Tom Erez
120 lines
3.7 KiB
C#
120 lines
3.7 KiB
C#
// Copyright 2019 DeepMind Technologies Limited
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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using System;
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using System.IO;
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using System.Runtime.InteropServices;
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using System.Text;
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using UnityEngine;
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namespace Mujoco {
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using static MujocoLib;
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// A wrapper around Mujoco's native _mjVFS that simplifies the process of creating memory files.
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public sealed class MjVfs : IDisposable {
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private _mjVFS _managedVfs;
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private IntPtr _unmanagedVfs;
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// Managed version of the underlying _mjVFS structure.
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public _mjVFS Data {
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get {
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_managedVfs = (_mjVFS)Marshal.PtrToStructure(_unmanagedVfs, typeof(_mjVFS));
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return _managedVfs;
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}
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set {
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_managedVfs = value;
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Marshal.StructureToPtr(_managedVfs, _unmanagedVfs, fDeleteOld: false);
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}
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}
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// Number of files added to the filesystem.
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public int FilesCount {
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get { return Data.nfile; }
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}
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// Adds a new file to the virtual filesystem.
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public unsafe void AddFile(string filename, string contents) {
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var result = mj_makeEmptyFileVFS(_unmanagedVfs.ToPointer(), filename, contents.Length);
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if (result != 0) {
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throw new Exception(
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"VFS error (" + result + ") encountered while creating an empty file");
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}
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var fileIndex = mj_findFileVFS(_unmanagedVfs.ToPointer(), filename);
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if (fileIndex < 0) {
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throw new IndexOutOfRangeException("VFS didn't properly create the empty file.");
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}
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SetFileContents(fileIndex, contents);
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}
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// Searches the VFS for the specified file and returns its index.
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// The index then can be used to retrieve the file contents from Data.filedata array.
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public unsafe int FindFile(string filename) {
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return mj_findFileVFS(_unmanagedVfs.ToPointer(), filename);
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}
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// Loads a model from the specified file.
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// The file is assumed to be located in the filesystem. If it's not found, the method will throw
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// an ArgumentException.
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public unsafe MujocoLib.mjModel_* LoadXML(string filename) {
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if (FindFile(filename) < 0) {
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throw new ArgumentException($"File {filename} was not added to the VFS.");
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}
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var errorBuf = new StringBuilder(1024);
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MujocoLib.mjModel_* model = MujocoLib.mj_loadXML(
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filename, _unmanagedVfs.ToPointer(), errorBuf, errorBuf.Capacity);
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if (model == null || errorBuf.Length > 0) {
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throw new IOException($"Error loading the model: {errorBuf}");
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}
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return model;
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}
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private unsafe void SetFileContents(int fileIndex, string contents) {
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var data = Data;
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Marshal.FreeHGlobal(data.filedata[fileIndex]);
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data.filedata[fileIndex] = Marshal.StringToHGlobalAnsi(contents);
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Data = data;
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}
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public MjVfs() {
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_managedVfs = new _mjVFS();
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_unmanagedVfs = Marshal.AllocHGlobal(Marshal.SizeOf(_managedVfs));
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Marshal.StructureToPtr(_managedVfs, _unmanagedVfs, true);
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}
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~MjVfs() {
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ReleaseUnmanagedMemory();
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}
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public void Dispose() {
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GC.SuppressFinalize(this);
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ReleaseUnmanagedMemory();
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}
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private void ReleaseUnmanagedMemory() {
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if (_unmanagedVfs != IntPtr.Zero) {
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var data = Data;
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for (var fileIndex = 0; fileIndex < data.nfile; ++fileIndex) {
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Marshal.FreeHGlobal(data.filedata[fileIndex]);
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}
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Marshal.FreeHGlobal(_unmanagedVfs);
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_unmanagedVfs = IntPtr.Zero;
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}
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}
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}
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}
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