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Is colorized subpixel rendering possible?

Subpixel rendering is used most commonly to anti alias fonts. It works by leveraging the physical layout of the color components of a display to give geometry details to an image that are smaller than ...
Alan Wolfe's user avatar
  • 7,801
17 votes
2 answers
1k views

Subpixel Rendering for a Ray Tracer

In font rendering, it is common to use subpixel rendering. The basic idea here is to break the pixel into its RGB components and then compute a value for each separately. Since each component is ...
geometrian's user avatar
  • 1,990
11 votes
1 answer
2k views

Ray Tracing with Cones: coverage, overlapping and abutting triangles

In his classic paper Ray Tracing with Cones, John Amanatides describes a variation on classical ray tracing. By extending the concept of a ray by an aperture angle, making it a cone, aliasing effects (...
David Kuri's user avatar
  • 2,293
4 votes
2 answers
4k views

Are there any gltf example datasets available? [closed]

I'm currently researching my options on effeciently exchanging data for a webgl application. I understand the gltf format is still being drafted but I need some example data to understand whether this ...
q9f's user avatar
  • 703
4 votes
2 answers
178 views

Software to compose separate models into an articulated model?

I've inherited a system which animates a humanoid avatar by loading various models and manually calculating transformations for each one. I'm in the process of porting part of this system to Three.js, ...
Peter Taylor's user avatar
8 votes
3 answers
311 views

Changing image so it would look like through colorful glasses

I am currently working on some simple pixel shader in HLSL. I send to shader texture and I want to make it more colorful (something like in the picture below). In the picture 1 there is original ...
bartosz.baczek's user avatar
15 votes
6 answers
694 views

How to produce simple 2D illustrations to accompany geometry answers?

In my answer about Affine Transformations I made some little illustrations to help the explanation. How do you make an upload-able PNG quickly which expresses a geometrical or mathematical idea? ...
luser droog's user avatar
  • 1,378
15 votes
1 answer
3k views

Synchronizing successive OpenGL Compute Shader invocations

I have a couple of compute shaders that need to be executed in a certain order and whose outputs depend on previous inputs. Ideally, I'll never need to copy a buffer client-side and do all of my work ...
Mokosha's user avatar
  • 1,144
8 votes
3 answers
335 views

How to denoise video?

Video noise is random and not correlated in time. I assume, the best method is using wavelet denoise in this case, right? If yes, how is wavelet denoise implemented for video? Is there something to ...
p2or's user avatar
  • 596
9 votes
2 answers
610 views

What is the meaning of words 'stochastic', 'temporal' in computer graphics?

Last time I see a lot of papers which operates on this words, i.e. stochastic AA, temporal coherence etc. What does that means? Can you provide examples with explanations in plain English?
nikitablack's user avatar
26 votes
1 answer
12k views

What are Affine Transformations?

What are Affine Tranformations? Do they apply just to points or to other shapes as well? What does it mean that they can be "composed"?
luser droog's user avatar
  • 1,378
8 votes
1 answer
5k views

What is occlusion?

Occlusion "is the effect of one object in a 3-D space blocking another object from view." With this definiton in mind I cannot understand sentences like: The interior of a tube is typically more ...
Joey's user avatar
  • 627
9 votes
2 answers
580 views

What is ambient occlusion?

Ambient occlusion "is a shading and rendering technique used to calculate how exposed each point in a scene is to ambient lighting. Ambient lighting is regarding to What is ambient lighting?: ... ...
Joey's user avatar
  • 627
10 votes
1 answer
21k views

Shading: Phong vs Gouraud vs Flat

How do they work and what are the differences between them? In what scenario should you use which one?
Joey's user avatar
  • 627
12 votes
2 answers
2k views

How is screen space ambient occlusion implemented?

I do not understand the explanation from wikipedia. For every pixel on the screen, the pixel shader samples the depth values around the current pixel and tries to compute the amount of occlusion ...
Joey's user avatar
  • 627
11 votes
2 answers
9k views

What is ambient lighting?

Wikipedia says: An ambient light source represents a fixed-intensity and fixed-color light source that affects all objects in the scene equally. By saying "affects all objects equally" they mean ...
Joey's user avatar
  • 627
22 votes
7 answers
4k views

How to raytrace Bezier surfaces?

I tried this question on math.SE and surprisingly, the answer was "the equations are too nasty, just feed the function it to a numerical root-finder". But if you consider yourself "a graphics guy" ...
luser droog's user avatar
  • 1,378
9 votes
1 answer
2k views

Shadow Mapping artefacts

I've been playing around with shadow mapping in OpenGL using depth textures. The depth texture is fine and I can map it onto the scene but I have some strange artefacts on the back of the object: My ...
Blarglenarf's user avatar
10 votes
1 answer
2k views

What is "Object Space Lighting"?

