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lightmapper_cpu.cpp
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/**************************************************************************/
/* lightmapper_cpu.cpp */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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 "lightmapper_cpu.h"
#include "core/math/geometry.h"
#include "core/os/os.h"
#include "core/os/threaded_array_processor.h"
#include "core/project_settings.h"
#include "modules/raycast/lightmap_raycaster.h"
#ifdef TOOLS_ENABLED
#include "editor/editor_settings.h"
#endif
Error LightmapperCPU::_layout_atlas(int p_max_size, Vector2i *r_atlas_size, int *r_atlas_slices) {
Vector2i atlas_size;
for (unsigned int i = 0; i < mesh_instances.size(); i++) {
if (mesh_instances[i].generate_lightmap) {
Vector2i size = mesh_instances[i].size;
atlas_size.width = MAX(atlas_size.width, size.width + 2);
atlas_size.height = MAX(atlas_size.height, size.height + 2);
}
}
int max = nearest_power_of_2_templated(atlas_size.width);
max = MAX(max, nearest_power_of_2_templated(atlas_size.height));
if (max > p_max_size) {
return ERR_INVALID_DATA;
}
Vector2i best_atlas_size;
int best_atlas_slices = 0;
int best_atlas_memory = 0x7FFFFFFF;
float best_atlas_mem_utilization = 0;
Vector<AtlasOffset> best_atlas_offsets;
Vector<Vector2i> best_scaled_sizes;
int first_try_mem_occupied = 0;
int first_try_mem_used = 0;
for (int recovery_percent = 0; recovery_percent <= 100; recovery_percent += 10) {
// These only make sense from the second round of the loop
float recovery_scale = 1;
int target_mem_occupied = 0;
if (recovery_percent != 0) {
target_mem_occupied = first_try_mem_occupied + (first_try_mem_used - first_try_mem_occupied) * recovery_percent * 0.01f;
float new_squared_recovery_scale = static_cast<float>(target_mem_occupied) / first_try_mem_occupied;
if (new_squared_recovery_scale > 1.0f) {
recovery_scale = Math::sqrt(new_squared_recovery_scale);
}
}
atlas_size = Vector2i(max, max);
while (atlas_size.x <= p_max_size && atlas_size.y <= p_max_size) {
if (recovery_percent != 0) {
// Find out how much memory is not recoverable (because of lightmaps that can't grow),
// to compute a greater recovery scale for those that can.
int mem_unrecoverable = 0;
for (unsigned int i = 0; i < mesh_instances.size(); i++) {
if (mesh_instances[i].generate_lightmap) {
Vector2i scaled_size = Vector2i(
static_cast<int>(recovery_scale * mesh_instances[i].size.x),
static_cast<int>(recovery_scale * mesh_instances[i].size.y));
if (scaled_size.x + 2 > atlas_size.x || scaled_size.y + 2 > atlas_size.y) {
mem_unrecoverable += scaled_size.x * scaled_size.y - mesh_instances[i].size.x * mesh_instances[i].size.y;
}
}
}
float new_squared_recovery_scale = static_cast<float>(target_mem_occupied - mem_unrecoverable) / (first_try_mem_occupied - mem_unrecoverable);
if (new_squared_recovery_scale > 1.0f) {
recovery_scale = Math::sqrt(new_squared_recovery_scale);
}
}
Vector<Vector2i> scaled_sizes;
scaled_sizes.resize(mesh_instances.size());
{
for (unsigned int i = 0; i < mesh_instances.size(); i++) {
if (mesh_instances[i].generate_lightmap) {
if (recovery_percent == 0) {
scaled_sizes.write[i] = mesh_instances[i].size;
} else {
Vector2i scaled_size = Vector2i(
static_cast<int>(recovery_scale * mesh_instances[i].size.x),
static_cast<int>(recovery_scale * mesh_instances[i].size.y));
if (scaled_size.x + 2 <= atlas_size.x && scaled_size.y + 2 <= atlas_size.y) {
scaled_sizes.write[i] = scaled_size;
} else {
scaled_sizes.write[i] = mesh_instances[i].size;
}
}
} else {
// Don't consider meshes with no generated lightmap here; will compensate later
scaled_sizes.write[i] = Vector2i();
}
}
}
Vector<Vector2i> source_sizes;
source_sizes.resize(scaled_sizes.size());
Vector<int> source_indices;
