delightport.blogg.se - Pacman chasing ghosts

Wall collision: every time a ghost collides with a wall object, it means it can't move further, and a new direction to move towards is required.This results in actual turning left or right when the monster reaches a corner or any crossing point in any case, the ChangeDirection algorithm doesn't allow a ghost to U-turn back Grid snap: every time a ghost snaps with the grid (which means, every time its position is such that it fits perfectly inside a single grid tile), the function can be called to test the opportunity to change direction.When implemented, this function must be executed when at least one of these two events occur: If chance 1 out of 3 and no collisions upwards: If chance 1 out of 3 and no collisions downwards: If chance 1 out of 3 and no collisions rightwards: If chance 1 out of 3 and no collisions leftwards: Then, a generic ghost AI behavior to change path could be described as follows: function ChangeDirection():

Ghosts reverse their horizontal and vertical speeds when collision with level walls occur.

Ghosts can move either horizontally or vertically, not diagonally.

Every level can be treated as a grid whose tiles' size is known, and level walls must be placed accordingly to such grid.

This said, you can try this approach instead of trying to implement A* in the first place. The reason it worked smoothly was because "ghosts" were sort of cooperating and able to patrol most of the level, eventually trapping the player and killing them. Monsters who got at intersections chose a new, random direction (not turning back), one of which was the right one to chase the player. Pac-Man developers didn't use neither A* or Dijkstra's algorithm for making enemies chase the player. In run-away mode, they either ran away or chose a random direction. In chase mode, each had a different chance of chasing the player or choosing a random direction.

For each state they took a semi-random route at each junction. Each of the four monsters was either chasing you or running away. Pac-Man relied on a very simple AI technique: a state machine. Pac-Man had definite enemy characters that seemed to conspire against you, moved around the level just as you did, and made life tough. Funge talk right about Pac-Man AI in their book " Artificial Intelligence for Games", paragraph 1.1.2: I don't think the effort of implementing such algorithms is worth, given the simplicity of a game such as Pac-Man. AI is not intelligent, it just acts like it