CesiumMath

Members

staticconstantCesium.CesiumMath.DEGREES_PER_RADIAN : Number

The number of degrees in a radian.

Default Value: 180.0 / Math.PI

staticconstantCesium.CesiumMath.EPSILON1 : Number

0.1

staticconstantCesium.CesiumMath.EPSILON2 : Number

0.01

staticconstantCesium.CesiumMath.EPSILON3 : Number

0.001

staticconstantCesium.CesiumMath.EPSILON4 : Number

0.0001

staticconstantCesium.CesiumMath.EPSILON5 : Number

0.00001

staticconstantCesium.CesiumMath.EPSILON6 : Number

0.000001

staticconstantCesium.CesiumMath.EPSILON7 : Number

0.0000001

staticconstantCesium.CesiumMath.EPSILON8 : Number

0.00000001

staticconstantCesium.CesiumMath.EPSILON9 : Number

0.000000001

staticconstantCesium.CesiumMath.EPSILON10 : Number

0.0000000001

staticconstantCesium.CesiumMath.EPSILON11 : Number

0.00000000001

staticconstantCesium.CesiumMath.EPSILON12 : Number

0.000000000001

staticconstantCesium.CesiumMath.EPSILON13 : Number

0.0000000000001

staticconstantCesium.CesiumMath.EPSILON14 : Number

0.00000000000001

staticconstantCesium.CesiumMath.EPSILON15 : Number

0.000000000000001

staticconstantCesium.CesiumMath.EPSILON16 : Number

0.0000000000000001

staticconstantCesium.CesiumMath.EPSILON17 : Number

0.00000000000000001

staticconstantCesium.CesiumMath.EPSILON18 : Number

0.000000000000000001

staticconstantCesium.CesiumMath.EPSILON19 : Number

0.0000000000000000001

staticconstantCesium.CesiumMath.EPSILON20 : Number

0.00000000000000000001

staticconstantCesium.CesiumMath.GRAVITATIONALPARAMETER : Number

3.986004418e14

staticconstantCesium.CesiumMath.LUNAR_RADIUS : Number

The mean radius of the moon, according to the "Report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and satellites: 2000", Celestial Mechanics 82: 83-110, 2002.

staticconstantCesium.CesiumMath.ONE_OVER_PI : Number

1/pi

staticconstantCesium.CesiumMath.ONE_OVER_TWO_PI : Number

1/2pi

staticconstantCesium.CesiumMath.PI : Number

pi

staticconstantCesium.CesiumMath.PI_OVER_FOUR : Number

pi/4

staticconstantCesium.CesiumMath.PI_OVER_SIX : Number

pi/6

staticconstantCesium.CesiumMath.PI_OVER_THREE : Number

pi/3

staticconstantCesium.CesiumMath.PI_OVER_TWO : Number

pi/2

staticconstantCesium.CesiumMath.RADIANS_PER_ARCSECOND : Number

The number of radians in an arc second.

Default Value: CesiumMath.RADIANS_PER_DEGREE / 3600.0

staticconstantCesium.CesiumMath.RADIANS_PER_DEGREE : Number

The number of radians in a degree.

Default Value: Math.PI / 180.0

staticconstantCesium.CesiumMath.SIXTY_FOUR_KILOBYTES : Number

64 * 1024

staticconstantCesium.CesiumMath.SOLAR_RADIUS : Number

Radius of the sun in meters: 6.955e8

staticconstantCesium.CesiumMath.THREE_PI_OVER_TWO : Number

3pi/2

staticconstantCesium.CesiumMath.TWO_PI : Number

2pi

Methods

staticCesium.CesiumMath.acosClamped(value) → Number

Computes Math.acos(value), but first clamps value to the range [-1.0, 1.0] so that the function will never return NaN.

Name	Type	Description
value	Number	The value for which to compute acos.

Returns:

The acos of the value if the value is in the range [-1.0, 1.0], or the acos of -1.0 or 1.0, whichever is closer, if the value is outside the range.

staticCesium.CesiumMath.asinClamped(value) → Number

Computes Math.asin(value), but first clamps value to the range [-1.0, 1.0] so that the function will never return NaN.

Name	Type	Description
value	Number	The value for which to compute asin.

Returns:

The asin of the value if the value is in the range [-1.0, 1.0], or the asin of -1.0 or 1.0, whichever is closer, if the value is outside the range.

staticCesium.CesiumMath.chordLength(angle, radius) → Number

Finds the chord length between two points given the circle's radius and the angle between the points.

Name	Type	Description
angle	Number	The angle between the two points.
radius	Number	The radius of the circle.

Returns:

The chord length.

staticCesium.CesiumMath.clamp(value, min, max) → Number

Constraint a value to lie between two values.

Name	Type	Description
value	Number	The value to constrain.
min	Number	The minimum value.
max	Number	The maximum value.

