paysages : Progress on bruneton atmospheric model (WIP).
git-svn-id: https://subversion.assembla.com/svn/thunderk/paysages@478 b1fd45b6-86a6-48da-8261-f70d1f35bdcc
This commit is contained in:
ThunderK
parent
983270ee56
commit
b765ae2cff
2 changed files with 159 additions and 85 deletions
|
|
@ -19,13 +19,36 @@ static const double Rg = 6360.0;
|
|||
static const double Rt = 6420.0;
|
||||
static const double RL = 6421.0;
|
||||
static const double exposure = 0.4;
|
||||
static const float ISun = 100.0;
|
||||
static const double 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
|
||||
/*#define SKY_W 64
|
||||
#define SKY_H 16*/
|
||||
#define SKY_W 640
|
||||
#define SKY_H 160
|
||||
|
||||
typedef struct
|
||||
{
|
||||
int xsize;
|
||||
int ysize;
|
||||
Color* data;
|
||||
} Texture2D;
|
||||
|
||||
typedef struct
|
||||
{
|
||||
int xsize;
|
||||
int ysize;
|
||||
int zsize;
|
||||
Color* data;
|
||||
} Texture3D;
|
||||
|
||||
Texture2D _transmittanceTexture = {0, 0, 0};
|
||||
Texture2D _irrDeltaETexture;
|
||||
Texture3D _inscatterSampler;
|
||||
|
||||
// Rayleigh
|
||||
static const double HR = 8.0;
|
||||
|
|
@ -49,8 +72,8 @@ static const vec3 betaMEx = betaMSca / 0.9;
|
|||
static const float mieG = 0.65;*/
|
||||
|
||||
#define step(_a_,_b_) ((_a_) < (_b_) ? 0 : 1)
|
||||
#define max(_a_,_b_) ((_a_) < (_b_) ? (_a_) : (_b_))
|
||||
#define min(_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 mix(_x_,_y_,_a_) ((_x_) * (1.0 - (_a_)) + (_y_) * (_a_))
|
||||
static inline Color vec4mix(Color v1, Color v2, double a)
|
||||
|
|
@ -109,20 +132,48 @@ static inline Color vec4(double r, double g, double b, double a)
|
|||
return result;
|
||||
}
|
||||
|
||||
typedef struct
|
||||
static Color _texture2D(Texture2D* tex, double x, double y)
|
||||
{
|
||||
int xsize;
|
||||
int ysize;
|
||||
Color* data;
|
||||
} Texture2D;
|
||||
if (x < 0.0) x = 0.0;
|
||||
if (x > 1.0) x = 1.0;
|
||||
if (y < 0.0) y = 0.0;
|
||||
if (y > 1.0) y = 1.0;
|
||||
/* TODO Interpolation */
|
||||
int ix = (int)round(x * ((double)(tex->xsize - 1)) + 0.5);
|
||||
int iy = (int)round(y * ((double)(tex->ysize - 1)) + 0.5);
|
||||
return tex->data[iy * tex->xsize + ix];
|
||||
}
|
||||
|
||||
typedef struct
|
||||
static Color _texture3D(Texture3D* tex, Vector3 p)
|
||||
{
|
||||
int xsize;
|
||||
int ysize;
|
||||
int zsize;
|
||||
Color* data;
|
||||
} Texture3D;
|
||||
/* TODO Interpolation */
|
||||
return tex->data[(int)(p.z * (tex->zsize - 1)) * tex->ysize * tex->xsize + (int)(p.y * (tex->ysize - 1)) * tex->xsize + (int)(p.x * (tex->xsize - 1))];
|
||||
}
|
||||
|
||||
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;
|
||||
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);
|
||||
}
|
||||
|
||||
/* Rayleigh phase function */
|
||||
static double _phaseFunctionR(double mu)
|
||||
|
|
@ -170,15 +221,92 @@ static double _opticalDepth(double H, double r, double mu, double d)
