math.vec: add tests for vec2,3,4 perpendicular (#25840)

Author: Linklancien

vlib/math/vec/vec2.v

@@ -258,7 +258,7 @@ pub fn (v Vec2[T]) perp_ccw() Vec2[T] {
 	return Vec2[T]{-v.y, v.x}
 }
 
-// perpendicular returns the `u` projected perpendicular vector to this vector.
+// perpendicular returns the `v` projected perpendicular vector to the 'u' vector.
 pub fn (v Vec2[T]) perpendicular(u Vec2[T]) Vec2[T] {
 	return v - v.project(u)
 }

vlib/math/vec/vec2_test.v

@@ -299,3 +299,24 @@ fn test_vec2_project_negative_components() {
 	assert tolerance(proj.x, 4.68, vec.vec_epsilon)
 	assert tolerance(proj.y, -6.24, vec.vec_epsilon)
 }
+
+// Test for perpendicularity
+// 'u' and 'v' are already perpendicular so it must return v
+fn test_vec2_perpendicularity_angle() {
+	u := vec.vec2(1.0, 0.0)
+	v := vec.vec2(0.0, 3.0)
+
+	per := v.perpendicular(u)
+	assert tolerance(per.x, v.x, vec.vec_epsilon)
+	assert tolerance(per.y, v.y, vec.vec_epsilon)
+}
+
+// 'u' and 'v' are collinear so it must return the null vector
+fn test_vec2_collinear() {
+	u := vec.vec2(1.0, 0.0)
+	v := vec.vec2(3.0, 0.0)
+
+	per := v.perpendicular(u)
+	assert tolerance(per.x, 0.0, vec.vec_epsilon)
+	assert tolerance(per.y, 0.0, vec.vec_epsilon)
+}

vlib/math/vec/vec3.v

@@ -253,7 +253,7 @@ pub fn (v Vec3[T]) unit() Vec3[T] {
 	return Vec3[T]{v.x * invm, v.y * invm, v.z * invm}
 }
 
-// perpendicular returns the `u` projected perpendicular vector to this vector.
+// perpendicular returns the `v` projected perpendicular vector to the 'u' vector.
 @[inline]
 pub fn (v Vec3[T]) perpendicular(u Vec3[T]) Vec3[T] {
 	return v - v.project(u)

vlib/math/vec/vec3_test.v

@@ -1,4 +1,4 @@
-import math { veryclose }
+import math { tolerance, veryclose }
 import math.vec
 
 fn test_vec3_int() {
@@ -131,3 +131,26 @@ fn test_vec3_project_onto_angle() {
 	assert veryclose(proj.y, 0.0)
 	assert veryclose(proj.z, 0.0)
 }
+
+// Test for perpendicularity
+// 'u' and 'v' are already perpendicular so it must return v
+fn test_vec3_perpendicularity_angle() {
+	u := vec.vec3(1.0, 0.0, 0.0)
+	v := vec.vec3(0.0, 3.0, 2.0)
+
+	per := v.perpendicular(u)
+	assert tolerance(per.x, v.x, vec.vec_epsilon)
+	assert tolerance(per.y, v.y, vec.vec_epsilon)
+	assert tolerance(per.z, v.z, vec.vec_epsilon)
+}
+
+// 'u' and 'v' are collinear so the result must be the null vector
+fn test_vec3_collinear() {
+	u := vec.vec3(1.0, 0.0, 0.0)
+	v := vec.vec3(3.0, 0.0, 0.0)
+
+	per := v.perpendicular(u)
+	assert tolerance(per.x, 0.0, vec.vec_epsilon)
+	assert tolerance(per.y, 0.0, vec.vec_epsilon)
+	assert tolerance(per.z, 0.0, vec.vec_epsilon)
+}

vlib/math/vec/vec4.v

@@ -270,7 +270,7 @@ pub fn (v Vec4[T]) unit() Vec4[T] {
 	}
 }
 
-// perpendicular returns the `u` projected perpendicular vector to this vector.
+// perpendicular returns the `v` projected perpendicular vector to the 'u' vector.
 pub fn (v Vec4[T]) perpendicular(u Vec4[T]) Vec4[T] {
 	return v - v.project(u)
 }

vlib/math/vec/vec4_test.v

@@ -1,3 +1,4 @@
+import math { tolerance }
 import math.vec
 
 fn test_vec4_int() {
@@ -123,3 +124,28 @@ fn test_vec4_project_onto_zero() {
 	assert proj.z == 0.0
 	assert proj.w == 0.0
 }
+
+// Test for perpendicularity
+// 'u' and 'v' are already perpendicular so it must return v
+fn test_vec4_perpendicularity_angle() {
+	u := vec.vec4(1.0, 0.0, 0.0, 0.0)
+	v := vec.vec4(0.0, 3.0, 2.0, 0.0)
+
+	per := v.perpendicular(u)
+	assert tolerance(per.x, v.x, vec.vec_epsilon)
+	assert tolerance(per.y, v.y, vec.vec_epsilon)
+	assert tolerance(per.z, v.z, vec.vec_epsilon)
+	assert tolerance(per.w, v.w, vec.vec_epsilon)
+}
+
+// 'u' and 'v' are collinear so it must return the null vector
+fn test_vec4_collinear() {
+	u := vec.vec4(1.0, 0.0, 0.0, 0.0)
+	v := vec.vec4(3.0, 0.0, 0.0, 0.0)
+
+	per := v.perpendicular(u)
+	assert tolerance(per.x, 0.0, vec.vec_epsilon)
+	assert tolerance(per.y, 0.0, vec.vec_epsilon)
+	assert tolerance(per.z, 0.0, vec.vec_epsilon)
+	assert tolerance(per.w, 0.0, vec.vec_epsilon)
+}