Atan

Return the arc-tangent of the parameters

Declaration

float atan(float y, float x)  
vec2 atan(vec2 y, vec2 x)  
vec3 atan(vec3 y, vec3 x)  
vec4 atan(vec4 y, vec4 x)

float atan(float y_over_x)  
vec2 atan(vec2 y_over_x)  
vec3 atan(vec3 y_over_x)  
vec4 atan(vec4 y_over_x)

Parameters

y specify the numerator of the fraction whose arctangent to return.

x specify the denominator of the fraction whose arctangent to return.

y_over_x specify the fraction whose arctangent to return.

Description

atan() returns the angle whose trigonometric arctangent is y,x or y_over_x, depending on which overload is invoked. In the first overload, the signs of y and x are used to determine the quadrant that the angle lies in. The values returned by atan in this case are in the range -PI and PI. Results are undefined if x is zero.

For the second overload, atan() returns the angle whose tangent is y_over_x. Values returned in this case are in the range -PI to PI.

See Also

cos, acos, sin, asin, atan, Chapter 05: Shaping Functions, Chapter 06: Color