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48 views

Using buffers correctly in OpenGL compute shaders

I'm re-writing an algorithm that I first wrote using matrix/vector operation into OpenGL kernels in order to try to maximiz the performances. I have a basic knowledge of OpenGL, so I was able to get ...
0
votes
0answers
28 views

Do scanners and scanning software compensate and enhance blurry sources?

I received a pdf from a client containing several invoices. Upon further inspecting, some lines on the invoice seem digitally produced. When I tried selecting the page, copying it then pasting it on ...
0
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0answers
40 views

Euclideon Unlimited Details Voxel Engine Architecture

As I understand Euclideon haven't just rendered voxels for these infamous demos, since the amount of geometry is still too large for the 2010 PC with software raytracer and the model taking whole HDD ...
0
votes
0answers
22 views

Implementing Feather feature of Photoshop

The "feather" in photo & video editing softwares like photoshop & Premiere Pro, I need to know whether it is simply a Gaussian blur around the edges of boundary or it is something ...
0
votes
0answers
21 views

How to use RWStructuredBuffer

Edit: I managed to get code compiling, but it doesn't work, so I changed question a little bit. Below code is working fine as read buffer, but I cannot make it to work as read-write buffer (...
2
votes
1answer
47 views

How can I make a graphics demo without a frame buffer?

I am programming a microcontroller - a tiny 8 bit computer that has about 100Mhz - 300Mhz CPU clock speed and 64K application RAM (actually ROM), but only a tiny amount of RAM (6K) - nowhere near ...
1
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2answers
67 views

Heat Method (Crane et Al) How do we pick u?

The heat method is a very interesting paper for distance computation: https://www.cs.cmu.edu/~kmcrane/Projects/HeatMethod/paperCACM.pdf The idea behind the paper is that, heat travels along the ...
1
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0answers
36 views

Combine box shadow with a signed distance field

I'm using 2d signed distance fields in my current project for drawing shapes (example: https://www.shadertoy.com/view/4llXD7) and I want to add drop shadows to them. At first I thought I could exploit ...
4
votes
1answer
74 views

How to interpolate vertices when clipping?

When we clip in homogeneous clip space, we have to generate a new vertex located at the intersection between the edge and the clip plane. We thus have to interpolate the $(x , y, z , w)$ position of ...
2
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3answers
42 views

Why is there a difference between the CIE XYZ colour gamut vs CIE RGB?

Yet another question about colour space... In my research on CIE XYZ system, I found that it is based on the CIE RGB colour matching experiments, and that because the RGB system needed occasional ...
0
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0answers
8 views

How is VK_COLOR_SPACE_PASS_THROUGH_EXT supposed to be used?

All other possible values of VkColorSpaceKHR specify a recognised colour space encoding, and I assume that creating a swapchain with those values would mean that the final pixel data submitted by the ...
0
votes
1answer
51 views

What is a tbuffer and what is their use case?

In HLSL, we have cbuffers and tbuffers. MSDN's description for tbuffers is the following: A texture buffer is a specialized buffer resource that is accessed like a texture. Texture access (as ...
0
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0answers
21 views

How does one obtain SDF of an octree?

As I understand the usual practice is to obtain the SDF by the means of a KD-tree. But the KD-tree generation and the lookup (for each ray step) are, well, slow, while the octree can be easily ...
0
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0answers
23 views

Compute shader threads confused

I am confused on how to pick the right numbers for my threads for a compute shader. I am trying to implement an FFT algorithm on a float2 buffer which is 1024 elements in size. Does that mean i have ...
1
vote
1answer
46 views

Texture value clamped to 1

I am working on ray/path-tracer using DXR and I'm starting with simple AO. In first pass, I am storing normal value and RayTCurrent(): ...
0
votes
1answer
28 views

Is the laplacian operator for meshes just the sum of the differences of neighbouring vertices?

I am starting to learn about the laplacian operator $\Delta = \nabla \cdot \nabla\phi(p)$ Which can be described as the divergence of the gradient of a scalar function $\phi$. This is equivalent to ...
0
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2answers
51 views

Shear(?) matrix projection along Z (depth) axis

I'm creating a primarily 2d game (platformer perspective) with 2d background parallax layers. The parallax effect falls out of the fact that I'm positioning a bunch of layers in 3d and using a ...
0
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2answers
57 views

What is the relation between colour spaces and what is actually displayed on our screens?

