3D Probability Map

These past days I’ve been hard at work with how the probabilistic occupancy map will be checked against the synthetic vision. As it turned out, my initial design where unusable.

My first thought where to render the map at different heights. This is so that the agent wont try to look beneath a box as the node at that level will be flagged as disabled as it is inside another object. The node on the next level is then considered the lowest one and the one used for logic.

The important thing to note is the word “render”. This where cumbersome to get working as I wanted to only get some objects, the nodes, to be rendered with a specific view. At first I tried to toggle the visibility of the objects so they would only be visible when the correct view where processed. This didn’t work, and I think I know why now. I was toggling the visibility of the objects but not the meshnodes the rendersystem used.

When this proved fruitless I my second thought where to put all these invisible entities in another stage, but the more I looked into it the more discourage I got as it would involve a third renderpass.

Then it hit me, I just needed to make another shader material that only the vision shader could/would render. With this I finally got something on the screen but to my dismay it was painfully slow even with instanced rendering, something I had hoped would make this a feasible solution.

So I looked back into the research papers and found the test-point method. Basically it translates a world point into NDC space and checks the depth of the point against the depth-buffer to determine if it is visible. This is fast enough to be used in real-time and it’s very easy to add my imaginary map planes to allow the agent to realize if the lowest node can’t be seen.

So all in all I spent two days to confirm that the culling present in the rendering pipeline wasn’t suitable to be used for visibility confirmation against such a dense grid and learned that I should read more carefully.

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