Makes buttons in games !?

Question

It's my first try to build a game ☝ I searched alot on Google and I found alot of guys who told me how to build on PC with keyboards .... But no one tell me how to be build to be suitable for touchscreens .
.
.
In brief
Let's say I build a simple snake 🐍 game . I put functions for keys( up down left right) on keyboard on PC
but

I get mazed to make buttons for movement on my phone !
https://code.sololearn.com/W179WPJJcS3n/?ref=app

Answer 1

Move the following event functions to global scope, outside of main()

function goLeft(){
v = -t;
w = 0;
}

function goUp(){
v = 0;
w = -t;
}

function goRight(){
v = t;
w = 0;
}

function goDown(){
v = 0;
w = t;
}

And the way you define functions inside switch case is wrong.

https://code.sololearn.com/Wcoq9ZA0ew17/?ref=app

Answer 2

The HTML:
<button onclick="goLeft();">Left</button>
<button onclick="goRight();">Right</button>
<button onclick="goDown();">Down</button>
<button onclick="goUp();">Up</button>

The JS:
function goLeft() {
// All your code in the switch statement for going left...
}
function goRight() {
// All your code in the switch statement for going right...
}
function goDown() {
// All your code in the switch statement for going down...
}
function goUp() {
// All your code in the switch statement for going up...
}

Answer 3

1. Without using window.onload

You define a function for a button in this way:

https://code.sololearn.com/W1jG7sDx95T6/?ref=app

Note: the function must have the same name.

2. With using window.onload

You use addEventListener, in this way:
https://code.sololearn.com/WriFNOoR188j/?ref=app

Answer 4

Thanks Rowsej for helping !
.
Yeah I tried that before and give me that onclick buttons in HTML aren't defined
And I tried it again and the same error , of course there's something I miss but I don't know what it is

Answer 5

Thanks Calviղ it works perfect ,,

Answer 6

Thanks Gordon now I understand how it works !

Answer 7

The best ever in the world

Answer 8

I don't understand

Answer 9

no