implemented CVector2D::NormaliseSafe for SkidMarks

src/math/Vector2D.h

@@ -11,14 +11,16 @@ public:
 	float Magnitude(void) const { return Sqrt(x*x + y*y); }
 	float MagnitudeSqr(void) const { return x*x + y*y; }
 
-	void Normalise(void){
+	void Normalise(void);
+
+	void NormaliseSafe(void) {
 		float sq = MagnitudeSqr();
-		//if(sq > 0.0f){
+		if(sq > 0.0f){
 			float invsqrt = RecipSqrt(sq);
 			x *= invsqrt;
 			y *= invsqrt;
-		//}else
-		//	x = 1.0f;
+		}else
+			y = 1.0f;
 	}
 
 	const CVector2D &operator+=(CVector2D const &right) {

src/math/math.cpp

@@ -4,6 +4,19 @@
 
 // TODO: move more stuff into here
 
+void
+CVector2D::Normalise(void)
+{
+	float sq = MagnitudeSqr();
+	assert(sq != 0.0f);	// just be safe here
+	//if(sq > 0.0f){
+		float invsqrt = RecipSqrt(sq);
+		x *= invsqrt;
+		y *= invsqrt;
+	//}else
+	//	x = 1.0f;
+}
+
 void
 CMatrix::SetRotate(float xAngle, float yAngle, float zAngle)
 {

src/render/Skidmarks.cpp

@@ -214,7 +214,8 @@ CSkidmarks::RegisterOne(uintptr id, CVector pos, float fwdX, float fwdY, bool *i
 		aSkidmarks[i].m_pos[aSkidmarks[i].m_last] = pos;
 
 		CVector2D dist = aSkidmarks[i].m_pos[aSkidmarks[i].m_last] - aSkidmarks[i].m_pos[aSkidmarks[i].m_last-1];
-		dist.Normalise();
+		dist.NormaliseSafe();
+		fwd.NormaliseSafe();
 		CVector2D right(dist.y, -dist.x);
 		float turn = DotProduct2D(fwd, right);
 		turn = Abs(turn) + 1.0f;