#include <algorithm>
#include "sky_math.h"
#include "sky_nishita.h"

Functions
static float3	geographical_to_direction (float lat, float lon)
static float3	spec_to_xyz (const float *spectrum)
static float	density_rayleigh (float height)
static float	density_mie (float height)
static float	density_ozone (float height)
static float	phase_rayleigh (float mu)
static float	phase_mie (float mu)
static bool	surface_intersection (float3 pos, float3 dir)
static float3	atmosphere_intersection (float3 pos, float3 dir)
static float3	ray_optical_depth (float3 ray_origin, float3 ray_dir)
static void	single_scattering (float3 ray_dir, float3 sun_dir, float3 ray_origin, float air_density, float aerosol_density, float ozone_density, float *r_spectrum)
void	SKY_single_scattering_precompute_texture (float *pixels, int stride, int width, int height, float sun_elevation, float altitude, float air_density, float aerosol_density, float ozone_density)
static void	sun_radiation (float3 cam_dir, float altitude, float air_density, float aerosol_density, float solid_angle, float *r_spectrum)
void	SKY_single_scattering_precompute_sun (float sun_elevation, float angular_diameter, float altitude, float air_density, float aerosol_density, float r_pixel_bottom[3], float r_pixel_top[3])

Variables
static const float	RAYLEIGH_SCALE = 8e3f
static const float	MIE_SCALE = 1.2e3f
static const float	MIE_COEFF = 2e-5f
static const float	MIE_G = 0.76f
static const float	SQR_G = MIE_G * MIE_G
static const float	EARTH_RADIUS = 6360e3f
static const float	ATMOSPHERE_RADIUS = 6420e3f
static const int	STEPS = 32
static const int	NUM_WAVELENGTHS = 21
static const int	MIN_WAVELENGTH = 380
static const int	MAX_WAVELENGTH = 780
static const float	STEP_LAMBDA = (MAX_WAVELENGTH - MIN_WAVELENGTH) / (NUM_WAVELENGTHS - 1)
static const float	IRRADIANCE []
static const float	RAYLEIGH_COEFF []
static const float	OZONE_COEFF []
static const float	CMF_XYZ [][3]
static const int	QUADRATURE_STEPS = 8
static const float	QUADRATURE_NODES []
static const float	QUADRATURE_WEIGHTS []

Function Documentation

◆ atmosphere_intersection()

float3 atmosphere_intersection	(	float3	pos,
		float3	dir )

static

Definition at line 164 of file sky_single_scattering.cpp.

References ATMOSPHERE_RADIUS, b, dot(), len_squared(), make_float3(), pos, sqr, sqrtf, float3::x, float3::y, and float3::z.

Referenced by ray_optical_depth(), and single_scattering().

◆ density_mie()

float density_mie ( float height )

static

Definition at line 128 of file sky_single_scattering.cpp.

References expf, and MIE_SCALE.

Referenced by ray_optical_depth(), and single_scattering().

◆ density_ozone()

float density_ozone ( float height )

static

Definition at line 133 of file sky_single_scattering.cpp.

References fabs().

Referenced by ray_optical_depth(), and single_scattering().

◆ density_rayleigh()

float density_rayleigh ( float height )

static

Definition at line 123 of file sky_single_scattering.cpp.

References expf, and RAYLEIGH_SCALE.

Referenced by ray_optical_depth(), and single_scattering().

◆ geographical_to_direction()

float3 geographical_to_direction	(	float	lat,
		float	lon )

static

Definition at line 106 of file sky_single_scattering.cpp.

References cosf, make_float3(), and sinf.

Referenced by SKY_single_scattering_precompute_sun(), and SKY_single_scattering_precompute_texture().

◆ phase_mie()

float phase_mie ( float mu )

static

Definition at line 143 of file sky_single_scattering.cpp.

References M_PI_F, MIE_G, powf, sqr, and SQR_G.

Referenced by single_scattering().

◆ phase_rayleigh()

float phase_rayleigh ( float mu )

static

Definition at line 138 of file sky_single_scattering.cpp.

References M_1_PI_F, and sqr.

Referenced by single_scattering().

