godot/thirdparty/manifold/src/subdivision.cpp

// Copyright 2024 The Manifold Authors.
//
// 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.

#include "./impl.h"
#include "./parallel.h"

template <>
struct std::hash<manifold::ivec4> { … };

namespace {
usingnamespacemanifold;

class Partition { … };
}  // namespace

namespace manifold {

/**
 * Returns the tri side index (0-2) connected to the other side of this quad if
 * this tri is part of a quad, or -1 otherwise.
 */
int Manifold::Impl::GetNeighbor(int tri) const { … }

/**
 * For the given triangle index, returns either the three halfedge indices of
 * that triangle and halfedges[3] = -1, or if the triangle is part of a quad, it
 * returns those four indices. If the triangle is part of a quad and is not the
 * lower of the two triangle indices, it returns all -1s.
 */
ivec4 Manifold::Impl::GetHalfedges(int tri) const { … }

/**
 * Returns the BaryIndices, which gives the tri and indices (0-3), such that
 * GetHalfedges(val.tri)[val.start4] points back to this halfedge, and val.end4
 * will point to the next one. This function handles this for both triangles and
 * quads. Returns {-1, -1, -1} if the edge is the interior of a quad.
 */
Manifold::Impl::BaryIndices Manifold::Impl::GetIndices(int halfedge) const { … }

/**
 * Retained verts are part of several triangles, and it doesn't matter which one
 * the vertBary refers to. Here, whichever is last will win and it's done on the
 * CPU for simplicity for now. Using AtomicCAS on .tri should work for a GPU
 * version if desired.
 */
void Manifold::Impl::FillRetainedVerts(Vec<Barycentric>& vertBary) const { … }

/**
 * Split each edge into n pieces as defined by calling the edgeDivisions
 * function, and sub-triangulate each triangle accordingly. This function
 * doesn't run Finish(), as that is expensive and it'll need to be run after
 * the new vertices have moved, which is a likely scenario after refinement
 * (smoothing).
 */
Vec<Barycentric> Manifold::Impl::Subdivide(
    std::function<int(vec3, vec4, vec4)> edgeDivisions, bool keepInterior) { … }

}  // namespace manifold