The game will be slow

[hemnf]

Hi,
Thank you for your code and I really like it. I have one issue, when the game reached more than 3 minutes, it will be very slow and the user can not move the dot.
Thanks

[JakeLin]

haha, this is a hidden feature since you are the best player in the world 😁 Which devices are you using? will it always happen after 3 minutes?

[hemnf]

Dear JakeLin,
Thank you for your reply, I am using iPhone, 5, 6, and 6s. Always when you reach 120 second you will face this. When I checked the Time profiling I found the 95% of CPU usage will come from this function:
func checkCollision() {
enemyViews.forEach {
guard let playerFrame = playerView.layer.presentation()?.frame,
let enemyFrame = $0.layer.presentation()?.frame,
playerFrame.intersects(enemyFrame) else {
return
}
gameOver()
}
}

especially with this line
let enemyFrame = $0.layer.presentation()?.frame,

I think it is not about hidden feature, if you reach more than 150 seconds the CPU usage will be the highest and the game will be jammed.

Kind regards

[JakeLin]

@hemnf it was a joke 😅, we call checkCollision too many times in the run loop, we can optimise that. Could you like to give it a go?

[imbaggaarm]

I think we need a maximum number of enemies, ex: 60.

[VNystad]

After a quick scan on your code, it seems that you iterate over all enemies to check if there is a collision. A possible workaround would be to save all positions of every enemy in a 2D list and update it on each tick with new positions. Then only checking the current position of the player in the list for collision, sudo code:
if (enemyPositionMap[playerPos.y, playerPos.x] != 0)
gameover

Not sure if this is doable but if it is,
this solution will cost a little memory tho for the fixed list size, but could save some cpu usage:
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