Finding the way
Learning paths through this topic
Load the world around the player in chunks without reloading at every border step
A big open world is built in pieces that load near the player and unload far away. If both happen at the same distance, walking back and forth over a border loads and drops the same piece again and again. Here is the rule that stops it, and a negative-coordinate trap.
A pet that follows the player's footsteps walks every loop and detour twice
Following the exact trail the player walked is cheap and never gets stuck, but it also replays every circle and zigzag. Here is how to cut those out of the trail as it is recorded, and what must happen to a follower standing on a cut piece.
A compass points the long way round a world whose edges connect
When walking off the east side brings you back on the west, the nearest ore may lie behind you across the edge. Here is how to measure distance and direction in such a world, and which way to point when both ways are equally far.
Should a worker dig straight through the rock or walk around the mountain
In a game where stone can be mined, the shortest way is often through a wall. Digging takes time, the tool may be too weak, and some rock cannot be dug at all. Here is how a route weighs digging against walking, and what to return.
Say which direction the camp lies in, in words, without the word flickering at the border
A text like north-east or south is easy to compute and annoying to read, because the word flips back and forth when the player walks along the line between two directions. Here is a small rule that calms it, and the wrap-around trap near west.
Show how much of the island is explored without counting the sea
An exploration meter that counts every revealed square never reaches the top on an island, and one that rounds up shows full when a last corner is still dark. Here is how to count what is worth counting, and when the meter may say all.
Fast travel that uses up food and stops on the road when the food runs out
Jumping between camps should not be free in a game about hunger. The cost has to follow the road that is actually taken, round in the right direction, and leave the player somewhere sensible when the bag runs dry halfway. Here is a rule that does that.
Pick the right fence or wall piece so lines, corners and crossings join up
Players place wall pieces one at a time and expect them to turn into corners, ends and crossings by themselves. Here is a compact way to choose the picture for each piece from its neighbours, and which pieces need to be redrawn when one is placed or removed.
Find the hidden camp from two towers that each report only a compass bearing
Two outposts each know which way a signal comes from, but not how far. Together they pin down the spot. Here is the intersection, with the cases that give no answer: lines that never meet, and lines that only meet behind the towers.
Pick the nearest berry bush the gatherer can still bring home from
A gatherer with a limited amount of strength should only head for food it can reach and still walk back from. The way home costs something different from the way out, and doubling the trip is wrong. Here is the calculation.
Let bushes and trees hide the player a little at a time instead of all or nothing
A single tree should not make a hunter blind, but a thick forest between two creatures should. Here is how to add up the cover along the line of sight, why the cell where the target stands counts too, and a mistake that skips cells on steep lines.
Decide which machines run when a generator's cables reach more than it can supply
Players wire up generators and machines and expect the lights to come on. Machines that touch no cable, or a network with no generator, stay dark, and a network with too little power must pick. Here is how to group the network and which machines get the power.