Patch from Miika Hämäläinen.
The old Material "Only Shadow" used an ancient 'best guess'
formula using Lamp Distance and some averaging for converting
shadow values to alpha.
A couple of bug reporters already complained about the not
very predictable renders. Miika fixed this by adding two
new options, to only give the true shadow factor exclusively,
or to give a result including light intensity values.
More info:
http://projects.blender.org/tracker/index.php?func=detail&aid=26413&group_id=9&atid=127
* Particle age can now be used as the texture x-coordinate, and location in a particle trail as the y-coordinate.
* This finally enables particles in 2.5 to change their color (or any other texturable material property) by their age.
* In 2.4x this was accomplished with the "100 frames == particle age", but this was both non-intuitive and slow as the animation system had to be recalculated for every particle.
* Currently these are 2d coordinates (age/lifetime == x-coordinate, trail particle index/number of trail particles == y-coordinate), but other particle properties or possibly even a user definable property can be added as coordinates in the future.
* On the code side this uses the same coordinate definition number (for halo materials) as strand coordinates (for surface materials). This is also nice as they intuitively mean nearly the same thing, i.e. along strand or during particle life.
Texture animation is now shown in the animation editors. Texture stacks are shown for each Material/Lamp/World block that uses them.
There is currently still a bit of a bug with this which means that unless the owner of the texture stack is animated too, the animation data for the textures won't show up. This will get rectified soon though.
Also: Changed 'Spread' value to be proportional to the light cache voxel grid
(i.e. 0.5 spreads half the width of the grid), so that it's independent of light
cache resolution. This means that results should be similar as you increase/
decrease resolution.
Volumes can now receive shadows from external objects, either raytraced shadows or shadow maps.
To use external shadows, enable 'external shadows' in volume material 'lighting' panel. This an extra toggle since it causes a performance hit, but this can probably be revisited/optimised when the new raytrace accelerator is integrated. For shadow maps at least, it's still very quick.
Renamed 'scattering mode' to 'lighting mode' (a bit simpler to understand), and the options inside. Now there's:
- Shadeless
takes light contribution, but without shadowing or self-shading (fast)
good for fog-like volumes, such as mist, or underwater effects
- Shadowed (new)
takes light contribution with shadows, but no self-shading. (medium)
good for mist etc. with directional light sources
eg. http://vimeo.com/6901636
- Shaded
takes light contribution with internal/external shadows, and self shading (slower)
good for thicker/textured volumes like smoke
- Multiple scattering etc (still doesn't work properly, on the todo).
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...
This solves one of the last remaining hurdles for
volume rendering. Previously it always used ray
tracing to shade other objects inside or behind the
volume. This meant that said objects would look
aliased, unless you used Full OSA on the volume
(which is slow!). As well as this, it meant that you didn't
get a good alpha channel out of the volume to use for
compositing, similar to ray refracting materials.
This commit enables z transparency for volume
materials. Although it can be potentially less
physically correct, in most situations there's no
difference, and you get the benefit of nice sampling for
other objects and an alpha channel for compositing too.
* data reorganisation - uses own values now instead of reusing surface material properties (i.e. an individual density value, rather than reusing alpha) Files saved with the old system won't load up the same after this.
* improved defaults and ui
* Transparency is now it's own panel, with a boolean toggle
+ enum for z/ray transparency (following mockup made by
William). Also had to change DNA flags for this.
* Disabled radiosity a bit more in render engine, it still had
some effects like auto autosmooth.
* Make some sliders in material buttons percentages in RNA.
* Some other small tweaks in layout and naming.
Integration is still very rough around the edges and WIP, but it works, and can render smoke (using new Smoke format in Voxel Data texture) --> http://vimeo.com/6030983
More to come, but this makes things much easier to work on for me :)
* Diffuse/specular ramps works again.
* Wire is now a material type next to Surface and Halo.
* Removed Volume material type option until it is actually there.
