Add a new job type that can render a single image. It is broken up
into separate tiles, each of which can be rendered independently by a
worker. Only tested with Cycles.
Adaptive sampling is supported. For this, each tile is expanded by 16
pixels in each direction, which is later cropped off before merging
the tiles.
Denoising is not (yet) supported, as Blender/Cycles does not output
all the necessary data into EXR layers.
Tile sizes should (for now) be a power of 2, to avoid alignment
issues.
Reviewed-on: https://projects.blender.org/studio/flamenco/pulls/104327
Reviewed-by: Sybren A. Stüvel <sybren@blender.org>
