paysages : Progress on bruneton atmospheric model.

git-svn-id: https://subversion.assembla.com/svn/thunderk/paysages@477 b1fd45b6-86a6-48da-8261-f70d1f35bdcc
This commit is contained in:
Michaël Lemaire 2012-12-12 13:21:46 +00:00 committed by ThunderK
parent f82b0f1e02
commit 983270ee56
3 changed files with 302 additions and 65 deletions

View file

@ -5,9 +5,11 @@
* http://evasion.inrialpes.fr/~Eric.Bruneton/ * http://evasion.inrialpes.fr/~Eric.Bruneton/
*/ */
#if 0 #if 1
#include <math.h> #include <math.h>
#include <stdlib.h>
#include "../system.h"
#define TRANSMITTANCE_NON_LINEAR #define TRANSMITTANCE_NON_LINEAR
#define INSCATTER_NON_LINEAR #define INSCATTER_NON_LINEAR
@ -19,6 +21,12 @@ static const double RL = 6421.0;
static const double exposure = 0.4; static const double exposure = 0.4;
static const float ISun = 100.0; static const float ISun = 100.0;
#define RES_MU 128
#define RES_MU_S 32
#define RES_R 32
#define RES_NU 8
#define TRANSMITTANCE_INTEGRAL_SAMPLES 500
// Rayleigh // Rayleigh
static const double HR = 8.0; static const double HR = 8.0;
static const Color betaR = {5.8e-3, 1.35e-2, 3.31e-2, 1.0}; static const Color betaR = {5.8e-3, 1.35e-2, 3.31e-2, 1.0};
@ -26,8 +34,8 @@ static const Color betaR = {5.8e-3, 1.35e-2, 3.31e-2, 1.0};
// Mie // Mie
// DEFAULT // DEFAULT
static const double HM = 1.2; static const double HM = 1.2;
/*static const vec3 betaMSca = vec3(4e-3); static const Vector3 betaMSca = {4e-3, 4e-3, 4e-3};
static const vec3 betaMEx = betaMSca / 0.9;*/ static const Vector3 betaMEx = {4e-3 / 0.9, 4e-3 / 0.9, 4e-3 / 0.9};
static const double mieG = 0.8; static const double mieG = 0.8;
// CLEAR SKY // CLEAR SKY
/*static const float HM = 1.2; /*static const float HM = 1.2;
@ -42,7 +50,79 @@ static const float mieG = 0.65;*/
#define step(_a_,_b_) ((_a_) < (_b_) ? 0 : 1) #define step(_a_,_b_) ((_a_) < (_b_) ? 0 : 1)
#define max(_a_,_b_) ((_a_) < (_b_) ? (_a_) : (_b_)) #define max(_a_,_b_) ((_a_) < (_b_) ? (_a_) : (_b_))
#define min(_a_,_b_) ((_a_) > (_b_) ? (_a_) : (_b_))
#define sign(_a_) ((_a_) < 0.0 ? -1.0 : ((_a_) > 0.0 ? 1.0 : 0.0)) #define sign(_a_) ((_a_) < 0.0 ? -1.0 : ((_a_) > 0.0 ? 1.0 : 0.0))
#define mix(_x_,_y_,_a_) ((_x_) * (1.0 - (_a_)) + (_y_) * (_a_))
static inline Color vec4mix(Color v1, Color v2, double a)
{
v1.r = mix(v1.r, v2.r, a);
v1.g = mix(v1.g, v2.g, a);
v1.b = mix(v1.b, v2.b, a);
v1.a = mix(v1.a, v2.a, a);
return v1;
}
static inline double clamp(double x, double minVal, double maxVal)
{
if (x < minVal)
{
x = minVal;
}
return (x > maxVal) ? maxVal : x;
}
static inline double smoothstep(double edge0, double edge1, double x)
{
double t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
return t * t * (3.0 - 2.0 * t);
}
static inline void _fixVec4Min(Color* vec, double minVal)
{
if (vec->r < minVal) { vec->r = minVal; }
if (vec->g < minVal) { vec->g = minVal; }
if (vec->b < minVal) { vec->b = minVal; }
if (vec->a < minVal) { vec->a = minVal; }
}
static inline Color vec4max(Color vec, double minVal)
{
