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yocto_pathtrace.cpp
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yocto_pathtrace.cpp
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//
// Implementation for Yocto/RayTrace.
//
//
// LICENSE:
//
// Copyright (c) 2016 -- 2020 Fabio Pellacini
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
#include "yocto_pathtrace.h"
#include <yocto/yocto_shape.h>
#include <atomic>
#include <deque>
#include <future>
#include <memory>
#include <mutex>
using namespace std::string_literals;
#ifdef YOCTO_EMBREE
#include <embree3/rtcore.h>
#include <cstring>
#endif
// -----------------------------------------------------------------------------
// MATH FUNCTIONS
// -----------------------------------------------------------------------------
namespace yocto::pathtrace {
// import math symbols for use
using math::abs;
using math::acos;
using math::atan2;
using math::clamp;
using math::cos;
using math::exp;
using math::flt_max;
using math::fmod;
using math::fresnel_conductor;
using math::fresnel_dielectric;
using math::identity3x3f;
using math::invalidb3f;
using math::log;
using math::make_rng;
using math::max;
using math::min;
using math::pif;
using math::pow;
using math::sample_discrete_cdf;
using math::sample_discrete_cdf_pdf;
using math::sample_uniform;
using math::sample_uniform_pdf;
using math::sin;
using math::sqrt;
using math::zero2f;
using math::zero2i;
using math::zero3f;
using math::zero3i;
using math::zero4f;
using math::zero4i;
using yocto::shape::compute_normals;
using yocto::shape::make_edge_map;
using yocto::shape::quads_to_triangles;
using yocto::shape::split_facevarying;
using yocto::extension::eval_hair_brdf;
using yocto::extension::eval_hair_scattering;
using yocto::extension::hair_brdf;
using yocto::extension::hair_material;
using yocto::extension::sample_hair_scattering;
using yocto::extension::sample_hair_scattering_pdf;
} // namespace yocto::pathtrace
// -----------------------------------------------------------------------------
// IMPLEMENTATION FOR SCENE EVALUATION
// -----------------------------------------------------------------------------
namespace yocto::pathtrace {
#ifdef YOCTO_EMBREE
static RTCDevice embree_device() {
static RTCDevice device = nullptr;
if (!device) {
device = rtcNewDevice("");
rtcSetDeviceErrorFunction(
device,
[](void* ctx, RTCError code, const char* str) {
switch (code) {
case RTC_ERROR_UNKNOWN:
throw std::runtime_error("RTC_ERROR_UNKNOWN: "s + str);
case RTC_ERROR_INVALID_ARGUMENT:
throw std::runtime_error("RTC_ERROR_INVALID_ARGUMENT: "s + str);
case RTC_ERROR_INVALID_OPERATION:
throw std::runtime_error("RTC_ERROR_INVALID_OPERATION: "s + str);
case RTC_ERROR_OUT_OF_MEMORY:
throw std::runtime_error("RTC_ERROR_OUT_OF_MEMORY: "s + str);
case RTC_ERROR_UNSUPPORTED_CPU:
throw std::runtime_error("RTC_ERROR_UNSUPPORTED_CPU: "s + str);
case RTC_ERROR_CANCELLED:
throw std::runtime_error("RTC_ERROR_CANCELLED: "s + str);
default: throw std::runtime_error("invalid error code");
}
},
nullptr);
}
return device;
}
#endif
// Check texture size
static vec2i texture_size(const ptr::texture* texture) {
if (!texture->colorf.empty()) {
return texture->colorf.size();
} else if (!texture->colorb.empty()) {
return texture->colorb.size();
} else if (!texture->scalarf.empty()) {
return texture->scalarf.size();
} else if (!texture->scalarb.empty()) {
return texture->scalarb.size();
} else {
return zero2i;
}
}
// Evaluate a texture
static vec3f lookup_texture(
