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 ...
7
votes
Accepted
Alternatives to Ambient Occlusion
Ambient occlusion cannot be physically based no matter what algorithm you use to calculate it. It's a simplification of global illumination that assumes all occluders only block light and are ...
- 434
6
votes
Accepted
Am I missing something for ambient occlusion?
It's a bit hard to tell from your image, but it does look a bit faint. When debugging these kinds of things, it's always useful to strip down your scene as much as possible to remove any unnecessary ...
- 2,595
6
votes
Accepted
What are some new Real-Time Graphics Rendering Techniques to get closer to real life?
PBR isn't just a feature you "add to a rendering engine" but an entire philosophy how to approach solving rendering problems. This seems to be a common prevailing misconception when people talk about ...
- 3,596
6
votes
Accepted
What is ambient occlusion?
Your point is correct when applied to ambient lighting as an approximation technique. This crude approach does indeed give the same lighting level to all surfaces regardless of their surroundings.
...
5
votes
Why wasn't CryTek SSAO multiplied by 2?
Ambient occlusion is the direct illumination at a Lambertian surface point due to a homogeneous light source at infinity. That means that you assume a light source with $L_e(\pm\infty, \omega_i) = 1$, ...
- 2,041
5
votes
What is the difference between shading and shadowing?
In simplified terms, shading controls how object's surface's brightness changes when the angle between its normal and light vector changes. Shadows are areas where the light cannot reach because it's ...
- 298
5
votes
What is ambient occlusion?
Ambient light does not really exist, if we do not talk about cosmology. What we call ambient is just light form many secondary reflections.
Image 1: No ambient light (left) and ambient light (right). ...
- 8,367
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 ...
- 1,353
4
votes
Accepted
Ambient occlusion of a sole object in a scene
When you compute ambient occlusion (AO) for a point on an object's surface, you sample multiple directions and measure what fraction of them escape. That is, you're trying to approximate what fraction ...
- 6,680
3
votes
Ambient occlusion of a sole object in a scene
Ambient occlusion is basically shooting out a large number of rays diffusely from a surface point. In a pipe some of the rays will intersect with the pipe itself, which means that this surface point ...
- 315
3
votes
Am I missing something for ambient occlusion?
I'll add some guidelines to help readers understand Benedikt Bitterli's statement "Make sure to gamma correct your images".
Gamma correcting images does not mean applying a power filter at the end.
...
- 623
3
votes
Accepted
What is Radiosity?
Radiosity is a way to calculate diffuse GI, i.e. every surface is assumed to be Lambertian surface without specular component. In the radiosity algorithm you split surfaces into small patches and ...
- 3,596
2
votes
What is the difference between shading and shadowing?
The distinction is not clear mainly because the term "shading" is an extremely broad term. One of the first uses for programmable "shaders" in real-time graphics pipeline was computing illumination on ...
- 593
2
votes
Accepted
Edge-aware spatial denoising (Ambient Occlusion)
I've also been working on GTAO denoising, and came across the same equation.The function is weighing the neighbouring samples by their depth-difference from the center sample, and also by their slopes....
2
votes
Accepted
SSAO with reconstructed depths yields strip artifacts
For anyone having the same problem:
I calculated the normalized texture coordinates by
...
- 163
2
votes
Accepted
Screen Space Ambient Occlusion Issues
You need to be careful about spaces - position and normal need to be in view space.
To transform depth into view space position I used this method.
So:
...
- 2,089
1
vote
Why wasn't CryTek SSAO multiplied by 2?
1 possible answer from RTR4:
"Doing so causes a flat surface to be darkened, with edges being brighter than their surroundings. Nonetheless, the results are often visually pleasing."
- 11
1
vote
Accepted
Ambient occlusion depth buffer normalization
Here is a linearize depth function that expects the non-linear values to be between [0,1] and works in Vulkan.
...
- 2,935
1
vote
Ambient occlusion depth buffer normalization
I feel it could do with the depth buffer since I was not sure what "ndc_linear_depth" meant. I was told to implement a
normalised device coordinate linear depth
Which confused me since ...
- 1,233
1
vote
Expected visibility
You need to perform integration of $P$ over the hemisphere to calculate the solution. There doesn't seem to be closed-form solution as the solution requires incomplete gamma function:
$$2\pi(e^{-\...
- 3,596
Only top scored, non community-wiki answers of a minimum length are eligible