if (vec.r < minVal) { vec.r = minVal; }
if (vec.g < minVal) { vec.g = minVal; }
if (vec.b < minVal) { vec.b = minVal; }
if (vec.a < minVal) { vec.a = minVal; }
return vec;
}
static inline Vector3 vec3(double x, double y, double z)
{
Vector3 result;
result.x = x;
result.y = y;
result.z = z;
return result;
}
static inline Color vec4(double r, double g, double b, double a)
{
Color result;
result.r = r;
result.g = g;
result.b = b;
result.a = a;
return result;
}
typedef struct
{
int xsize;
int ysize;
Color* data;
} Texture2D;
typedef struct
{
int xsize;
int ysize;
int zsize;
Color* data;
} Texture3D;
/* Rayleigh phase function */ /* Rayleigh phase function */
static double _phaseFunctionR(double mu) static double _phaseFunctionR(double mu)
@ -57,14 +137,16 @@ static double _phaseFunctionM(double mu)
} }
/* approximated single Mie scattering (cf. approximate Cm in paragraph "Angular precision") */ /* approximated single Mie scattering (cf. approximate Cm in paragraph "Angular precision") */
static Color _getMie(Color rayMie) Color getMie(Color rayMie)
{ {
double value = rayMie.a / max(rayMie.r, 1e-4) * (betaR.r / betaR); /* TODO divide by a vector ? */ Color result;
rayMie.r *= value;
rayMie.g *= value; result.r = rayMie.r * rayMie.a / max(rayMie.r, 1e-4) * (betaR.r / betaR.r);
rayMie.b *= value; result.g = rayMie.g * rayMie.a / max(rayMie.r, 1e-4) * (betaR.r / betaR.g);
rayMie.a = 1.0; result.b = rayMie.b * rayMie.a / max(rayMie.r, 1e-4) * (betaR.r / betaR.b);
return rayMie; result.a = 1.0;
return result;
} }
/* optical depth for ray (r,mu) of length d, using analytic formula /* optical depth for ray (r,mu) of length d, using analytic formula
@ -85,30 +167,145 @@ static double _opticalDepth(double H, double r, double mu, double d)
return sqrt((6.2831 * H) * r) * exp((Rg - r) / H) * (x + yx - yy); return sqrt((6.2831 * H) * r) * exp((Rg - r) / H) * (x + yx - yy);
} }
static Color _texture4D(sampler3D table, float r, float mu, float muS, float nu) static Texture3D _precomputeInscatterSampler()
{ {
float H = sqrt(Rt * Rt - Rg * Rg); Texture3D result;
float rho = sqrt(r * r - Rg * Rg);
#ifdef INSCATTER_NON_LINEAR result.xsize = 0;
float rmu = r * mu; result.ysize = 0;
float delta = rmu * rmu - r * r + Rg * Rg; result.zsize = 0;
vec4 cst = rmu < 0.0 && delta > 0.0 ? vec4(1.0, 0.0, 0.0, 0.5 - 0.5 / float(RES_MU)) : vec4(-1.0, H * H, H, 0.5 + 0.5 / float(RES_MU)); result.data = 0;
float uR = 0.5 / float(RES_R) + rho / H * (1.0 - 1.0 / float(RES_R));
float uMu = cst.w + (rmu * cst.x + sqrt(delta + cst.y)) / (rho + cst.z) * (0.5 - 1.0 / float(RES_MU)); return result;
// paper formula }
//float uMuS = 0.5 / float(RES_MU_S) + max((1.0 - exp(-3.0 * muS - 0.6)) / (1.0 - exp(-3.6)), 0.0) * (1.0 - 1.0 / float(RES_MU_S)); Texture3D _inscatterSampler;
// better formula
float uMuS = 0.5 / float(RES_MU_S) + (atan(max(muS, -0.1975) * tan(1.26 * 1.1)) / 1.1 + (1.0 - 0.26)) * 0.5 * (1.0 - 1.0 / float(RES_MU_S)); /* nearest intersection of ray r,mu with ground or top atmosphere boundary
