This allows users to implement arbitrary camera models using OSL by writing
shaders that take an image position as input and compute ray origin and
direction.
The obvious applications for this are e.g. panorama modes, lens distortion
models and realistic lens simulation, but the possibilities are endless.
Currently, this is only supported on devices with OSL support, so CPU and
OptiX. However, it is independent from the shading model used, so custom
cameras can be used without getting the performance hit of OSL shading.
A few samples are provided as Text Editor templates.
One notable current limitation (in addition to the limited device support)
is that inverse mapping is not supported, so Window texture coordinates and
the Vector pass will not work with custom cameras.
Pull Request: https://projects.blender.org/blender/blender/pulls/129495
I'm moving this for two (related) reasons:
* It depends a lot on the specifics of `Camera` and `Object` data-blocks.
* It links `Object::object_to_world()` which is not an inline function and thus
easily leads to linker errors. It mostly seems like luck that this is not
breaking our build due to early dead code elimination when linking binaries
which use the blenlib static library such as `msgfmt`.
I found this while working on a compilation tool which would not be as lucky and
has a linker error because of the dependence on `Object::object_to_world`.
Pull Request: https://projects.blender.org/blender/blender/pulls/136547