source_indices.resize(scaled_sizes.size());
for (int i = 0; i < source_sizes.size(); i++) {
source_sizes.write[i] = scaled_sizes[i] + Vector2i(2, 2); // Add padding between lightmaps
source_indices.write[i] = i;
}
Vector<AtlasOffset> curr_atlas_offsets;
curr_atlas_offsets.resize(source_sizes.size());
int slices = 0;
while (source_sizes.size() > 0) {
Vector<Geometry::PackRectsResult> offsets = Geometry::partial_pack_rects(source_sizes, atlas_size);
Vector<int> new_indices;
Vector<Vector2i> new_sources;
for (int i = 0; i < offsets.size(); i++) {
Geometry::PackRectsResult ofs = offsets[i];
int sidx = source_indices[i];
if (ofs.packed) {
curr_atlas_offsets.write[sidx] = { slices, ofs.x + 1, ofs.y + 1 };
} else {
new_indices.push_back(sidx);
new_sources.push_back(source_sizes[i]);
}
}
source_sizes = new_sources;
source_indices = new_indices;
slices++;
}
int mem_used = atlas_size.x * atlas_size.y * slices;
int mem_occupied = 0;
for (int i = 0; i < curr_atlas_offsets.size(); i++) {
mem_occupied += scaled_sizes[i].x * scaled_sizes[i].y;
}
float mem_utilization = static_cast<float>(mem_occupied) / mem_used;
if (mem_used < best_atlas_memory || (mem_used == best_atlas_memory && mem_utilization > best_atlas_mem_utilization)) {
best_atlas_size = atlas_size;
best_atlas_offsets = curr_atlas_offsets;
best_atlas_slices = slices;
best_atlas_memory = mem_used;
best_atlas_mem_utilization = mem_utilization;
best_scaled_sizes = scaled_sizes;
}
if (recovery_percent == 0) {
first_try_mem_occupied = mem_occupied;
first_try_mem_used = mem_used;
}
if (atlas_size.width == atlas_size.height) {
atlas_size.width *= 2;
} else {
atlas_size.height *= 2;
}
}
}
if (best_atlas_size == Vector2i()) {
return ERR_INVALID_DATA;
}
*r_atlas_size = best_atlas_size;
*r_atlas_slices = best_atlas_slices;
for (unsigned int i = 0; i < mesh_instances.size(); i++) {
if (best_scaled_sizes[i] != Vector2i()) {
mesh_instances[i].size = best_scaled_sizes[i];
mesh_instances[i].offset = Vector2i(best_atlas_offsets[i].x, best_atlas_offsets[i].y);
mesh_instances[i].slice = best_atlas_offsets[i].slice;
}
}
return OK;
}
void LightmapperCPU::_thread_func_callback(void *p_thread_data) {
ThreadData *thread_data = reinterpret_cast<ThreadData *>(p_thread_data);
#ifdef TOOLS_ENABLED
const int num_threads = EDITOR_GET("editors/3d/lightmap_baking_number_of_cpu_threads");
#else
const int num_threads = 0;
#endif
thread_process_array(thread_data->count, thread_data->instance, &LightmapperCPU::_thread_func_wrapper, thread_data, num_threads);
}
void LightmapperCPU::_thread_func_wrapper(uint32_t p_idx, ThreadData *p_thread_data) {
if (thread_cancelled) {
return;
}
(p_thread_data->instance->*p_thread_data->thread_func)(p_idx, p_thread_data->userdata);
thread_progress++;
}
bool LightmapperCPU::_parallel_run(int p_count, const String &p_description, BakeThreadFunc p_thread_func, void *p_userdata, BakeStepFunc p_substep_func) {
bool cancelled = false;
if (p_substep_func) {
cancelled = p_substep_func(0.0f, vformat("%s (%d/%d)", p_description, 0, p_count), nullptr, false);
}
thread_progress = 0;
thread_cancelled = false;
#ifdef NO_THREAD
for (int i = 0; !cancelled && i < p_count; i++) {
(this->*p_thread_func)(i, p_userdata);
float p = float(i) / p_count;
if (p_substep_func) {
cancelled = p_substep_func(p, vformat("%s (%d/%d)", p_description, i + 1, p_count), nullptr, false);
}
}
#else
if (p_count == 0) {
return cancelled;
}
ThreadData td;
td.instance = this;
td.count = p_count;
td.thread_func = p_thread_func;
td.userdata = p_userdata;
Thread runner_thread;
runner_thread.start(_thread_func_callback, &td);
int progress = thread_progress;
while (!cancelled && progress < p_count) {
float p = float(progress) / p_count;
if (p_substep_func) {
cancelled = p_substep_func(p, vformat("%s (%d/%d)", p_description, progress + 1, p_count), nullptr, false);
