Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/sky/source/sky_hosek.cpp

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+/* SPDX-FileCopyrightText: 2012-2013 Lukas Hosek and Alexander Wilkie. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause */
+
+/* ============================================================================
+
+This file is part of a sample implementation of the analytical skylight and
+solar radiance models presented in the SIGGRAPH 2012 paper
+
+
+           "An Analytic Model for Full Spectral Sky-Dome Radiance"
+
+and the 2013 IEEE CG&A paper
+
+       "Adding a Solar Radiance Function to the Hosek Skylight Model"
+
+                                   both by
+
+                       Lukas Hosek and Alexander Wilkie
+                Charles University in Prague, Czech Republic
+
+
+                        Version: 1.4a, February 22nd, 2013
+
+Version history:
+
+1.4a  February 22nd, 2013
+      Removed unnecessary and counter-intuitive solar radius parameters
+      from the interface of the color-space sky dome initialization functions.
+
+1.4   February 11th, 2013
+      Fixed a bug which caused the relative brightness of the solar disc
+      and the sky dome to be off by a factor of about 6. The sun was too
+      bright: this affected both normal and alien sun scenarios. The
+      coefficients of the solar radiance function were changed to fix this.
+
+1.3   January 21st, 2013 (not released to the public)
+      Added support for solar discs that are not exactly the same size as
+      the terrestrial sun. Also added support for suns with a different
+      emission spectrum ("Alien World" functionality).
+
+1.2a  December 18th, 2012
+      Fixed a mistake and some inaccuracies in the solar radiance function
+      explanations found in ArHosekSkyModel.h. The actual source code is
+      unchanged compared to version 1.2.
+
+1.2   December 17th, 2012
+      Native RGB data and a solar radiance function that matches the turbidity
+      conditions were added.
+
+1.1   September 2012
+      The coefficients of the spectral model are now scaled so that the output
+      is given in physical units: W / (m^-2 * sr * nm). Also, the output of the
+      XYZ model is now no longer scaled to the range [0...1]. Instead, it is
+      the result of a simple conversion from spectral data via the CIE 2 degree
+      standard observer matching functions. Therefore, after multiplication
+      with 683 lm / W, the Y channel now corresponds to luminance in lm.
+
+1.0   May 11th, 2012
+      Initial release.
+
+
+Please visit http://cgg.mff.cuni.cz/projects/SkylightModelling/ to check if
+an updated version of this code has been published!
+
+============================================================================ */
+
+/*
+
+All instructions on how to use this code are in the accompanying header file.
+
+*/
+
+/** \file
+ * \ingroup intern_sky_modal
+ */
+
+#include "sky_hosek.h"
+#include "sky_hosek_data.h"
+
+#include <cassert>
+#include <cmath>
+#include <cstdlib>
+
+//   Some macro definitions that occur elsewhere in ART, and that have to be
+//   replicated to make this a stand-alone module.
+
+#ifndef MATH_PI
+#  define MATH_PI 3.141592653589793
+#endif
+
+#ifndef MATH_DEG_TO_RAD
+#  define MATH_DEG_TO_RAD (MATH_PI / 180.0)
+#endif
+
+#ifndef DEGREES
+#  define DEGREES *MATH_DEG_TO_RAD
+#endif
+
+#ifndef TERRESTRIAL_SOLAR_RADIUS
+#  define TERRESTRIAL_SOLAR_RADIUS ((0.51 DEGREES) / 2.0)
+#endif
+
+#ifndef ALLOC
+#  define ALLOC(_struct) ((_struct *)malloc(sizeof(_struct)))
+#endif
+
+/* Not defined on all platforms (macOS & WIN32). */
+using uint = unsigned int;
+
+// internal definitions
+
+using ArHosekSkyModel_Dataset = const double *;
+using ArHosekSkyModel_Radiance_Dataset = const double *;
+
+// internal functions
+
+static void ArHosekSkyModel_CookConfiguration(ArHosekSkyModel_Dataset dataset,
+                                              SKY_ArHosekSkyModelConfiguration config,
+                                              double turbidity,
+                                              double albedo,
+                                              double solar_elevation)
+{
+  const double *elev_matrix;
+
+  int int_turbidity = int(turbidity);