* mu=cos(ray zenith angle at ray origin) */
static double limit(double r, double mu)
{
double dout = -r * mu + sqrt(r * r * (mu * mu - 1.0) + RL * RL);
double delta2 = r * r * (mu * mu - 1.0) + Rg * Rg;
if (delta2 >= 0.0)
{
float din = -r * mu - sqrt(delta2);
if (din >= 0.0) {
dout = min(dout, din);
}
}
return dout;
}
static double _opticalDepthTransmittance(double H, double r, double mu)
{
double result = 0.0;
double dx = limit(r, mu) / (double)TRANSMITTANCE_INTEGRAL_SAMPLES;
double xi = 0.0;
double yi = exp(-(r - Rg) / H);
int i;
for (i = 1; i <= TRANSMITTANCE_INTEGRAL_SAMPLES; ++i) {
double xj = (double)i * dx;
double yj = exp(-(sqrt(r * r + xj * xj + 2.0 * xj * r * mu) - Rg) / H);
result += (yi + yj) / 2.0 * dx;
xi = xj;
yi = yj;
}
return mu < -sqrt(1.0 - (Rg / r) * (Rg / r)) ? 1e9 : result;
}
static void _getTransmittanceRMu(double x, double y, double* r, double* muS)
{
#ifdef TRANSMITTANCE_NON_LINEAR
*r = Rg + (y * y) * (Rt - Rg);
*muS = -0.15 + tan(1.5 * x) / tan(1.5) * (1.0 + 0.15);
#else #else
float uR = 0.5 / float(RES_R) + rho / H * (1.0 - 1.0 / float(RES_R)); *r = Rg + y * (Rt - Rg);
float uMu = 0.5 / float(RES_MU) + (mu + 1.0) / 2.0 * (1.0 - 1.0 / float(RES_MU)); *muS = -0.15 + x * (1.0 + 0.15);
float uMuS = 0.5 / float(RES_MU_S) + max(muS + 0.2, 0.0) / 1.2 * (1.0 - 1.0 / float(RES_MU_S));
#endif #endif
float lerp = (nu + 1.0) / 2.0 * (float(RES_NU) - 1.0); }
float uNu = floor(lerp);
static Color _debugSave2D(void* data, int x, int y)
{
Texture2D* tex = (Texture2D*)data;
return tex->data[y * tex->xsize + x];
}
static Texture2D _precomputeTransmittanceSampler()
{
Texture2D result;
int x, y;
result.xsize = 256;
result.ysize = 64;
result.data = malloc(sizeof(Color) * result.xsize * result.ysize); /* TODO free */
for (x = 0; x < result.xsize; x++)
{
for (y = 0; y < result.ysize; y++)
{
double r, muS;
_getTransmittanceRMu((double)x / result.xsize, (double)y / result.ysize, &r, &muS);
double depth1 = _opticalDepthTransmittance(HR, r, muS);
double depth2 = _opticalDepthTransmittance(HM, r, muS);
Color trans;
trans.r = exp(-(betaR.r * depth1 + betaMEx.x * depth2));
trans.g = exp(-(betaR.g * depth1 + betaMEx.y * depth2));
trans.b = exp(-(betaR.b * depth1 + betaMEx.z * depth2));
trans.a = 1.0;
result.data[y * result.xsize + x] = trans; /* Eq (5) */
}
}
/* DEBUG */
systemSavePictureFile("debug.png", _debugSave2D, &result, result.xsize, result.ysize);
return result;
}
Texture2D _transmittanceSampler;
void brunetonInit()
{
_inscatterSampler = _precomputeInscatterSampler();
_transmittanceSampler = _precomputeTransmittanceSampler();
exit(1);
}
static Color _texture2D(Texture2D* tex, double x, double y)
{
/* TODO Sampling */
return COLOR_BLACK;
}
static Color _texture3D(Texture3D* tex, Vector3 location)
{
/* TODO Sampling */
return COLOR_BLACK;
}
static Color _texture4D(Texture3D* tex3d, double r, double mu, double muS, double nu)
{
double H = sqrt(Rt * Rt - Rg * Rg);
double rho = sqrt(r * r - Rg * Rg);
#ifdef INSCATTER_NON_LINEAR
