Computer Graphics Stack Exchange
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Why do most photorealistic renderers have similar material test scenes?

I notice that most photorealistic renderers have very similar material test scenes. Here are a few examples: Blender Mitsuba Vray My question is: why is this specific model / style chosen to test materials? Does it have some advantage over…
ap_
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How is anisotropic filtering typically implemented in modern GPUs?

Anisotropic filtering "retains the sharpness of a texture normally lost by MIP map texture's attempts to avoid aliasing". The Wikipedia article gives hints about how it can be implemented ("probe the texture (...) for any orientation of…
wip
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Difference between BVH and Octree/K-d trees

So I'm currently reading up on acceleration data structures and so far I've heard there are 2 main schemes. Object Subdivision and Spatial Subdivision. The Bounding Volume Hierarchy belongs to the Object Subdivision approach and K-d/Octree belong to…
gallickgunner
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How are mipmap levels computed in Metal?

My question is specifically in regards to Metal, since I don't know if the answer would change for another API. What I believe I understand so far is this: A mipmapped texture has precomputed "levels of detail", where lower levels of detail are…
lcmylin
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What is "Scanline Racing"

I've heard a lot of people working on VR talk about scanline racing and that it's supposed to help improve latency for motion-to-photon. However, it isn't clear to me how this can be done with OpenGL. Could someone explain how scanline racing…
Mokosha
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Why does increasing simplex noise dimension wash it out?

I just tried using this approach to create a tiling 2d simplex noise function with Gustavson's java implementation. The result tiled, but the texture seemed muddy / washed out. I decided to compare the result of using the 2d, 3d & 4d versions to…
Pikalek
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Is a constant condition more costly than switching shaders?

In general, branching in shaders is not a good idea. But now I have a shader with a condition that is constant with respect to the entire draw call. So the branch that is executed is always the same for one draw call. Is such kind of branching still…
nikitablack
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Choosing Reflection or Refraction in Path Tracing

I am trying to implement refraction and transmission in my path tracer and I'm a bit unsure on how to implement it. First, some background: When light hits a surface, a portion of it will reflect, and a portion will be refracted: How much light…
RichieSams
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3 answers

Importance Sampling of Environment Maps

What is the best currently known and ideally also production-verified approach for sampling environment maps (EM) in a MIS-based uni-directional path tracer and similar types of renderers? I would prefer solutions which are reasonably complicated…
ivokabel
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How are volumetric effects handled in raytracing?

How are volumetric effects such as smoke, fog, or clouds rendered by a raytracer? Unlike solid objects, these don't have a well-defined surface to compute an intersection with.
Mark
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What exact algorithm and parameters reproduce L-system plant growth figure in Algorithmic Beauty of Plants

I am interested in duplicating a figure (shown below, ch 1 fig 1.21) in the book Algorithmic Beauty of Plants. The book is available here http://algorithmicbotany.org/papers/#abop This image appears in several resources but I have been unable to…
Martin Krzywinski
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Fresnel reflectance of gold: red channel greater than 1?

I've been trying to understand some of the physical principles behind light and material interaction lately. In his talk Physics and Math of Shading, Naty Hoffman explains Fresnel reflectance and defines the characteristic specular color F0 of a…
David Kuri
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How to implement a trackball in OpenGL?

After so much reading about transformations it is time to implement a trackball for my app. I understand I have to create a vector from the origin to where the mouse is clicked and then another from the origin to where the mouse is released. My…
BRabbit27
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How does mip-mapping work with non-power-of-2 textures?

I have heard that recent GPUs all support non-power-of-2 textures and all features just work. However, I don't understand how mip-mapping would work in such a scenario. Can someone explain?
ap_
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What is the state of art in geometric LOD in games?

How do modern games do geometry level-of-detail for object meshes like characters, terrain, and foliage? There are two parts to my question: What does the asset pipeline look like? Do artists make a high-poly model which is later decimated? If so,…
ap_
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