Returns:

The value clamped so that min <= value <= max.

staticCesium.CesiumMath.clampToLatitudeRange(angle) → Number

Convenience function that clamps a latitude value, in radians, to the range [-Math.PI/2, Math.PI/2). Useful for sanitizing data before use in objects requiring correct range.

Name	Type	Description
angle	Number	The latitude value, in radians, to clamp to the range [-Math.PI/2, Math.PI/2).

Returns:

The latitude value clamped to the range [-Math.PI/2, Math.PI/2).

Example:

// Clamp 108 degrees latitude to 90 degrees latitude
var latitude = Cesium.Math.clampToLatitudeRange(Cesium.Math.toRadians(108.0));

staticCesium.CesiumMath.convertLongitudeRange(angle) → Number

Converts a longitude value, in radians, to the range [-Math.PI, Math.PI).

Name	Type	Description
angle	Number	The longitude value, in radians, to convert to the range [-Math.PI, Math.PI).

Returns:

The equivalent longitude value in the range [-Math.PI, Math.PI).

Example:

// Convert 270 degrees to -90 degrees longitude
var longitude = Cesium.Math.convertLongitudeRange(Cesium.Math.toRadians(270.0));

staticCesium.CesiumMath.cosh(value) → Number

Returns the hyperbolic cosine of a number. The hyperbolic cosine of value is defined to be (e^x + e^-x)/2.0 where e is Euler's number, approximately 2.71828183.

Special cases:

• If the argument is NaN, then the result is NaN.
• If the argument is infinite, then the result is positive infinity.
• If the argument is zero, then the result is 1.0.

Name	Type	Description
value	Number	The number whose hyperbolic cosine is to be returned.

Returns:

The hyperbolic cosine of value.

staticCesium.CesiumMath.equalsEpsilon(left, right, relativeEpsilon, absoluteEpsilon) → Boolean

Determines if two values are equal using an absolute or relative tolerance test. This is useful to avoid problems due to roundoff error when comparing floating-point values directly. The values are first compared using an absolute tolerance test. If that fails, a relative tolerance test is performed. Use this test if you are unsure of the magnitudes of left and right.

Name	Type	Default	Description
left	Number		The first value to compare.
right	Number		The other value to compare.
relativeEpsilon	Number		The maximum inclusive delta between left and right for the relative tolerance test.
absoluteEpsilon	Number	relativeEpsilon	optional The maximum inclusive delta between left and right for the absolute tolerance test.

Returns:

true if the values are equal within the epsilon; otherwise, false.

Example:

var a = Cesium.Math.equalsEpsilon(0.0, 0.01, Cesium.Math.EPSILON2); // true
var b = Cesium.Math.equalsEpsilon(0.0, 0.1, Cesium.Math.EPSILON2);  // false
var c = Cesium.Math.equalsEpsilon(3699175.1634344, 3699175.2, Cesium.Math.EPSILON7); // true
var d = Cesium.Math.equalsEpsilon(3699175.1634344, 3699175.2, Cesium.Math.EPSILON9); // false

staticCesium.CesiumMath.factorial(n) → Number

Computes the factorial of the provided number.

Name	Type	Description
n	Number	The number whose factorial is to be computed.

Returns:

The factorial of the provided number or undefined if the number is less than 0.

Throws:

• DeveloperError : A number greater than or equal to 0 is required.

Example:

//Compute 7!, which is equal to 5040
var computedFactorial = Cesium.Math.factorial(7);

See:

• Factorial on Wikipedia

staticCesium.CesiumMath.fromSNorm(value, rangeMax) → Number

Converts a SNORM value in the range [0, rangeMax] to a scalar in the range [-1.0, 1.0].

Name	Type	Default	Description
value	Number		SNORM value in the range [0, 255]
rangeMax	Number	255	optional The maximum value in the SNORM range, 255 by default.

Returns:

Scalar in the range [-1.0, 1.0].

See:

• CesiumMath.toSNorm

staticCesium.CesiumMath.incrementWrap(n, maximumValue, minimumValue) → Number

Increments a number with a wrapping to a minimum value if the number exceeds the maximum value.

Name	Type	Default	Description
n	Number		optional The number to be incremented.
maximumValue	Number		optional The maximum incremented value before rolling over to the minimum value.
minimumValue	Number	0.0	optional The number reset to after the maximum value has been exceeded.

Returns:

The incremented number.

Throws:

• DeveloperError : Maximum value must be greater than minimum value.

Example:

var n = Cesium.Math.incrementWrap(5, 10, 0); // returns 6
var n = Cesium.Math.incrementWrap(10, 10, 0); // returns 0

staticCesium.CesiumMath.isPowerOfTwo(n) → Boolean

Determines if a positive integer is a power of two.

Name	Type	Description
n	Number	The positive integer to test.

Returns:

true if the number if a power of two; otherwise, false.