}
progress = thread_progress;
}
thread_cancelled = cancelled;
runner_thread.wait_to_finish();
#endif
thread_cancelled = false;
return cancelled;
}
void LightmapperCPU::_generate_buffer(uint32_t p_idx, void *p_unused) {
const Size2i &size = mesh_instances[p_idx].size;
int buffer_size = size.x * size.y;
LocalVector<LightmapTexel> &lightmap = scene_lightmaps[p_idx];
LocalVector<int> &lightmap_indices = scene_lightmap_indices[p_idx];
lightmap_indices.resize(buffer_size);
for (unsigned int i = 0; i < lightmap_indices.size(); i++) {
lightmap_indices[i] = -1;
}
MeshData &md = mesh_instances[p_idx].data;
LocalVector<Ref<Image>> albedo_images;
LocalVector<Ref<Image>> emission_images;
for (int surface_id = 0; surface_id < md.albedo.size(); surface_id++) {
albedo_images.push_back(_init_bake_texture(md.albedo[surface_id], albedo_textures, Image::FORMAT_RGBA8));
emission_images.push_back(_init_bake_texture(md.emission[surface_id], emission_textures, Image::FORMAT_RGBH));
}
int surface_id = 0;
int surface_facecount = 0;
const Vector3 *points_ptr = md.points.ptr();
const Vector3 *normals_ptr = md.normal.ptr();
const Vector2 *uvs_ptr = md.uv.empty() ? nullptr : md.uv.ptr();
const Vector2 *uv2s_ptr = md.uv2.ptr();
for (int i = 0; i < md.points.size() / 3; i++) {
Ref<Image> albedo = albedo_images[surface_id];
Ref<Image> emission = emission_images[surface_id];
albedo->lock();
emission->lock();
_plot_triangle(&(uv2s_ptr[i * 3]), &(points_ptr[i * 3]), &(normals_ptr[i * 3]), uvs_ptr ? &(uvs_ptr[i * 3]) : nullptr, albedo, emission, size, lightmap, lightmap_indices);
albedo->unlock();
emission->unlock();
surface_facecount++;
if (surface_facecount == md.surface_facecounts[surface_id]) {
surface_id++;
surface_facecount = 0;
}
}
}
Ref<Image> LightmapperCPU::_init_bake_texture(const MeshData::TextureDef &p_texture_def, const Map<RID, Ref<Image>> &p_tex_cache, Image::Format p_default_format) {
Ref<Image> ret;
if (p_texture_def.tex_rid.is_valid()) {
ret = p_tex_cache[p_texture_def.tex_rid]->duplicate();
ret->lock();
for (int j = 0; j < ret->get_height(); j++) {
for (int i = 0; i < ret->get_width(); i++) {
ret->set_pixel(i, j, ret->get_pixel(i, j) * p_texture_def.mul + p_texture_def.add);
}
}
ret->unlock();
} else {
ret.instance();
ret->create(8, 8, false, p_default_format);
ret->fill(p_texture_def.add * p_texture_def.mul);
}
return ret;
}
Color LightmapperCPU::_bilinear_sample(const Ref<Image> &p_img, const Vector2 &p_uv, bool p_clamp_x, bool p_clamp_y) {
int width = p_img->get_width();
int height = p_img->get_height();
Vector2 uv;
uv.x = p_clamp_x ? p_uv.x : Math::fposmod(p_uv.x, 1.0f);
uv.y = p_clamp_y ? p_uv.y : Math::fposmod(p_uv.y, 1.0f);
float xf = uv.x * width;
float yf = uv.y * height;
int xi = (int)xf;
int yi = (int)yf;
Color texels[4];
for (int i = 0; i < 4; i++) {
int sample_x = xi + i % 2;
int sample_y = yi + i / 2;
sample_x = CLAMP(sample_x, 0, width - 1);
sample_y = CLAMP(sample_y, 0, height - 1);
texels[i] = p_img->get_pixel(sample_x, sample_y);
}
float tx = xf - xi;
float ty = yf - yi;
Color c = Color(0, 0, 0, 0);
for (int i = 0; i < 4; i++) {
c[i] = Math::lerp(Math::lerp(texels[0][i], texels[1][i], tx), Math::lerp(texels[2][i], texels[3][i], tx), ty);
}
return c;
}
Vector3 LightmapperCPU::_fix_sample_position(const Vector3 &p_position, const Vector3 &p_texel_center, const Vector3 &p_normal, const Vector3 &p_tangent, const Vector3 &p_bitangent, const Vector2 &p_texel_size) {
Basis tangent_basis(p_tangent, p_bitangent, p_normal);
tangent_basis.orthonormalize();
Vector2 half_size = p_texel_size / 2.0f;
Vector3 corrected = p_position;
for (int i = -1; i <= 1; i += 1) {
for (int j = -1; j <= 1; j += 1) {
if (i == 0 && j == 0) {
continue;
}
Vector3 offset = Vector3(half_size.x * i, half_size.y * j, 0.0);
