Add `angle_between` and `matrix2_rotate`

core/math/linalg/general.odin

@@ -267,6 +267,31 @@ to_ptr :: proc{vector_to_ptr, matrix_to_ptr}
 
 
 
+vector_angle_between :: proc "contextless" (a, b: $V/[$N]$E) -> E {
+	a0 := normalize0(a)
+	b0 := normalize0(b)
+	return math.acos(dot(a0, b0))
+}
+quaternion64_angle_between :: proc "contextless" (a, b: $Q/quaternion64) -> f16 {
+	c := normalize0(conj(a) * b)
+	return math.acos(c.w)
+}
+quaternion128_angle_between :: proc "contextless" (a, b: $Q/quaternion128) -> f32 {
+	c := normalize0(conj(a) * b)
+	return math.acos(c.w)
+}
+quaternion256_angle_between :: proc "contextless" (a, b: $Q/quaternion256) -> f64 {
+	c := normalize0(conj(a) * b)
+	return math.acos(c.w)
+}
+angle_between :: proc{
+	vector_angle_between,
+	quaternion64_angle_between,
+	quaternion128_angle_between,
+	quaternion256_angle_between,
+}
+
+
 
 // Splines
 

core/math/linalg/specific.odin

@@ -1270,6 +1270,43 @@ matrix2_adjoint :: proc{
 }
 
 
+@(require_results)
+matrix2_rotate_f16 :: proc "contextless" (angle_radians: f16) -> Matrix2f16 {
+	c := math.cos(angle_radians)
+	s := math.sin(angle_radians)
+
+	return Matrix2f16{
+		c, -s,
+		s,  c,
+	}
+}
+@(require_results)
+matrix2_rotate_f32 :: proc "contextless" (angle_radians: f32) -> Matrix2f32 {
+	c := math.cos(angle_radians)
+	s := math.sin(angle_radians)
+
+	return Matrix2f32{
+		c, -s,
+		s,  c,
+	}
+}
+@(require_results)
+matrix2_rotate_f64 :: proc "contextless" (angle_radians: f64) -> Matrix2f64 {
+	c := math.cos(angle_radians)
+	s := math.sin(angle_radians)
+
+	return Matrix2f64{
+		c, -s,
+		s,  c,
+	}
+}
+matrix2_rotate :: proc{
+	matrix2_rotate_f16,
+	matrix2_rotate_f32,
+	matrix2_rotate_f64,
+}
+
+
 @(require_results)
 matrix3_from_quaternion_f16 :: proc "contextless" (q: Quaternionf16) -> (m: Matrix3f16) {
 	qxx := q.x * q.x