Matt Ebb
71b3088596
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 Since this behaviour is very similar to absorption but more useful, absorption has been removed and has been replaced by a 'transmission colour' - controlling the colour of light penetrating through the volume after it has been scattered/absorbed.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...
47 lines
1.5 KiB
C++
47 lines
1.5 KiB
C++
/**
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*
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* ***** BEGIN GPL LICENSE BLOCK *****
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
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* All rights reserved.
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*
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* The Original Code is: all of this file.
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*
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* Contributor(s): Matt Ebb.
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*
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* ***** END GPL LICENSE BLOCK *****
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*/
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float vol_get_density(struct ShadeInput *shi, float *co);
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void vol_get_scattering(ShadeInput *shi, float *scatter_col, float *co_);
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void shade_volume_outside(ShadeInput *shi, ShadeResult *shr);
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void shade_volume_inside(ShadeInput *shi, ShadeResult *shr);
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void shade_volume_shadow(struct ShadeInput *shi, struct ShadeResult *shr, struct Isect *last_is);
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#define STEPSIZE_VIEW 0
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#define STEPSIZE_SHADE 1
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#define VOL_IS_BACKFACE 1
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#define VOL_IS_SAMEMATERIAL 2
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#define VOL_BOUNDS_DEPTH 0
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#define VOL_BOUNDS_SS 1
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#define VOL_SHADE_OUTSIDE 0
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#define VOL_SHADE_INSIDE 1
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