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1500 questions
18
votes
1 answer
Why integrate over a hemisphere (and not a sphere) to solve the rendering equation?
In most text books that I have seen, this is how the rendering equation is written:
$$L_0( \omega_0)= L_e(\omega_0)+\int_{\Omega}{f(\omega_i, \omega_0)L_i(\omega_i)\,\mathrm{d}\omega_i}$$
Where $\Omega$ is defined to be a hemisphere (and all those…
Mon ouïe
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18
votes
3 answers
How can I debug what is being rendered to a Frame Buffer Object in OpenGL?
I have a point cloud that is being rendered to the screen. Each point has its position and color as well as an ID.
I was asked to render the IDs for each point to a texture so I created a FBO and attached two textures, one for color and one for…
BRabbit27
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18
votes
2 answers
Cause of shadow acne
I know how shadow mapping works but I am not getting the cause of shadow acne!
Can anyone tell me cause of shadow acne in a simple way and how is it related to depth map resolution?
videogamechef
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18
votes
7 answers
Why are Homogeneous Coordinates used in Computer Graphics?
Why are Homogeneous Coordinates used in Computer Graphics?
What would be the problem if Homogeneous Coordinates were not used in matrix transformations?
user464
18
votes
2 answers
What is the accepted method of converting shininess to roughness, and vice versa?
Most modern renderers use physically-based materials and their models are often parameterized over roughness. Since this wasn't always the case with renderers, conventional assets often don't have a notion of roughness. Instead, we see "shininess"…
ap_
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18
votes
1 answer
What subdivision algorithm advances have occurred since Catmull-Clark?
In 1978 Edwin Catmull and Jim Clark defined the recursive subdivision process that bears their names, and although those principles are applicable still today, what advances have occurred as far as optimization and accuracy?
J Sargent
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18
votes
2 answers
What is the difference between various space-filling curves?
Space-filling curves are important in many graphics applications because they help expose spatial locality. We often hear about different algorithms using Z-curves, Morton codes, Hilbert curves, etc. What are the differences between some of these…
ap_
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17
votes
2 answers
Is gamma still important to take into account?
Do different monitors (including mobile screens) still use significantly different gamma functions when displaying colour images? Is there a standardised way to represent colour that can then be translated according to the gamma of the monitor, or…
trichoplax is on Codidact now
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17
votes
5 answers
Why do red, green, and blue make up all the colors?
Why do red, green, and blue combinations can make up all the visible colors?
Hedayat Mahdipour
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17
votes
1 answer
How can I generate procedural noise on a sphere?
I would like to generate procedural noise on the surface of a sphere (e.g. to procedurally generate planets or marble-textured balls). Of course, I could just take a standard noise algorithm and map it onto the sphere, but this has all the issues of…
Martin Ender
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17
votes
2 answers
Subpixel Rendering for a Ray Tracer
In font rendering, it is common to use subpixel rendering. The basic idea here is to break the pixel into its RGB components and then compute a value for each separately. Since each component is smaller than the entire pixel, higher quality…
geometrian
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17
votes
2 answers
Why use a tent filter in path tracing?
The 99 lines of C path tracer Smallpt renders a 2x2 subpixel grid for each pixel it intends to render and then does a tent filter to combine them.
There is an interesting presentation explaining the code here, and it mentions the tent filter but…
Alan Wolfe
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17
votes
3 answers
Why do we have graphics frameworks like OpenGL and DirectX, when games could just draw pixels directly?
Games and other graphically intensive applications use frameworks like OpenGL and DirectX. Also they require features like pixel shader and DX12.
But why would we need all these frameworks and GPU features when we could just draw everything pixel by…
Suici Doga
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17
votes
1 answer
why does black text have orange and blue pixels
Why is it that when you zoom in to some black text you find that it is made up of orange, slightly black and blue pixels like the picture below.
HEGX64
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17
votes
2 answers
How does hardware texture compression work?
That it compresses the data compared to the pixel array is obvious.
But what makes it different from from normal compression (like png, jpeg)?
ratchet freak
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