The last section of the chapter mentions some utility functions, which will be used in examples across the book, or just can be useful in your projects.

`ofMap( v, v0, v1, out0, out1 )`

: This function performs linear interpolation of a float value`v`

from the segment`[v0, v1]`

to the segment`[out0, out1]`

. Note, it does not control boundaries of`v`

, and just uses the formula*(v-v0)/(v1-v0)*(out1-out0) + out0*. For controlling boundaries, call this function with the last optional parameter set to`true`

:`ofMap( v, v0, v1, out0, out1, true )`

. Then the result will be clamped to`[out0, out1]`

.`ofClamp( v, v0, v1 )`

: This function clamps the float value`v`

to the segment`[v0, v1]`

that is returns`min( max( v, v0 ), v1 )`

.`ofRandom( a, b )`

: This function generates a pseudo-random number in the segment`[a, b]`

. (Actually, it returns a value always less than that of`b`

).`ofNoise ( x )`

,`ofNoise( x, y )`

,`ofNoise( x, y, z )`

, and`ofNoise( x, y, z, w )`

:These functions return Perlin noise value, see the details in Appendix B,*Perlin Noise*.`ofToString( v )`

: This function converts the`int`

or`float`

value`v`

into string-returning value`ofToInt( s )`

and`ofToFloat( s )`

: These functions convert the string`s`

into`int`

or`float`

returning values respectively.`ofGetWidth()`

and`ofGetHeight()`

: These functions return the current width and height of the project's screen, in pixels.`ofGetElapsedTimef()`

: This function returns the value of seconds lapsed from the project's start. This is a`float`

value, measured with millisecond accuracy. For example, returned value 123.4 means 123 seconds and 400 milliseconds.`ofShowCursor()`

and`ofHideCursor()`

: These functions show and hide the mouse cursor.

For printing information into a console window, you can use the standard `cout`

stream. For example, for printing time from the project's start, use the following code:

cout << "Time: " << ofGetElapsedTimef() << endl;

Here, `endl`

is a standard constant, which means starting a new line in the console.