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1500 questions
10
votes
2 answers
Rendering equation - why unsolvable directly?
Why is the rendering equation, introduced by Kajiya in 1986, not solvable directly/analytically?
Blongphong
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1 answer
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 tried looking around for anything on "object…
Ethan Shulman
- 138
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10
votes
0 answers
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. So it doesn't help me to implement even-odd…
luser droog
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10
votes
2 answers
Total emitted power of diffuse area light
I am reading the book Physically Based Rendering (Pharr, Humphreys). In the chapter on lights, they talk about approximating the total emitted power of different kinds of lights. For example, a point light's total power is intensity * 4 * pi. Here…
Rasmus Rønn Nielsen
- 103
- 4
10
votes
1 answer
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 triangles with the same texture, does it work worse for…
Felipe Lira
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10
votes
1 answer
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 Bezier curves, a comparison between these two would…
Ecir Hana
- 1,459
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10
votes
1 answer
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 reusing those to each different mesh with…
glampert
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10
votes
1 answer
Why do multiple Gaussian Blurs?
Applying multiple Gaussian blurs can result in an effect that is equivalent to a stronger Gaussian blur.
For instance this question says that: Is doing multiple Gaussian blurs the same as doing one larger blur?
Wikipedia also says it, but says that…
Alan Wolfe
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10
votes
1 answer
Full Monte-Carlo Volumetric Scattering
I would like to add full monte-carlo volumetric scattering to my path tracer, but I'm having a hard time researching how to do it. Let me explain what I would like to do:
A ray enters a material, and we apply the BTDF, then after some distance, a…
RichieSams
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10
votes
1 answer
What are sample gaps during scan conversion?
In this tutorial,
It is very often the case that triangles are rendered that share
edges. OpenGL offers a guarantee that, so long as the shared edge
vertex positions are identical, there will be no sample gaps during
scan conversion.
1 What…
AlexWei
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10
votes
1 answer
Gaussian blurring a function defined over a surface mesh
I have a scalar function defined over the vertices of a surface mesh. I want to compute an approximate (and generalized, I suppose) "Gaussian blur/convolution" of this function over the surface.
I can imagine for each vertex, taking an average of…
Museful
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10
votes
1 answer
Automatic generation of UV maps
Given an arbitrary triangle mesh, is it possible to automatically generate a UV mapping for it, and if so, how is it done?
Mark
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10
votes
1 answer
Map a texture onto a hyperbolic triangle
I've been stuck on how to approach this for a while, so any suggestions would be gratefully appreciated!
I want to map a texture in the form of a lower right euclidean triangle to a hyperbolic triangle on the Poincare Disk.
Here's the texture (the…
Lewy Blue
- 203
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10
votes
1 answer
Creating shared vertex normals on GPU
I've mostly succeeded at porting an implementation of Marching Cubes from CPU over to OpenGL compute shaders, but I haven't tackled normals yet and wondering the best way to go about it.
My implementation deals specifically with binary valued fields…
russ
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10
votes
2 answers
Reliable test for intersection of two Bezier curves
How to reliably find out whether two planar Bezier curves intersect? By "reliably" I mean the test will answer "yes" only when the curves intersect, and "no" only when they don't intersect. I don't need to know what parameters the intersection was…
Ecir Hana
- 1,459
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