I am not entirely sure that this is the right stack exchange, but I couldn't find any other suitable one - please redirect me if necessary. There exists mathematically defined colour spaces which help ...
7
votes
2answers
157 views

Is BVH faster than the octree/kd-tree for raytracing the objects on a GPU?

Apparently most people use BVHs in their raytracers. The ray-AABB intersection code is very fast and and the BVHs also compresses empty space efficiently, working even with infinitely large objects, ...
1
vote
1answer
42 views

How 3D painting software works

I am new to graphics programming and i'm learning opengl. I managed to make a really simple renderer where i can import models display theirs textures with all lighting. My goal is to make a simple ...
0
votes
1answer
82 views

What are the use cases for multiple render passes?

From what I understand of Vulkan, we have a render pass with its associated image resources and subpasses, and each subpass accesses those resources and may synchronise with previous subpasses to ...
1
vote
0answers
95 views

Isosurface with cracks between LODs

I have an octree containing different LODs of an isosurface that was extracted using Marching Cubes. Neighbouring chunks show surfaces that do not line up if they have different LOD. See image below. ...
0
votes
0answers
19 views

How to interpolate vertex while clipping in homogeneous clip space?

I want to clip triangles to the near plane, in homogeneous clip space, so for each edge, I have to see if it crossed the near plane. If it has, I linearly interpolate the two endpoints based on the ...
1
vote
1answer
19 views

Using original vertices coordinates after clipping

Clipping is down in homogeneous clip space, therefore after multiplying the vertices by the model-view matrix. But as we do clipping in clip space, the position of the new vertices that we interpolate ...
2
votes
1answer
84 views

How to work around the pointer limitations of GLSL?

(I am new to Computer Graphics in general) I am learning how to ray trace from a book called ''Peter Shirley - Ray Tracing in One Weekend''. In the book, the code is written in C++. I have ...
1
vote
0answers
40 views

How could I remove this colour interpolation artefact across a quad?

I've been reading up on a vulkan tutorial online, here: https://vulkan-tutorial.com. This question should apply to any 3D rendering API however. In this lesson https://vulkan-tutorial.com/...
0
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0answers
35 views

GPU accelerated 2D graphics library with signed distance functions

I want to create my own 2D graphics library using signed distance functions where everything is drawn on the GPU. Browsing the web I quickly found Inigo Quilez website that describes how to draw basic ...
3
votes
1answer
54 views

Interpolate vertex attributes with $z$ AFTER homogeneous divide

Usually, if we want to interpolate some vertex attributes, say $A_1$, $A_2$ and $A_3$, we have to first divide them by their corresponding $z$ in view space, then we interpolate them using barycentric ...
0
votes
1answer
35 views

Albedo image map to color's Light Reflectance Value (LRV)

In many datasets in the literature of both Computer Vision and Computer Graphics there is the albedo map of a scene represented as RGB images, which in principle corresponds to the diffuse reflecting ...
0
votes
1answer
35 views

Paint pixels on the image around the cursor for painting application

I'm trying to create a simple painting application. And I was wondering about an efficient way to draw pixels on the screen. I have a pixel struct: ...
0
votes
2answers
58 views

Get normalized device coordinate of an image pixel

I have an image rendered to the screen, and based on the normalized device coordinates of the cursor I would like to pick the pixel of the image under the cursor. Say the image has four channels, I ...
0
votes
0answers
37 views

GLSL asymmetric performance for point cloud

I'm currently using OpenTK (OpenGL binding for C#) to draw a lot of points (~17 million) - that very rarely change - in a cube (256 x 256 x 256) with different float "transparency weights". ...
0
votes
0answers
34 views

How to find closest points on two not intersecting convex polygons in 2D

I would like to know if it is possible to do this using GJK alghorythm. I know how to find if polygons intersect and also find closest point on polygon from a given external point. Using Minkovski ...
0
votes
0answers
7 views

MMP algorithm, no metion of “in window” intersections

If you are familiar with the MMP algorithm for geodesic finding, you know an important part of the algorithm revolves around solving intersections of windows. I am running into a case that I don't see ...
0
votes
0answers
32 views

Are there algorithms besides Canny edge detection that can create consistent width edges?

