How to add text labels? #2632

tonitonitonitoni · 2025-05-15T14:47:43Z

tonitonitonitoni
May 15, 2025

Intro

Hi!

I am a graduate student at TMU (Toronto Metropolitan University), I use MuJoCo for my research on space robotics.

My setup

I run MuJoCo (latest stable version) on Windows 10 / WSL2 Ubuntu 22.04 using VSCode, usually through Jupyter notebooks.

My question

I want to add labels to objects in the scene and I am having trouble setting up a context so that I can use mjr_text, mjr_label and mjr_overlay. What is the proper format for setting up a context? I would prefer to use the renderer or viewer.launch/viewer.launch_passive. I get the error "FatalError: an OpenGL platform library has not been loaded into this process, this most likely means that a valid OpenGL context has not been created before mjr_makeContext was called." Alternatively, I get "FatalError: Default framebuffer is not complete, error 0x0".
When I tried with the ctx = mujoco.GLContext(max_width, max_height) as suggested in the docs, I got an incompatible function argument, it expects MjrContext.

How do I set up the context and what is the best method to get text labels to display on the screen? Please help :)

Minimal model and/or code that explain my question

import mujoco
xml = """
<mujoco>
  <worldbody>
    <light name="top" pos="0 0 1"/>
    <body name="box_and_sphere" euler="0 0 -30">
      <joint name="swing" type="hinge" axis="1 -1 0" pos="-.2 -.2 -.2"/>
      <geom name="red_box" type="box" size=".2 .2 .2" rgba="1 0 0 1"/>
      <geom name="green_sphere" pos=".2 .2 .2" size=".1" rgba="0 1 0 1"/>
    </body>
  </worldbody>
</mujoco>

"""
model = mujoco.MjModel.from_xml_string(xml)
data = mujoco.MjData(model)
ctx = mujoco.MjrContext(model,1)

with mujoco.Renderer(model) as renderer:
  mujoco.mj_forward(model, data)
  renderer.update_scene(data)
  mujoco.mjr_text(0, "test", ctx, 100, 100, 1, 1, 1)
  media.show_image(renderer.render())

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How to add text labels? #2632

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tonitonitonitoni May 15, 2025

Intro

My setup

My question

Minimal model and/or code that explain my question

Confirmations

Replies: 0 comments

tonitonitonitoni
May 15, 2025