When number of OSA samples is larger than number of AO samples, the AO
loop doesn't function well. Since rendering 16 OSA samples with only 9
AO samples isn't very useful, I've made the AO render level to become
at least equal or larger than amount of OSA samples.
Is first bug in 2.37 that worked in 2.36...
It used to be a simple hack, scaling lens with 100, and moving the camera
to the back with an equivalent amount.
Because of the hack, making it 100% compatible with older files I could not
achieve (yet?). To help reminding users, I've added a print when reading
old files with Ortho cameras.
Full description of how it works can be found here;
http://www.blender3d.com/cms/Render_changes.515.0.html
channels to link texture to.
The amount of code changes seems large, but is mostly getting rind of
hardcoded values (6 and 8) for channels, replacing it with MAX_MTEX.
Further did some fixes;
- Ipo for Lamp showed too many mapping channels
- Texture MapTo buttons for lamp missed the slider to blend texture color
- Lamp texture mapping "View" only worked for Spot, now it uses lamp-
view vector for all types. (Nice for projections!)
- AO energy slider to control amount
- option "Use sky color" for colored AO. The horizon color will define
bottom diffuse color, the zenith works on top
- option "Use sky texture" will do a full sky render to define AO color
Please note that AO energy and color only is found when a ray does not
intersect. So for interior scenes make sure 'Dist' value is sufficient
low.
New also is:
- World "Map input" allows "Ang Map" (Angular mapping) which can be used
for 360 degree spherical maps, aka as Light Probes. Check samples here:
http://www.debevec.org/Probes/
Note that Blender doesn't support HDRI images yet, but option "Use sky tex"
already gives intersting results with such images
- World sky rendering with Image Textures now correctly filters and uses
antialiasing. Also noticable for raytrace mirror reflections
- World preview render for sky type "Real" now gives correct view as
defined by current used camera.
I tried to speed up AO tracing with coherence systems, none of it really
worked yet... time to tackle octree itself i guess!
- Ambient Occlusion is a more sophisticated ambient trick, which takes
nearby faces into account by firing a hemisphere of shadow-rays
around. AKA 'dirt shader'.
- Eeshlo made it a Lamp type, which doesn't fit well. I've moved the
settings to the World menu, and let the Material->ambient value control
the amount it contributes
- currently, the AO value is added/subtracted/mixed with the 'diffuse'
factor while shading, before it is multiplied with Material color
Buttons are in new Panel 'Amb Occ" in F8 menu. Note:
- "Dist:" by shortening the length of rays you get subtler effects and it
renders faster too
- "DistF:" the attennuation factor gives control over how the 'shadow'
spreads out.
Further it's just raytracing, so tends to be slooooow.... :)
Here same tricks as for other raytraced scenes apply, especially try to
keep the environment as small as possible (exclude faces from Octree by
giving them no Material Traceable).
I still have to think over a couple of aspects, will await feedback on it:
- AO color? Now it just adds 'white'
- other sampling patterns? I tried dithering, which was so-so
- method of controlling final 'samples' in F10? Might be useful for other
oversampling too (area light) to have it reacting to a percentage or so..
re-using old one. New one = 'exp'.
- at first I used the old 'exposure' value, and just mapped it to 0. this
causes a problem with upward compatibility, old blenders then render a
black picture. is too confusing!
- warning; exposure values saved with commit of last week will get lost.
- based at 1.0-exp(-color) trick in Yafray. But to guarantee backwards
compatibility, and some more control, Stefano Selleri hacked a useful
formula for it.
- We now have 2 values to set:
- "exp": the exponential correction value (0-1)
- "range": the light range that maps on color 1.0 (0-5)
- Using exp(x) (is e^x) we can much better prevent overflows from render,
which are currently hard-clipped in Blender. Setting a small 'exp' value
wil efficiently smooth out high energy and map that back to a color for
display.
- total formula:
newcol= linfac*(1.0-exp(col*logfac))
col, newcol are colors
linfac= 1.0 + 1.0/((2.0*wrld.exp +0.5)^10)
logfac= log( (linfac-1.0)/linfac )/wrld.range
wrld.exp and wrld.range are the button values
- default setting: exp=0.0 and range=1.0 give results extremely close to
previous rendering.
- graph: http://www.selleri.org/Blender/buffer/Image1.png for 'exp' setting
ranging from 0-1, and with 'range'=2
Thanks Stefano for the help!
Updated the Make environment to point to the correct location. The include
paths were still pointing to source/blender/bpython/include while it should be
source/blender/python.
I did not encounter the build problems because I'm always working with the
autoconf build environment.
