Add Built-In Functions

Built-In Functions.-.md

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+# Data Functions
+These are functions to access the data that `empty.js` provides.
+
+## Mouse Data
+### Mouse Position
+```js
+getMousePosGlobal()
+// returns {x : 0, y : 0}
+```
+
+Returns the "global" mouse pointer position. This position is not related to the canvas size or position. It only shows the position of the mouse inside the browser window.
+
+---
+
+```js
+getMousePos()
+// returns {x : 0, y : 0}
+```
+
+Returns the mouse pointer position relative to the position of the canvas (`{x : 0, y : 0}` would be top left)
+
+---
+
+```js
+getLastMousePos()
+// returns {x : 0, y : 0}
+```
+
+Returns the mouse pointer position relative to the position of the canvas during the last frame (if called from the `tick()` function, it will return the value `getMousePos()` would have returned in the last cycle).
+
+---
+```js
+getRelativeMouseMovement()
+// returns {x : 0, y : 0}
+```
+
+Returns the pixels the mouse moved since the last frame. Useful for calculating mouse movement speed for example.
+
+### Mouse Buttons
+```js
+getMouseKey(key);
+// returns boolean
+```
+
+Returns the state of the selected mouse key or button, `true` meaning button is currently pressed.
+
+```
+key = 0 : Left Mouse Button
+key = 1 : Middle Mouse Button
+key = 2 : Right Mouse Button
+```
+
+## Keyboard Data
+```js
+getKey(code)
+// returns boolean
+```
+
+Returns the state of a key from it's code (i.e. `keyA`, `Space` or `ShiftLeft`), `true` meaning the key is currently pressed.
+
+# Drawing Functions
+These are functions that are supposed to make drawing on the canvas a bit easier.
+
+All default JavaScript Canvas API functions are available by referencing the Canvas Context using `c`, i.e.
+
+```js
+c.fillRect(0, 5, 10, 15);
+```
+
+---
+
+```js
+fillBackground();
+```
+
+Fills the entire canvas with the current color defined in `c.fillStyle`.
+
+---
+
+```js
+fillCircle(x, y, r);
+```
+
+Draws a filled circle centered at `x, y` with a radius of `r` pixels.
+
+---
+
+```js
+strokeCircle(x, y, r);
+```
+
+Draws a stroked circle centered at `x, y` with a radius of `r` pixels.
+
+---
+
+```js
+line(x1, y1, x2, y2);
+```
+
+Draws a line from `x1, y2` to `x2, y2`.
+
+---
+
+```js
+drawRotatedImage(image, x, y, angle, width, height);
+```
+
+Draws a given image centered at `x, y` with a defined width and height, rotated by `angle` radiants around it's center.
+
+# Other
+Functions that don't necessarily have anything to do with `empty.js` but are simply useful shortcuts for common use cases.
+
+---
+
+```js
+distance(x1, y1, x2, y2)
+// returns number
+```
+
+Returns the distance between two points `x1, y1` and `x2, y2` calculated using Pythagorean theorem.
+
+---
+
+```js
+randomRange(min, max)
+// returns number
+```
+
+Returns a random integer between and including `min` and `max` defined using `Math.random()`. Do not use for cryptography.
+
+---
+
+```js
+range(i)
+// returns array of size i
+```
+
+Simmilar to Python's `range()` function. Returns an array with `i` elements. Each element contains its index.
+
+---
+
+```js
+minmax(num, min, max)
+// returns number
+```
+
+If `max` if `num` is greater than `max` and `min` if `num` is less than `min`, otherwise returns `num`.
+
+---
+
+## CSS Color Code Shortcuts
+
+```js
+rgb(r, g, b)
+rgba(r, g, b, a)
+hsl(h, s, l)
+hsla(h, s, l, a)
+// each return strings
+```
+
+These functions return the given values inside a String according to CSS Standard, i.e.
+
+```js
+rgb(0, 255, 100)
+// returns "rgb(0,255,100)"
+```
+
+This simply makes transforming numbers from JavaScript into CSS Color values a little more convenient.