Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

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How can I check if a polygon can completely contain a circle of a certain radius?

How can I check if a polygon (can also be irregular) can completely contain a circle of a certain radius? I do not want to actually draw a circle inside the polygon but just a boolean outcome whether or not it can be fit. I need this for an…
user7413
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What are the side effects of biasing brightness in continuous spectrum raytracing?

I want to model rays with a continuous range of frequencies so that I can get raytraced images with colour separation on refraction. I can model a light source with a specified frequency distribution by using the distribution to affect the…
trichoplax is on Codidact now
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Mitchell's Best Candidate Algorithm

I'm trying to generate an image where black dots are arranged in a blue noise distribution on a white background. I know that there are other ways to do this, one of the best being "Fast Capacity Constrained Voronoi Tessellation." [Hongwei 09], but…
Alan Wolfe
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Diffuse BRDF component of the Disney BRDF

In the SIGGRAPH course: BURLEY B.: Physically Based Shading at Disney, SIGGRAPH 2012 Course: Practical Physically Based Shading in Film and Game Production, 2012. it is mentioned that some BRDF models include a diffuse Fresnel factor such…
Matthias
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Why do I need to inverse the orientation matrix of a camera to be able to translate it in the direction it is facing?

I've been going over some OpenGL learning resources and one of them is this article: Modern OpenGL 04 - Cameras, Vectors & Input in which the author presents an approach to building a Camera class that can be used to derive the view and projection…
Mihai Bişog
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Why are width and height divided by 2 in the perspective projection matrix?

I'm using OpenGL to learn computer graphics. I'm trying to understand projection matrices. The following are shown in the OpenGL 'Red Book': I don't understand why the width and height are divided by 2?
mikeglaz
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Help with start up bias in Metropolis Light Transport

I'm trying to implement metropolis light transport based on this paper, and I have the basic thing working. I run the algorithm multiple times with different starting points, add the results for each starting point together and multiply them by a…
devil0150
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A recent approach for subsurface scattering

I read "A Practical Model for Subsurface Light Transport" and "A Rapid Hierarchical Rendering Technique for Translucent Materials". If I understand correctly, the former does not consider the case when an object is lit behind and we can see the…
Mustafa Işık
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Link between blue noise sampling and blue noise textures?

You can have blue noise sampling like these poisson disc samples: And you can have a blue noise texture like this: I get that in the first image, there is one input (the index of the sample) and two outputs (the x,y coordinate of the point) and…
Alan Wolfe
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How am I able to perform perspective projection without a near plane?

I'm learning about 3D computer graphics, but I'm having a hard time understanding why the near plane of a viewing frustum can not be placed at z position $0$ (right at the camera). I can understand conceptually that the near plane is essentially the…
William Breathitt Gray
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More accurate Fresnel approximation for a RGB-based Path Tracer

I'm writing a path tracer and, for the moment, spectra related data (spectral power distributions and spectral reflectance curves) are stored as RGB tuples. In the Cook-Torrance specular BRDF I am using the Schlick's approximation for the Fresnel…
user5681
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Understanding Jump Flooding Algorithm (JFA) for Voronoi Diagrams

I'm having trouble understanding the JFA. As far as I understood the algorithm, it walks log(n) times through every pixel (no matter if it is a seed or not) and looks at that pixel's neighbors in $(x+i, y+j)$ where $i,j \in \{-step\ length, 0, step\…
Muad
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How to achieve gimbal lock with Euler angles?

I was studying about Euler angles and I came across the problem gimbal lock which can occur by using Euler angles. In gimbal lock we lose one axis of rotation. But how? And when does it happen? On what conditions? All I know about Euler angles is…
videogamechef
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What is the most physically accurate representation of color possible in computer graphics?

I am looking for theoretical and implemented models to represent color in software that strives for physical accuracy. I know that "color only exists in the mind" and that it sort of does not make sense to look for "physical accuracy", but still,…
Mr. Developerdude
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Path weight for direct light sampling

I originally wrote a pathtracer that just bounces by the BRDF and each sample is added to a buffer that divides by the current number of frames. Now I'd like to do next event estimation at each bounce, directly sampling the light along the path. How…
newtorendering
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