assembly is executed for example after the Geometry ...
34 views

### Why is there a T factor in the definition of Shah given in Matt Pharr's Physically Based Rendering?

The specific chapter about this is here - Sampling Theory Unlike what I read anywhere else, it defines Shah as: $$Ш_T(x)=T\sum\nolimits_i{\delta{(x-Ti)}}$$ And the T is still present in the ...
15 views

### How to “preserve texture” when transforming vertices

Maya has a feature called preserve texture. It allows you to transform vertices of an object and basically have the texture "stay in place" in object space. Say I have a plane with unwrapped ...
20 views

### Determining input color space primaries from spectrum data

If I have an output device, for which I have a known spectrum data for each of it's primaries, I should be able to calculate the CIEXYZ of its primaries using using the integral equations together ...
18 views

### Why are these 2 buffers joint while extracting glTF information?

I am using tinyGLTF to parse gltf files and then render them in my program. I am currently during the third example in this page. In particular I am trying to extract the 2 animation buffers: My code:...
46 views

### Tetrahedron orientation

I am developing a software that needs to interact with a mesh processing program, using tetrahedral meshes, however I am finding difficulties in this. The program requires all tetrahedrons to have ...
27 views

### Rendering part of the scene inside bounding sphere

In this video https://youtu.be/0ckE-CZpXAo?t=445, it's suggested to render onto a sphere instead of screen quad to save computation time on lighting calculations. So you create a bounding sphere for ...
42 views

### Understanding VAO and VBO

I'm reading through Learn OpenGL to refresh the basic concepts as I haven't touched in quite some time. Specifically I still think I cannot quite understand the meaning of VAO and VBO, the book mainly ...
25 views

### Luminace, RGB, and SMPT ST 2084 EOTF

I need a point clarified. According to wikipedia, SMPT ST 2084 EOTF is this: I've seen this equation implemented in game engines where for L they feed the channels RGB, each of which is 0 to 10,000 ...
35 views

### Not sure why texture is rendering a black screen

I am converting my OpenCV frame to an OpenGL texture. I have the frame data loaded, but when I try to render it as a texture I get a black screen. I've looked through the OpenGL code countless times ...
38 views

### Is there a tool capable of drawing a triangular linear gradient fill?

I need to draw some shapes filled with linear gradients starting from every point and blending smoothly between points, like an OpenGL standard shading (I guess it is called ...
24 views

### CBV, IBV and VBV byte alignment

The CBV (constant buffer view) SizeInBytes is required to be 256-byte aligned. Should the associated ID3D12Resource have a ...
25 views

### Unbound descriptor tables and descriptors for fat root signatures

Unbound descriptor tables If a D3D12_VERSIONED_ROOT_SIGNATURE_DESC defines N D3D12_ROOT_PARAMETERs (with ...
70 views

### Determining Rational Quadratic Bezier Curve Weights for Circle

I am trying to create a spherical interpolation with 3 points. I'm currently using Quadratic Bezier Interpolation but have been told I should use Rational Quadratic Bezier Curve in order to get a ...
33 views

### How to pass only the needed portion of the data calculated in a fragment shader to another fragment shader?

I have an image and I want to draw an arbitrary number of objects on that image. The center coordinates of those objects are calculated inside a fragment shader after series of image processing ...
46 views

### Tone Mapping vs Gamma Correction

There is something about these concepts I'm not understanding. I thought the point of gamma correcting images is to make sure that the values in linear space map correctly when displayed on screen: ...
27 views

### Explanation of converting a look-at / direction vector to quaternion rotation?

Can someone please explain the math behind converting a direction-vector or lookAt-vector into a quaternion rotation? What I am trying to do? I am trying to create a custom aim-constraint for a DCC (...
18 views

### Vertices, Vertex Normals and Face Normals

Using Open 3D Model Viewer, I have converted an OBJ file to an STL file. In the source file, the Vertex Normals are specified and in the destination, the face normal of the triangles are present which ...
43 views

### Max number of elements in a vertex attribute

I want to load a vertex buffer with vertices of struct Vertex: ...
23 views

### Setting rendering context in single thread app

I am using GLFW3 with OSMesa for context handling and glad for API loading. The context and ...
71 views

### Rounding a 3D corner with Subdivisions

Following the instructions from this post on Stack Overflow, I have been able to find points A, B, and C from points V1, V2, and V3 and a radius value (code below). I would like to be able to find a ...
61 views

### Pathtracing - many bounces reduce shadows

I'm creating DXR PathTracer highly influence by Matt Pettineo's one - https://github.com/TheRealMJP/DXRPathTracer ; Relevant HLSL code below: ...
20 views

### Could the Tetradic color pattern be expanded to allow /dev/random be “pretty” for cryptographic key purposes?

Is there a way to take a random value (or set of values), and cause them to create a "pretty" pattern (as a thumbprint), and that array of thumbprints might have a rendering mask on just for ...
100 views