const ptr::texture* texture, const vec2i& ij, bool ldr_as_linear = false) {
if (!texture->colorf.empty()) {
return texture->colorf[ij];
} else if (!texture->colorb.empty()) {
return ldr_as_linear ? byte_to_float(texture->colorb[ij])
: srgb_to_rgb(byte_to_float(texture->colorb[ij]));
} else if (!texture->scalarf.empty()) {
return vec3f{texture->scalarf[ij]};
} else if (!texture->scalarb.empty()) {
return ldr_as_linear
? byte_to_float(vec3b{texture->scalarb[ij]})
: srgb_to_rgb(byte_to_float(vec3b{texture->scalarb[ij]}));
} else {
return {1, 1, 1};
}
}
// Evaluate a texture
static vec3f eval_texture(const ptr::texture* texture, const vec2f& uv,
bool ldr_as_linear = false, bool no_interpolation = false,
bool clamp_to_edge = false) {
// get texture
if (!texture) return {1, 1, 1};
// get yimg::image width/height
auto size = texture_size(texture);
// get coordinates normalized for tiling
auto s = 0.0f, t = 0.0f;
if (clamp_to_edge) {
s = clamp(uv.x, 0.0f, 1.0f) * size.x;
t = clamp(uv.y, 0.0f, 1.0f) * size.y;
} else {
s = fmod(uv.x, 1.0f) * size.x;
if (s < 0) s += size.x;
t = fmod(uv.y, 1.0f) * size.y;
if (t < 0) t += size.y;
}
// get yimg::image coordinates and residuals
auto i = clamp((int)s, 0, size.x - 1), j = clamp((int)t, 0, size.y - 1);
auto ii = (i + 1) % size.x, jj = (j + 1) % size.y;
auto u = s - i, v = t - j;
if (no_interpolation) return lookup_texture(texture, {i, j}, ldr_as_linear);
// handle interpolation
return lookup_texture(texture, {i, j}, ldr_as_linear) * (1 - u) * (1 - v) +
lookup_texture(texture, {i, jj}, ldr_as_linear) * (1 - u) * v +
lookup_texture(texture, {ii, j}, ldr_as_linear) * u * (1 - v) +
lookup_texture(texture, {ii, jj}, ldr_as_linear) * u * v;
}
static float eval_texturef(const ptr::texture* texture, const vec2f& uv,
bool ldr_as_linear = false, bool no_interpolation = false,
bool clamp_to_edge = false) {
return eval_texture(
texture, uv, ldr_as_linear, no_interpolation, clamp_to_edge)
.x;
}
// Generates a ray from a camera for yimg::image plane coordinate uv and
// the lens coordinates luv.
static ray3f eval_camera(
const ptr::camera* camera, const vec2f& image_uv, const vec2f& lens_uv) {
auto q = vec3f{camera->film.x * (0.5f - image_uv.x),
camera->film.y * (image_uv.y - 0.5f), camera->lens};
auto dc = -normalize(q);
auto e = vec3f{
lens_uv.x * camera->aperture / 2, lens_uv.y * camera->aperture / 2, 0};
auto p = dc * camera->focus / abs(dc.z);
auto d = normalize(p - e);
return ray3f{
transform_point(camera->frame, e), transform_direction(camera->frame, d)};
}
// Samples a camera ray at pixel ij of an image of size size with puv and luv
// as random numbers for pixel and lens respectively
static ray3f sample_camera(const ptr::camera* camera, const vec2i& ij,
const vec2i& size, const vec2f& puv, const vec2f& luv) {
return eval_camera(camera, ((vec2f)ij + puv) / (vec2f)size, sample_disk(luv));
}
// Eval position
static vec3f eval_position(
const ptr::object* object, int element, const vec2f& uv) {
auto shape = object->shape;
if (!shape->triangles.empty()) {
auto t = shape->triangles[element];
return transform_point(
object->frame, interpolate_triangle(shape->positions[t.x],
shape->positions[t.y], shape->positions[t.z], uv));
} else if (!shape->lines.empty()) {
auto l = shape->lines[element];
return transform_point(object->frame,
interpolate_line(shape->positions[l.x], shape->positions[l.y], uv.x));
} else if (!shape->points.empty()) {
return transform_point(
object->frame, shape->positions[shape->points[element]]);
} else {
return zero3f;
}
}
// Shape element normal.
