attempt to render to unbound program

Support
1

The software I’m working on uses multiple vtkCocoaGLView instances to display stuff. Since updating to recent VTK versions from VTK 5, the rendering pipeline stops working when switching between windows.

I tracked this down to an unbound vtkShaderProgram, where the corresponding vtkOpenGLShaderCache thinks the shader is bound, but it’s actually not. If using the debugger I ->Bind() the shader, the views are rendering again, until I switch windows again.

Any suggestions, how to fix this?

2

Maybe something outside of VTK is binding a different shader which the cache does not know about. In cases like that it can be fixed by calling something like

renderWindow->GetShaderCache()->ReleaseCurrentShader()

/**

  • Release the current shader. Basically go back to
  • having no shaders loaded. This is useful for old
  • legacy code that relies on no shaders being loaded.
    */
    void ReleaseCurrentShader();

at the end of your render (or right before it) either way it should force VTK to rebind the shader

3

Thanks for the suggestion. It only temporarily resolved my problem, but it came back later on anyway.

I found a fix: the original code used to draw a ‘disabled’ status of the view using macos specific drawing APIs, then passing control over to VTK. That probably messed with the OpenGL stack.

I cleared the custom code and it no longer misbehaves.