Sobel edge detection is pretty much the quintessential way to get edges out of an image. It however suffers from certain quirks. One example is, because it's gradient, based certain surfaces exhibit ...
1
vote
0answers
71 views

Why isn't the 'Map Colors' fixup changing text colors?

I saw this question some where, I think Reddit, but I can't find it. I have same issue. Please see the screenshot beneath. I've uploaded the PDF to mega.nz I'm using Adobe Acrobat Pro DC Version 2019....
2
votes
2answers
257 views

Why is eye-based ray tracing preferred over light-based ray tracing?

It seems that virtually all path tracers use eye-based or view-based path tracing. That is, the light rays originate from the camera rather than the light source. The reason given for this everywhere ...
2
votes
0answers
20 views

Deferred Decals

What's the proper of way of calculating the coords to apply decals by let's say linear interpolation? My understanding is that you render your GBuffer albedo, specular, etc... and after that you do ...
0
votes
1answer
16 views

Get binding point of sampler/image in shader

I have an image and a sampler declared in a shader as follow layout(binding = 5) uniform isampler2D heightmap; layout(binding = 3) uniform writeonly uimage2D info; ...
0
votes
1answer
58 views

Let GPU write to itself

As someone who is trying to dive into WebGL for parallelizing simulations, or Machine Learning, or typical IIR filters I've come to realize that for everything that I want to do requires the GPU to ...
0
votes
0answers
29 views

Does ffmpeg or NVDEC (nvidia decoder) support YUV444 video input?

I tried feeding an .h264 video with YUV444 color format to ffmpeg in hardware decoding mode on a GTX 1660 and it looks like this color input isn't supported. I get an error in the ...
0
votes
0answers
37 views

Clipping 3D Perspective matrix

I am trying to implement clipping in my simple renderer, but i have a trouble with setting the boundaries. I used the same projection matrix that is in OpenGL. The problem is, the vertices that are ...
0
votes
1answer
31 views

OpenGL shader introspection/interface queries for images

I've been looking at Interface queries in order to prevent common mistakes that are time consuming to debug, such as forgetting to bind a buffer, binding the wrong resource type, etc. However, I wasn'...
1
vote
1answer
47 views

Is it possible to send Texture Buffer to shader dynamically?

I want to send a series of integer to the geometry shader, while the data will be modified every frame. But when I try to retrive the sampleBuffer in geometry shader, it seems to keep output zero. Am ...
1
vote
0answers
46 views

alternative to spherical harmonics to model radiance aproximation, optimized for real-time evaluation

I'm looking for a compact representation of radiance over the hemisphere that is also performant to evaluate in realtime (in a pixel shader). The purpose of it is to compress surface lightfields so ...
1
vote
1answer
64 views

Transfer the texture between two different sets of uv

Say I have a mesh with two sets of uvs. And I have a texture made for the first set of uvs. I would like to create a second texture that has the same relationship between its pixels and the second set ...
2
votes
0answers
54 views

How to retrieve data from Compute Shader to CPU?

I want to retrieve data that has created by the compute shader but have no clue how it works. After researching a few forums and articles on how it should work and this is what I came up with. Compute ...
3
votes
1answer
87 views

Procedural generation of biological models

I was wondering if anyone can point me in the direction of some research papers, or articles that describe a method for generating biological 3D models. I am drafting a prototype for a new game that ...
0
votes
0answers
24 views

What method is used for baking grayscale curvature maps

I'm looking for a way to generate curvature maps like this: The map stores the Convexity and Concavity of each pixel as a value from 0 to 1, where .5 is no curvature and 1 and 0 are the extremes. I ...
1
vote
1answer
72 views

Approximating Geodesics in a half edge DS, how can I refine my mesh to get good approximations

I implemented Djikstra's shortest path algorithm to approximate Geodesics on arbitrary meshes. Djikstra's works, but I noticed a problem inherent to the discretization of my meshes. Consider the ...

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