static vec3f eval_element_normal(const ptr::object* object, int element) {
auto shape = object->shape;
if (!shape->triangles.empty()) {
auto t = shape->triangles[element];
return transform_normal(
object->frame, triangle_normal(shape->positions[t.x],
shape->positions[t.y], shape->positions[t.z]));
} else if (!shape->lines.empty()) {
auto l = shape->lines[element];
return transform_normal(object->frame,
line_tangent(shape->positions[l.x], shape->positions[l.y]));
} else if (!shape->points.empty()) {
return {0, 0, 1};
} else {
return {0, 0, 0};
}
}
// Eval normal
static vec3f eval_normal(
const ptr::object* object, int element, const vec2f& uv) {
auto shape = object->shape;
if (shape->normals.empty()) return eval_element_normal(object, element);
if (!shape->triangles.empty()) {
auto t = shape->triangles[element];
return transform_normal(
object->frame, normalize(interpolate_triangle(shape->normals[t.x],
shape->normals[t.y], shape->normals[t.z], uv)));
} else if (!shape->lines.empty()) {
auto l = shape->lines[element];
return transform_normal(object->frame,
normalize(
interpolate_line(shape->normals[l.x], shape->normals[l.y], uv.x)));
} else if (!shape->points.empty()) {
return transform_normal(
object->frame, normalize(shape->normals[shape->points[element]]));
} else {
return zero3f;
}
}
// Eval texcoord
static vec2f eval_texcoord(
const ptr::object* object, int element, const vec2f& uv) {
auto shape = object->shape;
if (shape->texcoords.empty()) return uv;
if (!shape->triangles.empty()) {
auto t = shape->triangles[element];
return interpolate_triangle(shape->texcoords[t.x], shape->texcoords[t.y],
shape->texcoords[t.z], uv);
} else if (!shape->lines.empty()) {
auto l = shape->lines[element];
return interpolate_line(shape->texcoords[l.x], shape->texcoords[l.y], uv.x);
} else if (!shape->points.empty()) {
return shape->texcoords[shape->points[element]];
} else {
return zero2f;
}
}
// Shape element normal.
static std::pair<vec3f, vec3f> eval_element_tangents(
const ptr::object* object, int element) {
auto shape = object->shape;
if (!shape->triangles.empty() && !shape->texcoords.empty()) {
auto t = shape->triangles[element];
auto [tu, tv] = triangle_tangents_fromuv(shape->positions[t.x],
shape->positions[t.y], shape->positions[t.z], shape->texcoords[t.x],
shape->texcoords[t.y], shape->texcoords[t.z]);
return {transform_direction(object->frame, tu),
transform_direction(object->frame, tv)};
} else {
return {};
}
}
static vec3f eval_normalmap(
const ptr::object* object, int element, const vec2f& uv) {
auto shape = object->shape;
auto normal_tex = object->material->normal_tex;
// apply normal mapping
auto normal = eval_normal(object, element, uv);
auto texcoord = eval_texcoord(object, element, uv);
if (normal_tex && !shape->triangles.empty()) {
auto normalmap = -1 + 2 * eval_texture(normal_tex, texcoord, true);
auto [tu, tv] = eval_element_tangents(object, element);
auto frame = frame3f{tu, tv, normal, zero3f};
frame.x = orthonormalize(frame.x, frame.z);
frame.y = normalize(cross(frame.z, frame.x));
auto flip_v = dot(frame.y, tv) < 0;
normalmap.y *= flip_v ? 1 : -1; // flip vertical axis
normal = transform_normal(frame, normalmap);
}
return normal;
}
// Eval shading normal
static vec3f eval_shading_normal(const ptr::object* object, int element,
const vec2f& uv, const vec3f& outgoing) {
auto shape = object->shape;
auto material = object->material;
if (!shape->triangles.empty()) {
auto normal = eval_normal(object, element, uv);
if (material->normal_tex) {
normal = eval_normalmap(object, element, uv);
}
if (!material->thin) return normal;
return dot(normal, outgoing) >= 0 ? normal : -normal;
} else if (!shape->lines.empty()) {
auto normal = eval_normal(object, element, uv);
return orthonormalize(outgoing, normal);
} else if (!shape->points.empty()) {
return -outgoing;
} else {
return zero3f;
}
}
// Brdf
struct brdf {
// brdf lobes
vec3f diffuse = {0, 0, 0};
vec3f specular = {0, 0, 0};
vec3f metal = {0, 0, 0};
vec3f transmission = {0, 0, 0};
vec3f refraction = {0, 0, 0};
float roughness = 0;
float opacity = 1;
float ior = 1;
vec3f meta = {0, 0, 0};
vec3f metak = {0, 0, 0};
// weights
float diffuse_pdf = 0;
float specular_pdf = 0;
float metal_pdf = 0;
float transmission_pdf = 0;
float refraction_pdf = 0;
// hair brdf
bool hair = false;
extension::hair_brdf hair_brdf;
};
// Eval material to obatain emission, brdf and opacity.