+  double turbidity_rem = turbidity - double(int_turbidity);
+
+  solar_elevation = pow(solar_elevation / (MATH_PI / 2.0), (1.0 / 3.0));
+
+  // alb 0 low turb
+
+  elev_matrix = dataset + (9 * 6 * (int_turbidity - 1));
+
+  for (uint i = 0; i < 9; ++i) {
+    //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+    config[i] =
+        (1.0 - albedo) * (1.0 - turbidity_rem) *
+        (pow(1.0 - solar_elevation, 5.0) * elev_matrix[i] +
+         5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[i + 9] +
+         10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[i + 18] +
+         10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[i + 27] +
+         5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[i + 36] +
+         pow(solar_elevation, 5.0) * elev_matrix[i + 45]);
+  }
+
+  // alb 1 low turb
+  elev_matrix = dataset + (9 * 6 * 10 + 9 * 6 * (int_turbidity - 1));
+  for (uint i = 0; i < 9; ++i) {
+    //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+    config[i] +=
+        (albedo) * (1.0 - turbidity_rem) *
+        (pow(1.0 - solar_elevation, 5.0) * elev_matrix[i] +
+         5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[i + 9] +
+         10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[i + 18] +
+         10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[i + 27] +
+         5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[i + 36] +
+         pow(solar_elevation, 5.0) * elev_matrix[i + 45]);
+  }
+
+  if (int_turbidity == 10) {
+    return;
+  }
+
+  // alb 0 high turb
+  elev_matrix = dataset + (9 * 6 * (int_turbidity));
+  for (uint i = 0; i < 9; ++i) {
+    //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+    config[i] +=
+        (1.0 - albedo) * (turbidity_rem) *
+        (pow(1.0 - solar_elevation, 5.0) * elev_matrix[i] +
+         5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[i + 9] +
+         10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[i + 18] +
+         10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[i + 27] +
+         5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[i + 36] +
+         pow(solar_elevation, 5.0) * elev_matrix[i + 45]);
+  }
+
+  // alb 1 high turb
+  elev_matrix = dataset + (9 * 6 * 10 + 9 * 6 * (int_turbidity));
+  for (uint i = 0; i < 9; ++i) {
+    //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+    config[i] +=
+        (albedo) * (turbidity_rem) *
+        (pow(1.0 - solar_elevation, 5.0) * elev_matrix[i] +
+         5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[i + 9] +
+         10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[i + 18] +
+         10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[i + 27] +
+         5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[i + 36] +
+         pow(solar_elevation, 5.0) * elev_matrix[i + 45]);
+  }
+}
+
+static double ArHosekSkyModel_CookRadianceConfiguration(ArHosekSkyModel_Radiance_Dataset dataset,
+                                                        double turbidity,
+                                                        double albedo,
+                                                        double solar_elevation)
+{
+  const double *elev_matrix;
+
+  int int_turbidity = int(turbidity);
+  double turbidity_rem = turbidity - double(int_turbidity);
+  double res;
+  solar_elevation = pow(solar_elevation / (MATH_PI / 2.0), (1.0 / 3.0));
+
+  // alb 0 low turb
+  elev_matrix = dataset + (6 * (int_turbidity - 1));
+  //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+  res = (1.0 - albedo) * (1.0 - turbidity_rem) *
+        (pow(1.0 - solar_elevation, 5.0) * elev_matrix[0] +
+         5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[1] +
+         10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[2] +
+         10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[3] +
+         5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[4] +
+         pow(solar_elevation, 5.0) * elev_matrix[5]);
+
+  // alb 1 low turb
+  elev_matrix = dataset + (6 * 10 + 6 * (int_turbidity - 1));
+  //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+  res += (albedo) * (1.0 - turbidity_rem) *
+         (pow(1.0 - solar_elevation, 5.0) * elev_matrix[0] +