Vector3 rotated_offset = tangent_basis.xform_inv(offset);
Vector3 target = p_texel_center + rotated_offset;
Vector3 ray_vector = target - corrected;
Vector3 ray_back_offset = -ray_vector.normalized() * parameters.bias / 2.0;
Vector3 ray_origin = corrected + ray_back_offset;
ray_vector = target - ray_origin;
float ray_length = ray_vector.length();
LightmapRaycaster::Ray ray(ray_origin + p_normal * parameters.bias, ray_vector.normalized(), 0.0f, ray_length + parameters.bias / 2.0);
bool hit = raycaster->intersect(ray);
if (hit) {
ray.normal.normalize();
if (ray.normal.dot(ray_vector.normalized()) > 0.0f) {
corrected = ray_origin + ray.dir * ray.tfar + ray.normal * (parameters.bias * 2.0f);
}
}
}
}
return corrected;
}
void LightmapperCPU::_plot_triangle(const Vector2 *p_vertices, const Vector3 *p_positions, const Vector3 *p_normals, const Vector2 *p_uvs, const Ref<Image> &p_albedo, const Ref<Image> &p_emission, Vector2i p_size, LocalVector<LightmapTexel> &r_lightmap, LocalVector<int> &r_lightmap_indices) {
Vector2 pv0 = p_vertices[0];
Vector2 pv1 = p_vertices[1];
Vector2 pv2 = p_vertices[2];
Vector2 v0 = pv0 * p_size;
Vector2 v1 = pv1 * p_size;
Vector2 v2 = pv2 * p_size;
Vector3 p0 = p_positions[0];
Vector3 p1 = p_positions[1];
Vector3 p2 = p_positions[2];
Vector3 n0 = p_normals[0];
Vector3 n1 = p_normals[1];
Vector3 n2 = p_normals[2];
Vector2 uv0 = p_uvs == nullptr ? Vector2(0.5f, 0.5f) : p_uvs[0];
Vector2 uv1 = p_uvs == nullptr ? Vector2(0.5f, 0.5f) : p_uvs[1];
Vector2 uv2 = p_uvs == nullptr ? Vector2(0.5f, 0.5f) : p_uvs[2];
#define edgeFunction(a, b, c) ((c)[0] - (a)[0]) * ((b)[1] - (a)[1]) - ((c)[1] - (a)[1]) * ((b)[0] - (a)[0])
if (edgeFunction(v0, v1, v2) < 0.0) {
SWAP(pv1, pv2);
SWAP(v1, v2);
SWAP(p1, p2);
SWAP(n1, n2);
SWAP(uv1, uv2);
}
Vector3 edge1 = p1 - p0;
Vector3 edge2 = p2 - p0;
Vector2 uv_edge1 = pv1 - pv0;
Vector2 uv_edge2 = pv2 - pv0;
float r = 1.0f / (uv_edge1.x * uv_edge2.y - uv_edge1.y * uv_edge2.x);
Vector3 tangent = (edge1 * uv_edge2.y - edge2 * uv_edge1.y) * r;
Vector3 bitangent = (edge2 * uv_edge1.x - edge1 * uv_edge2.x) * r;
tangent.normalize();
bitangent.normalize();
// Compute triangle bounding box
Vector2 bbox_min = Vector2(MIN(v0.x, MIN(v1.x, v2.x)), MIN(v0.y, MIN(v1.y, v2.y)));
Vector2 bbox_max = Vector2(MAX(v0.x, MAX(v1.x, v2.x)), MAX(v0.y, MAX(v1.y, v2.y)));
bbox_min = bbox_min.floor();
bbox_max = bbox_max.ceil();
uint32_t min_x = MAX(bbox_min.x - 2, 0);
uint32_t min_y = MAX(bbox_min.y - 2, 0);
uint32_t max_x = MIN(bbox_max.x, p_size.x - 1);
uint32_t max_y = MIN(bbox_max.y, p_size.y - 1);
Vector2 texel_size;
Vector2 centroid = (v0 + v1 + v2) / 3.0f;
Vector3 centroid_pos = (p0 + p1 + p2) / 3.0f;
for (int i = 0; i < 2; i++) {
Vector2 p = centroid;
p[i] += 1;
Vector3 bary = Geometry::barycentric_coordinates_2d(p, v0, v1, v2);
if (bary.length() <= 1.0) {
Vector3 pos = p0 * bary[0] + p1 * bary[1] + p2 * bary[2];
texel_size[i] = centroid_pos.distance_to(pos);
}
}
Vector<Vector2> pixel_polygon;
pixel_polygon.resize(4);
static const Vector2 corners[4] = { Vector2(0, 0), Vector2(0, 1), Vector2(1, 1), Vector2(1, 0) };
Vector<Vector2> triangle_polygon;
triangle_polygon.push_back(v0);
triangle_polygon.push_back(v1);
triangle_polygon.push_back(v2);
for (uint32_t j = min_y; j <= max_y; ++j) {
for (uint32_t i = min_x; i <= max_x; i++) {
int ofs = j * p_size.x + i;
int texel_idx = r_lightmap_indices[ofs];
if (texel_idx >= 0 && r_lightmap[texel_idx].area_coverage >= 0.5f) {
continue;
}
Vector3 barycentric_coords;
float area_coverage = 0.0f;
bool intersected = false;
for (int k = 0; k < 4; k++) {
pixel_polygon.write[k] = Vector2(i, j) + corners[k];
}
const float max_dist = 0.05;
bool v0eqv1 = v0.distance_squared_to(v1) < max_dist;
bool v1eqv2 = v1.distance_squared_to(v2) < max_dist;
bool v2eqv0 = v2.distance_squared_to(v0) < max_dist;