Looking at Star Swarm, a demo for the Nitrous engine, I found this little line: "Nitrous uses Object Space Lighting, the same techniques used in film, including real-time film-quality motion blur." I ...
Ethan Shulman's user avatar
10 votes
0 answers
169 views

How to describe the bi-directional links for the Weiler-Atherton algorithm?

My postscript interpreter currently implements the Hodgeman-Sutherland clipping algorithm but this is limited to simpler shapes and doesn't have a provision for utilizing various winding-number rules. ...
luser droog's user avatar
  • 1,378
19 votes
1 answer
6k views

Why is recursion forbidden in OpenCL?

I'd like to use OpenCL to accelerate rendering of raytraced images, but I notice that the Wikipedia page claims that recursion is forbidden in Open CL. Is this true? As I make extensive use of ...
trichoplax is on Codidact now's user avatar
14 votes
1 answer
1k views

Why is work-efficiency desired in GPU programming?

I've been reading the following article on how to do a parallel scan in CUDA: https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch39.html In the article, there is an emphasis on making the scan ...
Mokosha's user avatar
  • 1,144
13 votes
3 answers
445 views

Is a Lambertian reflector illuminated by a smaller fraction of the incident radiation when it's tilted?

In reading about Lambertian reflectance on Wikipedia I found the following phrase (in bold) which doesn't sound right to me: In computer graphics, Lambertian reflection is often used as a model for ...
trichoplax is on Codidact now's user avatar
9 votes
1 answer
204 views

Is the demoscene a source of advancements in computer graphics? [closed]

I'm interested to know whether the demoscene has historically introduced new techniques that would have otherwise taken longer to discover, contributing to the progress of computer graphics. Has it ...
trichoplax is on Codidact now's user avatar
8 votes
1 answer
2k views

NURBS knot multiplicity

In Splitting of NURBS curves there the answer relied on "maximum knot multiplicity". In order not to mix-up different topics I would like to kindly ask to answer it in another question: what is this "...
Ecir Hana's user avatar
  • 1,459
12 votes
2 answers
2k views

Is using many texture maps bad for caching?

If I have many textures (say 5+ maps) bound to the same texture unit, does it work worse for cache than if I had only 2 or 3 textures?
Felipe Lira's user avatar
  • 1,246
10 votes
1 answer
2k views

How does Texture Cache work in Tile Based Rendering GPU

How does cache work with tile based rendering? Are there any tips on how to improve cache hit ratio for it? (for instance, if tiles are processed horizontally and I have vertical segments of ...
Felipe Lira's user avatar
  • 1,246
13 votes
1 answer
5k views

How does Texture Cache work considering multiple shader units

Modern GPUs have many parallel shading units. I'd like to know how texture cache is managed in that scenario.
Felipe Lira's user avatar
  • 1,246
5 votes
0 answers
928 views

How Texture Prefetch works? [closed]

I know GPU prefetches textures and that's why dependent texture reads are slower, but how does it work and at what point that happens? EDIT: Split the content of this question into others as ...
Felipe Lira's user avatar
  • 1,246
56 votes
5 answers
40k views

Albedo vs Diffuse

Every time I think I understand the relationship between the two terms, I get more information that confuses me. I thought they were synonymous, but now I'm not sure. What is the difference between "...
hmind's user avatar
  • 663
9 votes
2 answers
304 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 ...
Nero's user avatar
  • 1,330
5 votes
1 answer
179 views

Are there specific techniques for generating False Radiosity in surfaces?

I thought of this after my radiosity vs ray tracing question. A radiosity algorithm seems to require increased calculations because it's viewpoint independent and therefore, false radiosity was born (...
Armfoot's user avatar
  • 615
9 votes
1 answer
2k views

Splitting of NURBS curves

Splitting Bezier curve into two parts at some parameter t is easy thanks to De Casteljau's algorithm. Is there a similar algorithm for NURBS curves? How to split a ...
Ecir Hana's user avatar
  • 1,459
7 votes
1 answer
710 views

NURBS curve drawing

How to draw a NURBS curve? Compared with Bezier curve, I just evaluate the Bernstein polynomial, multiply it with control point positions and that's it. Looking at the "General form of a NURBS curve"...
Ecir Hana's user avatar
  • 1,459
6 votes
1 answer
550 views