|
|||
static Texture3D _precomputeInscatterSampler()
|
||||
{
|
||||
Texture3D result;
|
||||
int x, y;
|
||||
|
||||
result.xsize = 0;
|
||||
result.ysize = 0;
|
||||
result.zsize = 0;
|
||||
result.data = 0;
|
||||
#if 0
|
||||
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) */
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
static inline void _getTransmittanceUV(double r, double mu, double* u, double* v)
|
||||
{
|
||||
#ifdef TRANSMITTANCE_NON_LINEAR
|
||||
*v = sqrt((r - Rg) / (Rt - Rg));
|
||||
*u = atan((mu + 0.15) / (1.0 + 0.15) * tan(1.5)) / 1.5;
|
||||
#else
|
||||
*v = (r - Rg) / (Rt - Rg);
|
||||
*u = (mu + 0.15) / (1.0 + 0.15);
|
||||
#endif
|
||||
}
|
||||
|
||||
/* transmittance(=transparency) of atmosphere for infinite ray (r,mu)
|
||||
(mu=cos(view zenith angle)), intersections with ground ignored */
|
||||
static Color _transmittance(double r, double mu)
|
||||
{
|
||||
double u, v;
|
||||
_getTransmittanceUV(r, mu, &u, &v);
|
||||
return _texture2D(&_transmittanceTexture, u, v);
|
||||
}
|
||||
|
||||
static void _getIrradianceRMuS(double x, double y, double* r, double* muS)
|
||||
{
|
||||
*r = Rg + y * (Rt - Rg);
|
||||
*muS = -0.2 + x * (1.0 + 0.2);
|
||||
}
|
||||
|
||||
static Texture2D _precomputeIrrDeltaETexture()
|
||||
{
|
||||
Texture2D result;
|
||||
int x, y;
|
||||
|
||||
result.xsize = SKY_W;
|
||||
result.ysize = SKY_H;
|
||||
result.data = malloc(sizeof(Color) * result.xsize * result.ysize); /* TODO free */
|
||||
|
||||
/* Irradiance program */
|
||||
for (x = 0; x < result.xsize; x++)
|
||||
{
|
||||
for (y = 0; y < result.ysize; y++)
|
||||
{
|
||||
double r, muS, u, v;
|
||||
Color trans, irr;
|
||||
_getIrradianceRMuS((double)x / result.xsize, (double)y / result.ysize, &r, &muS);
|
||||
trans = _transmittance(r, muS);
|
||||
|
||||
_getTransmittanceUV(r, muS, &u, &v);
|
||||
//printf("%d %d -> %f %f -> %f %f %f\n", x, y, u, v, trans.r, trans.g, trans.b);
|
||||
|
||||
irr.r = trans.r * max(muS, 0.0);
|
||||
irr.g = trans.g * max(muS, 0.0);
|
||||
irr.b = trans.b * max(muS, 0.0);
|
||||
irr.a = 1.0;
|
||||
result.data[y * result.xsize + x] = irr;
|
||||
}
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
Texture3D _inscatterSampler;
|
||||
|
||||
/* nearest intersection of ray r,mu with ground or top atmosphere boundary
|
||||
* mu=cos(ray zenith angle at ray origin) */
|
||||
|
|
@ -188,7 +316,7 @@ static double limit(double r, double mu)
|
|||
double delta2 = r * r * (mu * mu - 1.0) + Rg * Rg;
|
||||
if (delta2 >= 0.0)
|
||||
{
|
||||
float din = -r * mu - sqrt(delta2);
|
||||
double din = -r * mu - sqrt(delta2);
|
||||
if (din >= 0.0) {
|
||||
dout = min(dout, din);
|
||||
}
|
||||
|
|
@ -230,7 +358,7 @@ static Color _debugSave2D(void* data, int x, int y)
|
|||
return tex->data[y * tex->xsize + x];
|
||||
}
|
||||
|
||||
static Texture2D _precomputeTransmittanceSampler()
|
||||
