OpenGL dependencies not available in ComfyUI

If ComfyUI logs OpenGL dependencies not available, the built-in GLSL shader node failed its import-time dependency check.

In the tested portable repair lab, this did not kill the whole server. ComfyUI still opened, but nodes_glsl.py could not load until both PyOpenGL and glfw were installed in the same Python environment.

.\python_embeded\python.exe -s -m pip show PyOpenGL glfw
.\python_embeded\python.exe -s -m pip install PyOpenGL
.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

.\python_embeded\python.exe -s -m pip install glfw

What The Real Log Looked Like

In the repaired lab, the relevant lines were:

RuntimeError: OpenGL dependencies not available.
Cannot import ...\ComfyUI\comfy_extras\nodes_glsl.py module for custom nodes: OpenGL dependencies not available.

The built-in source check for nodes_glsl.py looks for two Python packages:

• glfw
• OpenGL from PyOpenGL

If either one is missing, the GLSL node stays unavailable.

Quick Diagnosis

Step 1: Check The Local Requirement Lines

In the tested lab, ComfyUI\requirements.txt included:

PyOpenGL
glfw

Check your local copy:

Get-Content ComfyUI\requirements.txt | Select-String "PyOpenGL|glfw"

Step 2: Repair The Missing Packages One At A Time

For Windows portable:

.\python_embeded\python.exe -s -m pip install PyOpenGL

Restart ComfyUI and read the log again. In the tested lab, that was not enough. The same OpenGL error remained until glfw was installed too:

.\python_embeded\python.exe -s -m pip install glfw

That is why this page is split out from the bigger runbook. The exact log string is not enough by itself; you need to know that the missing dependency can be either half of the pair.

Step 3: Restart And Verify The GLSL Node Came Back

Relaunch ComfyUI:

.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

In the tested lab:

• before glfw, the OpenGL error still appeared even after PyOpenGL
• after glfw, the error disappeared
• /object_info node count rose from 687 to 688

That last step is the cleanest confirmation that the node imported.

Step 4: Understand The Scope Of The Failure

This error usually means:

• the server can still start
• other nodes may still work
• the GLSL shader node is not available

So this is real, but it is not the same category as a hard startup blocker like missing torch or sqlalchemy.

If your workflow depends on the GLSL node, it is still urgent. If not, you can treat it as a built-in-extra node repair rather than a total ComfyUI outage.

What Not To Do

• do not assume PyOpenGL alone fixes this error
• do not install into system Python if ComfyUI runs from python_embeded or a venv
• do not confuse this Windows package-missing case with Linux headless display issues
• do not stop at "the browser opened" if the GLSL node you need is still missing

How Wonderful Launcher Helps

This is another case where "ComfyUI opened" is not the whole story. Wonderful Launcher helps when you need to verify whether the expected node surface came back after a repair, not only whether the web page loads.

Related Guides

• ComfyUI 便携版依赖损坏后，按一个报错一个包修启动
• ModuleNotFoundError: No module named 'kornia' in ComfyUI
• Plugin Missing Module Warning: When It Is Safe to Ignore
• ComfyUI Startup Failed
• ComfyUI Dependency Conflicts

Source References

• Windows portable repair lab, May 18, 2026: OpenGL dependencies not available blocked ComfyUI\comfy_extras\nodes_glsl.py
• Same lab ComfyUI\requirements.txt: PyOpenGL and glfw
• Same lab verification: PyOpenGL alone did not clear the error; installing glfw afterward restored the GLSL node and raised /object_info node count from 687 to 688