* Some button layout tweaks.
* World and Lamp previews now working here too.
* Experiment with list template, showing only icons. Unfortunately
texture icon render crashes combined with preview render so it
shows all icons the same.
* Influence panels updated, with slider for each option. The values
are still linked though, will fix that later.
* Image texture controls a bit more complete, still WIP.
* Color ramp back.
* Objects now support up to 32767 material slots. It's easy to
increase this further, but I prefer not to increase the memory
usage of mesh faces, it seems unlikely that someone would
create 32767 distinct materials?
* Forward compatibility: the only thing you can potentially lose
reading a 2.5 file in 2.4 is object linking (instead of default
data), though usually that will go fine too. Reading files with
> 32 material slots in 2.4 can start giving issues.
* The ob->colbits variable is deprecated by the array ob->matbits
but I didn't remove the ob->colbits updates in very few places
it is set.
* I hope I changed all the relevant things, various places just
hardcoded the number 16 instead of using the MAXMAT define.
* Join Objects operator back. This is using the version from the
animsys2 branch coded by Joshua, which means it now supports
joining of shape keys.
* Fix for crash reading file saved during render.
* Added material "type" property, with Surface/Volume/Halo
options, compatible with sim_physics, as requested for
material buttons layout. Obviously the Volume setting
does nothing currently.
* Deprecated MA_HALO flag in favor of this.
This is mostly a contribution from Raul 'farsthary' Hernandez - an approximation for
multiple scattering within volumes. Thanks, Raul! Where single scattering considers
the path from the light to a point in the volume, and to the eye, multiple scattering
approximates the interactions of light as it bounces around randomly within the
volume, before eventually reaching the eye.
It works as a diffusion process that effectively blurs the lighting information
that's already stored within the light cache.
A cloudy sky setup, with single scattering, and multiple scattering:
http://mke3.net/blender/devel/rendering/volumetrics/vol_sky_ss_ms.jpghttp://mke3.net/blender/devel/rendering/volumetrics/sky_ms.blend
To enable it, there is a menu in the volume panel (which needs a bit of cleanup, for
later), that lets you choose between self-shading methods:
* None: No attenuation of the light source by the volume - light passes straight
through at full strength
* Single Scattering: (same as previously, with 'self-shading' enabled)
* Multiple Scattering: Uses multiple scattering only for shading information
* Single + Multiple: Adds the multiple scattering lighting on top of the existing
single scattered light - this can be useful to tweak the strength of the effect,
while still retaining details in the lighting.
An example of how the different scattering methods affect the visual result:
http://mke3.net/blender/devel/rendering/volumetrics/ss_ms_comparison.jpghttp://mke3.net/blender/devel/rendering/volumetrics/ss_ms_comparison.blend
The multiple scattering methods introduce 3 new controls when enabled:
* Blur: A factor blending between fully diffuse/blurred lighting, and sharper
* Spread: The range that the diffuse blurred lighting spreads over - similar to a
blur width. The higher the spread, the slower the processing time.
* Intensity: A multiplier for the multiple scattering light brightness
Here's the effect of multiple scattering on a tight beam (similar to a laser). The
effect of the 'spread' value is pretty clear here:
http://mke3.net/blender/devel/rendering/volumetrics/ms_spread_laser.jpg
Unlike the rest of the system so far, this part of the volume rendering engine isn't
physically based, and currently it's not unusual to get non-physical results (i.e.
much more light being scattered out then goes in via lamps or emit). To counter this,
you can use the intensity slider to tweak the brightness - on the todo, perhaps there is a more automatic method we can work on for this later on. I'd also like to check
on speeding this up further with threading too.
* Made AnimData blocks be stored as pointer instead of directly in the ID-datablock, so that fewer files will need to be recompiled everytime some animation settings change.
* Tried to fix some of the compiler errors that pop up in Yafray code. If this commit doesn't fix it, just disable Yafray code for now (WITH_BF_YAFRAY=0 for scons)...
