XMVectorATan2

Computes the arctangent of Y/X.

Syntax

XMVECTOR XMVectorATan2(
         XMVECTOR Y,
         XMVECTOR X
)

Parameters

Y
Type: XMVECTOR

First vector.

X
Type: XMVECTOR

Second vector.

Return value

Type: XMVECTOR

Returns a vector. Each component is the arctangent of the corresponding Y component divided by the corresponding X component. Each component is in the range (-PI/2, PI/2).

XMVectorATan2 returns the following values for the specified special input values.

Input Value	Return Value
Y == 0 and X < 0	Pi with the same sign as Y
Y == 0 and X > 0	0 with the same sign as Y
Y != 0 and X == 0	Pi / 2 with the same sign as Y
X == -Infinity and Y is finite	Pi with the same sign as Y
X == +Infinity and Y is finite	0 with the same sign as Y
Y == Infinity and X is finite	Pi / 2 with the same sign as Y
Y == Infinity and X == -Infinity	3Pi / 4 with the same sign as Y
Y == Infinity and X == +Infinity	Pi / 4 with the same sign as Y

Remarks

This function uses a 17-degree minimax approximation.

Requirements

Header: Declared in directxmath.h.