kopaka1822
commented
4 years ago This is bad... Apparently this happens because of the HLSL pow function which is defined as:
| X | Y | Result |
|---|---|---|
| "< 0" | any | NAN |
| "> 0" | == 0 | 1 |
| "== 0" | > 0 | 0 |
| "== 0" | < 0 | inf |
| "> 0" | < 0 | 1/pow(X,-Y) |
| "== 0" | == 0 | Depends on the particular graphics processor 0, or 1, or NAN |
The GLSL pow function had undefined behaviour for X < 0 or X=0 and Y≤0.
The question would be how to handle the undefined behaviour inside the image viewer. My proposal would be:
| X | Y | Result |
|---|---|---|
| "< 0" | even | pow(-X, Y) |
| "< 0" | odd | -pow(-X, Y) |
| "< 0" | other | NaN |
| "> 0" | == 0 | 1 |
| "== 0" | > 0 | 0 |
| "== 0" | < 0 | inf |
| "> 0" | < 0 | 1/pow(X,-Y) |
| "== 0" | == 0 | NAN |
What are your thoughts?
(abs(I0-I1))^2 looks different and more correct
With (I0-I1)^2, the negative areas become 0