static Texture2D _precomputeTransmittanceTexture()
|
||||
{
|
||||
Texture2D result;
|
||||
int x, y;
|
||||
|
|
@ -256,58 +384,24 @@ static Texture2D _precomputeTransmittanceSampler()
|
|||
}
|
||||
}
|
||||
|
||||
/* DEBUG */
|
||||
systemSavePictureFile("debug.png", _debugSave2D, &result, result.xsize, result.ysize);
|
||||
|
||||
return result;
|
||||
}
|
||||
Texture2D _transmittanceSampler;
|
||||
|
||||
void brunetonInit()
|
||||
{
|
||||
_inscatterSampler = _precomputeInscatterSampler();
|
||||
_transmittanceSampler = _precomputeTransmittanceSampler();
|
||||
if (_transmittanceTexture.xsize == 0) /* TEMP */
|
||||
{
|
||||
_transmittanceTexture = _precomputeTransmittanceTexture();
|
||||
_irrDeltaETexture = _precomputeIrrDeltaETexture();
|
||||
//_inscatterSampler = _precomputeInscatterSampler();
|
||||
}
|
||||
|
||||
/* DEBUG */
|
||||
systemSavePictureFile("transmittance.png", _debugSave2D, &_transmittanceTexture, _transmittanceTexture.xsize, _transmittanceTexture.ysize);
|
||||
systemSavePictureFile("irrdeltae.png", _debugSave2D, &_irrDeltaETexture, _irrDeltaETexture.xsize, _irrDeltaETexture.ysize);
|
||||
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;
|
||||
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);
|
||||
}
|
||||
|
||||
/* transmittance(=transparency) of atmosphere for ray (r,mu) of length d
|
||||
(mu=cos(view zenith angle)), intersections with ground ignored
|
||||
uses analytic formula instead of transmittance texture */
|
||||
|
|
@ -483,26 +577,6 @@ static Color _inscatter(Vector3* _x, double* _t, Vector3 v, Vector3 s, double* _
|
|||
return result;
|
||||
}*/
|
||||
|
||||
static inline void _getTransmittanceUV(double r, double mu, double* u, double* v)
|
||||
{
|
||||
#ifdef TRANSMITTANCE_NON_LINEAR
|
||||
*v = sqrt((r - Rg) / (Rt - Rg));
|
||||
*u = atan((mu + 0.15) / (1.0 + 0.15) * tan(1.5)) / 1.5;
|
||||
#else
|
||||
*v = (r - Rg) / (Rt - Rg);
|
||||
*u = (mu + 0.15) / (1.0 + 0.15);
|
||||
#endif
|
||||
}
|
||||
|
||||
/* transmittance(=transparency) of atmosphere for infinite ray (r,mu)
|
||||
(mu=cos(view zenith angle)), intersections with ground ignored */
|
||||
static Color _transmittance(double r, double mu)
|
||||
{
|
||||
double u, v;
|
||||
_getTransmittanceUV(r, mu, &u, &v);
|
||||
return _texture2D(&_transmittanceSampler, u, v);
|
||||
}
|
||||
|
||||
/* transmittance(=transparency) of atmosphere for infinite ray (r,mu)
|
||||
(mu=cos(view zenith angle)), or zero if ray intersects ground */
|
||||
static Color _transmittanceWithShadow(double r, double mu)
|
||||
|
|
|
|||
|
|
@ -28,7 +28,7 @@ static AtmosphereDefinition* _createDefinition()
|
|||
{
|
||||
AtmosphereDefinition* result;
|
||||
|
||||
// brunetonInit(); /* DEBUG */
|
||||
//brunetonInit(); /* DEBUG */
|
||||
|
||||
result = malloc(sizeof(AtmosphereDefinition));
|
||||
result->model = ATMOSPHERE_MODEL_PREETHAM;
|
||||
|
|
|
|||
Loading…
Reference in a new issue