static vec3f eval_emission(const ptr::object* object, int element,
const vec2f& uv, const vec3f& normal, const vec3f& outgoing) {
auto material = object->material;
auto texcoord = eval_texcoord(object, element, uv);
return material->emission * eval_texture(material->emission_tex, texcoord);
}
// Eval material to obatain emission, brdf and opacity.
static brdf eval_brdf(const ptr::object* object, int element, const vec2f& uv,
const vec3f& normal, const vec3f& outgoing) {
// material -------
// initialize factors
auto material = object->material;
auto texcoord = eval_texcoord(object, element, uv);
auto base = material->color *
eval_texture(material->color_tex, texcoord, false);
auto specular = material->specular *
eval_texture(material->specular_tex, texcoord, true).x;
auto metallic = material->metallic *
eval_texture(material->metallic_tex, texcoord, true).x;
auto roughness = material->roughness *
eval_texture(material->roughness_tex, texcoord, true).x;
auto ior = material->ior;
auto transmission = material->transmission *
eval_texture(material->emission_tex, texcoord, true).x;
auto opacity = material->opacity *
mean(eval_texture(material->opacity_tex, texcoord, true));
auto thin = material->thin || !material->transmission;
// factors
auto brdf = ptr::brdf{};
auto weight = vec3f{1, 1, 1};
brdf.metal = weight * metallic;
weight *= 1 - metallic;
brdf.refraction = thin ? zero3f : (weight * transmission);
weight *= 1 - (thin ? 0 : transmission);
brdf.specular = weight * specular;
weight *= 1 - specular * fresnel_dielectric(ior, outgoing, normal);
brdf.transmission = thin ? (weight * transmission * base) : zero3f;
weight *= 1 - (thin ? transmission : 0);
brdf.diffuse = weight * base;
brdf.meta = reflectivity_to_eta(base);
brdf.metak = zero3f;
brdf.roughness = roughness * roughness;
brdf.ior = ior;
brdf.opacity = opacity;
// textures
if (brdf.diffuse != zero3f || brdf.roughness) {
brdf.roughness = clamp(brdf.roughness, 0.03f * 0.03f, 1.0f);
}
if (brdf.specular == zero3f && brdf.metal == zero3f &&
brdf.transmission == zero3f && brdf.refraction == zero3f) {
brdf.roughness = 1;
}
if (brdf.opacity > 0.999f) brdf.opacity = 1;
// weights
brdf.diffuse_pdf = max(brdf.diffuse);
brdf.specular_pdf = max(
brdf.specular * fresnel_dielectric(brdf.ior, normal, outgoing));
brdf.metal_pdf = max(
brdf.metal * fresnel_conductor(brdf.meta, brdf.metak, normal, outgoing));
brdf.transmission_pdf = max(brdf.transmission);
brdf.refraction_pdf = max(brdf.refraction);
auto pdf_sum = brdf.diffuse_pdf + brdf.specular_pdf + brdf.metal_pdf +
brdf.transmission_pdf + brdf.refraction_pdf;
if (pdf_sum) {
brdf.diffuse_pdf /= pdf_sum;
brdf.specular_pdf /= pdf_sum;
brdf.metal_pdf /= pdf_sum;
brdf.transmission_pdf /= pdf_sum;
brdf.refraction_pdf /= pdf_sum;
}
// hair brdf
brdf.hair = !object->shape->lines.empty();
if (brdf.hair) {
auto hair_material = extension::hair_material{};
hair_material.sigma_a = material->sigma_a;
hair_material.beta_m = material->beta_m;
hair_material.beta_n = material->beta_n;
hair_material.alpha = material->alpha;
hair_material.eta = material->eta;
hair_material.color = material->color;
hair_material.eumelanin = material->eumelanin;
hair_material.pheomelanin = material->pheomelanin;
auto v = uv.y;
auto tangent = eval_normal(object, element, uv);
brdf.hair_brdf = eval_hair_brdf(hair_material, v, normal, tangent);
}
return brdf;
}
// check if a brdf is a delta
static bool is_delta(const ptr::brdf& brdf) { return !brdf.roughness; }
// vsdf
struct vsdf {
vec3f density = {0, 0, 0};
vec3f scatter = {0, 0, 0};
float anisotropy = 0;
};
// evaluate volume
static vsdf eval_vsdf(const ptr::object* object, int element, const vec2f& uv) {
auto material = object->material;
// initialize factors
auto texcoord = eval_texcoord(object, element, uv);
auto base = material->color *
eval_texture(material->color_tex, texcoord, false);
auto transmission = material->transmission *
eval_texture(material->emission_tex, texcoord, true).x;
auto thin = material->thin || !material->transmission;
auto scattering = material->scattering *
eval_texture(material->scattering_tex, texcoord, false);
auto scanisotropy = material->scanisotropy;
auto trdepth = material->trdepth;
// factors
auto vsdf = ptr::vsdf{};
vsdf.density = (transmission && !thin)
? -log(clamp(base, 0.0001f, 1.0f)) / trdepth
: zero3f;
vsdf.scatter = scattering;
vsdf.anisotropy = scanisotropy;
return vsdf;
}
// check if we have a volume
static bool has_volume(const ptr::object* object) {
return !object->material->thin && object->material->transmission;
}
// Evaluate all environment color.
