* Convert all code to use new functions.
* Branch maintainers may want to skip this commit, and run this
conversion script instead, if they use a lot of math functions
in new code:
http://www.pasteall.org/9052/python
* Rendering twice or more could crash layer/pass buttons.
* Compositing would crash while drawing the image.
* Rendering animations could also crash drawing the image.
* Compositing could crash
* Starting to rendering while preview render / compo was
still running could crash.
* Exiting while rendering an animation would not abort the
renderer properly, making Blender seemingly freeze.
* Fixes theoretically possible issue with setting malloc
lock with nested threads.
* Drawing previews inside nodes could crash when those nodes
were being rendered at the same time.
There's more crashes, manipulating the scene data or undo can
still crash, this commit only focuses on making sure the image
buffer and render result access is thread safe.
Implementation:
* Rather than assuming the render result does not get freed
during render, which seems to be quite difficult to do given
that e.g. the compositor is allowed to change the size of
the buffer or output different passes, the render result is
now protected with a read/write mutex.
* The read/write mutex allows multiple readers (and pixel
writers) at the same time, but only allows one writer to
manipulate the data structure.
* Added BKE_image_acquire_ibuf/BKE_image_release_ibuf to access
images being rendered, cases where this is not needed (most
code) can still use BKE_image_get_ibuf.
* The job manager now allows only one rendering job at the same
time, rather than the G.rendering check which was not reliable.
After code review and experimentation, this commit makes some changes to the way that volumes are shaded. Previously, there were problems with the 'scattering' component, in that it wasn't physically correct - it didn't conserve energy and was just acting as a brightness multiplier. This has been changed to be more correct, so that as the light is scattered out of the volume, there is less remaining to penetrate through.
Since this behaviour is very similar to absorption but more useful, absorption has been removed and has been replaced by a 'transmission colour' - controlling the colour of light penetrating through the volume after it has been scattered/absorbed. As well as this, there's now 'reflection', a non-physically correct RGB multiplier for out-scattered light. This is handy for tweaking the overall colour of the volume, without having to worry about wavelength dependent absorption, and its effects on transmitted light. Now at least, even though there is the ability to tweak things non-physically, volume shading is physically based by default, and has a better combination of correctness and ease of use.
There's more detailed information and example images here:
http://wiki.blender.org/index.php/User:Broken/VolumeRendering
Also did some tweaks/optimisation:
* Removed shading step size (was a bit annoying, if it comes back, it will be in a different form)
* Removed phase function options, now just one asymmetry slider controls the range between back-scattering, isotropic scattering, and forward scattering. (note, more extreme values gives artifacts with light cache, will fix...)
* Disabled the extra 'bounce lights' from the preview render for volumes, speeds updates significantly
* Enabled voxeldata texture in preview render
* Fixed volume shadows (they were too dark, fixed by avoiding using the shadfac/AddAlphaLight stuff)
More revisions to come later...
Editors Modules
* render/ module added in editors, moved the preview render code there and
also shading related operators.
* physics/ module made more consistent with other modules. renaming files,
making a single physics_ops.c for operators and keymaps. Also move all
particle related operators here now.
* space_buttons/ now should have only operators relevant to the buttons
specificially.
Updates & Notifiers
* Material/Texture/World/Lamp can now be passed to DAG_id_flush_update,
which will go back to a callback in editors. Eventually these should
be in the depsgraph itself, but for now this gives a unified call for
doing updates.
* GLSL materials are now refreshed on changes. There's still various
cases missing,
* Preview icons now hook into this system, solving various update cases
that were missed before.
* Also fixes issue in my last commit, where some preview would not render,
problem is avoided in the new system.
Icon Rendering
* On systems with support for non-power of two textures, an OpenGL texture
is now used instead of glDrawPixels. This avoids problems with icons get
clipped on region borders. On my Linux desktop, this gives an 1.1x speedup,
and on my Mac laptop a 2.3x speedup overall in redrawing the full window,
with the default setup. The glDrawPixels implementation on Mac seems to
have a lot of overhread.
* Preview icons are now drawn using proper premul alpha, and never faded so
you can see them clearly.
* Also tried to fix issue with texture node preview rendering, globals can't
be used with threads reliably.