Finally, here is the basic (functional) prototype of the new animation system which will allow for the infamous "everything is animatable", and which also addresses several of the more serious shortcomings of the old system. Unfortunately, this will break old animation files (especially right now, as I haven't written the version patching code yet), however, this is for the future.
Highlights of the new system:
* Scrapped IPO-Curves/IPO/(Action+Constraint-Channels)/Action system, and replaced it with F-Curve/Action.
- F-Curves (animators from other packages will feel at home with this name) replace IPO-Curves.
- The 'new' Actions, act as the containers for F-Curves, so that they can be reused. They are therefore more akin to the old 'IPO' blocks, except they do not have the blocktype restriction, so you can store materials/texture/geometry F-Curves in the same Action as Object transforms, etc.
* F-Curves use RNA-paths for Data Access, hence allowing "every" (where sensible/editable that is) user-accessible setting from RNA to be animated.
* Drivers are no longer mixed with Animation Data, so rigs will not be that easily broken and several dependency problems can be eliminated. (NOTE: drivers haven't been hooked up yet, but the code is in place)
* F-Curve modifier system allows useful 'large-scale' manipulation of F-Curve values, including (I've only included implemented ones here): envelope deform (similar to lattices to allow broad-scale reshaping of curves), curve generator (polynomial or py-expression), cycles (replacing the old cyclic extrapolation modes, giving more control over this). (NOTE: currently this cannot be tested, as there's not access to them, but the code is all in place)
* NLA system with 'tracks' (i.e. layers), and multiple strips per track. (NOTE: NLA system is not yet functional, as it's only partially coded still)
There are more nice things that I will be preparing some nice docs for soon, but for now, check for more details:
http://lists.blender.org/pipermail/bf-taskforce25/2009-January/000260.html
So, what currently works:
* I've implemented two basic operators for the 3D-view only to Insert and Delete Keyframes. These are tempolary ones only that will be replaced in due course with 'proper' code.
* Object Loc/Rot/Scale can be keyframed. Also, the colour of the 'active' material (Note: this should really be for nth material instead, but that doesn't work yet in RNA) can also be keyframed into the same datablock.
* Standard animation refresh (i.e. animation resulting from NLA and Action evaluation) is now done completely separate from drivers before anything else is done after a frame change. Drivers are handled after this in a separate pass, as dictated by depsgraph flags, etc.
Notes:
* Drivers haven't been hooked up yet
* Only objects and data directly linked to objects can be animated.
* Depsgraph will need further tweaks. Currently, I've only made sure that it will update some things in the most basic cases (i.e. frame change).
* Animation Editors are currently broken (in terms of editing stuff). This will be my next target (priority to get Dopesheet working first, then F-Curve editor - i.e. old IPO Editor)
* I've had to put in large chunks of XXX sandboxing for old animation system code all around the place. This will be cleaned up in due course, as some places need special review.
In particular, the particles and sequencer code have far too many manual calls to calculate + flush animation info, which is really bad (this is a 'please explain yourselves' call to Physics coders!).
Merged 'backend' changes from AnimSys2. Many of these changes are necessary for the Dopesheet and other changes I'm currently still stabilising. Those will come in due course.
This commit introduces a new texture ('Voxel Data'), used to load up saved voxel
data sets for rendering, contributed by Raúl 'farsthary' Fernández Hernández
with some additional tweaks. Thanks, Raúl!
The texture works similar to the existing point density texture, currently it
only provides intensity information, which can then be mapped (for example) to
density in a volume material. This is an early version, intended to read the
voxel format saved by Raúl's command line simulators, in future revisions
there's potential for making a more full-featured 'Blender voxel file format',
and also for supporting other formats too.