static vec3f eval_environment(const ptr::scene* scene, const ray3f& ray) {
auto emission = zero3f;
for (auto environment : scene->environments) {
auto wl = transform_direction(inverse(environment->frame), ray.d);
auto texcoord = vec2f{
atan2(wl.z, wl.x) / (2 * pif), acos(clamp(wl.y, -1.0f, 1.0f)) / pif};
if (texcoord.x < 0) texcoord.x += 1;
emission += environment->emission *
eval_texture(environment->emission_tex, texcoord);
}
return emission;
}
} // namespace yocto::pathtrace
// -----------------------------------------------------------------------------
// IMPLEMENTATION FOR SHAPE/SCENE BVH
// -----------------------------------------------------------------------------
namespace yocto::pathtrace {
// primitive used to sort bvh entries
struct bvh_primitive {
bbox3f bbox = invalidb3f;
vec3f center = zero3f;
int primitive = 0;
};
// Splits a BVH node. Returns split position and axis.
static std::pair<int, int> split_middle(
std::vector<bvh_primitive>& primitives, int start, int end) {
// initialize split axis and position
auto axis = 0;
auto mid = (start + end) / 2;
// compute primintive bounds and size
auto cbbox = invalidb3f;
for (auto i = start; i < end; i++) cbbox = merge(cbbox, primitives[i].center);
auto csize = cbbox.max - cbbox.min;
if (csize == zero3f) return {mid, axis};
// split along largest
if (csize.x >= csize.y && csize.x >= csize.z) axis = 0;
if (csize.y >= csize.x && csize.y >= csize.z) axis = 1;
if (csize.z >= csize.x && csize.z >= csize.y) axis = 2;
// split the space in the middle along the largest axis
mid = (int)(std::partition(primitives.data() + start, primitives.data() + end,
[axis, middle = center(cbbox)[axis]](auto& primitive) {
return primitive.center[axis] < middle;
}) -
primitives.data());
// if we were not able to split, just break the primitives in half
if (mid == start || mid == end) {
// throw std::runtime_error("bad bvh split");
mid = (start + end) / 2;
}
return {mid, axis};
}
// Maximum number of primitives per BVH node.
const int bvh_max_prims = 4;
// Build BVH nodes
static void build_bvh(
std::vector<bvh_node>& nodes, std::vector<bvh_primitive>& primitives) {
// prepare to build nodes
nodes.clear();
nodes.reserve(primitives.size() * 2);
// queue up first node
auto queue = std::deque<vec3i>{{0, 0, (int)primitives.size()}};
nodes.emplace_back();
// create nodes until the queue is empty
while (!queue.empty()) {
// grab node to work on
auto next = queue.front();
queue.pop_front();
auto nodeid = next.x, start = next.y, end = next.z;
// grab node
auto& node = nodes[nodeid];
// compute bounds
node.bbox = invalidb3f;
for (auto i = start; i < end; i++)
node.bbox = merge(node.bbox, primitives[i].bbox);
// split into two children
if (end - start > bvh_max_prims) {
// get split
auto [mid, axis] = split_middle(primitives, start, end);
// make an internal node
node.internal = true;
node.axis = axis;
node.num = 2;
node.start = (int)nodes.size();
nodes.emplace_back();
nodes.emplace_back();
queue.push_back({node.start + 0, start, mid});
queue.push_back({node.start + 1, mid, end});
} else {
// Make a leaf node
node.internal = false;
node.num = end - start;
node.start = start;
}
}
// cleanup
nodes.shrink_to_fit();
}
static void init_bvh(ptr::shape* shape, const trace_params& params) {
#ifdef YOCTO_EMBREE
auto edevice = embree_device();