◆ ray_optical_depth()

float3 ray_optical_depth	(	float3	ray_origin,
		float3	ray_dir )

static

Definition at line 172 of file sky_single_scattering.cpp.

References atmosphere_intersection(), density_mie(), density_ozone(), density_rayleigh(), distance(), EARTH_RADIUS, i, len, make_float3(), P, QUADRATURE_NODES, QUADRATURE_STEPS, and QUADRATURE_WEIGHTS.

Referenced by single_scattering(), and sun_radiation().

◆ single_scattering()

void single_scattering	(	float3	ray_dir,
		float3	sun_dir,
		float3	ray_origin,
		float	air_density,
		float	aerosol_density,
		float	ozone_density,
		float *	r_spectrum )

static

Definition at line 208 of file sky_single_scattering.cpp.

References atmosphere_intersection(), density_mie(), density_ozone(), density_rayleigh(), distance(), dot(), EARTH_RADIUS, expf, i, IRRADIANCE, len, make_float3(), MIE_COEFF, NUM_WAVELENGTHS, OZONE_COEFF, P, phase_mie(), phase_rayleigh(), ray_optical_depth(), RAYLEIGH_COEFF, reduce_add(), STEPS, and surface_intersection().

Referenced by SKY_single_scattering_precompute_texture().

◆ SKY_single_scattering_precompute_sun()

void SKY_single_scattering_precompute_sun	(	float	sun_elevation,
		float	angular_diameter,
		float	altitude,
		float	air_density,
		float	aerosol_density,
		float	r_pixel_bottom[3],
		float	r_pixel_top[3] )

Definition at line 381 of file sky_single_scattering.cpp.

References clamp(), cosf, geographical_to_direction(), M_2PI_F, make_float3(), NUM_WAVELENGTHS, spec_to_xyz(), sun_radiation(), top, float3::x, float3::y, and float3::z.

Referenced by SkyTextureNode::get_sun_average_radiance(), and sky_texture_precompute_nishita().

◆ SKY_single_scattering_precompute_texture()

void SKY_single_scattering_precompute_texture	(	float *	pixels,
		int	stride,
		int	width,
		int	height,
		float	sun_elevation,
		float	altitude,
		float	air_density,
		float	aerosol_density,
		float	ozone_density )

Definition at line 291 of file sky_single_scattering.cpp.

References begin(), clamp(), EARTH_RADIUS, fade(), geographical_to_direction(), M_2PI_F, M_PI_2_F, M_PI_F, make_float3(), NUM_WAVELENGTHS, single_scattering(), SKY_parallel_for(), spec_to_xyz(), sqr, float3::x, x, float3::y, y, and float3::z.

Referenced by SkyLoader::load_pixels(), and blender::nodes::node_shader_tex_sky_cc::node_shader_gpu_tex_sky().

◆ spec_to_xyz()

float3 spec_to_xyz ( const float * spectrum )

static

Definition at line 111 of file sky_single_scattering.cpp.

References CMF_XYZ, i, make_float3(), NUM_WAVELENGTHS, STEP_LAMBDA, float3::x, float3::y, and float3::z.

Referenced by SKY_single_scattering_precompute_sun(), and SKY_single_scattering_precompute_texture().

◆ sun_radiation()

void sun_radiation	(	float3	cam_dir,
		float	altitude,
		float	air_density,
		float	aerosol_density,
		float	solid_angle,
		float *	r_spectrum )

static

Definition at line 362 of file sky_single_scattering.cpp.

References EARTH_RADIUS, expf, i, IRRADIANCE, make_float3(), MIE_COEFF, NUM_WAVELENGTHS, ray_optical_depth(), RAYLEIGH_COEFF, float3::x, and float3::y.

Referenced by SKY_single_scattering_precompute_sun().

◆ surface_intersection()

bool surface_intersection	(	float3	pos,
		float3	dir )

static

Definition at line 150 of file sky_single_scattering.cpp.

References b, dot(), EARTH_RADIUS, len_squared(), pos, sqr, and float3::z.

Referenced by single_scattering().

Variable Documentation

◆ ATMOSPHERE_RADIUS

const float ATMOSPHERE_RADIUS = 6420e3f

static

Definition at line 21 of file sky_single_scattering.cpp.

