Merge pull request #9 from joshlarsen/add-2d-cross-product

add 2D cross product
deeean · Dec 10, 2024 · d72c947 · d72c947
2 parents 44b5366 + 8ff5f3e
commit d72c947
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Showing 3 changed files with 16 additions and 1 deletion.
diff --git a/README.md b/README.md
@@ -77,6 +77,8 @@ func (v *Vector2) DivScalars(x float64, y float64) *Vector2
 
 func (v *Vector2) Distance(other *Vector2) float64
 
+func (v *Vector2) Cross(other *Vector2) float64
+
 func (v *Vector2) Dot(other *Vector2) float64
 
 func (v *Vector2) Lerp(other *Vector2, t float64) *Vector2

diff --git a/vector2/vector2.go b/vector2/vector2.go
@@ -102,6 +102,10 @@ func (v *Vector2) Distance(other *Vector2) float64 {
 	return math.Sqrt(dx*dx + dy*dy)
 }
 
+func (v *Vector2) Cross(other *Vector2) float64 {
+	return v.X*other.Y - v.Y*other.X
+}
+
 func (v *Vector2) Dot(other *Vector2) float64 {
 	return v.X*other.X + v.Y*other.Y
 }

diff --git a/vector2/vector2_test.go b/vector2/vector2_test.go
@@ -2,8 +2,9 @@ package vector2
 
 import (
 	"fmt"
-	"github.com/stretchr/testify/assert"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestNew(t *testing.T) {
@@ -139,6 +140,14 @@ func TestVector2_Distance(t *testing.T) {
 	assert.Equal(t, res, 3.1622776601683795)
 }
 
+func TestVector2_Cross(t *testing.T) {
+	a := New(1, 2)
+	b := New(4, 3)
+	res := a.Cross(b)
+
+	assert.Equal(t, res, -5.0)
+}
+
 func TestVector2_Dot(t *testing.T) {
 	a := New(1, 2)
 	b := New(4, 3)