Workshop › Conway's Game of Life › Step 6 of 32

Draw every living cell

What we are doing

draw should show the data: visit every cell of grid with two nested loops and paint a green square where the cell is 1.

```js
ctx.fillStyle = '#4ade80'
for (let r = 0; r < ROWS; r++) {
  for (let c = 0; c < COLS; c++) {
    if (grid[r][c]) ctx.fillRect(c * CELL, TOP + r * CELL, CELL - 1, CELL - 1)
  }
}
```

What it means

• for (let r = 0; r < ROWS; r++) runs its body with r = 0, 1, 2 ... 47: every row.
• The inner loop does the same with c for every column of that row.
• if (grid[r][c]) is true for 1 and false for 0, so only live cells are painted, at column c and row r.

Your turn

In draw, replace the line that paints the fixed square with the two loops. The fillStyle line above stays.

Skills: Loops

← The world in memory A random soup →

All steps

1. The board
2. Measure the grid
3. One living cell
4. A function that draws
5. The world in memory
6. Draw every living cell
7. A random soup
8. Count the neighbours
9. Four rules
10. Draw again and again
11. Next generation with N
12. Count the generations
13. Show the generation
14. A world without edges
15. Count the living
16. A generation every few frames
17. Let it live
18. Running or not
19. One place for the buttons
20. Space to play, N to step
21. Clear and shuffle
22. Where is the pointer?
23. Which cell?
24. Click a cell
25. Paint or erase?
26. Drag to paint
27. Patterns from text
28. The glider gun
29. Fire the gun
30. Buttons on the screen
31. Tap the buttons
32. Build it yourself: a world at rest