shape->embree_bvh = rtcNewScene(edevice);
rtcSetSceneBuildQuality(shape->embree_bvh, RTC_BUILD_QUALITY_HIGH);
if (!shape->lines.empty()) {
auto elines = std::vector<int>{};
auto epositions = std::vector<vec4f>{};
auto last_index = -1;
for (auto& l : shape->lines) {
if (last_index == l.x) {
elines.push_back((int)epositions.size() - 1);
epositions.push_back({shape->positions[l.y], shape->radius[l.y]});
} else {
elines.push_back((int)epositions.size());
epositions.push_back({shape->positions[l.x], shape->radius[l.x]});
epositions.push_back({shape->positions[l.y], shape->radius[l.y]});
}
last_index = l.y;
}
auto egeometry = rtcNewGeometry(
edevice, RTC_GEOMETRY_TYPE_FLAT_LINEAR_CURVE);
rtcSetGeometryVertexAttributeCount(egeometry, 1);
auto embree_positions = rtcSetNewGeometryBuffer(egeometry,
RTC_BUFFER_TYPE_VERTEX, 0, RTC_FORMAT_FLOAT4, 16, epositions.size());
auto embree_lines = rtcSetNewGeometryBuffer(
egeometry, RTC_BUFFER_TYPE_INDEX, 0, RTC_FORMAT_UINT, 4, elines.size());
memcpy(embree_positions, epositions.data(), epositions.size() * 16);
memcpy(embree_lines, elines.data(), elines.size() * 4);
rtcCommitGeometry(egeometry);
rtcAttachGeometryByID(shape->embree_bvh, egeometry, 0);
} else if (!shape->triangles.empty()) {
auto egeometry = rtcNewGeometry(edevice, RTC_GEOMETRY_TYPE_TRIANGLE);
rtcSetGeometryVertexAttributeCount(egeometry, 1);
auto embree_positions = rtcSetNewGeometryBuffer(egeometry,
RTC_BUFFER_TYPE_VERTEX, 0, RTC_FORMAT_FLOAT3, 12,
shape->positions.size());
auto embree_triangles = rtcSetNewGeometryBuffer(egeometry,
RTC_BUFFER_TYPE_INDEX, 0, RTC_FORMAT_UINT3, 12,
shape->triangles.size());
memcpy(embree_positions, shape->positions.data(),
shape->positions.size() * 12);
memcpy(embree_triangles, shape->triangles.data(),
shape->triangles.size() * 12);
rtcCommitGeometry(egeometry);
rtcAttachGeometryByID(shape->embree_bvh, egeometry, 0);
}
return rtcCommitScene(shape->embree_bvh);
#endif
// build primitives
auto primitives = std::vector<bvh_primitive>{};
if (!shape->points.empty()) {
for (auto idx = 0; idx < shape->points.size(); idx++) {
auto& p = shape->points[idx];
auto& primitive = primitives.emplace_back();
primitive.bbox = point_bounds(shape->positions[p], shape->radius[p]);
primitive.center = center(primitive.bbox);
primitive.primitive = idx;
}
} else if (!shape->lines.empty()) {
for (auto idx = 0; idx < shape->lines.size(); idx++) {
auto& l = shape->lines[idx];
auto& primitive = primitives.emplace_back();
primitive.bbox = line_bounds(shape->positions[l.x], shape->positions[l.y],
shape->radius[l.x], shape->radius[l.y]);
primitive.center = center(primitive.bbox);
primitive.primitive = idx;
}
} else if (!shape->triangles.empty()) {
for (auto idx = 0; idx < shape->triangles.size(); idx++) {
auto& primitive = primitives.emplace_back();
auto& t = shape->triangles[idx];
primitive.bbox = triangle_bounds(
shape->positions[t.x], shape->positions[t.y], shape->positions[t.z]);
primitive.center = center(primitive.bbox);
primitive.primitive = idx;
}
}
// build nodes
if (shape->bvh) delete shape->bvh;
shape->bvh = new bvh_tree{};
build_bvh(shape->bvh->nodes, primitives);
// set bvh primitives
shape->bvh->primitives.reserve(primitives.size());
for (auto& primitive : primitives) {
shape->bvh->primitives.push_back(primitive.primitive);
}
}
void init_bvh(ptr::scene* scene, const trace_params& params,
