>>> Prompt:
add a pause function on mouse click in the update function
>>> Prompt 2:
We're making a game (Lemmings), to optmize the drawing, I want to change something...
Instead of clearing entire canvas every frame and redrawing it, just redraw the lemming that moved.
Before the lemming was drawn, it needs to keep track of the background and restore that. Make sure
we do not get any memory leaks around keeping track of the previous background.
A lemming structure looks like this:
const lemming = {
id: -49152,
x: 0,
y: 0,
width: 20,
height: 20,
velX: 0,
velY: 0,
onGround: false,
isDead: false,
update: function () { Do NOT change this function }
draw: function() {
// Draw the blue box and green hair
ctx.fillStyle = 'rgb(' + blueBox.join(',') + ')';
ctx.fillRect(this.x, this.y, this.width, this.height);
ctx.fillStyle = 'rgb(' + greenBox.join(',') + ')';
ctx.fillRect(this.x, this.y, 5, 5);
ctx.fillRect(this.x + 15, this.y, 5, 5);
}
}
And the frame update currently looks like this:
function update() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Update and draw each lemming
lemmings.forEach((lemming) => {
lemming.update();
lemming.draw();
if (lemming.isDead) {
// Remove dead lemmings from the array as optimization
const index = lemmings.indexOf(lemming);
lemmings.splice(index, 1);
console.log("removing dead lemming");
}
});
// Schedule the next frame
requestAnimationFrame(update);
}
These variables are already declared, use them.
const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");
Do not use ctx.save() and ctx.restore() (you don't understand what they do). In essence, what you
want to do is save the pixel data before you draw a lemming. Next frame you want to restore that,
then draw the lemming at its new position. You probably should do all saving/restoring for all lemmings
in one pass, then draw all lemmings. To avoid getting lemmings that move part of the background.
You may NOT change the lemming.update() method.
It is important that you use the declared things I mentioned above and just give me the code with
minor comments -- be brief, don't explain anything in plain text.
>>> Updated version of prompt 2:
Instead of clearing entire canvas every frame, make sure we draw back the background, and then the
lemmings on top of that. Fix this method:
function update() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Update and draw each lemming
lemmings.forEach((lemming) => {
lemming.update();
lemming.draw();
if (lemming.isDead) {
// Remove dead lemmings from the array as optimization
const index = lemmings.indexOf(lemming);
lemmings.splice(index, 1);
console.log("removing dead lemming");
}
});
// Schedule the next frame
requestAnimationFrame(update);
}
Also tell me how I should get the background data before we get to our first update.
>>> Catch-up notes:
Backup was named: 'index - Copy (19) - collisions fixed - rounding problem.html'
Associated LLM context: You-manually-fixed-faulty-redraw.md