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blender/intern/cycles/kernel/svm/svm_sky.h

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Cycles render engine, initial commit. This is the engine itself, blender modifications and build instructions will follow later. Cycles uses code from some great open source projects, many thanks them: * BVH building and traversal code from NVidia's "Understanding the Efficiency of Ray Traversal on GPUs": http://code.google.com/p/understanding-the-efficiency-of-ray-traversal-on-gpus/ * Open Shading Language for a large part of the shading system: http://code.google.com/p/openshadinglanguage/ * Blender for procedural textures and a few other nodes. * Approximate Catmull Clark subdivision from NVidia Mesh tools: http://code.google.com/p/nvidia-mesh-tools/ * Sobol direction vectors from: http://web.maths.unsw.edu.au/~fkuo/sobol/ * Film response functions from: http://www.cs.columbia.edu/CAVE/software/softlib/dorf.php
2011-04-27 11:58:34 +00:00
/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
CCL_NAMESPACE_BEGIN
/*
* "A Practical Analytic Model for Daylight"
* A. J. Preetham, Peter Shirley, Brian Smits
*/
__device float sky_angle_between(float thetav, float phiv, float theta, float phi)
{
float cospsi = sinf(thetav)*sinf(theta)*cosf(phi - phiv) + cosf(thetav)*cosf(theta);
return safe_acosf(cospsi);
}
Cycles: some steps to getting OpenCL backend to compile.
2011-05-20 12:26:01 +00:00
__device float sky_perez_function(__constant float *lam, float theta, float gamma)
Cycles render engine, initial commit. This is the engine itself, blender modifications and build instructions will follow later. Cycles uses code from some great open source projects, many thanks them: * BVH building and traversal code from NVidia's "Understanding the Efficiency of Ray Traversal on GPUs": http://code.google.com/p/understanding-the-efficiency-of-ray-traversal-on-gpus/ * Open Shading Language for a large part of the shading system: http://code.google.com/p/openshadinglanguage/ * Blender for procedural textures and a few other nodes. * Approximate Catmull Clark subdivision from NVidia Mesh tools: http://code.google.com/p/nvidia-mesh-tools/ * Sobol direction vectors from: http://web.maths.unsw.edu.au/~fkuo/sobol/ * Film response functions from: http://www.cs.columbia.edu/CAVE/software/softlib/dorf.php
2011-04-27 11:58:34 +00:00
{
float ctheta = cosf(theta);
float cgamma = cosf(gamma);
return (1.0f + lam[0]*expf(lam[1]/ctheta)) * (1.0f + lam[2]*expf(lam[3]*gamma) + lam[4]*cgamma*cgamma);
}
__device float3 sky_radiance(KernelGlobals *kg, float3 dir)
{
/* convert vector to spherical coordinates */
float2 spherical = direction_to_spherical(dir);
float theta = spherical.x;
float phi = spherical.y;
/* angle between sun direction and dir */
float gamma = sky_angle_between(theta, phi, kernel_data.sunsky.theta, kernel_data.sunsky.phi);
/* clamp theta to horizon */
theta = min(theta, M_PI_2_F - 0.001f);
/* compute xyY color space values */
float x = kernel_data.sunsky.zenith_x * sky_perez_function(kernel_data.sunsky.perez_x, theta, gamma);
float y = kernel_data.sunsky.zenith_y * sky_perez_function(kernel_data.sunsky.perez_y, theta, gamma);
float Y = kernel_data.sunsky.zenith_Y * sky_perez_function(kernel_data.sunsky.perez_Y, theta, gamma);
/* convert to RGB */
float3 xyz = xyY_to_xyz(x, y, Y);
return xyz_to_rgb(xyz.x, xyz.y, xyz.z);
}
__device void svm_node_tex_sky(KernelGlobals *kg, ShaderData *sd, float *stack, uint dir_offset, uint out_offset)
{
float3 dir = stack_load_float3(stack, dir_offset);
float3 f = sky_radiance(kg, dir);
stack_store_float3(stack, out_offset, f);
}
CCL_NAMESPACE_END
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