forked from bartvdbraak/blender
9020df976c
* Added a node to convert wavelength (in nanometers, from 380nm to 780nm) to RGB values. This can be useful to match real world colors easier. * Code cleanup: ** Moved color functions (xyz and hsv) into dedicated utility files. ** Remove svm_lerp(), use interp() instead. Documentation: http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Wavelength Example render: http://www.pasteall.org/pic/show.php?id=53202 This is part of my GSoC 2013. (revisions 57322, 57326, 57335 and 57367 from soc-2013-dingto).
151 lines
4.6 KiB
Plaintext
151 lines
4.6 KiB
Plaintext
/*
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* Copyright 2011, Blender Foundation.
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "stdosl.h"
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#include "node_color.h"
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struct KernelSunSky {
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/* sun direction in spherical and cartesian */
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float theta, phi;
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vector dir;
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/* perez function parameters */
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float zenith_Y, zenith_x, zenith_y;
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float perez_Y[5], perez_x[5], perez_y[5];
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};
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float sky_angle_between(float thetav, float phiv, float theta, float phi)
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{
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float cospsi = sin(thetav) * sin(theta) * cos(phi - phiv) + cos(thetav) * cos(theta);
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if (cospsi > 1.0)
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return 0.0;
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if (cospsi < -1.0)
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return M_PI;
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return acos(cospsi);
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}
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vector sky_spherical_coordinates(vector dir)
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{
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return vector(acos(dir[2]), atan2(dir[0], dir[1]), 0);
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}
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float sky_perez_function(float lam[5], float theta, float gamma)
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{
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float ctheta = cos(theta);
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float cgamma = cos(gamma);
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return (1.0 + lam[0] * exp(lam[1] / ctheta)) * (1.0 + lam[2] * exp(lam[3] * gamma) + lam[4] * cgamma * cgamma);
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}
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color sky_xyz_radiance(KernelSunSky sunsky, vector dir)
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{
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/* convert vector to spherical coordinates */
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vector spherical = sky_spherical_coordinates(dir);
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float theta = spherical[0];
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float phi = spherical[1];
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/* angle between sun direction and dir */
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float gamma = sky_angle_between(theta, phi, sunsky.theta, sunsky.phi);
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/* clamp theta to horizon */
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theta = min(theta, M_PI_2 - 0.001);
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/* compute xyY color space values */
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float x = sunsky.zenith_x * sky_perez_function(sunsky.perez_x, theta, gamma);
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float y = sunsky.zenith_y * sky_perez_function(sunsky.perez_y, theta, gamma);
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float Y = sunsky.zenith_Y * sky_perez_function(sunsky.perez_Y, theta, gamma);
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/* convert to RGB */
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color xyz = xyY_to_xyz(x, y, Y);
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return xyz_to_rgb(xyz[0], xyz[1], xyz[2]);
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}
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void precompute_sunsky(vector dir, float turbidity, output KernelSunSky sunsky)
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{
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vector spherical = sky_spherical_coordinates(dir);
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float theta = spherical[0];
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float phi = spherical[1];
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sunsky.theta = theta;
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sunsky.phi = phi;
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sunsky.dir = dir;
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float theta2 = theta * theta;
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float theta3 = theta2 * theta;
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float T = turbidity;
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float T2 = T * T;
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float chi = (4.0 / 9.0 - T / 120.0) * (M_PI - 2.0 * theta);
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sunsky.zenith_Y = (4.0453 * T - 4.9710) * tan(chi) - 0.2155 * T + 2.4192;
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sunsky.zenith_Y *= 0.06;
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sunsky.zenith_x =
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( 0.00166 * theta3 - 0.00375 * theta2 + 0.00209 * theta) * T2 +
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(-0.02903 * theta3 + 0.06377 * theta2 - 0.03202 * theta + 0.00394) * T +
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( 0.11693 * theta3 - 0.21196 * theta2 + 0.06052 * theta + 0.25886);
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sunsky.zenith_y =
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( 0.00275 * theta3 - 0.00610 * theta2 + 0.00317 * theta) * T2 +
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(-0.04214 * theta3 + 0.08970 * theta2 - 0.04153 * theta + 0.00516) * T +
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( 0.15346 * theta3 - 0.26756 * theta2 + 0.06670 * theta + 0.26688);
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sunsky.perez_Y[0] = ( 0.1787 * T - 1.4630);
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sunsky.perez_Y[1] = (-0.3554 * T + 0.4275);
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sunsky.perez_Y[2] = (-0.0227 * T + 5.3251);
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sunsky.perez_Y[3] = ( 0.1206 * T - 2.5771);
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sunsky.perez_Y[4] = (-0.0670 * T + 0.3703);
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sunsky.perez_x[0] = (-0.0193 * T - 0.2592);
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sunsky.perez_x[1] = (-0.0665 * T + 0.0008);
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sunsky.perez_x[2] = (-0.0004 * T + 0.2125);
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sunsky.perez_x[3] = (-0.0641 * T - 0.8989);
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sunsky.perez_x[4] = (-0.0033 * T + 0.0452);
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sunsky.perez_y[0] = (-0.0167 * T - 0.2608);
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sunsky.perez_y[1] = (-0.0950 * T + 0.0092);
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sunsky.perez_y[2] = (-0.0079 * T + 0.2102);
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sunsky.perez_y[3] = (-0.0441 * T - 1.6537);
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sunsky.perez_y[4] = (-0.0109 * T + 0.0529);
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sunsky.zenith_Y /= sky_perez_function(sunsky.perez_Y, 0, theta);
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sunsky.zenith_x /= sky_perez_function(sunsky.perez_x, 0, theta);
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sunsky.zenith_y /= sky_perez_function(sunsky.perez_y, 0, theta);
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}
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shader node_sky_texture(
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int use_mapping = 0,
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matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
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vector Vector = P,
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vector sun_direction = vector(0, 0, 1),
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float turbidity = 2.2,
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output color Color = 0.0)
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{
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vector p = Vector;
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if (use_mapping)
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p = transform(mapping, p);
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KernelSunSky sunsky;
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precompute_sunsky(sun_direction, turbidity, sunsky);
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Color = sky_xyz_radiance(sunsky, p);
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}
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