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/*
* Copyright 2011-2013 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "node_color.h"
#include "stdcycles.h"
float sky_angle_between(float thetav, float phiv, float theta, float phi)
{
float cospsi = sin(thetav) * sin(theta) * cos(phi - phiv) + cos(thetav) * cos(theta);
if (cospsi > 1.0)
return 0.0;
if (cospsi < -1.0)
return M_PI;
return acos(cospsi);
}
vector sky_spherical_coordinates(vector dir)
{
return vector(acos(dir[2]), atan2(dir[0], dir[1]), 0);
}
/* Preetham */
float sky_perez_function(float lam[9], float theta, float gamma)
{
float ctheta = cos(theta);
float cgamma = cos(gamma);
return (1.0 + lam[0] * exp(lam[1] / ctheta)) *
(1.0 + lam[2] * exp(lam[3] * gamma) + lam[4] * cgamma * cgamma);
}
color sky_radiance_old(normal dir,
float sunphi,
float suntheta,
color radiance,
float config_x[9],
float config_y[9],
float config_z[9])
{
/* convert vector to spherical coordinates */
vector spherical = sky_spherical_coordinates(dir);
float theta = spherical[0];
float phi = spherical[1];
/* angle between sun direction and dir */
float gamma = sky_angle_between(theta, phi, suntheta, sunphi);
/* clamp theta to horizon */
theta = min(theta, M_PI_2 - 0.001);
/* compute xyY color space values */
float x = radiance[1] * sky_perez_function(config_y, theta, gamma);
float y = radiance[2] * sky_perez_function(config_z, theta, gamma);
float Y = radiance[0] * sky_perez_function(config_x, theta, gamma);
/* convert to RGB */
color xyz = xyY_to_xyz(x, y, Y);
return xyz_to_rgb(xyz[0], xyz[1], xyz[2]);
}
/* Hosek / Wilkie */
float sky_radiance_internal(float config[9], float theta, float gamma)
{
float ctheta = cos(theta);
float cgamma = cos(gamma);
float expM = exp(config[4] * gamma);
float rayM = cgamma * cgamma;
float mieM = (1.0 + rayM) / pow((1.0 + config[8] * config[8] - 2.0 * config[8] * cgamma), 1.5);
float zenith = sqrt(ctheta);
return (1.0 + config[0] * exp(config[1] / (ctheta + 0.01))) *
(config[2] + config[3] * expM + config[5] * rayM + config[6] * mieM + config[7] * zenith);
}
color sky_radiance_new(normal dir,
float sunphi,
float suntheta,
color radiance,
float config_x[9],
float config_y[9],
float config_z[9])
{
/* convert vector to spherical coordinates */
vector spherical = sky_spherical_coordinates(dir);
float theta = spherical[0];
float phi = spherical[1];
/* angle between sun direction and dir */
float gamma = sky_angle_between(theta, phi, suntheta, sunphi);
/* clamp theta to horizon */
theta = min(theta, M_PI_2 - 0.001);
/* compute xyz color space values */
float x = sky_radiance_internal(config_x, theta, gamma) * radiance[0];
float y = sky_radiance_internal(config_y, theta, gamma) * radiance[1];
float z = sky_radiance_internal(config_z, theta, gamma) * radiance[2];
/* convert to RGB and adjust strength */
return xyz_to_rgb(x, y, z) * (M_2PI / 683);
}
shader node_sky_texture(int use_mapping = 0,
matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
vector Vector = P,
string type = "hosek_wilkie",
float theta = 0.0,
float phi = 0.0,
color radiance = color(0.0, 0.0, 0.0),
float config_x[9] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
float config_y[9] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
float config_z[9] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
output color Color = color(0.0, 0.0, 0.0))
{
vector p = Vector;
if (use_mapping)
p = transform(mapping, p);
if (type == "hosek_wilkie")
Color = sky_radiance_new(p, phi, theta, radiance, config_x, config_y, config_z);
else
Color = sky_radiance_old(p, phi, theta, radiance, config_x, config_y, config_z);
}
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