Note: Due to some subtleties in Raúl's existing released simulators, in order
to load them correctly the voxel data texture, you'll need to raise the
'resolution' value by 2. So if you baked out the simulation at resolution 50,
enter 52 for the resolution in the texture panel. This can possibly be fixed in
the simulator later on.
Right now, the way the texture is mapped is just in the space 0,0,0 <-> 1,1,1
and it can appear rotated 90 degrees incorrectly. This will be tackled, for now,
probably the easiest way to map it is with and empty, using Map Input -> Object.
Smoke test: http://www.vimeo.com/2449270
One more note, trilinear interpolation seems a bit slow at the moment, we'll
look into this.
For curiosity, while testing/debugging this, I made a script that exports a mesh
to voxel data. Here's a test of grogan (www.kajimba.com) converted to voxels,
rendered as a volume: http://www.vimeo.com/2512028
The script is available here: http://mke3.net/projects/bpython/export_object_voxeldata.py
* Another smaller thing, brought back early ray termination (was disabled
previously for debugging) and made it user configurable. It now appears as a new
value in the volume material: 'Depth Cutoff'. For some background info on what
this does, check:
http://farsthary.wordpress.com/2008/12/11/cutting-down-render-times/
* Also some disabled work-in-progess code for light cache
alpha channel based on the volume's transmission properties, allowing you
to use it in comp etc.
I'd rather not have this button at all, and make it just work properly
by default, however it causes problems with overlapping volumes when
'premul' is on (stoopid thing..) so for the time being, there's the
button. I'll try and fix this up later on when I have more time.
This is on by default, and trades random noise for banding. It jitters
the step size from 75% to 125% of its original amount, and since it
uses the threaded random seeds, shouldn't flicker during animation.
These two images took roughly the same time to render:
http://mke3.net/blender/devel/rendering/volumetrics/vol_stepsize_randomized.jpg
- modified point density so that it returns a more consistent
density with regards to search radius. Previously larger radii
would give much higher density but this is equalised out now.
- Added a new volume material option 'density scale'. This is an
overall scale multiplier for density, allowing you to (for
example) crank down the density to a more desirable range if
you're working at a large physical scale. Volume rendering is
fundamentally scale dependant so this lets you correct to get the
right visual result.
- Also tweaked a few constants, old files won't render exactly
the same, just minor things though.
Otherwise known as a phase function, this determines in which directions
the light is scattered in the volume. Until now it's been isotropic
scattering, meaning that the light gets scattered equally in all
directions. This adds some new types for anisotropic scattering, to
scatter light more forwards or backwards towards the viewing direction,
which can be more similar to how light is scattered by particles in nature.
Here's a diagram of how light is scattered isotropically and anisotropically:
http://mke3.net/blender/devel/rendering/volumetrics/phase_diagram.png
The new additions are:
- Rayleigh
describes scattering by very small particles in the atmosphere.
- Mie Hazy / Mie Murky
more generalised, describes scattering from large particle sizes.
- Henyey-Greenstein
a very flexible formula, that can be used to simulate a wide range of
scattering. It uses an additional 'Asymmetry' slider, ranging from -1.0
(backward scattering) to 1.0 (forward scattering) to control the
direction of scattering.
- Schlick
an approximation of Henyey-Greenstein, working similarly but faster.
And a description of how they look visually (just an omnidirectional lamp
inside a volume box)
http://mke3.net/blender/devel/rendering/volumetrics/phasefunctions.jpg
* Sun/sky integration
Volumes now correctly render in front of the new physical sky. Atmosphere
still doesn't work correctly with volumes, due to something that i hope
can be fixed in the atmosphere rendering, but the sky looks quite good.
http://mke3.net/blender/devel/rendering/volumetrics/sky_clouds.png
This also works very nicely with the anisotropic scattering, giving
clouds their signature bright halos when the sun is behind them:
http://mke3.net/blender/devel/rendering/volumetrics/phase_cloud.mov
in comparison here's a render with isotropic scattering:
http://mke3.net/blender/devel/rendering/volumetrics/phase_cloud_isotropic.png
* Added back the max volume depth tracing limit, as a hard coded value -
fixes crashes with weird geometry, like the overlapping faces around
suzanne's eyes. As a general note, it's always best to use volume
materials on airtight geometry, without intersecting or overlapping faces.
limit ray intersections like as for ray transparency). It
remains to be seen if it's even that useful, and was
preventing refracting materials behind volumes from
working easily.
