On the one hand, this improves initialization time since we don't need to
load/compile the full OSL module with all the shading logic if we're only
using a custom camera with SVM shading.
On the other hand, it also fixes a bug I noticed while preparing test scenes:
The AO and Bevel nodes don't work when using custom cameras with SVM on OptiX.
The issue there is that those two are handled by the SHADE_SURFACE_RAYTRACE
kernel, but since that one has intersection logic, we use the OptiX-specific
kernel even if OSL shading is disabled.
However, with the previous unified OSL module, this would mean loading
SHADE_SURFACE_RAYTRACE from kernel_osl.cu, which has `#undef __SVM__` and
therefore doesn't handle them correctly.
With this change, we'll use the kernels from kernel_shader_raytrace.cu in that
case, which do support SVM nodes just fine.
Disk usage of the new kernel_optix_osl_camera.ptx.zst file is 30KB, so this
also doesn't blow up the kernel disk size (and kernel_optix_osl.ptx.zst is
probably smaller by that amount now).
Since it seems that we can mix modules just fine, I'm suspecting that we could
split the modules properly (intersection, SVM shading with raytracing,
OSL shading, OSL camera), instead of the current approach where modules
essentially correspond to feature set tiers and each includes the previous
one's kernels as well - but that's a separate refactor.
Pull Request: https://projects.blender.org/blender/blender/pulls/138021
0dc4754da4