if (v0eqv1 && v1eqv2 && v2eqv0) {
intersected = true;
barycentric_coords = Vector3(1, 0, 0);
} else if (v0eqv1 || v1eqv2 || v2eqv0) {
Vector<Vector2> segment;
segment.resize(2);
if (v0eqv1) {
segment.write[0] = v0;
segment.write[1] = v2;
} else if (v1eqv2) {
segment.write[0] = v1;
segment.write[1] = v0;
} else {
segment.write[0] = v0;
segment.write[1] = v1;
}
Vector<Vector<Vector2>> intersected_segments = Geometry::intersect_polyline_with_polygon_2d(segment, pixel_polygon);
ERR_FAIL_COND_MSG(intersected_segments.size() > 1, "[Lightmapper] Itersecting a segment and a convex polygon should give at most one segment.");
if (!intersected_segments.empty()) {
const Vector<Vector2> &intersected_segment = intersected_segments[0];
ERR_FAIL_COND_MSG(intersected_segment.size() != 2, "[Lightmapper] Itersecting a segment and a convex polygon should give at most one segment.");
Vector2 sample_pos = (intersected_segment[0] + intersected_segment[1]) / 2.0f;
float u = (segment[0].distance_to(sample_pos)) / (segment[0].distance_to(segment[1]));
float v = (1.0f - u) / 2.0f;
intersected = true;
if (v0eqv1) {
barycentric_coords = Vector3(v, v, u);
} else if (v1eqv2) {
barycentric_coords = Vector3(u, v, v);
} else {
barycentric_coords = Vector3(v, u, v);
}
}
} else if (edgeFunction(v0, v1, v2) < 0.005) {
Vector2 direction = v0 - v1;
Vector2 perpendicular = Vector2(direction.y, -direction.x);
Vector<Vector2> line;
int middle_vertex;
if (SGN(edgeFunction(v0, v0 + perpendicular, v1)) != SGN(edgeFunction(v0, v0 + perpendicular, v2))) {
line.push_back(v1);
line.push_back(v2);
middle_vertex = 0;
} else if (SGN(edgeFunction(v1, v1 + perpendicular, v0)) != SGN(edgeFunction(v1, v1 + perpendicular, v2))) {
line.push_back(v0);
line.push_back(v2);
middle_vertex = 1;
} else {
line.push_back(v0);
line.push_back(v1);
middle_vertex = 2;
}
Vector<Vector<Vector2>> intersected_lines = Geometry::intersect_polyline_with_polygon_2d(line, pixel_polygon);
ERR_FAIL_COND_MSG(intersected_lines.size() > 1, "[Lightmapper] Itersecting a line and a convex polygon should give at most one line.");
if (!intersected_lines.empty()) {
intersected = true;
const Vector<Vector2> &intersected_line = intersected_lines[0];
Vector2 sample_pos = (intersected_line[0] + intersected_line[1]) / 2.0f;
float line_length = line[0].distance_to(line[1]);
float norm = line[0].distance_to(sample_pos) / line_length;
if (middle_vertex == 0) {
barycentric_coords = Vector3(0.0f, 1.0f - norm, norm);
} else if (middle_vertex == 1) {
barycentric_coords = Vector3(1.0f - norm, 0.0f, norm);
} else {
barycentric_coords = Vector3(1.0f - norm, norm, 0.0f);
}
}
} else {
Vector<Vector<Vector2>> intersected_polygons = Geometry::intersect_polygons_2d(pixel_polygon, triangle_polygon);
ERR_FAIL_COND_MSG(intersected_polygons.size() > 1, "[Lightmapper] Itersecting two convex polygons should give at most one polygon.");
if (!intersected_polygons.empty()) {
const Vector<Vector2> &intersected_polygon = intersected_polygons[0];
// do centroid sampling
Vector2 sample_pos = intersected_polygon[0];
Vector2 area_center = Vector2(i, j) + Vector2(0.5f, 0.5f);
float intersected_area = (intersected_polygon[0] - area_center).cross(intersected_polygon[intersected_polygon.size() - 1] - area_center);
for (int k = 1; k < intersected_polygon.size(); k++) {
sample_pos += intersected_polygon[k];
intersected_area += (intersected_polygon[k] - area_center).cross(intersected_polygon[k - 1] - area_center);
}
if (intersected_area != 0.0f) {
sample_pos /= intersected_polygon.size();
barycentric_coords = Geometry::barycentric_coordinates_2d(sample_pos, v0, v1, v2);
intersected = true;
area_coverage = ABS(intersected_area) / 2.0f;
}
}
if (!intersected) {
for (int k = 0; k < 4; ++k) {
for (int l = 0; l < 3; ++l) {
Vector2 intersection_point;