Removed all the old particle rendering code and options I had in there
before, in order to make way for...
A new procedural texture: 'Point Density'
Point Density is a 3d texture that find the density of a group of 'points'
in space and returns that in the texture as an intensity value. Right now,
its at an early stage and it's only enabled for particles, but it would be
cool to extend it later for things like object vertices, or point cache
files from disk - i.e. to import point cloud data into Blender for
rendering volumetrically.
Currently there are just options for an Object and its particle system
number, this is the particle system that will get cached before rendering,
and then used for the texture's density estimation.
It works totally consistent with as any other procedural texture, so
previously where I've mapped a clouds texture to volume density to make
some of those test renders, now I just map a point density texture to
volume density.
Here's a version of the same particle smoke test file from before, updated
to use the point density texture instead:
http://mke3.net/blender/devel/rendering/volumetrics/smoke_test02.blend
There are a few cool things about implementing this as a texture:
- The one texture (and cache) can be instanced across many different
materials:
http://mke3.net/blender/devel/rendering/volumetrics/pointdensity_instanced.png
This means you can calculate and bake one particle system, but render it
multiple times across the scene, with different material settings, at no
extra memory cost.
Right now, the particles are cached in world space, so you have to map it
globally, and if you want it offset, you have to do it in the material (as
in the file above). I plan to add an option to bake in local space, so you
can just map the texture to local and it just works.
- It also works for solid surfaces too, it just gets the density at that
particular point on the surface, eg:
http://mke3.net/blender/devel/rendering/volumetrics/pointdensity_solid.mov
- You can map it to whatever you want, not only density but the various
emissions and colours as well. I'd like to investigate using the other
outputs in the texture too (like the RGB or normal outputs), perhaps with
options to colour by particle age, generating normals for making particle
'dents' in a surface, whatever!
sure if this is 'correct' but so far in testing it's been working
pretty well.
This also exposes a new 'Nearest' value, to determine how many
nearby particles are taken into account when determining density.
A greater number is more accurate, but slower.
Initial commit for supporting rendering particles directly as
volume density. It works by looking up how many particles are
within a specified radius of the currently shaded point and using
that to calculate density (which is used just as any other
measure of density would be).
http://mke3.net/blender/devel/rendering/volumetrics/smoke_test01.movhttp://mke3.net/blender/devel/rendering/volumetrics/smoke_test01.blend
Right now it's an early implementation, just to see that it can
work - it may end up changing quite a bit. Currently, it's just a
single switch on the volume material - it looks up all particles
in the scene for density at the current shaded point in world
space (so the volume region must enclose the particles in order
to render them.
This will probably change - one idea I have is to make the
particle density estimation a procedural texture with options for:
* the object and particle system to use
* the origin of the co-ordinate system, i.e. object center, world
space, etc.
This would allow you in a sense, to instance particle systems for
render - you only need to bake one particle system, but you can
render it anywhere.
Anyway, plenty of work to do here, firstly on getting a nice
density evaluation with falloff etc...
solids, in front of other volumes, etc. Now there's a 'layer depth'
value that works similarly to refraction depth - a limit for how many
times the view ray will penetrate different volumetric surfaces.
I have it close to being able to return alpha, but it's still not 100%
correct and needs a bit more work. Going to sit on this for a while.
Rather than a single absorption value to control how much light is absorbed as it
travels through a volume, there's now an additional absorption colour. This is
used to absorb different R/G/B components of light at different amounts. For
example, if a white light shines on a volume which absorbs green and blue
components, the volume will appear red.
