21 votes
Accepted

How is Depth of Field Implemented?

The depth of field is a characteristic of a camera lens setting, although the name "Depth of Field" is commonly used to describe the effect caused by such characteristic. Camera lenses can only ...
user avatar
  • 2,468
16 votes
Accepted

Is doing multiple Gaussian blurs the same as doing one larger blur?

If I did two Gaussian blurs of size N, would that be the same mathematically as doing one Gaussian blur of size 2N? Almost. Applying two Gaussian blurs is equivalent to doing one Gaussian blur, but ...
user avatar
10 votes
Accepted

Why is AO considered Post-Processing?

This is a potentially confusing re-use of terminology. Ambient Occlusion is not in itself a post processing effect. Screen Space Ambient Occlusion is a post processing effect using the depth buffer to ...
user avatar
  • 5,882
8 votes
Accepted

How is motion blur implemented in modern realtime renderers?

There are several techniques used. A simple, but limited, post-process approach that is not really used any more consists in reconstructing the world space position of a pixel using both the view ...
user avatar
  • 2,468
6 votes

Making low discrepancy sequence noise textures, not LDS sample positions

In theory, it is possible to stuff every sample distribution into a texture to "pre-bake" it for fast access. The question is whether any of the results might be useful. For blue noise, this makes a ...
user avatar
6 votes
Accepted

Artifacts when gamma correcting

Short answer, set the precision of the image to a higher value. Long answer, When looking at a gamma correction curve, you can see that the lower values get changed much more, this means that the ...
user avatar
  • 1,565
5 votes
Accepted

How does temporal reprojection work?

One strategy mentioned in Brian Karis's talk about TAA is neighborhood clamping. The general idea is that, for the previous frame's pixel to be valid, its color should be in the color range found in ...
user avatar
4 votes
Accepted

How does directional Gaussian blurring work?

If I understand your question, you are asking how to actually perform said directional blur in code? A Gaussian blur is typically done by sampling your image in all directions around your current ...
user avatar
4 votes

Why is AO considered Post-Processing?

Ambient occlusion isn't a technique, but rather a concept. It can be implemented (and approximated) as a post-processing effect such as SSAO, SSDO, HBAO+, etc. @trichoplax gave a good answer, I just ...
user avatar
  • 1,323
4 votes
Accepted

Adding noise to gradient

It's generally a good idea to add noise like this when you're using a gradient, to avoid visible banding in the gradient, especially on smartphones. Often smartphone screens claim to be 24-bit colour ...
user avatar
  • 6,450
3 votes
Accepted

Deriving blur from real optical formulae

First we can calculate the physical diameter of CoC in the image plane, given the lens parameters. This equation is from Wikipedia – Circle of confusion: $$ c = {|S_2 - S_1| \over S_2} {f^2 \over N(...
user avatar
  • 23.6k
1 vote
Accepted

SSR/RTLR - hitting object/ending condition

The termination condition is that the ray passes through the surface represented in the depth buffer. To track this, you have to calculate the z position of the ray at the current step, and compare it ...
user avatar
  • 23.6k
1 vote
Accepted

Downscaling texture via mipmap [DirectX 11]

I found the problem. By zeroing the sampler description I implicitly set LOD bounds to 0. After adding ...
user avatar
  • 1,377
1 vote

What is a common approach to smooth structures in textures?

I don't have enough rep to add a comment so... You could use a post process based anti-aliasing technique like FXAA or SMAA. Also, if performance is not a priority, you could go for SSAA. Another ...
user avatar
  • 110
1 vote

How does temporal reprojection work?

temporal reprojection works surprisingly well and simplistic with (in between) volume-marching (where rays scatter through a cloud of different density, with hard or smooth density-gradients) validity ...
user avatar
  • 21

Only top scored, non community-wiki answers of a minimum length are eligible