double rmu = r * mu;
double delta = rmu * rmu - r * r + Rg * Rg;
Color cst = (rmu < 0.0 && delta > 0.0) ? vec4(1.0, 0.0, 0.0, 0.5 - 0.5 / (double)(RES_MU)) : vec4(-1.0, H * H, H, 0.5 + 0.5 / (double)(RES_MU));
double uR = 0.5 / (double)(RES_R) + rho / H * (1.0 - 1.0 / (double)(RES_R));
double uMu = cst.a + (rmu * cst.r + sqrt(delta + cst.g)) / (rho + cst.b) * (0.5 - 1.0 / (double)(RES_MU));
// paper formula
//float uMuS = 0.5 / (double)(RES_MU_S) + max((1.0 - exp(-3.0 * muS - 0.6)) / (1.0 - exp(-3.6)), 0.0) * (1.0 - 1.0 / (double)(RES_MU_S));
// better formula
double uMuS = 0.5 / (double)(RES_MU_S) + (atan(max(muS, -0.1975) * tan(1.26 * 1.1)) / 1.1 + (1.0 - 0.26)) * 0.5 * (1.0 - 1.0 / (double)(RES_MU_S));
#else
float uR = 0.5 / (double)(RES_R) + rho / H * (1.0 - 1.0 / (double)(RES_R));
float uMu = 0.5 / (double)(RES_MU) + (mu + 1.0) / 2.0 * (1.0 - 1.0 / (double)(RES_MU));
float uMuS = 0.5 / (double)(RES_MU_S) + max(muS + 0.2, 0.0) / 1.2 * (1.0 - 1.0 / (double)(RES_MU_S));
#endif
double lerp = (nu + 1.0) / 2.0 * ((double)(RES_NU) - 1.0);
double uNu = floor(lerp);
lerp = lerp - uNu; lerp = lerp - uNu;
return texture3D(table, vec3((uNu + uMuS) / float(RES_NU), uMu, uR)) * (1.0 - lerp) + return vec4mix(_texture3D(tex3d, vec3((uNu + uMuS + 1.0) / (double)(RES_NU), uMu, uR)), _texture3D(tex3d, vec3((uNu + uMuS) / (double)(RES_NU), uMu, uR)), lerp);
texture3D(table, vec3((uNu + uMuS + 1.0) / float(RES_NU), uMu, uR)) * lerp;
} }
/* transmittance(=transparency) of atmosphere for ray (r,mu) of length d /* transmittance(=transparency) of atmosphere for ray (r,mu) of length d
@ -116,31 +313,53 @@ static Color _texture4D(sampler3D table, float r, float mu, float muS, float nu)
uses analytic formula instead of transmittance texture */ uses analytic formula instead of transmittance texture */
static Vector3 _analyticTransmittance(double r, double mu, double d) static Vector3 _analyticTransmittance(double r, double mu, double d)
{ {
return exp(-betaR * _opticalDepth(HR, r, mu, d) - betaMEx * _opticalDepth(HM, r, mu, d)); Vector3 result;
double opt = _opticalDepth(HR, r, mu, d);
result.x = exp(-betaR.r * opt) - betaMEx.x * opt;
result.y = exp(-betaR.g * opt) - betaMEx.y * opt;
result.z = exp(-betaR.b * opt) - betaMEx.z * opt;
return result;
}
static inline Color _applyInscatter(Color inscatter, Color attmod, Color samp)
{
inscatter.r = inscatter.r - attmod.r * samp.r;
inscatter.g = inscatter.g - attmod.g * samp.g;
inscatter.b = inscatter.b - attmod.b * samp.b;
inscatter.a = inscatter.a - attmod.a * samp.a;
return vec4max(inscatter, 0.0);
} }
/* inscattered light along ray x+tv, when sun in direction s (=S[L]-T(x,x0)S[L]|x0) */ /* inscattered light along ray x+tv, when sun in direction s (=S[L]-T(x,x0)S[L]|x0) */
static Color _inscatter(Vector3* x, double* t, Vector3 v, Vector3 s, double* _r, double* _mu, Color* attenuation) static Color _inscatter(Vector3* _x, double* _t, Vector3 v, Vector3 s, double* _r, double* _mu, Vector3* attenuation)
{ {
Color result; Color result;
