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32 views

coverage vs transparency

2D application users seem to be using transparency as a proxy for coverage more often than not. However they are not the same, although nearly everybody makes the assumption that they are. Given that ...
0
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0answers
48 views

How to retrieve RGBA mask used to transform image1 into image2

Let image1 be: And RGBA mask be: (45, 78, 251, 102) Apply mask on top of ...
0
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0answers
57 views

Comparing two triangle meshes

How to quantitatively compare two meshes? For example, comparing the same object mesh before and after processing it. Is there any library or code readily available for this?
1
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1answer
32 views

Using instanced arrays for dynamic objects

With the help of instanced arrays we can specify an array of transforms and render a number of objects with a single render call. I'm wondering if using instanced arrays make sense in situations where ...
1
vote
1answer
49 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 ...
2
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0answers
21 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 ...
1
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1answer
64 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 ...
0
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1answer
37 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 ...
1
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0answers
40 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 ...
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0answers
17 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 ...
1
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0answers
22 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 ...
1
vote
1answer
20 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:...
2
votes
1answer
63 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 ...
0
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1answer
28 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 ...
1
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2answers
109 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 ...
1
vote
1answer
27 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 ...
0
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0answers
37 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 ...
0
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2answers
47 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 ...
2
votes
0answers
26 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 ...
1
vote
1answer
32 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 ...
2
votes
1answer
72 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 ...
1
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0answers
39 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 ...
1
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1answer
85 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: ...
0
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0answers
29 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 (...
0
votes
1answer
46 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 ...
1
vote
1answer
46 views

Max number of elements in a vertex attribute

I want to load a vertex buffer with vertices of struct Vertex: ...
0
votes
2answers
85 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 ...
0
votes
1answer
68 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: ...
0
votes
1answer
26 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 ...
0
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0answers
101 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 ...
1
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0answers
44 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 ...
0
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1answer
30 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 ...
0
votes
1answer
60 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 ) ...
1
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0answers
42 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 ...
0
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0answers
42 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 ...
0
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0answers
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 ...
3
votes
1answer
97 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 ...
3
votes
1answer
49 views

Deriving radiance from irradiance and intensity

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 ...
1
vote
2answers
31 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 ...
1
vote
1answer
53 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 ...
0
votes
1answer
44 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 ...
1
vote
1answer
41 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 ...
1
vote
1answer
50 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 ...
1
vote
1answer
68 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 ...
1
vote
1answer
47 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 ...
1
vote
0answers
30 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 ...
0
votes
0answers
23 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 ...
0
votes
1answer
78 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: ...
0
votes
1answer
35 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 ...
3
votes
1answer
49 views

Why is the valence of regular vertices 6?

So I recently learnt that supposedly for any mesh, and pretty much any scheme, the valence of regular vertices must be 6. It seems to be related to the Euler-Poincare formula but I have not been able ...

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