Fix vector2angle (#2832)

* Fix vector2angle

* Fix ;

* use acosf

* need a break

* add comments

src/raymath.h

@@ -307,9 +307,15 @@ RMAPI float Vector2DistanceSqr(Vector2 v1, Vector2 v2)
 }
 
 // Calculate angle from two vectors
+// Parameters need to be normalized
 RMAPI float Vector2Angle(Vector2 v1, Vector2 v2)
 {
-    float result = -acos(v1.x*v2.x + v1.y*v2.y);
+    float dotProduct = v1.x*v2.x + v1.y*v2.y; // Dot product
+
+    float t = dotProduct < -1 ? -1 : dotProduct; // Clamp
+    if (t > 1) t = 1;
+
+    float result = acosf(t);
 
     return result;
 }