initial commit

crates/comet_math/src/quaternion.rs

@@ -0,0 +1,60 @@
+use std::ops::Mul;
+
+use crate::vector::Vec3;
+
+/// Representation of a quaternion in scalar/vector form
+pub struct Quat {
+	pub s: f32,
+	pub v: Vec3,
+}
+
+impl Quat {
+	pub const fn zero() -> Self {
+		Self {
+			s: 0.0,
+			v: Vec3 {
+				x: 0.0,
+				y: 0.0,
+				z: 0.0,
+			},
+		}
+	}
+	pub const fn new(s: f32, v: Vec3) -> Self {
+		Self { s, v }
+	}
+
+	pub fn conjugate(&self) -> Self {
+		Self {
+			s: self.s,
+			v: self.v * (-1.0),
+		}
+	}
+
+	pub fn normalize(&self) -> Self {
+		let inverse_squareroot = 1.0/(self.s*self.s + self.v.x*self.v.x + self.v.y*self.v.y + self.v.z*self.v.z).sqrt();
+		Self::new(self.s*inverse_squareroot, self.v*inverse_squareroot)
+	}
+
+	pub fn into_vec(&self) -> Vec3 {
+		Vec3 {
+			x: self.v.x,
+			y: self.v.y,
+			z: self.v.z,
+		}
+	}
+}
+
+impl Mul<Quat> for Quat {
+	type Output = Quat;
+
+	fn mul(self, other: Quat) -> Quat {
+		Quat {
+			s: self.s*other.s - self.v.x*other.v.x - self.v.y*other.v.y - self.v.z*other.v.z,
+			v: Vec3 {
+				x: self.s*other.v.x + self.v.x*other.s + self.v.y*other.v.z - self.v.z*other.v.y,
+				y: self.s*other.v.y + self.v.y*other.s + self.v.z*other.v.x - self.v.x*other.v.z,
+				z: self.s*other.v.z + self.v.z*other.s + self.v.x*other.v.y - self.v.y*other.v.x,
+			}
+		}
+	}
+}