progress_callback progress_cb) {
// handle progress
auto progress = vec2i{0, 1 + (int)scene->shapes.size()};
// shapes
for (auto idx = 0; idx < scene->shapes.size(); idx++) {
if (progress_cb) progress_cb("build shape bvh", progress.x++, progress.y);
init_bvh(scene->shapes[idx], params);
}
// handle progress
if (progress_cb) progress_cb("build scene bvh", progress.x++, progress.y);
#ifdef YOCTO_EMBREE
auto edevice = embree_device();
scene->embree_bvh = rtcNewScene(edevice);
rtcSetSceneBuildQuality(scene->embree_bvh, RTC_BUILD_QUALITY_HIGH);
for (auto idx = 0; idx < scene->objects.size(); idx++) {
auto object = scene->objects[idx];
auto egeometry = rtcNewGeometry(edevice, RTC_GEOMETRY_TYPE_INSTANCE);
rtcSetGeometryInstancedScene(egeometry, object->shape->embree_bvh);
rtcSetGeometryTransform(
egeometry, 0, RTC_FORMAT_FLOAT3X4_COLUMN_MAJOR, &object->frame);
rtcCommitGeometry(egeometry);
rtcAttachGeometryByID(scene->embree_bvh, egeometry, idx);
}
// handle progress
if (progress_cb) progress_cb("build bvh", progress.x++, progress.y);
return rtcCommitScene(scene->embree_bvh);
#endif
// instance bboxes
auto primitives = std::vector<bvh_primitive>{};
auto object_id = 0;
for (auto object : scene->objects) {
auto& primitive = primitives.emplace_back();
primitive.bbox =
object->shape->bvh->nodes.empty()
? invalidb3f
: transform_bbox(object->frame, object->shape->bvh->nodes[0].bbox);
primitive.center = center(primitive.bbox);
primitive.primitive = object_id++;
}
// build nodes
if (scene->bvh) delete scene->bvh;
scene->bvh = new bvh_tree{};
build_bvh(scene->bvh->nodes, primitives);
// set bvh primitives
scene->bvh->primitives.reserve(primitives.size());
for (auto& primitive : primitives) {
scene->bvh->primitives.push_back(primitive.primitive);
}
// handle progress
if (progress_cb) progress_cb("build bvh", progress.x++, progress.y);
}
// Intersect ray with a bvh->
static bool intersect_shape_bvh(ptr::shape* shape, const ray3f& ray_,
int& element, vec2f& uv, float& distance, bool find_any) {
#ifdef YOCTO_EMBREE
RTCRayHit eray;
eray.ray.org_x = ray_.o.x;
eray.ray.org_y = ray_.o.y;
eray.ray.org_z = ray_.o.z;
eray.ray.dir_x = ray_.d.x;
eray.ray.dir_y = ray_.d.y;
eray.ray.dir_z = ray_.d.z;
eray.ray.tnear = ray_.tmin;
eray.ray.tfar = ray_.tmax;
eray.ray.flags = 0;
eray.hit.geomID = RTC_INVALID_GEOMETRY_ID;
eray.hit.instID[0] = RTC_INVALID_GEOMETRY_ID;
RTCIntersectContext ctx;
rtcInitIntersectContext(&ctx);
rtcIntersect1(shape->embree_bvh, &ctx, &eray);
if (eray.hit.geomID == RTC_INVALID_GEOMETRY_ID) return false;
element = (int)eray.hit.primID;
uv = {eray.hit.u, eray.hit.v};
distance = eray.ray.tfar;
return true;
#endif
// get bvh and shape pointers for fast access
auto bvh = shape->bvh;
// check empty
if (bvh->nodes.empty()) return false;
// node stack
int node_stack[128];
auto node_cur = 0;
node_stack[node_cur++] = 0;
// shared variables
auto hit = false;
// copy ray to modify it
auto ray = ray_;
// prepare ray for fast queries
auto ray_dinv = vec3f{1 / ray.d.x, 1 / ray.d.y, 1 / ray.d.z};
auto ray_dsign = vec3i{(ray_dinv.x < 0) ? 1 : 0, (ray_dinv.y < 0) ? 1 : 0,
(ray_dinv.z < 0) ? 1 : 0};
// walking stack
while (node_cur) {
// grab node
auto& node = bvh->nodes[node_stack[--node_cur]];
// intersect bbox
// if (!intersect_bbox(ray, ray_dinv, ray_dsign, node.bbox)) continue;
