Physical interactions

[dev-zzo]

PC needs to be restricted to certain parts of the location. Implement semi-physical collision model.

[dev-zzo]

Requirements... what do we want?

1. Test whether a PC can move into the desired direction; gather any objects found within the test shape. 1.1. PCs taking damage from shots?
2. NPCs use it to navigate the world; same as above as for API. 2.1. Provide API to enable path finding for NPCs.
3. Triggers to execute a scripted event.

These 3 should cover all the major physical interactions with the world.

[dev-zzo]

Approach 1: tile based.

We remain devoted to our tiles: the physical model is based on a rectangular array with each tile marked as passable or otherwise.

Pros:

• Implementation complexity is low.
• Static collision probing complexity is low (check a nearby cell).
• Pathfinding algorithm complexity is low (BFS vanilla).

Cons:

• Does not implement dynamic collision testing in any way (e.g. character vs character, character vs projectile). Same goes for triggers.
• Only roughly approximates terrain; the tile is either passable or not.

[dev-zzo]

Approach 2: geometry based.

We represent each obstacle as a geometric shape (say, either a circle or an axis-aligned box), and use that information to do tests.

Pros:

• Much more precise in approximating terrain.
• Since each obstacle is now a proper object, can notify about collisions.
• Dynamic object collisions are implemented the same as statics.

Cons:

• Implementation complexity is much higher.
• Static collision probing complexity is rather high; selecting potential candidates and then testing each.
• Does not immediately help with navigation.

[dev-zzo]

Moving all the stuff to a wiki page.

[dev-zzo]

Well, this seems to be implemented.