Tilemap painting in Unity - Step-by-Step Execution

Concept Flow - Tilemap painting

Start

↓

Select Tilemap Component

↓

Choose Tile to Paint

↓

Click on Tilemap Grid Position

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Place Tile at Position

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Repeat or Finish

This flow shows how you select a tile and paint it onto a tilemap grid step-by-step.

Execution Sample

Unity

using UnityEngine;
using UnityEngine.Tilemaps;

public class PaintTile : MonoBehaviour {
    public Tilemap tilemap;
    public Tile tile;

    void Paint(Vector3Int pos) {
        tilemap.SetTile(pos, tile);
    }
}

This code paints a chosen tile onto the tilemap at a given grid position.

Execution Table

Step	Action	Input Position	Tile Placed?	Tilemap State
1	Select Tilemap Component	-	No	{} (empty)
2	Choose Tile to Paint	-	No	{} (empty)
3	Call Paint() with pos=(0,0,0)	(0,0,0)	Yes	{(0,0,0): tile}
4	Call Paint() with pos=(1,0,0)	(1,0,0)	Yes	{(0,0,0): tile, (1,0,0): tile}
5	Call Paint() with pos=(0,1,0)	(0,1,0)	Yes	{(0,0,0): tile, (1,0,0): tile, (0,1,0): tile}
6	Finish Painting	-	No	Final tilemap with 3 tiles placed

💡 Painting stops when user finishes or no more positions are given.

Variable Tracker

Variable	Start	After Step 3	After Step 4	After Step 5	Final
tilemap	empty	{(0,0,0): tile}	{(0,0,0): tile, (1,0,0): tile}	{(0,0,0): tile, (1,0,0): tile, (0,1,0): tile}	same as After Step 5
pos	null	(0,0,0)	(1,0,0)	(0,1,0)	last used (0,1,0)
tile	assigned	assigned	assigned	assigned	assigned

Key Moments - 3 Insights

Why does the tilemap state change only after calling Paint()?

Because SetTile() is called inside Paint(), the tilemap updates only when Paint() runs, as shown in steps 3-5 of the execution_table.

What happens if you call Paint() with the same position twice?

The tile at that position is replaced with the new tile, updating the tilemap state at that position. This is implied by how SetTile() works but not shown in this trace.

Why is the tilemap empty before any Paint() calls?

Because no tiles have been placed yet; the tilemap starts empty as shown in step 1 and 2 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the tilemap state after step 4?

A {} (empty)

B {(0,0,0): tile}

C {(0,0,0): tile, (1,0,0): tile}

D {(0,0,0): tile, (0,1,0): tile}

💡 Hint

Check the 'Tilemap State' column at step 4 in the execution_table.

At which step does the first tile get placed on the tilemap?

A Step 1

B Step 3

C Step 2

D Step 6

💡 Hint

Look for the first 'Yes' in 'Tile Placed?' column in the execution_table.

If you call Paint() with position (2,0,0) after step 5, how would the tilemap state change?

A It adds {(2,0,0): tile} to the tilemap

B It removes all previous tiles

C It replaces tile at (0,0,0)

D No change happens

💡 Hint

Refer to how tilemap state grows after each Paint() call in variable_tracker.

Concept Snapshot

Tilemap painting in Unity:
- Use Tilemap component and Tile assets
- Call tilemap.SetTile(position, tile) to paint
- Position is Vector3Int grid coordinate
- Each call places or replaces tile at position
- Repeat to paint multiple tiles
- Tilemap updates visually in scene

Full Transcript

Tilemap painting in Unity involves selecting a Tilemap component and a Tile asset. You then call the Paint function with a grid position to place the tile there using tilemap.SetTile. The tilemap starts empty and updates each time Paint is called with a new position. This process repeats until painting is finished. The execution table shows each step: selecting components, calling Paint with positions, and how the tilemap state changes by adding tiles. Variables like tilemap and pos update accordingly. Common confusions include why tilemap changes only after Paint calls and what happens if the same position is painted twice. The visual quiz tests understanding of tilemap state changes and painting steps. This method lets you build tile-based maps visually and programmatically in Unity.