Waypoint systems in Unity - Step-by-Step Execution

Concept Flow - Waypoint systems

Start

↓

Set waypoints array

↓

Set current waypoint index = 0

↓

Move object towards current waypoint

↓

Check if reached current waypoint?

No→Continue moving

Yes↓

Update current waypoint index to next

↓

Loop back to move towards new waypoint

↓

Repeat until all waypoints visited or loop

↓

End or restart loop

The object moves step-by-step towards each waypoint in order, updating the target when it reaches one.

Execution Sample

Unity

Vector3[] waypoints = {A, B, C};
int current = 0;
while(true) {
  MoveTowards(waypoints[current]);
  if (Reached(waypoints[current])) current = (current + 1) % waypoints.Length;
}

Moves an object through points A, B, C in a loop, updating target when each is reached.

Execution Table

Step	Current Waypoint Index	Current Target Position	Object Position	Distance to Target	Action
1	0	A	(0,0,0)	5	Move towards A
2	0	A	(1,0,0)	4	Move towards A
3	0	A	(3,0,0)	2	Move towards A
4	0	A	(5,0,0)	0	Reached A, update index to 1
5	1	B	(5,0,0)	7	Move towards B
6	1	B	(7,0,0)	5	Move towards B
7	1	B	(10,0,0)	2	Move towards B
8	1	B	(12,0,0)	0	Reached B, update index to 2
9	2	C	(12,0,0)	4	Move towards C
10	2	C	(14,0,0)	2	Move towards C
11	2	C	(16,0,0)	0	Reached C, update index to 0 (loop)
12	0	A	(16,0,0)	11	Move towards A again

💡 Loop continues indefinitely, cycling through waypoints A, B, C

Variable Tracker

Variable	Start	After Step 4	After Step 8	After Step 11	After Step 12
current	0	1	2	0	0
Object Position	(0,0,0)	(5,0,0)	(12,0,0)	(16,0,0)	(16,0,0)
Current Target	A	B	C	A	A

Key Moments - 3 Insights

Why does the current waypoint index reset to 0 after reaching the last waypoint?

Because the code uses modulo (%) with the waypoints length to loop back, as shown in step 11 where index changes from 2 to 0 (execution_table row 11). This makes the movement repeat.

What happens if the object never exactly reaches the waypoint position?

The code checks if distance is zero to update index (execution_table column 'Distance to Target'). If never zero, the index won't update and the object keeps moving towards the same waypoint.

How does the object know which waypoint to move towards next?

The variable 'current' stores the index of the target waypoint and updates when the object reaches it (variable_tracker shows 'current' changes at steps 4, 8, 11).

Visual Quiz - 3 Questions

Look at the execution table at step 4. What is the current waypoint index after reaching waypoint A?

A 1

B 0

C 2

D 3

💡 Hint

Check the 'Action' column at step 4 where it says 'Reached A, update index to 1'

At which step does the object start moving towards waypoint C?

A Step 5

B Step 8

C Step 9

D Step 11

💡 Hint

Look at 'Current Target Position' column to see when it changes to C

If the object never reaches a waypoint, what happens to the 'current' index in variable_tracker?

A It keeps increasing beyond waypoints length

B It stays the same and does not update

C It resets to 0 immediately

D It becomes negative

💡 Hint

Refer to key moment 2 and execution_table 'Distance to Target' column

Concept Snapshot

Waypoint systems move an object through a list of points in order.
Use an index to track the current target waypoint.
Move the object towards the current waypoint each update.
When the object reaches the waypoint, update the index to the next.
Use modulo (%) to loop back to the first waypoint.
This creates smooth, repeatable path movement.

Full Transcript

This visual execution shows how a waypoint system works in Unity. We start with an array of waypoints and a current index set to zero. The object moves towards the waypoint at the current index. Each step, we check if the object has reached the waypoint by measuring distance. If reached, we update the index to the next waypoint, looping back to zero after the last. The execution table tracks the object's position, current target, and index changes step-by-step. Key moments clarify why the index loops and how the object knows which waypoint to move to next. The quiz tests understanding of index updates and movement flow. This helps beginners see how waypoint navigation works in a game or simulation.