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/*
* Parts adapted from Open Shading Language with this license:
*
* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
* All Rights Reserved.
*
* Modifications Copyright 2011, Blender Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Sony Pictures Imageworks nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
CCL_NAMESPACE_BEGIN
/* Spherical coordinates <-> Cartesian direction. */
ccl_device float2 direction_to_spherical(float3 dir)
{
float theta = safe_acosf(dir.z);
float phi = atan2f(dir.x, dir.y);
return make_float2(theta, phi);
}
ccl_device float3 spherical_to_direction(float theta, float phi)
{
float sin_theta = sinf(theta);
return make_float3(sin_theta * cosf(phi), sin_theta * sinf(phi), cosf(theta));
}
/* Equirectangular coordinates <-> Cartesian direction */
ccl_device float2 direction_to_equirectangular_range(float3 dir, float4 range)
{
if (is_zero(dir))
return zero_float2();
float u = (atan2f(dir.y, dir.x) - range.y) / range.x;
float v = (acosf(dir.z / len(dir)) - range.w) / range.z;
return make_float2(u, v);
}
ccl_device float3 equirectangular_range_to_direction(float u, float v, float4 range)
{
float phi = range.x * u + range.y;
float theta = range.z * v + range.w;
float sin_theta = sinf(theta);
return make_float3(sin_theta * cosf(phi), sin_theta * sinf(phi), cosf(theta));
}
ccl_device float2 direction_to_equirectangular(float3 dir)
{
return direction_to_equirectangular_range(dir, make_float4(-M_2PI_F, M_PI_F, -M_PI_F, M_PI_F));
}
ccl_device float3 equirectangular_to_direction(float u, float v)
{
return equirectangular_range_to_direction(u, v, make_float4(-M_2PI_F, M_PI_F, -M_PI_F, M_PI_F));
}
/* Fisheye <-> Cartesian direction */
ccl_device float2 direction_to_fisheye(float3 dir, float fov)
{
float r = atan2f(sqrtf(dir.y * dir.y + dir.z * dir.z), dir.x) / fov;
float phi = atan2f(dir.z, dir.y);
float u = r * cosf(phi) + 0.5f;
float v = r * sinf(phi) + 0.5f;
return make_float2(u, v);
}
ccl_device float3 fisheye_to_direction(float u, float v, float fov)
{
u = (u - 0.5f) * 2.0f;
v = (v - 0.5f) * 2.0f;
float r = sqrtf(u * u + v * v);
if (r > 1.0f)
return zero_float3();
float phi = safe_acosf((r != 0.0f) ? u / r : 0.0f);
float theta = r * fov * 0.5f;
if (v < 0.0f)
phi = -phi;
return make_float3(cosf(theta), -cosf(phi) * sinf(theta), sinf(phi) * sinf(theta));
}
ccl_device float2 direction_to_fisheye_equisolid(float3 dir, float lens, float width, float height)
{
float theta = safe_acosf(dir.x);
float r = 2.0f * lens * sinf(theta * 0.5f);
float phi = atan2f(dir.z, dir.y);
float u = r * cosf(phi) / width + 0.5f;
float v = r * sinf(phi) / height + 0.5f;
return make_float2(u, v);
}
ccl_device_inline float3
fisheye_equisolid_to_direction(float u, float v, float lens, float fov, float width, float height)
{
u = (u - 0.5f) * width;
v = (v - 0.5f) * height;
float rmax = 2.0f * lens * sinf(fov * 0.25f);
float r = sqrtf(u * u + v * v);
if (r > rmax)
return zero_float3();
float phi = safe_acosf((r != 0.0f) ? u / r : 0.0f);
float theta = 2.0f * asinf(r / (2.0f * lens));
if (v < 0.0f)
phi = -phi;
return make_float3(cosf(theta), -cosf(phi) * sinf(theta), sinf(phi) * sinf(theta));
}
ccl_device_inline float3
fisheye_lens_polynomial_to_direction(float u, float v, float coeff0, float4 coeffs,
float fov, float width, float height)
{
u = (u - 0.5f) * width;
v = (v - 0.5f) * height;
float r = sqrtf(u * u + v * v);
float r2 = r*r;
float4 rr = make_float4(r, r2, r2*r, r2*r2);
float theta = -(coeff0 + dot(coeffs, rr));
if (fabsf(theta) > 0.5f * fov)
return zero_float3();
float phi = safe_acosf((r != 0.0f) ? u / r : 0.0f);
if (v < 0.0f)
phi = -phi;
return make_float3(cosf(theta), -cosf(phi) * sinf(theta), sinf(phi) * sinf(theta));
}
ccl_device float2 direction_to_fisheye_lens_polynomial(float3 dir, float coeff0, float4 coeffs,
float width, float height)
{
float theta = -safe_acosf(dir.x);