+          5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[1] +
+          10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[2] +
+          10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[3] +
+          5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[4] +
+          pow(solar_elevation, 5.0) * elev_matrix[5]);
+  if (int_turbidity == 10) {
+    return res;
+  }
+
+  // alb 0 high turb
+  elev_matrix = dataset + (6 * (int_turbidity));
+  //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+  res += (1.0 - albedo) * (turbidity_rem) *
+         (pow(1.0 - solar_elevation, 5.0) * elev_matrix[0] +
+          5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[1] +
+          10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[2] +
+          10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[3] +
+          5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[4] +
+          pow(solar_elevation, 5.0) * elev_matrix[5]);
+
+  // alb 1 high turb
+  elev_matrix = dataset + (6 * 10 + 6 * (int_turbidity));
+  //(1-t).^3* A1 + 3*(1-t).^2.*t * A2 + 3*(1-t) .* t .^ 2 * A3 + t.^3 * A4;
+  res += (albedo) * (turbidity_rem) *
+         (pow(1.0 - solar_elevation, 5.0) * elev_matrix[0] +
+          5.0 * pow(1.0 - solar_elevation, 4.0) * solar_elevation * elev_matrix[1] +
+          10.0 * pow(1.0 - solar_elevation, 3.0) * pow(solar_elevation, 2.0) * elev_matrix[2] +
+          10.0 * pow(1.0 - solar_elevation, 2.0) * pow(solar_elevation, 3.0) * elev_matrix[3] +
+          5.0 * (1.0 - solar_elevation) * pow(solar_elevation, 4.0) * elev_matrix[4] +
+          pow(solar_elevation, 5.0) * elev_matrix[5]);
+  return res;
+}
+
+static double ArHosekSkyModel_GetRadianceInternal(
+    const SKY_ArHosekSkyModelConfiguration configuration, const double theta, const double gamma)
+{
+  const double expM = exp(configuration[4] * gamma);
+  const double rayM = cos(gamma) * cos(gamma);
+  const double mieM =
+      (1.0 + cos(gamma) * cos(gamma)) /
+      pow((1.0 + configuration[8] * configuration[8] - 2.0 * configuration[8] * cos(gamma)), 1.5);
+  const double zenith = sqrt(cos(theta));
+
+  return (1.0 + configuration[0] * exp(configuration[1] / (cos(theta) + 0.01))) *
+         (configuration[2] + configuration[3] * expM + configuration[5] * rayM +
+          configuration[6] * mieM + configuration[7] * zenith);
+}
+
+void SKY_arhosekskymodelstate_free(SKY_ArHosekSkyModelState *state)
+{
+  free(state);
+}
+
+double SKY_arhosekskymodel_radiance(SKY_ArHosekSkyModelState *state,
+                                    double theta,
+                                    double gamma,
+                                    double wavelength)
+{
+  int low_wl = int((wavelength - 320.0) / 40.0);
+
+  if (low_wl < 0 || low_wl >= 11) {
+    return 0.0;
+  }
+
+  double interp = fmod((wavelength - 320.0) / 40.0, 1.0);
+
+  double val_low = ArHosekSkyModel_GetRadianceInternal(state->configs[low_wl], theta, gamma) *
+                   state->radiances[low_wl] * state->emission_correction_factor_sky[low_wl];
+
+  if (interp < 1e-6) {
+    return val_low;
+  }
+
+  double result = (1.0 - interp) * val_low;
+
+  if (low_wl + 1 < 11) {
+    result += interp *
+              ArHosekSkyModel_GetRadianceInternal(state->configs[low_wl + 1], theta, gamma) *
+              state->radiances[low_wl + 1] * state->emission_correction_factor_sky[low_wl + 1];
+  }
+
+  return result;
+}
+
+// xyz and rgb versions
+
+SKY_ArHosekSkyModelState *SKY_arhosek_xyz_skymodelstate_alloc_init(const double turbidity,
+                                                                   const double albedo,
+                                                                   const double elevation)
+{
+  SKY_ArHosekSkyModelState *state = ALLOC(SKY_ArHosekSkyModelState);
+
+  state->solar_radius = TERRESTRIAL_SOLAR_RADIUS;
+  state->turbidity = turbidity;
+  state->albedo = albedo;
+  state->elevation = elevation;
+
+  for (uint channel = 0; channel < 3; ++channel) {
+    ArHosekSkyModel_CookConfiguration(
+        datasetsXYZ[channel], state->configs[channel], turbidity, albedo, elevation);
+
+    state->radiances[channel] = ArHosekSkyModel_CookRadianceConfiguration(
+        datasetsXYZRad[channel], turbidity, albedo, elevation);
+  }
+
+  return state;
+}