227 lines
7.3 KiB
Plaintext
227 lines
7.3 KiB
Plaintext
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#include "node_color.h"
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#include "stdcycles.h"
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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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/* Preetham */
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float sky_perez_function(float lam[9], 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)) *
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(1.0 + lam[2] * exp(lam[3] * gamma) + lam[4] * cgamma * cgamma);
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}
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color sky_radiance_preetham(normal dir,
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float sunphi,
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float suntheta,
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color radiance,
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float config_x[9],
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float config_y[9],
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float config_z[9])
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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, suntheta, sunphi);
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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 = radiance[1] * sky_perez_function(config_y, theta, gamma);
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float y = radiance[2] * sky_perez_function(config_z, theta, gamma);
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float Y = radiance[0] * sky_perez_function(config_x, 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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/* Hosek / Wilkie */
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float sky_radiance_internal(float config[9], 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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float expM = exp(config[4] * gamma);
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float rayM = cgamma * cgamma;
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float mieM = (1.0 + rayM) / pow((1.0 + config[8] * config[8] - 2.0 * config[8] * cgamma), 1.5);
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float zenith = sqrt(ctheta);
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return (1.0 + config[0] * exp(config[1] / (ctheta + 0.01))) *
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(config[2] + config[3] * expM + config[5] * rayM + config[6] * mieM + config[7] * zenith);
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}
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color sky_radiance_hosek(normal dir,
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float sunphi,
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float suntheta,
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color radiance,
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float config_x[9],
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float config_y[9],
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float config_z[9])
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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, suntheta, sunphi);
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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 xyz color space values */
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float x = sky_radiance_internal(config_x, theta, gamma) * radiance[0];
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float y = sky_radiance_internal(config_y, theta, gamma) * radiance[1];
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float z = sky_radiance_internal(config_z, theta, gamma) * radiance[2];
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/* convert to RGB and adjust strength */
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return xyz_to_rgb(x, y, z) * (M_2PI / 683);
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}
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/* Nishita improved */
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vector geographical_to_direction(float lat, float lon)
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{
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return vector(cos(lat) * cos(lon), cos(lat) * sin(lon), sin(lat));
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}
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float precise_angle(vector a, vector b)
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{
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return 2.0 * atan2(length(a - b), length(a + b));
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}
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color sky_radiance_nishita(vector dir, float nishita_data[10], string filename)
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{
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/* definitions */
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float sun_elevation = nishita_data[6];
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float sun_rotation = nishita_data[7];
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float angular_diameter = nishita_data[8];
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float sun_intensity = nishita_data[9];
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int sun_disc = angular_diameter > 0;
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float alpha = 1.0;
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color xyz;
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/* convert dir to spherical coordinates */
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vector direction = sky_spherical_coordinates(dir);
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/* render above the horizon */
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if (dir[2] >= 0.0) {
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/* definitions */
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vector sun_dir = geographical_to_direction(sun_elevation, sun_rotation + M_PI_2);
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float sun_dir_angle = precise_angle(dir, sun_dir);
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float half_angular = angular_diameter * 0.5;
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float dir_elevation = M_PI_2 - direction[0];
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/* If the ray is inside the sun disc, render it, otherwise render the sky.
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* Alternatively, ignore the sun if we're evaluating the background texture. */
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if (sun_dir_angle < half_angular && sun_disc == 1 && raytype("importance_bake") != 1) {
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/* get 2 pixels data */
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color pixel_bottom = color(nishita_data[0], nishita_data[1], nishita_data[2]);
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color pixel_top = color(nishita_data[3], nishita_data[4], nishita_data[5]);
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float y;
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/* sun interpolation */
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if (sun_elevation - half_angular > 0.0) {
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if ((sun_elevation + half_angular) > 0.0) {
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y = ((dir_elevation - sun_elevation) / angular_diameter) + 0.5;
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xyz = mix(pixel_bottom, pixel_top, y) * sun_intensity;
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}
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}
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else {
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if (sun_elevation + half_angular > 0.0) {
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y = dir_elevation / (sun_elevation + half_angular);
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xyz = mix(pixel_bottom, pixel_top, y) * sun_intensity;
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}
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}
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/* limb darkening, coefficient is 0.6f */
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float angle_fraction = sun_dir_angle / half_angular;
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float limb_darkening = (1.0 - 0.6 * (1.0 - sqrt(1.0 - angle_fraction * angle_fraction)));
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xyz *= limb_darkening;
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}
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/* sky */
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else {
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/* sky interpolation */
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float x = (direction[1] + M_PI + sun_rotation) / M_2PI;
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/* more pixels toward horizon compensation */
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float y = 1.0 - sqrt(dir_elevation / M_PI_2);
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if (x > 1.0) {
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x = x - 1.0;
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}
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xyz = (color)texture(filename, x, y, "wrap", "clamp", "interp", "linear", "alpha", alpha);
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}
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}
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/* ground */
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else {
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if (dir[2] < -0.4) {
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xyz = color(0, 0, 0);
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}
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else {
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/* black ground fade */
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float mul = pow(1.0 + dir[2] * 2.5, 3.0);
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/* interpolation */
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float x = (direction[1] + M_PI + sun_rotation) / M_2PI;
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float y = 1.5;
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if (x > 1.0) {
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x = x - 1.0;
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}
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xyz = (color)texture(
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filename, x, y, "wrap", "periodic", "interp", "linear", "alpha", alpha) *
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mul;
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}
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}
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/* convert to RGB */
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return xyz_to_rgb(xyz[0], xyz[1], xyz[2]);
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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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string sky_type = "hosek_wilkie",
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float theta = 0.0,
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float phi = 0.0,
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string filename = "",
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color radiance = color(0.0, 0.0, 0.0),
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float config_x[9] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
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float config_y[9] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
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float config_z[9] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
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float nishita_data[10] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
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output color Color = color(0.0, 0.0, 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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if (sky_type == "nishita_improved")
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Color = sky_radiance_nishita(p, nishita_data, filename);
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if (sky_type == "hosek_wilkie")
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Color = sky_radiance_hosek(p, phi, theta, radiance, config_x, config_y, config_z);
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if (sky_type == "preetham")
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Color = sky_radiance_preetham(p, phi, theta, radiance, config_x, config_y, config_z);
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}
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