if (Geometry::segment_intersects_segment_2d(pixel_polygon[k], pixel_polygon[(k + 1) % 4], triangle_polygon[l], triangle_polygon[(l + 1) % 3], &intersection_point)) {
intersected = true;
barycentric_coords = Geometry::barycentric_coordinates_2d(intersection_point, v0, v1, v2);
break;
}
}
if (intersected) {
break;
}
}
}
}
if (texel_idx >= 0 && area_coverage < r_lightmap[texel_idx].area_coverage) {
continue; // A previous triangle gives better pixel coverage
}
Vector2 pixel = Vector2(i, j);
if (!intersected && v0.floor() == pixel) {
intersected = true;
barycentric_coords = Vector3(1, 0, 0);
}
if (!intersected && v1.floor() == pixel) {
intersected = true;
barycentric_coords = Vector3(0, 1, 0);
}
if (!intersected && v2.floor() == pixel) {
intersected = true;
barycentric_coords = Vector3(0, 0, 1);
}
if (!intersected) {
continue;
}
if (Math::is_nan(barycentric_coords.x) || Math::is_nan(barycentric_coords.y) || Math::is_nan(barycentric_coords.z)) {
continue;
}
if (Math::is_inf(barycentric_coords.x) || Math::is_inf(barycentric_coords.y) || Math::is_inf(barycentric_coords.z)) {
continue;
}
r_lightmap_indices[ofs] = r_lightmap.size();
Vector3 pos = p0 * barycentric_coords[0] + p1 * barycentric_coords[1] + p2 * barycentric_coords[2];
Vector3 normal = n0 * barycentric_coords[0] + n1 * barycentric_coords[1] + n2 * barycentric_coords[2];
Vector2 uv = uv0 * barycentric_coords[0] + uv1 * barycentric_coords[1] + uv2 * barycentric_coords[2];
Color c = _bilinear_sample(p_albedo, uv);
Color e = _bilinear_sample(p_emission, uv);
Vector2 texel_center = Vector2(i, j) + Vector2(0.5f, 0.5f);
Vector3 texel_center_bary = Geometry::barycentric_coordinates_2d(texel_center, v0, v1, v2);
if (texel_center_bary.length_squared() <= 1.3 && !Math::is_nan(texel_center_bary.x) && !Math::is_nan(texel_center_bary.y) && !Math::is_nan(texel_center_bary.z) && !Math::is_inf(texel_center_bary.x) && !Math::is_inf(texel_center_bary.y) && !Math::is_inf(texel_center_bary.z)) {
Vector3 texel_center_pos = p0 * texel_center_bary[0] + p1 * texel_center_bary[1] + p2 * texel_center_bary[2];
pos = _fix_sample_position(pos, texel_center_pos, normal, tangent, bitangent, texel_size);
}
LightmapTexel texel;
texel.normal = normal.normalized();
texel.pos = pos;
texel.albedo = Vector3(c.r, c.g, c.b);
texel.alpha = c.a;
texel.emission = Vector3(e.r, e.g, e.b);
texel.area_coverage = area_coverage;
r_lightmap.push_back(texel);
}
}
}
_ALWAYS_INLINE_ float uniform_rand() {
/* Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs" */
static thread_local uint32_t state = Math::rand();
state ^= state << 13;
state ^= state >> 17;
state ^= state << 5;
/* implicit conversion from 'unsigned int' to 'float' changes value from 4294967295 to 4294967296 */
return float(state) / float(UINT32_MAX);
}
float LightmapperCPU::_get_omni_attenuation(float distance, float inv_range, float decay) const {
float nd = distance * inv_range;
nd *= nd;
nd *= nd; // nd^4
nd = MAX(1.0 - nd, 0.0);
nd *= nd; // nd^2
return nd * powf(MAX(distance, 0.0001f), -decay);
}
void LightmapperCPU::_compute_direct_light(uint32_t p_idx, void *r_lightmap) {
LightmapTexel *lightmap = (LightmapTexel *)r_lightmap;
for (unsigned int i = 0; i < lights.size(); ++i) {
const Light &light = lights[i];
Vector3 normal = lightmap[p_idx].normal;
Vector3 position = lightmap[p_idx].pos;
Color c = light.color;
Vector3 light_energy = Vector3(c.r, c.g, c.b) * light.energy;
Vector3 light_to_point = light.direction;
if (light.type == LIGHT_TYPE_OMNI || light.type == LIGHT_TYPE_SPOT) {
light_to_point = (position - light.position).normalized();
}
if (normal.dot(light_to_point) >= 0.0) {
continue;
}
float dist;
float attenuation;
float soft_shadowing_disk_size;
if (light.type == LIGHT_TYPE_OMNI || light.type == LIGHT_TYPE_SPOT) {
dist = position.distance_to(light.position);
