I currently have a scene graph set up where a pre-render camera renders
content to a texture via an FBO, and the main camera uses this texture
to texture a quad with it. This works, in principle.
However I need mipmapping for that texture, and all but the 0th mipmap
level of the texture are empty.
With an apitracer, I found out that the glGenerateMipMap call happens
1. only in the first frame (but I want it to be called every frame).
2. before any draw calls towards the FBO (but I want it after the draw
I tried to inject a glGenerateMipMap via a DrawCallback which I attached
to the quad, and which just extends the original draw implementation
(glGenerateMipMap immediately before the original draw implementation).
With the apitracer, I validated that, at the position where I injected
a. the correct texture is bound
b. the frame buffer is un-bound.
But glGenerateMipMap just seg'faults. Because of the seg'fault (I mean
we are all used to GL_ERRORS, but seg'faults?) I suspected a driver
issue, but I tried it on an alternative platform (one is Intel Graphics,
one is Nvidia, both on Linux). Both to the same result.
Can you please help? Maybe I overlooked a simple osg-ish way to achieve
this (maybe I just have to set something dirty()?)
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