double r = v3Norm(x); double r = v3Norm(*_x);
double mu = v3Dot(x, v) / r; double mu = v3Dot(*_x, v) / r;
double d = -r * mu - sqrt(r * r * (mu * mu - 1.0) + Rt * Rt); double d = -r * mu - sqrt(r * r * (mu * mu - 1.0) + Rt * Rt);
if (d > 0.0) if (d > 0.0)
{ // if x in space and ray intersects atmosphere {
// move x to nearest intersection of ray with top atmosphere boundary /* if x in space and ray intersects atmosphere
x += d * v; move x to nearest intersection of ray with top atmosphere boundary */
t -= d; _x->x += d * v.x;
_x->y += d * v.y;
_x->z += d * v.z;
*_t -= d;
mu = (r * mu + d) / Rt; mu = (r * mu + d) / Rt;
r = Rt; r = Rt;
} }
double t = *_t;
Vector3 x = *_x;
if (r <= Rt) if (r <= Rt)
{ // if ray intersects atmosphere {
/* if ray intersects atmosphere */
double nu = v3Dot(v, s); double nu = v3Dot(v, s);
double muS = v3Dot(x, s) / r; double muS = v3Dot(x, s) / r;
double phaseR = _phaseFunctionR(nu); double phaseR = _phaseFunctionR(nu);
double phaseM = _phaseFunctionM(nu); double phaseM = _phaseFunctionM(nu);
vec4 inscatter = max(texture4D(inscatterSampler, r, mu, muS, nu), 0.0); Color inscatter = vec4max(_texture4D(&_inscatterSampler, r, mu, muS, nu), 0.0);
if (t > 0.0) if (t > 0.0)
{ {
Vector3 x0 = v3Add(x, v3Scale(v, t)); Vector3 x0 = v3Add(x, v3Scale(v, t));
@ -149,50 +368,58 @@ static Color _inscatter(Vector3* x, double* t, Vector3 v, Vector3 s, double* _r,
double mu0 = rMu0 / r0; double mu0 = rMu0 / r0;
double muS0 = v3Dot(x0, s) / r0; double muS0 = v3Dot(x0, s) / r0;
#ifdef FIX #ifdef FIX
// avoids imprecision problems in transmittance computations based on textures /* avoids imprecision problems in transmittance computations based on textures */
*attenuation = _analyticTransmittance(r, mu, t); *attenuation = _analyticTransmittance(r, mu, t);
#else #else
*attenuation = _transmittance(r, mu, v, x0); *attenuation = _transmittance(r, mu, v, x0);
#endif #endif
if (r0 > Rg + 0.01) if (r0 > Rg + 0.01)
{ {
// computes S[L]-T(x,x0)S[L]|x0 /* computes S[L]-T(x,x0)S[L]|x0 */
inscatter = max(inscatter - attenuation.rgbr * texture4D(inscatterSampler, r0, mu0, muS0, nu), 0.0); Color attmod = {attenuation->x, attenuation->y, attenuation->z, attenuation->x};
Color samp = _texture4D(&_inscatterSampler, r0, mu0, muS0, nu);
inscatter = _applyInscatter(inscatter, attmod, samp);
#ifdef FIX #ifdef FIX
// avoids imprecision problems near horizon by interpolating between two points above and below horizon /* avoids imprecision problems near horizon by interpolating between two points above and below horizon */
const float EPS = 0.004; const double EPS = 0.004;
float muHoriz = -sqrt(1.0 - (Rg / r) * (Rg / r)); double muHoriz = -sqrt(1.0 - (Rg / r) * (Rg / r));
if (abs(mu - muHoriz) < EPS) if (fabs(mu - muHoriz) < EPS)
{ {
float a = ((mu - muHoriz) + EPS) / (2.0 * EPS); double a = ((mu - muHoriz) + EPS) / (2.0 * EPS);
mu = muHoriz - EPS; mu = muHoriz - EPS;
r0 = sqrt(r * r + t * t + 2.0 * r * t * mu); r0 = sqrt(r * r + t * t + 2.0 * r * t * mu);
