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書名： Mastering openFrameworks：Creative Coding Demystified
作者名： Denis Perevalov
本章字數： 336字
更新時間： 2021-08-06 16:54:15

Basic utility functions

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.

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Mastering openFrameworks：Creative Coding Demystified

Basic utility functions