Implementation:Google deepmind Mujoco User Objects

Knowledge Sources	Google_deepmind_Mujoco
Domains	Physics Simulation, Model Objects
Last Updated	2026-02-15 04:00 GMT

Overview

Implements the C++ classes for all MuJoCo model objects including bodies, joints, geoms, textures, materials, sensors, and actuators.

Description

user_objects.cc is the largest file in the user module (8206 lines) and implements the concrete behavior of all MuJoCo specification object types. It includes PNGImage loading via lodepng, and provides the implementation for classes such as mjCBody, mjCJoint, mjCGeom, mjCSite, mjCCamera, mjCLight, mjCTexture, mjCMaterial, mjCSensor, mjCActuator, and many more. Each class handles its own compilation, validation, and conversion to the runtime format.

Usage

Used throughout the model compilation pipeline as the implementations of all model object types, from initial creation through parsing to final compilation into an mjModel.

Code Reference

Source Location

• Repository: Google_deepmind_Mujoco
• File: src/user/user_objects.cc
• Lines: 1-8206

Key Functions

class PNGImage {
 public:
  static PNGImage Load(const mjCBase* obj, mjResource* resource,
                       LodePNGColorType color_type);
  int Width() const;
  int Height() const;
  bool IsSRGB() const;
  mjByteVec&& MoveData() &&;
};

Import

#include "user/user_objects.h"
#include "lodepng.h"
#include <mujoco/mujoco.h>

I/O Contract

Inputs

Name	Type	Required	Description
obj	const mjCBase*	Yes	Base object providing context for resource loading
resource	mjResource*	Yes	Resource handle for file data
color_type	LodePNGColorType	Yes	PNG color type for texture loading

Outputs

Name	Type	Description
PNGImage	PNGImage	Loaded PNG image with width, height, sRGB flag, and pixel data
compiled objects	various	Compiled model objects ready for runtime use

Related Pages

• Environment:Google_deepmind_Mujoco_C_Build_Environment