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/*
* Copyright 2011-2017 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __UTIL_MATH_INTERSECT_H__
#define __UTIL_MATH_INTERSECT_H__
CCL_NAMESPACE_BEGIN
/* Ray Intersection */
ccl_device bool ray_sphere_intersect(
float3 ray_P, float3 ray_D, float ray_t,
float3 sphere_P, float sphere_radius,
float3 *isect_P, float *isect_t)
{
const float3 d = sphere_P - ray_P;
const float radiussq = sphere_radius*sphere_radius;
const float tsq = dot(d, d);
if(tsq > radiussq) {
/* Ray origin outside sphere. */
const float tp = dot(d, ray_D);
if(tp < 0.0f) {
/* Ray points away from sphere. */
return false;
}
const float dsq = tsq - tp*tp; /* pythagoras */
if(dsq > radiussq) {
/* Closest point on ray outside sphere. */
return false;
}
const float t = tp - sqrtf(radiussq - dsq); /* pythagoras */
if(t < ray_t) {
*isect_t = t;
*isect_P = ray_P + ray_D*t;
return true;
}
}
return false;
}
ccl_device bool ray_aligned_disk_intersect(
float3 ray_P, float3 ray_D, float ray_t,
float3 disk_P, float disk_radius,
float3 *isect_P, float *isect_t)
{
/* Aligned disk normal. */
float disk_t;
const float3 disk_N = normalize_len(ray_P - disk_P, &disk_t);
const float div = dot(ray_D, disk_N);
if(UNLIKELY(div == 0.0f)) {
return false;
}
/* Compute t to intersection point. */
const float t = -disk_t/div;
if(t < 0.0f || t > ray_t) {
return false;
}
/* Test if within radius. */
float3 P = ray_P + ray_D*t;
if(len_squared(P - disk_P) > disk_radius*disk_radius) {
return false;
}
*isect_P = P;
*isect_t = t;
return true;
}
#if defined(__KERNEL_CUDA__) && __CUDA_ARCH__ < 300
ccl_device_inline
#else
ccl_device_forceinline
#endif
bool ray_triangle_intersect(
float3 ray_P, float3 ray_dir, float ray_t,
#if defined(__KERNEL_SSE2__) && defined(__KERNEL_SSE__)
const ssef *ssef_verts,
#else
const float3 tri_a, const float3 tri_b, const float3 tri_c,
#endif
float *isect_u, float *isect_v, float *isect_t)
{
#if defined(__KERNEL_SSE2__) && defined(__KERNEL_SSE__)
typedef ssef float3;
const float3 tri_a(ssef_verts[0]);
const float3 tri_b(ssef_verts[1]);
const float3 tri_c(ssef_verts[2]);
const float3 P(ray_P);
const float3 dir(ray_dir);
#else
# define dot3(a, b) dot(a, b)
const float3 P = ray_P;
const float3 dir = ray_dir;
#endif
/* Calculate vertices relative to ray origin. */
const float3 v0 = tri_c - P;
const float3 v1 = tri_a - P;
const float3 v2 = tri_b - P;
/* Calculate triangle edges. */
const float3 e0 = v2 - v0;
const float3 e1 = v0 - v1;
const float3 e2 = v1 - v2;
/* Perform edge tests. */
#ifdef __KERNEL_SSE2__
const float3 crossU = cross(v2 + v0, e0);
const float3 crossV = cross(v0 + v1, e1);
const float3 crossW = cross(v1 + v2, e2);
# ifndef __KERNEL_SSE__
const ssef crossX(crossU.x, crossV.x, crossW.x, crossW.x);
const ssef crossY(crossU.y, crossV.y, crossW.y, crossW.y);
const ssef crossZ(crossU.z, crossV.z, crossW.z, crossW.z);
# else
ssef crossX(crossU);
ssef crossY(crossV);
ssef crossZ(crossW);
ssef zero = _mm_setzero_ps();
_MM_TRANSPOSE4_PS(crossX, crossY, crossZ, zero);
# endif
const ssef dirX(ray_dir.x);
const ssef dirY(ray_dir.y);
const ssef dirZ(ray_dir.z);
/*const*/ ssef UVWW = crossX*dirX + crossY*dirY + crossZ*dirZ;
const float minUVW = reduce_min(UVWW);
const float maxUVW = reduce_max(UVWW);
#else /* __KERNEL_SSE2__ */
const float U = dot(cross(v2 + v0, e0), ray_dir);
const float V = dot(cross(v0 + v1, e1), ray_dir);
const float W = dot(cross(v1 + v2, e2), ray_dir);
const float minUVW = min(U, min(V, W));
const float maxUVW = max(U, max(V, W));
#endif /* __KERNEL_SSE2__ */
if(minUVW < 0.0f && maxUVW > 0.0f) {
return false;
}
/* Calculate geometry normal and denominator. */
const float3 Ng1 = cross(e1, e0);
//const Vec3vfM Ng1 = stable_triangle_normal(e2,e1,e0);
const float3 Ng = Ng1 + Ng1;
const float den = dot3(Ng, dir);
/* Avoid division by 0. */
if(UNLIKELY(den == 0.0f)) {
return false;
}
/* Perform depth test. */
const float T = dot3(v0, Ng);
const int sign_den = (__float_as_int(den) & 0x80000000);
const float sign_T = xor_signmask(T, sign_den);
if((sign_T < 0.0f) ||
(sign_T > ray_t * xor_signmask(den, sign_den)))
{
return false;
}
const float inv_den = 1.0f / den;
#ifdef __KERNEL_SSE2__
UVWW *= inv_den;
_mm_store_ss(isect_u, UVWW);
_mm_store_ss(isect_v, shuffle<1,1,3,3>(UVWW));
#else
*isect_u = U * inv_den;
*isect_v = V * inv_den;
#endif
*isect_t = T * inv_den;
return true;
#undef dot3
}
ccl_device bool ray_quad_intersect(float3 ray_P, float3 ray_D,
float ray_mint, float ray_maxt,
float3 quad_P,
float3 quad_u, float3 quad_v, float3 quad_n,
float3 *isect_P, float *isect_t,
float *isect_u, float *isect_v)
{
/* Perform intersection test. */
float t = -(dot(ray_P, quad_n) - dot(quad_P, quad_n)) / dot(ray_D, quad_n);
if(t < ray_mint || t > ray_maxt) {
return false;
}
const float3 hit = ray_P + t*ray_D;
const float3 inplane = hit - quad_P;
const float u = dot(inplane, quad_u) / dot(quad_u, quad_u) + 0.5f;
if(u < 0.0f || u > 1.0f) {
return false;
}
const float v = dot(inplane, quad_v) / dot(quad_v, quad_v) + 0.5f;
if(v < 0.0f || v > 1.0f) {
return false;
}
/* Store the result. */
/* TODO(sergey): Check whether we can avoid some checks here. */
if(isect_P != NULL) *isect_P = hit;
if(isect_t != NULL) *isect_t = t;
if(isect_u != NULL) *isect_u = u;
if(isect_v != NULL) *isect_v = v;
return true;
}
CCL_NAMESPACE_END
#endif /* __UTIL_MATH_INTERSECT_H__ */
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