New feature: Exporting rendered model as png.
A offscreen render been introduced for generating normal and depth maps, which are been generated for toon shader edge detection.
In the previous version, the nodes get selected and copied, without lost selection after new nodes pasted.
This commit fix this problem. Now, the old nodes lose selection while new pasted nodes gettting selected.
This feature will make the following use case much easier:
Extrude:
Select some nodes, copy, paste then scale.
Jeremy Hu