Some operations may use no preferredResolution ({0, 0}) when calling determineResolution on inputs to check if they have resolution on their own. See MixOperation or MathOperation determineResolution implementation. In such cases {0, 0} resolution ends up being set when an input doesn't have own resolution, breaking propagation of the original preferredResolution. They don't mean to set it as resolution, it's just a check.
This patch only allows to set valid resolutions (>0). When it's 0 it may be understood as "No preferred or determined resolution" so it should not be set to give output operations another chance of finding a proper resolution by calling determineResolution again with a different preferredResolution.
Test file:
{F9932526}
Reviewed By: #compositing, jbakker
Differential Revision: https://developer.blender.org/D10972
File output node always received the resolution from the first socket.
When that socket didn't had a link it would use a resolution of 0,0.
What lead to not saving the file at all.
This only effected Multi layer OpenEXR files.
This change would go over all the links to find the first valid
resolution.
For debugging purposes to convert the internal state of the
NodeOperationBuilder to a graphviz.
Usage:
std::cout << *this << "\n";
Inside any method of the NodeOperationBuilder.
