💿🐜 Antkeeper source code
https://antkeeper.com
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106 lines
3.6 KiB
106 lines
3.6 KiB
/*
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* Copyright (C) 2023 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <engine/geom/brep/brep-operations.hpp>
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#include <engine/math/vector.hpp>
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#include <algorithm>
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namespace geom {
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void generate_face_normals(brep_mesh& mesh)
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{
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const auto& vertex_positions = mesh.vertices().attributes().at<math::fvec3>("position");
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auto& face_normals = static_cast<brep_attribute<math::fvec3>&>(*mesh.faces().attributes().try_emplace<math::fvec3>("normal").first);
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for (brep_face* face: mesh.faces())
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{
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auto loop = face->loops().begin();
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const auto& a = vertex_positions[loop->vertex()->index()];
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const auto& b = vertex_positions[(++loop)->vertex()->index()];
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const auto& c = vertex_positions[(++loop)->vertex()->index()];
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face_normals[face->index()] = math::normalize(math::cross(b - a, c - a));
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}
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}
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void generate_vertex_normals(brep_mesh& mesh)
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{
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const auto& vertex_positions = mesh.vertices().attributes().at<math::fvec3>("position");
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auto& vertex_normals = static_cast<brep_attribute<math::fvec3>&>(*mesh.vertices().attributes().try_emplace<math::fvec3>("normal").first);
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// Init vertex normals to zero
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std::fill(vertex_normals.begin(), vertex_normals.end(), math::fvec3::zero());
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if (auto face_normals_it = mesh.faces().attributes().find("normals"); face_normals_it != mesh.faces().attributes().end())
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{
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const auto& face_normals = static_cast<const brep_attribute<math::fvec3>&>(*face_normals_it);
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for (brep_face* face: mesh.faces())
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{
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// Get face normal from face normal attribute
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const auto& face_normal = face_normals[face->index()];
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// Accumulate vertex normals
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for (brep_loop* loop: face->loops())
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{
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vertex_normals[loop->vertex()->index()] += face_normal;
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}
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}
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}
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else
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{
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for (brep_face* face: mesh.faces())
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{
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// Calculate face normal
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auto loop = face->loops().begin();
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const auto& a = vertex_positions[loop->vertex()->index()];
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const auto& b = vertex_positions[(++loop)->vertex()->index()];
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const auto& c = vertex_positions[(++loop)->vertex()->index()];
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const auto face_normal = math::normalize(math::cross(b - a, c - a));
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// Accumulate vertex normals
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for (brep_loop* loop: face->loops())
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{
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vertex_normals[loop->vertex()->index()] += face_normal;
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}
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}
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}
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// Normalize vertex normals
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for (auto& vertex_normal: vertex_normals)
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{
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vertex_normal = math::normalize(vertex_normal);
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}
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}
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void generate_loop_barycentric(brep_mesh& mesh)
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{
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const auto& vertex_positions = mesh.vertices().attributes().at<math::fvec3>("position");
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auto& loop_barycentric = static_cast<brep_attribute<math::fvec3>&>(*mesh.loops().attributes().try_emplace<math::fvec3>("barycentric").first);
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for (brep_face* face: mesh.faces())
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{
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auto loop = face->loops().begin();
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loop_barycentric[loop->index()] = {1.0f, 0.0f, 0.0f};
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loop_barycentric[(++loop)->index()] = {0.0f, 1.0f, 0.0f};
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loop_barycentric[(++loop)->index()] = {0.0f, 0.0f, 1.0f};
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}
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}
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} // namespace geom
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