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1500 questions
4
votes
1 answer
How do I make sure my cosine-weighted sampling works fine?
I'm working on a pathtracer and while it's working mostly fine, I'm getting different outputs with cosine-weighted sampling and uniform sampling :
Uniform sampling is on the left, cosine-weighted is on the right. The difference is somewhat subtle,…
Octave
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4
votes
1 answer
Analytical derivative of a 3D Simplex Noise field
I am using Simplex Noise to generate a 3D field. The specific implementation is FastNoise-SIMD.
Assume I want to have a gradient (or derivative) for a sample at Sx, Sy, Sz in that field.
Do I actually need to sample the value of the field at all…
Bram
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4
votes
1 answer
Three quaternions interpolation with barycentric coordinates
I have three quaternions A, B, C.
I also have a 3D vector P which describes the barycentric coordinate to interpolate.
I want to interpolate the three quaternions with respect to the barycentric coordinate P
This Image shows how to do it would A, B…
Thomas
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4
votes
3 answers
Visual Artifact in Wireframe Grid/Plane
I have a simplistic shader program that adds reference coordinate planes to a scene.
These planes are drawn as intersecting lines.
When viewed at a distance, a visual artifact is created; there is a ripple of lighter and darker areas going left to…
user13167
4
votes
1 answer
Understanding distinct vs. not distinct knots in B-splines
In reading the wikipedia page about B-Splines https://en.wikipedia.org/wiki/B-spline, I am getting confused about the concept of knots.
If we have a spline of order $n$, with a knot vector ($t_0, \cdots, t_k$),
then if the $k$ knots are distinct, I…
IntegrateThis
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4
votes
1 answer
Saving a mesh and textures into a single file
I'm looking for a format where I could store a triangle mesh and multiple textures into a single file. Most formats only reference an external file for textures. I found that the FBX format should support this, but I need something with an…
M.K.
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4
votes
1 answer
Shader or formula that distorts inward
I am looking for a shader (or at least the right terminology) for crushing an image. It should be something very similar to barrel distortion, but instead of the center crushing outward to the edges, I want to edges to crush inward to the…
aggregate1166877
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- 5
4
votes
4 answers
Why isn't rasterization combined with raytracing more often?
If I'm not mistaken, you can make a hybrid renderer which lets a rasterizer solve the visibility problem, then shade all of the projected shapes with a raytracing algorithm. It seems that this isn't commonly done however, what's the reason for that?…
AnnoyinC
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4
votes
2 answers
What does texture resolve mean?
In the context of render targets or textures, what does "resolve" mean?
For example: To resolve a color texture.
From my understanding, it seems to mean, "copy but process/convert at the same time", but I can't seem to find a good definition for it…
Todd
- 143
- 4
4
votes
2 answers
Creating a Smooth 3D Mesh from a 2D Outline
I am trying to find (or maybe create) an algorithm for creating a smooth, rounded 3D mesh given a 2D outline. I'm trying to recreate a system from a Gamecube game called Amazing Island, and you can see an example of how it works here. A more modern…
hamulstdubbins
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4
votes
1 answer
Determining the Bounding Box values of a glTF file
Is there a way when looking at the source of a glTF file that you can determine what the boundingBox values of the object are?
Jamie Bresner
- 41
- 2
4
votes
1 answer
What's the justification of multiplying colors together?
In Phong shading model (and other shading models as well), the light color is multiplied together with the surface color component-wise. I want to know the justification for this. Is this some what related to the physics of light?
Rui Liu
- 141
- 1
4
votes
1 answer
Why is OpenGL recompiling my depth map vertex shader based on the GL state?
I've written a shader that writes depth to each face of a cube map, as part of rendering cube map shadows for a realtime 3D engine I'm writing with OpenGL and C++.
The shader transforms each vertex into world space in the vertex shader, then…
b1skit
- 161
- 3
4
votes
0 answers
Are there any reasons to use power of two textures with modern mobile platforms?
Are there any reasons to use power of two textures (like 128x128 sized) if one targets modern mobile platforms (with OpenGL ES 3.0, Metal and/or Vulkan)?
With iOS the PVRTC only supports power of two textures that have equal width and height, but…
Kaarlo Räihä
- 41
- 1
4
votes
1 answer
How to approximate the heightmap of processed wood?
In the above image, you can see that there is some slight variation of the height of each wood plank. These variations do NOT come from the wood texture itself, but from the way it was cut, i.e if a different tool had been used to cut the same…
Makogan
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