Shadow Terminator problem
Posted: Wed Aug 07, 2019 9:20 am
Introduction
This was the starting point in a quite extreme case:
Fixing a couple of problems
As first step I have fixed 2 problems:
1) the self-shadow problem in 2 triangles with a glancing angle with the light source (i.e. see the noise due to some self-intersection of shadow rays);
2) the horrible bounce back of light intensity on the edge.
and the result is:
Note: the black triangles on the edge are unavoidable, their geometric normal points away from the light source so there is no way to fix them aside increasing tessellation and/or using softer shadows (due to a larger light source, etc.).
"Taming the Shadow Terminator" ... when using bump/normal mapping
This is another test:
Now look what happen if I add bump mapping:
Lights magically appears from no where and start to illuminate also over the shadow termination. This is what
"Taming the Shadow Terminator"
by Matt Jen-Yuan Chiang, Yining Karl Li and Brent Burley
https://www.yiningkarlli.com/projects/s ... nator.html
can fix. This is the same rendering using the shadow terminator avoidance factor described in the paper:
Better, now the renderings with and without bump mapping match each other.
P.S. this code is not part of beta3 but only available in daily builds.
This was the starting point in a quite extreme case:
Fixing a couple of problems
As first step I have fixed 2 problems:
1) the self-shadow problem in 2 triangles with a glancing angle with the light source (i.e. see the noise due to some self-intersection of shadow rays);
2) the horrible bounce back of light intensity on the edge.
and the result is:
Note: the black triangles on the edge are unavoidable, their geometric normal points away from the light source so there is no way to fix them aside increasing tessellation and/or using softer shadows (due to a larger light source, etc.).
"Taming the Shadow Terminator" ... when using bump/normal mapping
This is another test:
Now look what happen if I add bump mapping:
Lights magically appears from no where and start to illuminate also over the shadow termination. This is what
"Taming the Shadow Terminator"
by Matt Jen-Yuan Chiang, Yining Karl Li and Brent Burley
https://www.yiningkarlli.com/projects/s ... nator.html
can fix. This is the same rendering using the shadow terminator avoidance factor described in the paper:
Better, now the renderings with and without bump mapping match each other.
P.S. this code is not part of beta3 but only available in daily builds.