if (dist > light.range) {
continue;
}
soft_shadowing_disk_size = light.size / dist;
if (light.type == LIGHT_TYPE_OMNI) {
if (parameters.use_physical_light_attenuation) {
attenuation = _get_omni_attenuation(dist, 1.0f / light.range, light.attenuation);
} else {
attenuation = powf(1.0 - dist / light.range, light.attenuation);
}
} else /* (light.type == LIGHT_TYPE_SPOT) */ {
float angle = Math::acos(light.direction.dot(light_to_point));
if (angle > light.spot_angle) {
continue;
}
float normalized_dist = dist * (1.0f / MAX(0.001f, light.range));
float norm_light_attenuation;
if (parameters.use_physical_light_attenuation) {
norm_light_attenuation = _get_omni_attenuation(dist, 1.0f / light.range, light.attenuation);
} else {
norm_light_attenuation = Math::pow(MAX(1.0f - normalized_dist, 0.001f), light.attenuation);
}
float spot_cutoff = Math::cos(light.spot_angle);
float scos = MAX(light_to_point.dot(light.direction), spot_cutoff);
float spot_rim = (1.0f - scos) / (1.0f - spot_cutoff);
attenuation = norm_light_attenuation * (1.0f - pow(MAX(spot_rim, 0.001f), light.spot_attenuation));
}
} else /*if (light.type == LIGHT_TYPE_DIRECTIONAL)*/ {
dist = INFINITY;
attenuation = 1.0f;
soft_shadowing_disk_size = light.size;
}
float penumbra = 0.0f;
if (light.size > 0.0) {
Vector3 light_to_point_tan;
Vector3 light_to_point_bitan;
if (light.type == LIGHT_TYPE_OMNI || light.type == LIGHT_TYPE_SPOT) {
light_to_point = (position - light.position).normalized();
Vector3 aux = light_to_point.y < 0.777 ? Vector3(0, 1, 0) : Vector3(1, 0, 0);
light_to_point_tan = light_to_point.cross(aux).normalized();
light_to_point_bitan = light_to_point.cross(light_to_point_tan).normalized();
} else /*if (light.type == LIGHT_TYPE_DIRECTIONAL)*/ {
Vector3 aux = light_to_point.y < 0.777 ? Vector3(0, 1, 0) : Vector3(1, 0, 0);
light_to_point_tan = light_to_point.cross(aux).normalized();
light_to_point_bitan = light_to_point.cross(light_to_point_tan).normalized();
}
const static int shadowing_rays_check_penumbra_denom = 2;
int shadowing_ray_count = parameters.samples;
int hits = 0;
Vector3 light_disk_to_point = light_to_point;
for (int j = 0; j < shadowing_ray_count; j++) {
// Optimization:
// Once already casted an important proportion of rays, if all are hits or misses,
// assume we're not in the penumbra so we can infer the rest would have the same result
if (j == shadowing_ray_count / shadowing_rays_check_penumbra_denom) {
if (hits == j) {
// Assume totally lit
hits = shadowing_ray_count;
break;
} else if (hits == 0) {
// Assume totally dark
hits = 0;
break;
}
}
float r = uniform_rand();
float a = uniform_rand() * Math_TAU;
Vector2 disk_sample = (r * Vector2(Math::cos(a), Math::sin(a))) * soft_shadowing_disk_size;
light_disk_to_point = (light_to_point + disk_sample.x * light_to_point_tan + disk_sample.y * light_to_point_bitan).normalized();
LightmapRaycaster::Ray ray = LightmapRaycaster::Ray(position, -light_disk_to_point, parameters.bias, dist);
if (raycaster->intersect(ray)) {
continue;
}
hits++;
}
penumbra = (float)hits / shadowing_ray_count;
} else {
LightmapRaycaster::Ray ray = LightmapRaycaster::Ray(position, -light_to_point, parameters.bias, dist);
if (!raycaster->intersect(ray)) {
penumbra = 1.0f;
}
}
Vector3 final_energy = attenuation * penumbra * light_energy * MAX(0, normal.dot(-light_to_point));
lightmap[p_idx].direct_light += final_energy * light.indirect_multiplier;
if (light.bake_direct) {
lightmap[p_idx].output_light += final_energy;
}
}
}
void LightmapperCPU::_compute_indirect_light(uint32_t p_idx, void *r_lightmap) {
LightmapTexel *lightmap = (LightmapTexel *)r_lightmap;
LightmapTexel &texel = lightmap[p_idx];
Vector3 accum;
const Vector3 const_forward = Vector3(0, 0, 1);
const Vector3 const_up = Vector3(0, 1, 0);
for (int i = 0; i < parameters.samples; i++) {