### Searching for papers about brush engines

I am aware this question might be a bit vague, but i am searching for papers or posts about how raster based brush engine, normally used with pens (as in Krita fE), work. I already implemented a ...
69 views

### Is OpenGL rendering overkill for UI? [closed]

I am looking to build my own custom AR UI design library. I want to design my own buttons and components. My current approach is to use OpenCV to get a live video stream, have a pipeline for pattern ...
42 views

### What's the name of the transformation that can remove horizontal convergence from a picture?

Say that you are taking pictures from a street like this one: As you can see, the picture is taken perpendicular to the direction of the street. The problem is that cars at the left look as if they ...
28 views

### Tessellation Controll Shader how to get maximum subdivisions limit?

I have a low-poly mesh and I want to add structure on the surface. The setup: The mesh consists of triangles. Within the TCS the pixel-length for each of the three edges will be calculated and ...
58 views

### Importance sampling GGX NDF - fireflies and bright final result

https://schuttejoe.github.io/post/ggximportancesamplingpart1/ - I have problem implementing this method. Somebody asked question about this before ( Can't understand the Importance sampling GGX ) ...
40 views

### Creating a UI component library from scratch

I've been playing around with OpenGL and I'm trying to build out my own UI component library containing things like buttons, text views, labels, views, etc. Eventually I want to abstract it similar to ...
28 views

### How to create a zoomable and pannable infinite grid using javascript canvas?

How to create a zoomable and pannable infinite grid using javascript canvas? Following is the code for creating a draggable infinite grid using library called snap.js ...
19 views

### Retaining hierarchy of assembly when converting STEP to GLTF

I want to convert STEP files to gLTF. I know that gLTF suuports hierarchy of assemblies and parts. Source: https://cadexchanger.com/blog/283-how-to-load-3d-cad-data-into-three-js-part-2 However, it is ...
94 views

### Efficient methods to rasterize a scene of connected triangles

Assuming I wanted to rasterize a scene of triangles that are all connected that is similar to the image below, what would be an efficient way to do it on a GPU and a CPU? The triangles can be of any ...
44 views

I'm reading PBRT and am stuck in chapter 5.4 about radiometry. In particular: We define the irradiance as the average density flux arriving at a surface with units $\frac{W}{m^2}$. So for a point ...
30 views

### splitting hue & saturating and leaving value behind

In an HSV model, the Hue is the color model. So when we split the image or remove H, should we get an image without rgb colors? Similarly, saturation is the gray shade. I read that images become more ...
48 views

### Importance sampling a cosine distribution

Let's take a look at this blog article - https://schuttejoe.github.io/post/ggximportancesamplingpart1/ and image presented as a result of implementing it: Inside above link, you can see description ...
43 views

### Perlin Noise, surface deformation NOT along the normal vector

I've a question about surface deformation using Perlin noise or Simplex noise. You can see everywhere on google images how these results look like, if you calculate a 2D / 3D noise and move the ...
40 views

### How do I efficiently calculate the distance to the edge of a shape?

I'm trying to implement something like an "inner glow". That is, I have an image which defines the shape of an object, and then I want to create overlay that is a gradient that goes from the ...
47 views

### What's the simplest, open, animation format?

I have an obj parser that handles triangle meshes specifically. I want to extend it (and the rest of my system) to handle animations as well. However, I don't think I am ready to tackle the glTF ...
64 views

### “Importance Sampling of Many Lights with Adaptive Tree Splitting” - paper: participating media

I'm reading and implementing a paper about Importance Sampling of Many Lights with Adaptive Tree Splitting. In section 5.2 on cluster importance for participating media, there is a part that I don't ...
39 views

### How to calculate spatial frequency of an image just in one direction?

FFT spectra is not what is needed; what I need is a histogram showing which frequencies are there in image in horizontal direction, and which one is dominant Such spatial frequency is usually known ...
27 views

### How to merge voxels

I'm trying to implement a voxelization algorithm. I successfully implemented cube triangle intersection test and made a basic voxel model from discrete box meshes. However I can't find any information ...
21 views

### How to display and manipulate a structured 3D voxel image?

Can you please give a suggestion? I have a .mhd image (Voxel 3D). I want to visualize it and manipulate it with the mouse. What you suggest? How I can display a 3D Image in OpenGL? I only found in ...
65 views

### Drawing a cube and wireframe opengl

I'm trying to render a cube and it's wireframe together using OpenGL The main function is this: ...
29 views

### In place sorting of a half edge DS?

Cross posting from SO because I didn;t know where to put this question. I have an implementation of the half edge and I am trying to sort the edges such that edge n+1 is the pair of edge n. Setup I ...