What is the use of the Mathf.ClosestPowerOfTwo?

czx_main · April 16, 2009, 1:53am

Mathf.ClosestPowerOfTwo( -10 ) : 0
Mathf.ClosestPowerOfTwo( -9 ) : 0
Mathf.ClosestPowerOfTwo( -8 ) : 0
Mathf.ClosestPowerOfTwo( -7 ) : 0
Mathf.ClosestPowerOfTwo( -6 ) : 0
Mathf.ClosestPowerOfTwo( -5 ) : 0
Mathf.ClosestPowerOfTwo( -4 ) : 0
Mathf.ClosestPowerOfTwo( -3 ) : 0
Mathf.ClosestPowerOfTwo( -2 ) : 0
Mathf.ClosestPowerOfTwo( -1 ) : 0
Mathf.ClosestPowerOfTwo( 0 ) : 0
Mathf.ClosestPowerOfTwo( 1 ) : 1
Mathf.ClosestPowerOfTwo( 2 ) : 2
Mathf.ClosestPowerOfTwo( 3 ) : 4
Mathf.ClosestPowerOfTwo( 4 ) : 4
Mathf.ClosestPowerOfTwo( 5 ) : 4
Mathf.ClosestPowerOfTwo( 6 ) : 8
Mathf.ClosestPowerOfTwo( 7 ) : 8
Mathf.ClosestPowerOfTwo( 8 ) : 8
Mathf.ClosestPowerOfTwo( 9 ) : 8
Mathf.ClosestPowerOfTwo( 10 ) : 8
Mathf.ClosestPowerOfTwo( 11 ) : 8
Mathf.ClosestPowerOfTwo( 12 ) : 16
Mathf.ClosestPowerOfTwo( 13 ) : 16
Mathf.ClosestPowerOfTwo( 14 ) : 16
Mathf.ClosestPowerOfTwo( 15 ) : 16
Mathf.ClosestPowerOfTwo( 16 ) : 16
Mathf.ClosestPowerOfTwo( 17 ) : 16
Mathf.ClosestPowerOfTwo( 18 ) : 16
Mathf.ClosestPowerOfTwo( 19 ) : 16
Mathf.ClosestPowerOfTwo( 20 ) : 16
Mathf.ClosestPowerOfTwo( 21 ) : 16
Mathf.ClosestPowerOfTwo( 22 ) : 16
Mathf.ClosestPowerOfTwo( 23 ) : 16
Mathf.ClosestPowerOfTwo( 24 ) : 32
Mathf.ClosestPowerOfTwo( 25 ) : 32
Mathf.ClosestPowerOfTwo( 26 ) : 32
Mathf.ClosestPowerOfTwo( 27 ) : 32
Mathf.ClosestPowerOfTwo( 28 ) : 32
Mathf.ClosestPowerOfTwo( 29 ) : 32
Mathf.ClosestPowerOfTwo( 30 ) : 32
Mathf.ClosestPowerOfTwo( 31 ) : 32
Mathf.ClosestPowerOfTwo( 32 ) : 32
Mathf.ClosestPowerOfTwo( 33 ) : 32
Mathf.ClosestPowerOfTwo( 34 ) : 32
Mathf.ClosestPowerOfTwo( 35 ) : 32
Mathf.ClosestPowerOfTwo( 36 ) : 32
Mathf.ClosestPowerOfTwo( 37 ) : 32
Mathf.ClosestPowerOfTwo( 38 ) : 32
Mathf.ClosestPowerOfTwo( 39 ) : 32
Mathf.ClosestPowerOfTwo( 40 ) : 32
Mathf.ClosestPowerOfTwo( 41 ) : 32
Mathf.ClosestPowerOfTwo( 42 ) : 32
Mathf.ClosestPowerOfTwo( 43 ) : 32
Mathf.ClosestPowerOfTwo( 44 ) : 32
Mathf.ClosestPowerOfTwo( 45 ) : 32
Mathf.ClosestPowerOfTwo( 46 ) : 32
Mathf.ClosestPowerOfTwo( 47 ) : 32
Mathf.ClosestPowerOfTwo( 48 ) : 64
Mathf.ClosestPowerOfTwo( 49 ) : 64
Mathf.ClosestPowerOfTwo( 50 ) : 64
Mathf.ClosestPowerOfTwo( 51 ) : 64
Mathf.ClosestPowerOfTwo( 52 ) : 64
Mathf.ClosestPowerOfTwo( 53 ) : 64
Mathf.ClosestPowerOfTwo( 54 ) : 64
Mathf.ClosestPowerOfTwo( 55 ) : 64
Mathf.ClosestPowerOfTwo( 56 ) : 64
Mathf.ClosestPowerOfTwo( 57 ) : 64
Mathf.ClosestPowerOfTwo( 58 ) : 64
Mathf.ClosestPowerOfTwo( 59 ) : 64
Mathf.ClosestPowerOfTwo( 60 ) : 64
Mathf.ClosestPowerOfTwo( 61 ) : 64
Mathf.ClosestPowerOfTwo( 62 ) : 64
Mathf.ClosestPowerOfTwo( 63 ) : 64
Mathf.ClosestPowerOfTwo( 64 ) : 64
Mathf.ClosestPowerOfTwo( 65 ) : 64
Mathf.ClosestPowerOfTwo( 66 ) : 64
Mathf.ClosestPowerOfTwo( 67 ) : 64
Mathf.ClosestPowerOfTwo( 68 ) : 64
Mathf.ClosestPowerOfTwo( 69 ) : 64
Mathf.ClosestPowerOfTwo( 70 ) : 64
Mathf.ClosestPowerOfTwo( 71 ) : 64
Mathf.ClosestPowerOfTwo( 72 ) : 64
Mathf.ClosestPowerOfTwo( 73 ) : 64
Mathf.ClosestPowerOfTwo( 74 ) : 64
Mathf.ClosestPowerOfTwo( 75 ) : 64
Mathf.ClosestPowerOfTwo( 76 ) : 64
Mathf.ClosestPowerOfTwo( 77 ) : 64
Mathf.ClosestPowerOfTwo( 78 ) : 64
Mathf.ClosestPowerOfTwo( 79 ) : 64
Mathf.ClosestPowerOfTwo( 80 ) : 64
Mathf.ClosestPowerOfTwo( 81 ) : 64
Mathf.ClosestPowerOfTwo( 82 ) : 64
Mathf.ClosestPowerOfTwo( 83 ) : 64
Mathf.ClosestPowerOfTwo( 84 ) : 64
Mathf.ClosestPowerOfTwo( 85 ) : 64
Mathf.ClosestPowerOfTwo( 86 ) : 64
Mathf.ClosestPowerOfTwo( 87 ) : 64
Mathf.ClosestPowerOfTwo( 88 ) : 64
Mathf.ClosestPowerOfTwo( 89 ) : 64
Mathf.ClosestPowerOfTwo( 90 ) : 64
Mathf.ClosestPowerOfTwo( 91 ) : 64
Mathf.ClosestPowerOfTwo( 92 ) : 64
Mathf.ClosestPowerOfTwo( 93 ) : 64
Mathf.ClosestPowerOfTwo( 94 ) : 64
Mathf.ClosestPowerOfTwo( 95 ) : 64
Mathf.ClosestPowerOfTwo( 96 ) : 128
Mathf.ClosestPowerOfTwo( 97 ) : 128
Mathf.ClosestPowerOfTwo( 98 ) : 128
Mathf.ClosestPowerOfTwo( 99 ) : 128
Mathf.ClosestPowerOfTwo( 100 ) : 128
Mathf.ClosestPowerOfTwo( 101 ) : 128
Mathf.ClosestPowerOfTwo( 102 ) : 128
Mathf.ClosestPowerOfTwo( 103 ) : 128
Mathf.ClosestPowerOfTwo( 104 ) : 128
Mathf.ClosestPowerOfTwo( 105 ) : 128
Mathf.ClosestPowerOfTwo( 106 ) : 128
Mathf.ClosestPowerOfTwo( 107 ) : 128
Mathf.ClosestPowerOfTwo( 108 ) : 128
Mathf.ClosestPowerOfTwo( 109 ) : 128
Mathf.ClosestPowerOfTwo( 110 ) : 128
Mathf.ClosestPowerOfTwo( 111 ) : 128
Mathf.ClosestPowerOfTwo( 112 ) : 128
Mathf.ClosestPowerOfTwo( 113 ) : 128
Mathf.ClosestPowerOfTwo( 114 ) : 128
Mathf.ClosestPowerOfTwo( 115 ) : 128
Mathf.ClosestPowerOfTwo( 116 ) : 128
Mathf.ClosestPowerOfTwo( 117 ) : 128
Mathf.ClosestPowerOfTwo( 118 ) : 128
Mathf.ClosestPowerOfTwo( 119 ) : 128
Mathf.ClosestPowerOfTwo( 120 ) : 128