Vector3 color;
Vector3 throughput = Vector3(1.0f, 1.0f, 1.0f);
Vector3 position = texel.pos;
Vector3 normal = texel.normal;
Vector3 direction;
for (int depth = 0; depth < parameters.bounces; depth++) {
Vector3 tangent = const_forward.cross(normal);
if (unlikely(tangent.length_squared() < 0.005f)) {
tangent = const_up.cross(normal);
}
tangent.normalize();
Vector3 bitangent = tangent.cross(normal);
bitangent.normalize();
Basis normal_xform = Basis(tangent, bitangent, normal);
normal_xform.transpose();
float u1 = uniform_rand();
float u2 = uniform_rand();
float radius = Math::sqrt(u1);
float theta = Math_TAU * u2;
Vector3 axis = Vector3(radius * Math::cos(theta), radius * Math::sin(theta), Math::sqrt(MAX(0.0f, 1.0f - u1)));
direction = normal_xform.xform(axis);
// We can skip multiplying throughput by cos(theta) because de sampling PDF is also cos(theta) and they cancel each other
//float pdf = normal.dot(direction);
//throughput *= normal.dot(direction)/pdf;
LightmapRaycaster::Ray ray(position, direction, parameters.bias);
bool hit = raycaster->intersect(ray);
if (!hit) {
if (parameters.environment_panorama.is_valid()) {
direction = parameters.environment_transform.xform_inv(direction);
Vector2 st = Vector2(Math::atan2(direction.z, direction.x), Math::acos(direction.y));
if (Math::is_nan(st.y)) {
st.y = direction.y > 0.0 ? 0.0 : Math_PI;
}
st.x += Math_PI;
st /= Vector2(Math_TAU, Math_PI);
st.x = Math::fmod(st.x + 0.75, 1.0);
Color c = _bilinear_sample(parameters.environment_panorama, st, false, true);
color += throughput * Vector3(c.r, c.g, c.b) * c.a;
}
break;
}
unsigned int hit_mesh_id = ray.geomID;
const Vector2i &size = mesh_instances[hit_mesh_id].size;
int x = CLAMP(ray.u * size.x, 0, size.x - 1);
int y = CLAMP(ray.v * size.y, 0, size.y - 1);
const int idx = scene_lightmap_indices[hit_mesh_id][y * size.x + x];
if (idx < 0) {
break;
}
const LightmapTexel &sample = scene_lightmaps[hit_mesh_id][idx];
if (sample.normal.dot(ray.dir) > 0.0 && !no_shadow_meshes.has(hit_mesh_id)) {
// We hit a back-face
break;
}
color += throughput * sample.emission;
throughput *= sample.albedo;
color += throughput * sample.direct_light * parameters.bounce_indirect_energy;
// Russian Roulette
// https://computergraphics.stackexchange.com/questions/2316/is-russian-roulette-really-the-answer
const float p = throughput[throughput.max_axis()];
if (uniform_rand() > p) {
break;
}
throughput *= 1.0f / p;
position = sample.pos;
normal = sample.normal;
}
accum += color;
}
texel.output_light += accum / parameters.samples;
}
void LightmapperCPU::_post_process(uint32_t p_idx, void *r_output) {
const MeshInstance &mesh = mesh_instances[p_idx];
if (!mesh.generate_lightmap) {
return;
}
LocalVector<int> &indices = scene_lightmap_indices[p_idx];
LocalVector<LightmapTexel> &lightmap = scene_lightmaps[p_idx];
Vector3 *output = ((LocalVector<Vector3> *)r_output)[p_idx].ptr();
Vector2i size = mesh.size;
// Blit texels to buffer
const int margin = 4;
for (int i = 0; i < size.y; i++) {
for (int j = 0; j < size.x; j++) {
int idx = indices[i * size.x + j];
if (idx >= 0) {
output[i * size.x + j] = lightmap[idx].output_light;
continue; // filled, skip
}
int closest_idx = -1;
float closest_dist = 1e20;
for (int y = i - margin; y <= i + margin; y++) {
for (int x = j - margin; x <= j + margin; x++) {
if (x == j && y == i) {
continue;
}
if (x < 0 || x >= size.x) {
continue;
}
if (y < 0 || y >= size.y) {
continue;
}
int cell_idx = indices[y * size.x + x];
if (cell_idx < 0) {
continue; //also ensures that blitted stuff is not reused
}
float dist = Vector2(i - y, j - x).length_squared();
if (dist < closest_dist) {
closest_dist = dist;
closest_idx = cell_idx;
}
}
}
if (closest_idx != -1) {
output[i * size.x + j] = lightmap[closest_idx].output_light;
}
}
}
lightmap.clear();