PoorlyDrawnCircle Any idea why this might be?
Perhaps it's the fact that the shaders are rewritten.
Introducing Reverse Z (AKA I'm sorry for breaking your shader)
You may need to tweak your shaders if you use a custom spatial shader that:
- Writes to POSITION in the vertex processor function
- Writes to DEPTH in the fragment processor function
- Reads from depth_texture
- Operates in clip space
PoorlyDrawnCircle source_color and hint_depth_texture are kinda mutually exclusive. It's not really clear from your screenshots what the difference is. Reading from any screen texture may alter the shader's place in rendering pipeline causing unwanted behavior.
xyz Now that you say it, I have no idea why source_color is there. I copied the code from a guide and it has worked for me until now so didn't notice. I removed it.
The only difference between the two scripts is whether the "awooga" function is in the script or not. The function is not used in any way.
Tomcat It certainly looks like a z-order problem.
I thought that code that wasn't used in shaders would be removed during compilation, but it seems like something still happens when texture(depth_texture, screen_uv) exists somewhere in the code, even if it is not used. Besides, to me it looks like the code that is written should work according to the article you linked, so I don't understand how this problem could arise from that.
But anyway. My shaders work as long as I remove that code-block, so 
Thanks for letting me know about Reverse Z, perhaps the guide I followed was from before that change