Seems from the results of the Binary

But I still do not understand … :?: :?:

GargerathSunman · April 16, 2009, 2:04am

Just the closest “2 to the power of” number to the number you inputted.

The closest “2 to the power of” to 58 is 64, etc…

Eric5h5 · April 16, 2009, 2:05am

It returns the closest power of two. A power of two is 2^x. I use it in Fractscape, and also the ApplySplatmap script that comes with Fractscape:

	if (Mathf.ClosestPowerOfTwo(w) != w) {
		EditorUtility.DisplayDialog("Wrong size", "Splatmap width and height must be a power of two", "Cancel"); 
		return;	
	}

–Eric

czx_main · April 16, 2009, 7:12am

"":

It returns the closest power of two. A power of two is 2^x. I use it in Fractscape, and also the ApplySplatmap script that comes with Fractscape:
	if (Mathf.ClosestPowerOfTwo(w) != w) {
		EditorUtility.DisplayDialog("Wrong size", "Splatmap width and height must be a power of two", "Cancel"); 
		return;	
	}
–Eric

o~~~
I seem to understand.
return the closest power of “2”?
e.t.c 6 is 8 , 9 is 8 too …
If is 12 of inputted,It would have two results（8 and 16）,to take large values,So return the 16.is right ?

czx_main · April 16, 2009, 7:14am

thank very much to GargerathSunman and Eric