mu0 = (r * mu + t) / r0; mu0 = (r * mu + t) / r0;
vec4 inScatter0 = texture4D(inscatterSampler, r, mu, muS, nu); Color inScatter0 = _texture4D(&_inscatterSampler, r, mu, muS, nu);
vec4 inScatter1 = texture4D(inscatterSampler, r0, mu0, muS0, nu); Color inScatter1 = _texture4D(&_inscatterSampler, r0, mu0, muS0, nu);
vec4 inScatterA = max(inScatter0 - attenuation.rgbr * inScatter1, 0.0); Color inScatterA = _applyInscatter(inScatter0, attmod, inScatter1);
mu = muHoriz + EPS; mu = muHoriz + EPS;
r0 = sqrt(r * r + t * t + 2.0 * r * t * mu); r0 = sqrt(r * r + t * t + 2.0 * r * t * mu);
mu0 = (r * mu + t) / r0; mu0 = (r * mu + t) / r0;
inScatter0 = texture4D(inscatterSampler, r, mu, muS, nu); inScatter0 = _texture4D(&_inscatterSampler, r, mu, muS, nu);
inScatter1 = texture4D(inscatterSampler, r0, mu0, muS0, nu); inScatter1 = _texture4D(&_inscatterSampler, r0, mu0, muS0, nu);
vec4 inScatterB = max(inScatter0 - attenuation.rgbr * inScatter1, 0.0); Color inScatterB = _applyInscatter(inScatter0, attmod, inScatter1);
inscatter = mix(inScatterA, inScatterB, a); inscatter = vec4mix(inScatterA, inScatterB, a);
} }
#endif #endif
} }
} }
#ifdef FIX #ifdef FIX
// avoids imprecision problems in Mie scattering when sun is below horizon /* avoids imprecision problems in Mie scattering when sun is below horizon */
inscatter.w *= smoothstep(0.00, 0.02, muS); inscatter.a *= smoothstep(0.00, 0.02, muS);
#endif #endif
result = max(inscatter.rgb * phaseR + getMie(inscatter) * phaseM, 0.0); Color mie = getMie(inscatter);
result.r = inscatter.r * phaseR + mie.r * phaseM;
result.g = inscatter.g * phaseR + mie.g * phaseM;
result.b = inscatter.b * phaseR + mie.b * phaseM;
result.a = inscatter.a * phaseR + mie.a * phaseM;
_fixVec4Min(&result, 0.0);
} }
else else
{ // x in space and ray looking in space {
/* x in space and ray looking in space */
result = COLOR_BLACK; result = COLOR_BLACK;
} }
@ -207,7 +434,6 @@ static Color _inscatter(Vector3* x, double* t, Vector3 v, Vector3 s, double* _r,
/*ground radiance at end of ray x+tv, when sun in direction s /*ground radiance at end of ray x+tv, when sun in direction s
*attenuated bewteen ground and viewer (=R[L0]+R[L*]) */ *attenuated bewteen ground and viewer (=R[L0]+R[L*]) */
/*static Color _groundColor(Vector3 x, double t, Vector3 v, Vector3 s, double r, double mu, Color attenuation) /*static Color _groundColor(Vector3 x, double t, Vector3 v, Vector3 s, double r, double mu, Color attenuation)
{ {
Color result; Color result;
@ -273,8 +499,8 @@ static inline void _getTransmittanceUV(double r, double mu, double* u, double* v
static Color _transmittance(double r, double mu) static Color _transmittance(double r, double mu)
{ {
double u, v; double u, v;
_getTransmittanceUV(r, mu, u, v); _getTransmittanceUV(r, mu, &u, &v);
return texture2D(transmittanceSampler, uv).rgb; return _texture2D(&_transmittanceSampler, u, v);
} }
/* transmittance(=transparency) of atmosphere for infinite ray (r,mu) /* transmittance(=transparency) of atmosphere for infinite ray (r,mu)
