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Cycles / Sky Model:

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* Replaced the Preetham model with the newer Hosek / Wilkie model:
"An Analytic Model for Full Spectral Sky-Dome Radiance" http://cgg.mff.cuni.cz/projects/SkylightModelling/ 

* We use the sample code data, which comes with the paper, but removed some unnecessary parts, we only need the xyz version.
* New "Albedo" UI paraemeter, to control the ground albedo (between 0 and 1). 
* Works with SVM only atm (CPU and CUDA). 

Example render:
http://www.pasteall.org/pic/show.php?id=57635

ToDo / Open Questions:
* OSL still uses the old model, will be done later. In the meantime it's useful to compare the two models this way.
* The new model needs a much weaker Strength value (0.01), otherwise it's white. Can this be fixed? 
* Code cleanup.
This commit is contained in:
Thomas Dinges
2013-08-17 16:08:03 +00:00
parent 0786eebd11
commit 8b955e9b19
13 changed files with 5217 additions and 57 deletions
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83
intern/cycles/render/nodes.cpp
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@@ -20,6 +20,7 @@
#include "nodes.h"
#include "svm.h"
#include "osl.h"
#include "sky_model.h"
#include "util_transform.h"
@@ -386,13 +387,9 @@ static float2 sky_spherical_coordinates(float3 dir)
return make_float2(acosf(dir.z), atan2f(dir.x, dir.y));
}
static float sky_perez_function(float lam[6], float theta, float gamma)
{
return (1.0f + lam[0]*expf(lam[1]/cosf(theta))) * (1.0f + lam[2]*expf(lam[3]*gamma) + lam[4]*cosf(gamma)*cosf(gamma));
}
static void sky_texture_precompute(KernelSunSky *ksunsky, float3 dir, float turbidity)
static void sky_texture_precompute(KernelSunSky *ksunsky, float3 dir, float turbidity, float albedo)
{
/* Calculate Sun Direction and save coordinates */
float2 spherical = sky_spherical_coordinates(dir);
float theta = spherical.x;
float phi = spherical.y;
@@ -400,46 +397,49 @@ static void sky_texture_precompute(KernelSunSky *ksunsky, float3 dir, float turb
ksunsky->theta = theta;
ksunsky->phi = phi;
float theta2 = theta*theta;
float theta3 = theta2*theta;
float T = turbidity;
float T2 = T * T;
double solarElevation = M_PI_2_F - theta;
float chi = (4.0f / 9.0f - T / 120.0f) * (M_PI_F - 2.0f * theta);
ksunsky->zenith_Y = (4.0453f * T - 4.9710f) * tanf(chi) - 0.2155f * T + 2.4192f;
ksunsky->zenith_Y *= 0.06f;
/* Initialize Sky Model */
ArHosekSkyModelState *sky_state;
sky_state = arhosek_xyz_skymodelstate_alloc_init(turbidity, albedo, solarElevation);
ksunsky->zenith_x =
(0.00166f * theta3 - 0.00375f * theta2 + 0.00209f * theta) * T2 +
(-0.02903f * theta3 + 0.06377f * theta2 - 0.03202f * theta + 0.00394f) * T +
(0.11693f * theta3 - 0.21196f * theta2 + 0.06052f * theta + 0.25886f);
/* Copy values from sky_state to kernel_data */
ksunsky->config_x[0] = sky_state->configs[0][0];
ksunsky->config_x[1] = sky_state->configs[0][1];
ksunsky->config_x[2] = sky_state->configs[0][2];
ksunsky->config_x[3] = sky_state->configs[0][3];