◆ CMF_XYZ

const float CMF_XYZ[][3]

static

Initial value:

= {{0.00136800000f, 0.00003900000f, 0.00645000100f},
        {0.01431000000f, 0.00039600000f, 0.06785001000f},
        {0.13438000000f, 0.00400000000f, 0.64560000000f},
        {0.34828000000f, 0.02300000000f, 1.74706000000f},
        {0.29080000000f, 0.06000000000f, 1.66920000000f},
        {0.09564000000f, 0.13902000000f, 0.81295010000f},
        {0.00490000000f, 0.32300000000f, 0.27200000000f},
        {0.06327000000f, 0.71000000000f, 0.07824999000f},
        {0.29040000000f, 0.95400000000f, 0.02030000000f},
        {0.59450000000f, 0.99500000000f, 0.00390000000f},
        {0.91630000000f, 0.87000000000f, 0.00165000100f},
        {1.06220000000f, 0.63100000000f, 0.00080000000f},
        {0.85444990000f, 0.38100000000f, 0.00019000000f},
        {0.44790000000f, 0.17500000000f, 0.00002000000f},
        {0.16490000000f, 0.06100000000f, 0.00000000000f},
        {0.04677000000f, 0.01700000000f, 0.00000000000f},
        {0.01135916000f, 0.00410200000f, 0.00000000000f},
        {0.00289932700f, 0.00104700000f, 0.00000000000f},
        {0.00069007860f, 0.00024920000f, 0.00000000000f},
        {0.00016615050f, 0.00006000000f, 0.00000000000f},
        {0.00004150994f, 0.00001499000f, 0.00000000000f}}

Definition at line 56 of file sky_single_scattering.cpp.

Referenced by spec_to_xyz().

◆ EARTH_RADIUS

const float EARTH_RADIUS = 6360e3f

static

Definition at line 20 of file sky_single_scattering.cpp.

◆ IRRADIANCE

const float IRRADIANCE[]

static

Initial value:

                          = {
45756829855592995315f, 1.56596305559738380175f, 1.65148449067670455293f,
71496242737209314555f, 1.75797983805020541226f, 1.78256407885924539336f,
79095108475838560302f, 1.78541550133410664714f, 1.76815554864306845317f,
74122069647250410362f, 1.70647127164943679389f, 1.66556087452739887134f,
61993437242451854274f, 1.57083597368892080581f, 1.51932335059305478886f,
46628494965214395407f, 1.41245852740172450623f, 1.35844961970384092709f,
30474913844739281998f, 1.25174963272610817455f, 1.19975998755420620867f}

Definition at line 29 of file sky_single_scattering.cpp.

Referenced by single_scattering(), and sun_radiation().

◆ MAX_WAVELENGTH

const int MAX_WAVELENGTH = 780

static

Definition at line 25 of file sky_single_scattering.cpp.

◆ MIE_COEFF

const float MIE_COEFF = 2e-5f

static

Definition at line 17 of file sky_single_scattering.cpp.

Referenced by single_scattering(), and sun_radiation().

◆ MIE_G

const float MIE_G = 0.76f

static

Definition at line 18 of file sky_single_scattering.cpp.

Referenced by phase_mie().

◆ MIE_SCALE

const float MIE_SCALE = 1.2e3f

static

Definition at line 16 of file sky_single_scattering.cpp.

Referenced by density_mie().

◆ MIN_WAVELENGTH

const int MIN_WAVELENGTH = 380

static

Definition at line 24 of file sky_single_scattering.cpp.

◆ NUM_WAVELENGTHS

const int NUM_WAVELENGTHS = 21

static

Definition at line 23 of file sky_single_scattering.cpp.

Referenced by single_scattering(), SKY_single_scattering_precompute_sun(), SKY_single_scattering_precompute_texture(), spec_to_xyz(), and sun_radiation().