Throws:

• DeveloperError : A number greater than or equal to 0 is required.

Example:

var t = Cesium.Math.isPowerOfTwo(16); // true
var f = Cesium.Math.isPowerOfTwo(20); // false

staticCesium.CesiumMath.lerp(p, q, time) → Number

Computes the linear interpolation of two values.

Name	Type	Description
p	Number	The start value to interpolate.
q	Number	The end value to interpolate.
time	Number	The time of interpolation generally in the range [0.0, 1.0].

Returns:

The linearly interpolated value.

Example:

var n = Cesium.Math.lerp(0.0, 2.0, 0.5); // returns 1.0

staticCesium.CesiumMath.logBase(number, base) → Number

Finds the logarithm of a number to a base.

Name	Type	Description
number	Number	The number.
base	Number	The base.

Returns:

The result.

staticCesium.CesiumMath.mod(m, n) → Number

The modulo operation that also works for negative dividends.

Name	Type	Description
m	Number	The dividend.
n	Number	The divisor.

Returns:

The remainder.

staticCesium.CesiumMath.negativePiToPi(angle) → Number

Produces an angle in the range -Pi <= angle <= Pi which is equivalent to the provided angle.

Name	Type	Description
angle	Number	in radians

Returns:

The angle in the range [-CesiumMath.PI, CesiumMath.PI].

staticCesium.CesiumMath.nextPowerOfTwo(n) → Number

Computes the next power-of-two integer greater than or equal to the provided positive integer.

Name	Type	Description
n	Number	The positive integer to test.

Returns:

The next power-of-two integer.

Throws:

• DeveloperError : A number greater than or equal to 0 is required.

Example:

var n = Cesium.Math.nextPowerOfTwo(29); // 32
var m = Cesium.Math.nextPowerOfTwo(32); // 32

staticCesium.CesiumMath.nextRandomNumber() → Number

Generates a random floating point number in the range of [0.0, 1.0) using a Mersenne twister.

Returns:

A random number in the range of [0.0, 1.0).

See:

• CesiumMath.setRandomNumberSeed
• Mersenne twister on Wikipedia

staticCesium.CesiumMath.randomBetween(min, max) → Number

Generates a random number between two numbers.

Name	Type	Description
min	Number	The minimum value.
max	Number	The maximum value.

Returns:

A random number between the min and max.

staticCesium.CesiumMath.setRandomNumberSeed(seed)

Sets the seed used by the random number generator in CesiumMath#nextRandomNumber.

Name	Type	Description
seed	Number	An integer used as the seed.

staticCesium.CesiumMath.sign(value) → Number

Returns the sign of the value; 1 if the value is positive, -1 if the value is negative, or 0 if the value is 0.

Name	Type	Description
value	Number	The value to return the sign of.

Returns:

The sign of value.

staticCesium.CesiumMath.signNotZero(value) → Number

Returns 1.0 if the given value is positive or zero, and -1.0 if it is negative. This is similar to CesiumMath#sign except that returns 1.0 instead of 0.0 when the input value is 0.0.

Name	Type	Description
value	Number	The value to return the sign of.

Returns:

The sign of value.

staticCesium.CesiumMath.sinh(value) → Number

Returns the hyperbolic sine of a number. The hyperbolic sine of value is defined to be (e^x - e^-x)/2.0 where e is Euler's number, approximately 2.71828183.

Special cases:

• If the argument is NaN, then the result is NaN.
• If the argument is infinite, then the result is an infinity with the same sign as the argument.
• If the argument is zero, then the result is a zero with the same sign as the argument.

Name	Type	Description
value	Number	The number whose hyperbolic sine is to be returned.

Returns:

The hyperbolic sine of value.

staticCesium.CesiumMath.toDegrees(radians) → Number

Converts radians to degrees.

Name	Type	Description
radians	Number	The angle to convert in radians.

Returns:

The corresponding angle in degrees.

staticCesium.CesiumMath.toRadians(degrees) → Number

Converts degrees to radians.

Name	Type	Description
degrees	Number	The angle to convert in degrees.

Returns:

The corresponding angle in radians.

staticCesium.CesiumMath.toSNorm(value, rangeMax) → Number

Converts a scalar value in the range [-1.0, 1.0] to a SNORM in the range [0, rangeMax]

Name	Type	Default	Description
value	Number		The scalar value in the range [-1.0, 1.0]
rangeMax	Number	255	optional The maximum value in the mapped range, 255 by default.

Returns:

A SNORM value, where 0 maps to -1.0 and rangeMax maps to 1.0.

See:

• CesiumMath.fromSNorm

staticCesium.CesiumMath.zeroToTwoPi(angle) → Number

Produces an angle in the range 0 <= angle <= 2Pi which is equivalent to the provided angle.

Name	Type	Description
angle	Number	in radians

Returns:

The angle in the range [0, CesiumMath.TWO_PI].