DotVec3+Cross product

gglm/geometric.go

@@ -1,5 +1,35 @@
 package gglm
 
-func DotVec2(v1 *Vec2, v2 *Vec2) float32 {
+import "gonum.org/v1/gonum/blas/blas32"
+
+func DotVec2(v1, v2 *Vec2) float32 {
 	return v1.X()*v2.X() + v1.Y()*v2.Y()
 }
+
+func DotVec3(v1, v2 *Vec3) float32 {
+	return v1.X()*v2.X() + v1.Y()*v2.Y() + v1.Z()*v2.Z()
+}
+
+func Cross(v1, v2 *Vec3) *Vec3 {
+
+	// x = a[1]*b[2] - a[2]*b[1]
+	// y = a[2]*b[0] - a[0]*b[2]
+	// z = a[0]*b[1] - a[1]*b[0]
+
+	//Note: It's done this way to get inlining. Any small changes
+	//break inlining so check before any changes.
+	f := [3]float32{
+		v1.Arr[1]*v2.Arr[2] - v1.Arr[2]*v2.Arr[1],
+		v1.Arr[2]*v2.Arr[0] - v1.Arr[0]*v2.Arr[2],
+		v1.Arr[0]*v2.Arr[1] - v1.Arr[1]*v2.Arr[0],
+	}
+
+	return &Vec3{
+		Arr: f,
+		Vector: &blas32.Vector{
+			N:    3,
+			Inc:  1,
+			Data: f[:],
+		},
+	}
+}

main.go

@@ -23,12 +23,19 @@ func main() {
 		0, 0, 0, 0,
 	}
 	m2 := gglm.NewMat4(f)
-
-	println("m1:", m1.String())
-	println("m2:", m2.String())
-
 	m3 := gglm.AddMat4(m1, m2)
+
+	m2.Add(m3)
+
 	println("m1:", m1.String())
 	println("m2:", m2.String())
 	println("m3:", m3.String())
+
+	v1 := gglm.NewVec3([]float32{5, 4, 2})
+	v2 := gglm.NewVec3([]float32{32, 10, 9})
+	cp := gglm.Cross(v1, v2)
+	dp := gglm.DotVec3(v1, v2)
+	println(cp.String())
+	println(dp)
+
 }