◆ OZONE_COEFF

const float OZONE_COEFF[]

static

Initial value:

                           = {
00000000325126849861f, 0.00000000585395365047f, 0.00000001977191155085f,
00000007309568762914f, 0.00000020084561514287f, 0.00000040383958096161f,
00000063551335912363f, 0.00000096707041180970f, 0.00000154797400424410f,
00000209038647223331f, 0.00000246128056164565f, 0.00000273551299461512f,
00000215125863128643f, 0.00000159051840791988f, 0.00000112356197979857f,
00000073527551487574f, 0.00000046450130357806f, 0.00000033096079921048f,
00000022512612292678f, 0.00000014879129266490f, 0.00000016828623364192f}

Definition at line 47 of file sky_single_scattering.cpp.

Referenced by single_scattering().

◆ QUADRATURE_NODES

const float QUADRATURE_NODES[]

static

Initial value:

= {0.006811185292f,
03614807107f,
09004346519f,
1706680068f,
2818362161f,
4303406404f,
6296271457f,
9145252695f}

Definition at line 89 of file sky_single_scattering.cpp.

Referenced by ray_optical_depth().

◆ QUADRATURE_STEPS

const int QUADRATURE_STEPS = 8

static

Definition at line 88 of file sky_single_scattering.cpp.

Referenced by ray_optical_depth().

◆ QUADRATURE_WEIGHTS

const float QUADRATURE_WEIGHTS[]

static

Initial value:

= {0.01750893642f,
04135477391f,
06678839063f,
09507698807f,
1283416365f,
1707430204f,
2327233347f,
3562490486f}

Definition at line 97 of file sky_single_scattering.cpp.

Referenced by ray_optical_depth().

◆ RAYLEIGH_COEFF

const float RAYLEIGH_COEFF[]

static

Initial value:

                              = {
00005424820087636473f, 0.00004418549866505454f, 0.00003635151910165377f,
00003017929012024763f, 0.00002526320226989157f, 0.00002130859310621843f,
00001809838025320633f, 0.00001547057129129042f, 0.00001330284977336850f,
00001150184784075764f, 0.00000999557429990163f, 0.00000872799973630707f,
00000765513700977967f, 0.00000674217203751443f, 0.00000596134125832052f,
00000529034598065810f, 0.00000471115687557433f, 0.00000420910481110487f,
00000377218381260133f, 0.00000339051255477280f, 0.00000305591531679811f}

Definition at line 38 of file sky_single_scattering.cpp.

Referenced by single_scattering(), and sun_radiation().

◆ RAYLEIGH_SCALE

const float RAYLEIGH_SCALE = 8e3f

static

Definition at line 15 of file sky_single_scattering.cpp.

Referenced by density_rayleigh().

◆ SQR_G

const float SQR_G = MIE_G * MIE_G

static

Definition at line 19 of file sky_single_scattering.cpp.

◆ STEP_LAMBDA

const float STEP_LAMBDA = (MAX_WAVELENGTH - MIN_WAVELENGTH) / (NUM_WAVELENGTHS - 1)

static

Definition at line 27 of file sky_single_scattering.cpp.

Referenced by spec_to_xyz().

◆ STEPS

const int STEPS = 32

static

Definition at line 22 of file sky_single_scattering.cpp.

Referenced by single_scattering().

Functions

Variables

Function Documentation

◆ atmosphere_intersection()

◆ density_mie()

◆ density_ozone()

◆ density_rayleigh()

◆ geographical_to_direction()

◆ phase_mie()

◆ phase_rayleigh()

◆ ray_optical_depth()

◆ single_scattering()

◆ SKY_single_scattering_precompute_sun()

◆ SKY_single_scattering_precompute_texture()

◆ spec_to_xyz()

◆ sun_radiation()

◆ surface_intersection()

Variable Documentation

◆ ATMOSPHERE_RADIUS

◆ CMF_XYZ

◆ EARTH_RADIUS

◆ IRRADIANCE

◆ MAX_WAVELENGTH

◆ MIE_COEFF

◆ MIE_G

◆ MIE_SCALE

◆ MIN_WAVELENGTH

◆ NUM_WAVELENGTHS

◆ OZONE_COEFF

◆ QUADRATURE_NODES

◆ QUADRATURE_STEPS

◆ QUADRATURE_WEIGHTS

◆ RAYLEIGH_COEFF

◆ RAYLEIGH_SCALE

◆ SQR_G

◆ STEP_LAMBDA

◆ STEPS