if (!intersect_bbox(ray, ray_dinv, node.bbox)) continue;
// intersect node, switching based on node type
// for each type, iterate over the the primitive list
if (node.internal) {
// for internal nodes, attempts to proceed along the
// split axis from smallest to largest nodes
if (ray_dsign[node.axis]) {
node_stack[node_cur++] = node.start + 0;
node_stack[node_cur++] = node.start + 1;
} else {
node_stack[node_cur++] = node.start + 1;
node_stack[node_cur++] = node.start + 0;
}
} else if (!shape->points.empty()) {
for (auto idx = node.start; idx < node.start + node.num; idx++) {
auto& p = shape->points[shape->bvh->primitives[idx]];
if (intersect_point(
ray, shape->positions[p], shape->radius[p], uv, distance)) {
hit = true;
element = shape->bvh->primitives[idx];
ray.tmax = distance;
}
}
} else if (!shape->lines.empty()) {
for (auto idx = node.start; idx < node.start + node.num; idx++) {
auto& l = shape->lines[shape->bvh->primitives[idx]];
if (intersect_line(ray, shape->positions[l.x], shape->positions[l.y],
shape->radius[l.x], shape->radius[l.y], uv, distance)) {
hit = true;
element = shape->bvh->primitives[idx];
ray.tmax = distance;
}
}
} else if (!shape->triangles.empty()) {
for (auto idx = node.start; idx < node.start + node.num; idx++) {
auto& t = shape->triangles[shape->bvh->primitives[idx]];
if (intersect_triangle(ray, shape->positions[t.x],
shape->positions[t.y], shape->positions[t.z], uv, distance)) {
hit = true;
element = shape->bvh->primitives[idx];
ray.tmax = distance;
}
}
}
// check for early exit
if (find_any && hit) return hit;
}
return hit;
}
// Intersect ray with a bvh->
static bool intersect_scene_bvh(const ptr::scene* scene, const ray3f& ray_,
int& object, int& element, vec2f& uv, float& distance, bool find_any,
bool non_rigid_frames) {
#ifdef YOCTO_EMBREE
RTCRayHit eray;
eray.ray.org_x = ray_.o.x;
eray.ray.org_y = ray_.o.y;
eray.ray.org_z = ray_.o.z;
eray.ray.dir_x = ray_.d.x;
eray.ray.dir_y = ray_.d.y;
eray.ray.dir_z = ray_.d.z;
eray.ray.tnear = ray_.tmin;
eray.ray.tfar = ray_.tmax;
eray.ray.flags = 0;
eray.hit.geomID = RTC_INVALID_GEOMETRY_ID;
eray.hit.instID[0] = RTC_INVALID_GEOMETRY_ID;
RTCIntersectContext ctx;
rtcInitIntersectContext(&ctx);
rtcIntersect1(scene->embree_bvh, &ctx, &eray);
if (eray.hit.geomID == RTC_INVALID_GEOMETRY_ID) return false;
object = (int)eray.hit.instID[0];
element = (int)eray.hit.primID;
uv = {eray.hit.u, eray.hit.v};
distance = eray.ray.tfar;
return true;
#endif
// get bvh and scene pointers for fast access
auto bvh = scene->bvh;
// check empty
if (bvh->nodes.empty()) return false;
// node stack
int node_stack[128];
auto node_cur = 0;
node_stack[node_cur++] = 0;
// shared variables
auto hit = false;
// copy ray to modify it
auto ray = ray_;
// prepare ray for fast queries
auto ray_dinv = vec3f{1 / ray.d.x, 1 / ray.d.y, 1 / ray.d.z};
auto ray_dsign = vec3i{(ray_dinv.x < 0) ? 1 : 0, (ray_dinv.y < 0) ? 1 : 0,
(ray_dinv.z < 0) ? 1 : 0};
// walking stack
while (node_cur) {
// grab node
auto& node = bvh->nodes[node_stack[--node_cur]];
// intersect bbox
// if (!intersect_bbox(ray, ray_dinv, ray_dsign, node.bbox)) continue;
if (!intersect_bbox(ray, ray_dinv, node.bbox)) continue;
// intersect node, switching based on node type
// for each type, iterate over the the primitive list
if (node.internal) {
// for internal nodes, attempts to proceed along the