fix #33 NaN prevention not working

Author: jakecoffman

collision.go

@@ -245,7 +245,7 @@ func (v0 MinkowskiPoint) ClosestPoints(v1 MinkowskiPoint) ClosestPoints {
 
 	// Vertex/vertex collisions need special treatment since the MSA won't be shared with an axis of the minkowski difference.
 	d2 := p.Length()
-	n2 := p.Mult(1 / (d2 + math.SmallestNonzeroFloat64))
+	n2 := p.Mult(1 / (d2 + 1e-15))
 
 	return ClosestPoints{pa, pb, n2, d2, id}
 }
@@ -325,8 +325,8 @@ func ContactPoints(e1, e2 Edge, points ClosestPoints, info *CollisionInfo) {
 	dE2B := e2.b.p.Cross(n)
 
 	// TODO + min isn't a complete fix
-	e1Denom := 1 / (dE1B - dE1A + math.SmallestNonzeroFloat64)
-	e2Denom := 1 / (dE2B - dE2A + math.SmallestNonzeroFloat64)
+	e1Denom := 1 / (dE1B - dE1A + 1e-15)
+	e2Denom := 1 / (dE2B - dE2A + 1e-15)
 
 	// Project the endpoints of the two edges onto the opposing edge, clamping them as necessary.
 	// Compare the projected points to the collision normal to see if the shapes overlap there.

vector.go

@@ -86,7 +86,7 @@ func (v Vector) Lerp(other Vector, t float64) Vector {
 }
 
 func (v Vector) Normalize() Vector {
-	return v.Mult(1.0 / (v.Length() + math.SmallestNonzeroFloat64))
+	return v.Mult(1.0 / (v.Length() + 1e-15))
 }
 
 func (v Vector) SLerp(other Vector, t float64) Vector {

vector_test.go

@@ -0,0 +1,13 @@
+package cp
+
+import (
+	"testing"
+)
+
+func TestVector_Normalize(t *testing.T) {
+	v := Vector{}
+	u := v.Normalize()
+	if u.X != 0.0 || u.Y != 0.0 {
+		t.Errorf("Expected zero vector, got %v", u)
+	}
+}