ksunsky->config_x[4] = sky_state->configs[0][4];
ksunsky->config_x[5] = sky_state->configs[0][5];
ksunsky->config_x[6] = sky_state->configs[0][6];
ksunsky->config_x[7] = sky_state->configs[0][7];
ksunsky->config_x[8] = sky_state->configs[0][8];
ksunsky->zenith_y =
(0.00275f * theta3 - 0.00610f * theta2 + 0.00317f * theta) * T2 +
(-0.04214f * theta3 + 0.08970f * theta2 - 0.04153f * theta + 0.00516f) * T +
(0.15346f * theta3 - 0.26756f * theta2 + 0.06670f * theta + 0.26688f);
ksunsky->config_y[0] = sky_state->configs[1][0];
ksunsky->config_y[1] = sky_state->configs[1][1];
ksunsky->config_y[2] = sky_state->configs[1][2];
ksunsky->config_y[3] = sky_state->configs[1][3];
ksunsky->config_y[4] = sky_state->configs[1][4];
ksunsky->config_y[5] = sky_state->configs[1][5];
ksunsky->config_y[6] = sky_state->configs[1][6];
ksunsky->config_y[7] = sky_state->configs[1][7];
ksunsky->config_y[8] = sky_state->configs[1][8];
ksunsky->perez_Y[0] = (0.1787f * T - 1.4630f);
ksunsky->perez_Y[1] = (-0.3554f * T + 0.4275f);
ksunsky->perez_Y[2] = (-0.0227f * T + 5.3251f);
ksunsky->perez_Y[3] = (0.1206f * T - 2.5771f);
ksunsky->perez_Y[4] = (-0.0670f * T + 0.3703f);
ksunsky->config_z[0] = sky_state->configs[2][0];
ksunsky->config_z[1] = sky_state->configs[2][1];
ksunsky->config_z[2] = sky_state->configs[2][2];
ksunsky->config_z[3] = sky_state->configs[2][3];
ksunsky->config_z[4] = sky_state->configs[2][4];
ksunsky->config_z[5] = sky_state->configs[2][5];
ksunsky->config_z[6] = sky_state->configs[2][6];
ksunsky->config_z[7] = sky_state->configs[2][7];
ksunsky->config_z[8] = sky_state->configs[2][8];
ksunsky->perez_x[0] = (-0.0193f * T - 0.2592f);
ksunsky->perez_x[1] = (-0.0665f * T + 0.0008f);
ksunsky->perez_x[2] = (-0.0004f * T + 0.2125f);
ksunsky->perez_x[3] = (-0.0641f * T - 0.8989f);
ksunsky->perez_x[4] = (-0.0033f * T + 0.0452f);
ksunsky->radiance_x = sky_state->radiances[0];
ksunsky->radiance_y = sky_state->radiances[1];
ksunsky->radiance_z = sky_state->radiances[2];
ksunsky->perez_y[0] = (-0.0167f * T - 0.2608f);
ksunsky->perez_y[1] = (-0.0950f * T + 0.0092f);
ksunsky->perez_y[2] = (-0.0079f * T + 0.2102f);
ksunsky->perez_y[3] = (-0.0441f * T - 1.6537f);
ksunsky->perez_y[4] = (-0.0109f * T + 0.0529f);
ksunsky->zenith_Y /= sky_perez_function(ksunsky->perez_Y, 0, theta);
ksunsky->zenith_x /= sky_perez_function(ksunsky->perez_x, 0, theta);
ksunsky->zenith_y /= sky_perez_function(ksunsky->perez_y, 0, theta);
/* Free sky_state */
arhosekskymodelstate_free(sky_state);
}
SkyTextureNode::SkyTextureNode()
@@ -447,6 +447,7 @@ SkyTextureNode::SkyTextureNode()
{
sun_direction = make_float3(0.0f, 0.0f, 1.0f);
turbidity = 2.2f;
albedo = 0.3f;
add_input("Vector", SHADER_SOCKET_VECTOR, ShaderInput::POSITION);
add_output("Color", SHADER_SOCKET_COLOR);
@@ -458,7 +459,7 @@ void SkyTextureNode::compile(SVMCompiler& compiler)
ShaderOutput *color_out = output("Color");
if(compiler.sunsky) {
sky_texture_precompute(compiler.sunsky, sun_direction, turbidity);
sky_texture_precompute(compiler.sunsky, sun_direction, turbidity, albedo);
compiler.sunsky = NULL;
}