@ -295,7 +521,11 @@ static Color _sunColor(Vector3 x, double t, Vector3 v, Vector3 s, double r, doub
{ {
Color transmittance = r <= Rt ? _transmittanceWithShadow(r, mu) : COLOR_WHITE; // T(x,xo) Color transmittance = r <= Rt ? _transmittanceWithShadow(r, mu) : COLOR_WHITE; // T(x,xo)
double isun = step(cos(M_PI / 180.0), v3Dot(v, s)) * ISun; // Lsun double isun = step(cos(M_PI / 180.0), v3Dot(v, s)) * ISun; // Lsun
return transmittance * isun; // Eq (9) transmittance.r *= isun;
transmittance.g *= isun;
transmittance.b *= isun;
transmittance.a *= isun;
return transmittance; // Eq (9)
} }
} }
@ -303,7 +533,11 @@ static Color _hdr(Color c1, Color c2, Color c3)
{ {
Color L = {c1.r + c2.r + c3.r, c1.g + c2.g + c3.g, c1.b + c2.b + c3.b, 1.0}; Color L = {c1.r + c2.r + c3.r, c1.g + c2.g + c3.g, c1.b + c2.b + c3.b, 1.0};
L = L * exposure; L.r *= exposure;
L.g *= exposure;
L.b *= exposure;
L.a *= exposure;
L.r = L.r < 1.413 ? pow(L.r * 0.38317, 1.0 / 2.2) : 1.0 - exp(-L.r); L.r = L.r < 1.413 ? pow(L.r * 0.38317, 1.0 / 2.2) : 1.0 - exp(-L.r);
L.g = L.g < 1.413 ? pow(L.g * 0.38317, 1.0 / 2.2) : 1.0 - exp(-L.g); L.g = L.g < 1.413 ? pow(L.g * 0.38317, 1.0 / 2.2) : 1.0 - exp(-L.g);
L.b = L.b < 1.413 ? pow(L.b * 0.38317, 1.0 / 2.2) : 1.0 - exp(-L.b); L.b = L.b < 1.413 ? pow(L.b * 0.38317, 1.0 / 2.2) : 1.0 - exp(-L.b);
@ -342,7 +576,7 @@ Color brunetonGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3
} }
Vector3 attenuation; Vector3 attenuation;
Color inscatterColor = _inscatter(x, t, v, s, &r, &mu, &attenuation); //S[L]-T(x,xs)S[l]|xs Color inscatterColor = _inscatter(&x, &t, v, s, &r, &mu, &attenuation); //S[L]-T(x,xs)S[l]|xs
/*Color groundColor = _groundColor(x, t, v, s, r, mu, attenuation); //R[L0]+R[L*]*/ /*Color groundColor = _groundColor(x, t, v, s, r, mu, attenuation); //R[L0]+R[L*]*/
Color groundColor = COLOR_BLACK; Color groundColor = COLOR_BLACK;
Color sunColor = _sunColor(x, t, v, s, r, mu); //L0 Color sunColor = _sunColor(x, t, v, s, r, mu); //L0

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@ -28,6 +28,8 @@ static AtmosphereDefinition* _createDefinition()
{ {
AtmosphereDefinition* result; AtmosphereDefinition* result;
// brunetonInit(); /* DEBUG */
result = malloc(sizeof(AtmosphereDefinition)); result = malloc(sizeof(AtmosphereDefinition));
result->model = ATMOSPHERE_MODEL_PREETHAM; result->model = ATMOSPHERE_MODEL_PREETHAM;
result->daytime = 0.0; result->daytime = 0.0;

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@ -3,6 +3,7 @@
#define SPHERE_SIZE 1000.0 #define SPHERE_SIZE 1000.0
void brunetonInit();
Color brunetonGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3 direction, Vector3 sun_position); Color brunetonGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3 direction, Vector3 sun_position);
Color preethamGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3 direction, Vector3 sun_position); Color preethamGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3 direction, Vector3 sun_position);