Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

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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 diffuse reflection. This technique causes all…
trichoplax is on Codidact now
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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
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Is this the correct way to implement Beer's Law?

When I implement Beer's law (color absorption over distance through an object), it never looks very good for some reason. When i have the color behind the object, I calculate the adjusted color like this: const vec3 c_absorb =…
Alan Wolfe
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What physical properties are “lacking” to keep this 3D scene from looking like a real photograph?

So I know that I'm basically asking to identify the main problem to be solved in creating realistic 3d Graphics, but as someone without much technical experience in the field, I'm curious that if these problems can be identified, what the issue is…
galois
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In a physically based BRDF, what vector should be used to compute the Fresnel coefficient?

The well known Schlick approximation of the Fresnel coefficient gives the equation: $F=F_0+(1 - F_0)(1 - cos(\theta))^5$ And $cos(\theta)$ is equal to the dot product of the surface normal vector and the view vector. It is still unclear to me though…
Julien Guertault
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What's the difference between orthographic and perspective projection?

I have been studying computer graphics, from the book Fundamentals of Computer Graphic (but the third edition), and I lastly read about projections. Though, I didn't exactly understand what's the difference between orthographic and perspective…
phong
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Loop performance in a shader

I am wondering what's the best way to integrate a dynamic loop function in a shader? First, it seems that dynamic arrays are not possible. So, is it better to create a maximum size array and only fill a part of it or define arrays with predefined…
MaT
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Is there a standard specification for 3D graphic representation?

I'm reading a book on computer graphics, and at some point, it shows a 3D model, created from a .dat file. Here are a few rules for the .dat file creation: Made of a list of vertex positions / faces Written counter-clockwise Faces end with a dot…
Daniel
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What does "6-separating" and "26-separating" voxelization mean?

I was reading this paper about Voxelpipe, a voxelization library from NVIDIA and I found on section 2 Voxelization the terms 6-separating and 26-separating I found this website that tries to explain the basic ideas on voxelization but it wasn't very…
BRabbit27
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Sub-pixel antialiasing rules

I recently had an issue with sub-pixel anti-aliasing of text, which produces very harsh colours and made me wonder how it is meant to be done properly: I've drawn some cases of a black tile covering thirds of pixels below. The colours match the…
jozxyqk
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Ray Transformation to Object Space for Motion Blur

My raytracer supports a wide variety of objects. To intersect them, I use the standard technique of transforming rays into object-space. This works fantastically until I add motion blur. I model motion blur as a sequence of transforms (to simplify…
geometrian
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Realistic rendering: which processes of the human eye and brain do I need to consider?

Photorealistic rendering has the goal of rendering an image as a real camera would capture it. While this is already an ambitious goal, for certain scenarios you might want to take it further: render an image as the human eye would capture it or…
David Kuri
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Physically based rendering and ray tracing

I've got a lot of confusion and I need to clarify some terminology and put together the knowledge. If I say that an engine is a ray tracer (so it uses the ray tracing algorithm to render the scene), is it automatically a physically based engine? I…
TodorokiM
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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, while octrees (a more uniform subtype of BVH)…
Nash Gold
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Polarising reflection and refraction for a wrap around water surface

I want to render realistic images of water in an orbiting space habitat. The image does not need to be generated in real time, although I wouldn't want it to take weeks either. I'm looking for an approach that can generate realistic images in hours…
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