Trigonometry

Overview

Trigonometric functions, angle conversions, angle wrapping, and angular interpolation. All angle parameters are in radians unless noted.

Why Use This?

Game and graphics code constantly works with angles for rotation, field of view, arc calculations, and smooth angular interpolation.

Functions

Basic Trig

Function	Description
`lm2_cos_f32(angle_rad)`	Cosine
`lm2_sin_f32(angle_rad)`	Sine
`lm2_tan_f32(angle_rad)`	Tangent
`lm2_acos_f32(value)`	Inverse cosine
`lm2_asin_f32(value)`	Inverse sine
`lm2_atan_f32(value)`	Inverse tangent
`lm2_atan2_f32(y, x)`	Two-argument inverse tangent

Conversions

Function	Description
`lm2_deg_to_rad_f32(degrees)`	Degrees to radians
`lm2_rad_to_deg_f32(radians)`	Radians to degrees

Angle Operations (Radians)

Function	Description
`lm2_wrap_rad_f32(angle)`	Wrap angle to [-PI, PI]
`lm2_shortest_rad_f32(from, to)`	Shortest angular distance in [-PI, PI]
`lm2_lerp_rad_f32(a, t, b)`	Interpolate angles using shortest path

Angle Operations (Degrees)

Function	Description
`lm2_wrap_deg_f32(angle)`	Wrap angle to [-180, 180]
`lm2_shortest_deg_f32(from, to)`	Shortest angular distance in [-180, 180]
`lm2_lerp_deg_f32(a, t, b)`	Interpolate angles using shortest path

All functions are available in _f64 and _f32 variants.

Constants

Constant	Value	Description
`LM2_PI_F32`	3.14159…	PI
`LM2_2PI_F32`	6.28318…	2 * PI
`LM2_HPI_F32`	1.57079…	PI / 2
`LM2_RAD_TO_DEG_F32`	57.2957…	Radians-to-degrees multiplier
`LM2_DEG_TO_RAD_F32`	0.01745…	Degrees-to-radians multiplier
`LM2_EULER_F32`	0.57721…	Euler-Mascheroni constant
`LM2_SQRT2_F32`	1.41421…	Square root of 2
`LM2_E_F32`	2.71828…	Euler’s number

All constants also available with _F64 suffix.

Example

float angle_deg = 270.0f;
float angle_rad = lm2_deg_to_rad_f32(angle_deg);
float wrapped = lm2_wrap_deg_f32(angle_deg); // -90

// Smoothly interpolate between two angles
float from = lm2_deg_to_rad_f32(350.0f);
float to   = lm2_deg_to_rad_f32(10.0f);
float mid  = lm2_lerp_rad_f32(from, 0.5f, to);  // goes through 0, not 180