Isometric Movement in Javascript In the DOM

Question

I am creating a game using Javascript. I am not using the HTML5 Canvas Element. The game requires both side view controlles, and Isometric controls, hence the movementMode variable.

I have got the specific angles, but I am stuck on an aspect of this.

https://chillibyte.makes.org/thimble/movement

function draw() {
            if (keyPressed) {
                if (whichKey == keys.left) {
                    move(-1,0)
                }
                if (whichKey == keys.right) {
                    move(1,0)
                }
                if (whichKey == keys.up) {

                    move(0,-1)
                }
                if (whichKey == keys.down) {

                    move(0,1)
                }
            }
        }

This gives normal up, down , left, and right. i want to refactor this so that i can plugin two variables into the move() function, which will give the movement wanted.

Now for the trig.

         /|
        / |
       /  | y
      /   |
     /a___|
        x

Take This Right angled Triangle.

given that x is 1, y must be equal to tan(a)

That Seems right. However, when I do Math.tan(45), i get a number similar to 1.601. Why?

To Sum up this question.

I have a function, and i need a function which will converts an angle to a value, which will tell me the number of pixels that i need to go up by, if i only go across 1. Is it Math.tan that i want? or is it something else?

Answer 1

If I'm not mistaken Math.tan(x) does not take angles as degrees, but rather radians. If you want to supply angles as degrees, try the following code sample:

function getTanDeg(deg) {
   var rad = deg * Math.PI/180;
   return Math.tan(rad);
}

Source - Mozilla Developer Network