Your program starts with dino initialized to undefined because you declare it like this, without giving it a value:
var dino;
You do have code elsewhere to assign it a value that is not undefined:
function setup() {
size(400, 400, P2D); // Set the canvas size
dino = { x: 50, y: height - 50, speed: 0 }; // Initialize 'dino' inside 'setup' function
}
Note there is a comment specifically calling out that there is a line in setup() that initializes dino to a non-default value. So it must be the case that a function that is trying to use dino.x or dino.width is getting called _before_ setup() is being called.
I hope that helps!
Mark R.
tutor
Well, you have two different errors here. One has to do with dino not being defined -- that's the error "Cannot read properties of undefined (reading 'x')". Fixing that by either just declaring
var dino = { x: 50, y: height - 50, speed: 0 };
or by calling setup() early is fine.
But then you get an error:
Cannot read properties of undefined (reading 'width')
Notice that width is never accessed off of dino (I don't see you actually have dino.width anywhere). It's always being used as a global variable (not as a property of an object). And I notice there are lots of comments saying that width is a global variable. Now, normally, outside of Khan Academy's sandbox, width would not be a global variable. But it looks like it's meant to be in their special environment/sandbox they're providing for you that's using ProcessingJS. I see that in their documentation: https://www.khanacademy.org/computer-programming/width/5933816543707136 But obviously, that's not working in the specific environment hosting the program you're linking to for this question.
I don't know really anything about Khan Academy's sandbox. You're probably better off asking in their forums or on StackOverflow (I notice there's a khan-academy tag there).
Report
04/16/24
Samuel D.
So, I should find where dino.x or dino.width is being used before the setup function? I moved preload() to after setup() and still got the same error. I don't see where dino.x or dino.width are being called before setup(), unless it is in one of the variables I set up. var dino; var obstacles = []; var obstacleSpeed = 5; var jumpForce = -15; var gravity = 0.6; var isJumping = false; var score = 0; var dinoImg; // Declare variable for dinosaur image var cactusImg; // Declare variable for cactus image function setup() { size(400, 400, P2D); // Set the canvas size dino = { x: 50, y: height - 50, speed: 0 }; // Initialize 'dino' inside 'setup' function } function preload() { // Load pixelated images for the dinosaur and cacti dinoImg = loadImage('dinosaur.png'); cactusImg = loadImage('cactus.png'); }04/16/24