General Explanation of the ADND Collision Viewing

This will be more of an overview / layman's explanation of the collision viewing that you see in this video. A more technical explanation can be found here: https://pastebin.com/anhYewtn

OoT defines the polygons you see, and the polygons used for collision checking in different lists. Most of the time, when there is a visual polygon for a wall / floor / ceiling, there is a corresponding collision polygon at the same place. That way when you see a wall / floor / ceiling, you know link will interact with it. There are some exceptions though. Casually, the exceptions you will encounter involve the lens of truth. There will be a visual polygon without a collision one, which is revealed when the wall disappears when using the lens. Alternatively, there are collision polygons without a visual polygon, which again is revealed when a wall appears while using the lens of truth. However, there are other exceptions that don't involve the lens of truth. Sometimes you will just have an invisible wall that doesn't have any visual polygons attached to it. But whats even more important is the way OoT handels rooms.

Every map in the game can be divided into rooms. Some maps (like hyrule field) have only one room, while on the other end fire temple has 27 different rooms. The game will only have the visuals and actors (anything dynamic) for at most 2 rooms loaded at once, however the entire scene collision is always loaded. What this means is that if you if you leave the currently loaded room in an unintended way, you will just be in void of invisible walls / floors / ceilings.

What this collision viewer is is a camera hack. This camera hack will draw custom visual polygons ontop of every collision triangle. This way it is much easier to understand what is going on during these sections in unloaded rooms.

You may notice a bit of striping in the loaded rooms. This is just an affect of 2 visual polygons (the game's intended visual polygon and the custom one) trying to be drawn in the exact same or essentially the same position.

The coloring for the custom polygons were chosen randomly, so that adjacent polygons are easier to distinguish. If it were a solid color, depth and adjacent polygons are a lot harder to make out.