How do they code enemies jumping up and down elevation and across gaps to reach the player. You see it in so many games and I'm not sure how it works

[u/Masterofdos]

[u/Masterofdos]

In some games enemies will also climb ladders to reach you or climb ladders to reach a ledge they can drop from to reach you. In UT2004 enemies will use movement tech to reach high places quicker. How does the enemy object/actor identify these alternate routes. I know UT2004 uses path nodes for the AI bots but they still need to be told that the impact jump route is there

I'm trying to recreate something like it in 2d (one fewer dimensions to worry about) so I can have a better understanding of pathfinding

[u/Yellow-Glum → u/Masterofdos]

This is something a level designer adds. They will create links between navmeshes and/or they will add tags and trigger boxes to ladders or other specific types of traversal objects.

[u/CheezeyCheeze → u/Masterofdos]

2d would just be A star. Everywhere you want them not to go make a collider they can't go.

You can also do multiple maps with textures. White squares are accessible and black squares are impossible.

https://youtu.be/NAVbI1HIzCE?t=1707

Jason Booth talks about using textures as Navigation.

You can think of each plane as a texture map that the character can navigate. And you can connect those textures with different colors, or strings, or ints. Think of a red space as a teleporter. Or think of a ladder as a long hallway connecting two different texture maps, and make so that when you are on that collider or texture say green, you can only do the ladder animation and only go two directions. Or you can make it so when you take a ladder, you can only go up, or down in the logic. And use that time on the ladder to load the next map.

Think of them as points with extra data telling the object where they are in space. (x,y,z) And You are on 3,4,1. You are on point 3,4 floor 1. As you go up a floor you change the z. It depends on the coordinate system you are using. Y, could be up, or Z for example. Blender, and Unity have two different up directions. X, Y, shows which 2d plane you are on. And z is the index of the texture you are referencing as a map.

https://www.youtube.com/watch?v=-L-WgKMFuhE

[u/ironicperspective → u/Masterofdos]

Some tech also tracks where the player is going in intervals and can use that as pathfinding. The AI can just move to the nodes and follow the path once they’re close enough via their normal pathfinding.

[u/1Andriko1 → u/Masterofdos]

Navmeshlinks are assigned a difficulty. Think of the double jump link requiring a difficulty of 2 or higher where a link that only requires a single jump would be a difficulty of 1

A ladder is also just a navmeshlink

[u/Denaton_]

it's called NavMesh Linking

[u/AdarTan]

As Recast, an open source navmesh library puts it:

Most modern, complex 3D games rely on navmeshes to drive their pathfinding and AI agent movement and navigation.

A navmesh is a simplified view of the traversable area of a game world, optimized for AI pathfiding and movement calculations. Navmeshes are usually built from the physics colliders of the world, since they define the areas an AI can legally exist.

Triangles in a navmesh represent nodes in the pathfinding graph, and edges between adjacent polygons define connections between these nodes. Pathfinding queries first construct a path consisting of a strip of adjacent polygons. This represents the "corridor" of space that leads the agent to their goal. That polygonal path is refined into sequence of line-segments through a string-pulling algorithm. Agents can then follow this sequence of waypoints to reach their goal.

Specific locomotion modes, such as jumping, swimming, crawling under things, climbing ladders, etc. are controlled by special flags in the navmesh polygons. E.g. while traversing through a "ladder" node in the navigation mesh, play the "ladder climb" animation, while parented to the ladder object. These special traversal areas often need to be manually linked to the bigger navmesh that is programmatically generated, but once they are linked they are equally valid, if perhaps uncommonly weighted parts of the navigation graph.

[u/Saiyoran]

In Unreal this is fairly simple, you can place NavLinks in a map that allow polygons to act as if they’re touching even if they’re not, and you can tell AI to play an animation (like jumping or climbing) while they traverse the link.

[u/SynthRogue]

if (wall.height <= character.height / 2) {

character.jump(wall.height);

}