From 562aa1bf763150a0a6434639e2d4eb20b36f83cc Mon Sep 17 00:00:00 2001 From: Peter Eastman Date: Sat, 13 Aug 2022 20:11:56 -0700 Subject: Optimized support function for large meshes --- servers/physics_3d/godot_shape_3d.cpp | 113 +++++++++++++++++++++++++++------- servers/physics_3d/godot_shape_3d.h | 2 + 2 files changed, 92 insertions(+), 23 deletions(-) (limited to 'servers') diff --git a/servers/physics_3d/godot_shape_3d.cpp b/servers/physics_3d/godot_shape_3d.cpp index cd61ceab62..1443cd166b 100644 --- a/servers/physics_3d/godot_shape_3d.cpp +++ b/servers/physics_3d/godot_shape_3d.cpp @@ -817,48 +817,78 @@ GodotCylinderShape3D::GodotCylinderShape3D() {} /********** CONVEX POLYGON *************/ void GodotConvexPolygonShape3D::project_range(const Vector3 &p_normal, const Transform3D &p_transform, real_t &r_min, real_t &r_max) const { - int vertex_count = mesh.vertices.size(); + uint32_t vertex_count = mesh.vertices.size(); if (vertex_count == 0) { return; } const Vector3 *vrts = &mesh.vertices[0]; - for (int i = 0; i < vertex_count; i++) { - real_t d = p_normal.dot(p_transform.xform(vrts[i])); + if (vertex_count > 3 * extreme_vertices.size()) { + // For a large mesh, two calls to get_support() is faster than a full + // scan over all vertices. - if (i == 0 || d > r_max) { - r_max = d; - } - if (i == 0 || d < r_min) { - r_min = d; + Vector3 n = p_transform.basis.xform_inv(p_normal).normalized(); + r_min = p_normal.dot(p_transform.xform(get_support(-n))); + r_max = p_normal.dot(p_transform.xform(get_support(n))); + } else { + for (uint32_t i = 0; i < vertex_count; i++) { + real_t d = p_normal.dot(p_transform.xform(vrts[i])); + + if (i == 0 || d > r_max) { + r_max = d; + } + if (i == 0 || d < r_min) { + r_min = d; + } } } } Vector3 GodotConvexPolygonShape3D::get_support(const Vector3 &p_normal) const { - Vector3 n = p_normal; - - int vert_support_idx = -1; - real_t support_max = 0; - - int vertex_count = mesh.vertices.size(); - if (vertex_count == 0) { + if (mesh.vertices.size() == 0) { return Vector3(); } - const Vector3 *vrts = &mesh.vertices[0]; - - for (int i = 0; i < vertex_count; i++) { - real_t d = n.dot(vrts[i]); + // Find an initial guess for the support vertex by checking the ones we + // found in _setup(). - if (i == 0 || d > support_max) { - support_max = d; - vert_support_idx = i; + int best_vertex = -1; + real_t max_support = 0.0; + for (uint32_t i = 0; i < extreme_vertices.size(); i++) { + real_t s = p_normal.dot(mesh.vertices[extreme_vertices[i]]); + if (best_vertex == -1 || s > max_support) { + best_vertex = extreme_vertices[i]; + max_support = s; } } + if (extreme_vertices.size() == mesh.vertices.size()) { + // We've already checked every vertex, so we can return now. + return mesh.vertices[best_vertex]; + } + + // Move along the surface until we reach the true support vertex. - return vrts[vert_support_idx]; + int last_vertex = -1; + while (true) { + int next_vertex = -1; + for (uint32_t i = 0; i < vertex_neighbors[best_vertex].size(); i++) { + int vert = vertex_neighbors[best_vertex][i]; + if (vert != last_vertex) { + real_t s = p_normal.dot(mesh.vertices[vert]); + if (s > max_support) { + next_vertex = vert; + max_support = s; + break; + } + } + } + if (next_vertex == -1) { + return mesh.vertices[best_vertex]; + } + last_vertex = best_vertex; + best_vertex = next_vertex; + } } void GodotConvexPolygonShape3D::get_supports(const Vector3 &p_normal, int p_max, Vector3 *r_supports, int &r_amount, FeatureType &r_type) const { @@ -1067,6 +1097,43 @@ void GodotConvexPolygonShape3D::_setup(const Vector &p_vertices) { } configure(_aabb); + + // Pre-compute the extreme vertices in 26 directions. This will be used + // to speed up get_support() by letting us quickly get a good guess for + // the support vertex. + + for (int x = -1; x < 2; x++) { + for (int y = -1; y < 2; y++) { + for (int z = -1; z < 2; z++) { + if (x != 0 || y != 0 || z != 0) { + Vector3 dir(x, y, z); + dir.normalize(); + real_t max_support = 0.0; + int best_vertex = -1; + for (uint32_t i = 0; i < mesh.vertices.size(); i++) { + real_t s = dir.dot(mesh.vertices[i]); + if (best_vertex == -1 || s > max_support) { + best_vertex = i; + max_support = s; + } + } + if (extreme_vertices.find(best_vertex) == -1) + extreme_vertices.push_back(best_vertex); + } + } + } + } + + // Record all the neighbors of each vertex. This is used in get_support(). + + if (extreme_vertices.size() < mesh.vertices.size()) { + vertex_neighbors.resize(mesh.vertices.size()); + for (uint32_t i = 0; i < mesh.edges.size(); i++) { + Geometry3D::MeshData::Edge &edge = mesh.edges[i]; + vertex_neighbors[edge.vertex_a].push_back(edge.vertex_b); + vertex_neighbors[edge.vertex_b].push_back(edge.vertex_a); + } + } } void GodotConvexPolygonShape3D::set_data(const Variant &p_data) { diff --git a/servers/physics_3d/godot_shape_3d.h b/servers/physics_3d/godot_shape_3d.h index 1fc8f7c711..dc8e34e2bc 100644 --- a/servers/physics_3d/godot_shape_3d.h +++ b/servers/physics_3d/godot_shape_3d.h @@ -277,6 +277,8 @@ public: struct GodotConvexPolygonShape3D : public GodotShape3D { Geometry3D::MeshData mesh; + LocalVector extreme_vertices; + LocalVector> vertex_neighbors; void _setup(const Vector &p_vertices); -- cgit v1.2.3