conv.go

package glm

import (
	"github.com/EngoEngine/math"
)

// CartesianToSpherical converts 3-dimensional cartesian coordinates (x,y,z) to
// spherical coordinates with radius r, inclination theta, and azimuth phi.
func CartesianToSpherical(coord Vec3) (r, theta, phi float32) {
	r = coord.Len()
	theta = math.Acos(coord[2] / r)
	phi = math.Atan2(coord[1], coord[0])
	return
}

// SphericalToCartesian converts spherical coordinates with radius r,
// inclination theta, and azimuth phi to cartesian coordinates (x,y,z).
func SphericalToCartesian(r, theta, phi float32) Vec3 {
	st, ct := math.Sincos(theta)
	sp, cp := math.Sincos(phi)

	return Vec3{r * st * cp, r * st * sp, r * ct}
}

// CartesianToCylindrical converts 3-dimensional cartesian coordinates (x,y,z)
// to cylindrical coordinates with radial distance r, azimuth phi, and height z.
func CartesianToCylindrical(coord Vec3) (rho, phi, z float32) {
	rho = math.Hypot(coord[0], coord[1])
	phi = math.Atan2(coord[1], coord[0])
	z = coord[2]
	return
}

// CylindricalToCartesian converts cylindrical coordinates with radial distance
// r, azimuth phi, and height z to cartesian coordinates (x,y,z).
func CylindricalToCartesian(rho, phi, z float32) Vec3 {
	s, c := math.Sincos(phi)

	return Vec3{rho * c, rho * s, z}
}

// SphericalToCylindrical converts spherical coordinates with radius r,
// inclination theta, and azimuth phi to cylindrical coordinates with radial
// distance r, azimuth phi, and height z.
func SphericalToCylindrical(r, theta, phi float32) (rho, phi2, z float32) {
	s, c := math.Sincos(theta)

	rho = r * s
	z = r * c
	phi2 = phi

	return
}

// CylindricalToSpherical converts cylindrical coordinates with radial distance
// r, azimuth phi, and height z to spherical coordinates with radius r,
// inclination theta, and azimuth phi.
func CylindricalToSpherical(rho, phi, z float32) (r, theta, phi2 float32) {
	r = math.Hypot(rho, z)
	phi2 = phi
	theta = math.Atan2(rho, z)
	return
}

// DegToRad converts degrees to radians
func DegToRad(angle float32) float32 {
	return angle * math.Pi / 180
}

// RadToDeg converts radians to degrees
func RadToDeg(angle float32) float32 {
	return angle * 180 / math.Pi
}