float r = (theta - coeff0) / coeffs.x;
for (int i=0; i<20; i++) {
float r2 = r*r;
float4 rr = make_float4(r, r2, r2*r, r2*r2);
r = (theta - (coeff0 + dot(coeffs, rr))) / coeffs.x;
}
float phi = atan2f(dir.z, dir.y);
float u = r * cosf(phi) / width + 0.5f;
float v = r * sinf(phi) / height + 0.5f;
return make_float2(u, v);
}
/* Mirror Ball <-> Cartesion direction */
ccl_device float3 mirrorball_to_direction(float u, float v)
{
/* point on sphere */
float3 dir;
dir.x = 2.0f * u - 1.0f;
dir.z = 2.0f * v - 1.0f;
if (dir.x * dir.x + dir.z * dir.z > 1.0f)
return zero_float3();
dir.y = -sqrtf(max(1.0f - dir.x * dir.x - dir.z * dir.z, 0.0f));
/* reflection */
float3 I = make_float3(0.0f, -1.0f, 0.0f);
return 2.0f * dot(dir, I) * dir - I;
}
ccl_device float2 direction_to_mirrorball(float3 dir)
{
/* inverse of mirrorball_to_direction */
dir.y -= 1.0f;
float div = 2.0f * sqrtf(max(-0.5f * dir.y, 0.0f));
if (div > 0.0f)
dir /= div;
float u = 0.5f * (dir.x + 1.0f);
float v = 0.5f * (dir.z + 1.0f);
return make_float2(u, v);
}
ccl_device_inline float3 panorama_to_direction(ccl_constant KernelCamera *cam, float u, float v)
{
switch (cam->panorama_type) {
case PANORAMA_EQUIRECTANGULAR:
return equirectangular_range_to_direction(u, v, cam->equirectangular_range);
case PANORAMA_MIRRORBALL:
return mirrorball_to_direction(u, v);
case PANORAMA_FISHEYE_EQUIDISTANT:
return fisheye_to_direction(u, v, cam->fisheye_fov);
case PANORAMA_FISHEYE_LENS_POLYNOMIAL:
return fisheye_lens_polynomial_to_direction(
u, v, cam->fisheye_lens_polynomial_bias, cam->fisheye_lens_polynomial_coefficients, cam->fisheye_fov,
cam->sensorwidth, cam->sensorheight);
case PANORAMA_FISHEYE_EQUISOLID:
default:
return fisheye_equisolid_to_direction(
u, v, cam->fisheye_lens, cam->fisheye_fov, cam->sensorwidth, cam->sensorheight);
}
}
ccl_device_inline float2 direction_to_panorama(ccl_constant KernelCamera *cam, float3 dir)
{
switch (cam->panorama_type) {
case PANORAMA_EQUIRECTANGULAR:
return direction_to_equirectangular_range(dir, cam->equirectangular_range);
case PANORAMA_MIRRORBALL:
return direction_to_mirrorball(dir);
case PANORAMA_FISHEYE_EQUIDISTANT:
return direction_to_fisheye(dir, cam->fisheye_fov);
case PANORAMA_FISHEYE_LENS_POLYNOMIAL:
return direction_to_fisheye_lens_polynomial(
dir, cam->fisheye_lens_polynomial_bias, cam->fisheye_lens_polynomial_coefficients,
cam->sensorwidth, cam->sensorheight);
case PANORAMA_FISHEYE_EQUISOLID:
default:
return direction_to_fisheye_equisolid(
dir, cam->fisheye_lens, cam->sensorwidth, cam->sensorheight);
}
}
ccl_device_inline void spherical_stereo_transform(ccl_constant KernelCamera *cam,
ccl_private float3 *P,
ccl_private float3 *D)
{
float interocular_offset = cam->interocular_offset;
/* Interocular offset of zero means either non stereo, or stereo without
* spherical stereo. */
kernel_assert(interocular_offset != 0.0f);
if (cam->pole_merge_angle_to > 0.0f) {
const float pole_merge_angle_from = cam->pole_merge_angle_from,
pole_merge_angle_to = cam->pole_merge_angle_to;
float altitude = fabsf(safe_asinf((*D).z));
if (altitude > pole_merge_angle_to) {
interocular_offset = 0.0f;
}
else if (altitude > pole_merge_angle_from) {
float fac = (altitude - pole_merge_angle_from) /
(pole_merge_angle_to - pole_merge_angle_from);
float fade = cosf(fac * M_PI_2_F);
interocular_offset *= fade;
}
}
float3 up = make_float3(0.0f, 0.0f, 1.0f);
float3 side = normalize(cross(*D, up));
float3 stereo_offset = side * interocular_offset;
*P += stereo_offset;
/* Convergence distance is FLT_MAX in the case of parallel convergence mode,
* no need to modify direction in this case either. */
const float convergence_distance = cam->convergence_distance;
if (convergence_distance != FLT_MAX) {
float3 screen_offset = convergence_distance * (*D);
*D = normalize(screen_offset - stereo_offset);
}
}
CCL_NAMESPACE_END
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