NURBS curve offset

One of the benefits of NURBS curve over, say Bezier curve, is the ability to create offset curves exactly. How to proceed with such computation? Do I just translate the control points?
Ecir Hana's user avatar
  • 1,459
15 votes
1 answer
12k views

Radiosity VS Ray tracing

Radiosity is basically what allows this: In a tutorial of Cornell University about Radiosity it is mentioned that: A ray-traced version of the image shows only the light reaching the viewer by ...
Armfoot's user avatar
  • 615
7 votes
2 answers
5k views

Image rotation using FFT

I'm not sure how practical this might be but is it possible to use Fast Fourier Transform to rotate a raster image? To be honest, I never really understood FFT, but I saw it being used for JPEG, for ...
Ecir Hana's user avatar
  • 1,459
10 votes
1 answer
2k views

Non-uniform rational B-spline (NURBS) Basics

I'm trying to understand NURBS curves (surfaces later!) but I have some trouble understanding the very basics of its inner workings. Could someone please explain a few things to me? As I come from ...
Ecir Hana's user avatar
  • 1,459
4 votes
1 answer
118 views

Is there a way for me to record every shading sample for a deep texture

Im developing a deep texture processing engine. Right now I have a software renderer to generate the raster samples. Now, for bigger renders it would be nice to do this on hardware. Is there a ...
joojaa's user avatar
  • 8,437
4 votes
1 answer
86 views

Why is the color in the cube being weirdly swapped?

I am implementing a trackball, i.e. a camera orbiting about a fixed point, in my case the origin. When I do left click with the mouse and start moving it, I compute delta values for the angles of a ...
BRabbit27's user avatar
  • 969
10 votes
1 answer
2k views

Is it good practice to use all the available texture units?

When applying multiple textures to a mesh, like for bump-mapping, I usually bind the textures to the first few fixed texture units, e.g.: diffuse = unit 0, bump = unit 1, specular = unit 2, then keep ...
glampert's user avatar
  • 1,509
5 votes
2 answers
165 views

Is it possible to render red / blue 3d from one image and a depth buffer?

To render an image for use with red & blue 3d glasses, the usual way to do it is to render from one point of view, convert it to a single intensity (greyscale) value per pixel, and then put that ...
Alan Wolfe's user avatar
  • 7,801
9 votes
1 answer
1k 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?
Felipe Lira's user avatar
  • 1,246
5 votes
1 answer
299 views

Is this smaller grid for Poisson disc sampling still correct?

I've seen a number of 2D Poisson disc sampling algorithms online that use a grid to accelerate checking for existing points within the minimum radius [![r][r image]][r link] of a candidate point. For ...
trichoplax is on Codidact now's user avatar
12 votes
1 answer
672 views

Can I raytrace gravitational lensing using only a single point source of gravity?

I'd like to simulate the magnification of very distant objects by the lensing effect of a less distant galaxy. Will I need to model large numbers of point masses or can I get away with just a single ...
trichoplax is on Codidact now's user avatar
12 votes
2 answers
2k views

Should JPEG encoding take into account gamma?

When an image is encoded using JPEG, the RGB pixels are first encoded into YUV, and then the UV channels are downsampled. Before actually doing the DCT and encoding the coefficients, JPEG doesn't ...
Mokosha's user avatar
  • 1,144
8 votes
1 answer
2k views

How to improve on bilateral upsampling in real time scenarios

It is a well known "standard" to use bilateral upscaling when it comes to comes to combine a low resolution target and an higher res one. I have personally noticed that using the basic algorithm (...
cifz's user avatar
  • 2,558
8 votes
0 answers
725 views

Code runs differently on different hardware

I wrote a 2D fluid-solver in OpenGL (code here) some time back. While it runs flawlessly on my onboard Intel GPU, the simulation very quickly "blows-up" when same code is run using nvidia card : ...
nilspin's user avatar
  • 81
18 votes
1 answer
736 views

Why integrate over a hemisphere (and not a sphere) to solve the rendering equation?

In most text books that I have seen, this is how the rendering equation is written: $$L_0( \omega_0)= L_e(\omega_0)+\int_{\Omega}{f(\omega_i, \omega_0)L_i(\omega_i)\,\mathrm{d}\omega_i}$$ Where $\...
Mon ouïe's user avatar
  • 283
9 votes
2 answers
90 views

Is there a way to achieve the look of a distant flock or shoal without full simulation?

Although simulation models like Boids give good results for bird flocks or fish shoals on a small scale, simulating every single member in real time becomes unrealistic for huge numbers. Is there a ...
trichoplax is on Codidact now's user avatar

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