To make it easier to use, the colour set in the UI is actually the inverse of the
absorption colour, so the colour you set is the colour that the volume will
appear as.
Here's an example of how it works:
http://mke3.net/blender/devel/rendering/volumetrics/vol_col_absorption.jpg
And this can be textured too:
http://mke3.net/blender/devel/rendering/volumetrics/vol_absorb_textured.png
Keep in mind, this doesn't use accurate spectral light wavelength mixing (just
R/G/B channels) so in cases where the absorption colour is fully red green or
blue, you'll get non-physical results.
Todo: refactor the volume texturing internal interface...
- Fixed a shading bug, due to issues in the raytrace engine where it would ignore
intersections from the starting face (as it should). Disabled this for single
scattering intersections, thanks to Brecht for a hint there. It still shows a
little bit of noise, I think due to raytrace inaccuracy, which will have to be
fixed up later.
before: http://mke3.net/blender/devel/rendering/volumetrics/vol_shaded_old.png
after: http://mke3.net/blender/devel/rendering/volumetrics/vol_shaded_correct.png
Now single scatttering shading works very nicely and is capable of things like this:
http://mke3.net/blender/devel/rendering/volumetrics/vol_shaded_clouds.mov
- Added colour emission. Now as well as the overall 'Emit:' slider to control
overall emission strength, there's also a colour swatch for the volume to emit
that colour. This can also be textured, using 'Emit Col' in the map to panel.
This animation was made using a clouds texture, with colour band, mapped to both
emit colour and emit (strength):
http://mke3.net/blender/devel/rendering/volumetrics/vol_col_emit.mov
- Added 'Local' mapping to 'map input' - it's similar to Orco
- Fixed texture 'map input', wasn't using the offsets or scale values.
This is an initial commit to get it in SVN and make it easier to work on.
Don't expect it to work perfectly, it's still in development and there's
plenty of work still needing to be done. And so no I'm not very interested
in hearing bug reports or feature requests at this stage :)
There's some info on this, and a todo list at:
http://mke3.net/weblog/volume-rendering/
Right now I'm trying to focus on getting shading working correctly (there's
currently a problem in which 'surfaces' of the volume facing towards or away
from light sources are getting shaded differently to how they should be),
then I'll work on integration issues, like taking materials behind the volume
into account, blending with alpha, etc. You can do simple testing though,
mapping textures to density or emission on a cube with volume material.
- Added blending mode and factor option, so it's more clear and
controllable what happens with it. Also nice for crazy effects
of course!
- Preview render now shows preview for it too
On the todos:
- have this in World buttons (as well) for quicker sky setups
- review math of color clamping and scaling, this is definitely
not good... but a fix will make old files look very different.
the features that are needed to run the game. Compile tested with
scons, make, but not cmake, that seems to have an issue not related
to these changes. The changes include:
* GLSL support in the viewport and game engine, enable in the game
menu in textured draw mode.
* Synced and merged part of the duplicated blender and gameengine/
gameplayer drawing code.
* Further refactoring of game engine drawing code, especially mesh
storage changed a lot.
* Optimizations in game engine armatures to avoid recomputations.
* A python function to get the framerate estimate in game.
* An option take object color into account in materials.
* An option to restrict shadow casters to a lamp's layers.
* Increase from 10 to 18 texture slots for materials, lamps, word.
An extra texture slot shows up once the last slot is used.
* Memory limit for undo, not enabled by default yet because it
needs the .B.blend to be changed.
* Multiple undo for image painting.
* An offset for dupligroups, so not all objects in a group have to
be at the origin.
Ton Roosendaal
Nathan Letwory
Janne Karhu
Joshua Leung
Campbell Barton
Brecht Van Lommel
Matt Ebb
Robert Holcomb
William Reynish
Daniel Genrich
Chris Want
