From 37e4f8befa63ad18f8bc06f4de2d8799a46c3607 Mon Sep 17 00:00:00 2001 From: Malcolm Nixon Date: Mon, 2 Jan 2023 20:30:33 -0500 Subject: Micro-optimizations of the GodotConvexPolygonShape3D::get_support function. Specifically this uses pointer-array-dereference rather than LocalVector dereference as this performs range-checking on known-good indexes. Added more comments. Changed loops back to classic for-iteration style. --- servers/physics_3d/godot_shape_3d.cpp | 55 +++++++++++++++++++++++++---------- 1 file changed, 39 insertions(+), 16 deletions(-) diff --git a/servers/physics_3d/godot_shape_3d.cpp b/servers/physics_3d/godot_shape_3d.cpp index 1a016fbc72..6015f5575b 100644 --- a/servers/physics_3d/godot_shape_3d.cpp +++ b/servers/physics_3d/godot_shape_3d.cpp @@ -844,36 +844,55 @@ void GodotConvexPolygonShape3D::project_range(const Vector3 &p_normal, const Tra } Vector3 GodotConvexPolygonShape3D::get_support(const Vector3 &p_normal) const { + // Skip if there are no vertices in the mesh if (mesh.vertices.size() == 0) { return Vector3(); } - // Find an initial guess for the support vertex by checking the ones we - // found in _setup(). + // Get the array of vertices + const Vector3 *const vertices_array = mesh.vertices.ptr(); - 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]; + // Get the array of extreme vertices + const int *const extreme_array = extreme_vertices.ptr(); + const uint32_t extreme_size = extreme_vertices.size(); + + // Start with an initial assumption of the first extreme vertex + int best_vertex = extreme_array[0]; + real_t max_support = p_normal.dot(vertices_array[best_vertex]); + + // Check the remaining extreme vertices for a better vertex + for (uint32_t i = 0; i < extreme_size; ++i) { + int vert = extreme_array[i]; + real_t s = p_normal.dot(vertices_array[vert]); + if (s > max_support) { + best_vertex = vert; 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]; + + // If we checked all vertices in the mesh then we're done + if (extreme_size == mesh.vertices.size()) { + return vertices_array[best_vertex]; } - // Move along the surface until we reach the true support vertex. + // Get the array of neighbor arrays for each vertex + const LocalVector *const vertex_neighbors_array = vertex_neighbors.ptr(); + // Move along the surface until we reach the true support vertex. 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]; + + // Get the array of neighbors around the best vertex + const LocalVector &neighbors = vertex_neighbors_array[best_vertex]; + const int *const neighbors_array = neighbors.ptr(); + const uint32_t neighbors_size = neighbors.size(); + + // Iterate over all the neighbors checking for a better vertex + for (uint32_t i = 0; i < neighbors_size; ++i) { + int vert = neighbors_array[i]; if (vert != last_vertex) { - real_t s = p_normal.dot(mesh.vertices[vert]); + real_t s = p_normal.dot(vertices_array[vert]); if (s > max_support) { next_vertex = vert; max_support = s; @@ -881,9 +900,13 @@ Vector3 GodotConvexPolygonShape3D::get_support(const Vector3 &p_normal) const { } } } + + // No better vertex found, we have the best if (next_vertex == -1) { - return mesh.vertices[best_vertex]; + return vertices_array[best_vertex]; } + + // Move to the better vertex and try again last_vertex = best_vertex; best_vertex = next_vertex; } -- cgit v1.2.3