REVIEWED: `Vector2Angle()`

examples/others/raymath_vector_angle.c

@@ -78,9 +78,7 @@ int main(void)
                 DrawLineEx(v0, v2, 2.0f, RED);
                 
                 float startangle = 90 - Vector2LineAngle(v0, v1)*RAD2DEG;
-                DrawCircleSector(v0, 40.0f, startangle, angle + startangle, 32, Fade(GREEN, 0.6f));
-                
-                //DrawCircleSector(v0, 40.0f, 90 - Vector2LineAngle(v0, v1)*RAD2DEG, angle, 32, Fade(GREEN, 0.6f));
+                DrawCircleSector(v0, 40.0f, startangle, startangle + angle - 360.0f*(angle > 180.0f), 32, Fade(GREEN, 0.6f));
             }
             else if (angleMode == 1)
             {

src/raymath.h

@@ -316,15 +316,9 @@ RMAPI float Vector2Angle(Vector2 v1, Vector2 v2)
 {
     float result = 0.0f;
     
-    float dot = v1.x*v2.x + v1.y*v2.y;              // Dot product
-    float dotClamp = (dot < -1.0f)? -1.0f : dot;    // Clamp
-    if (dotClamp > 1.0f) dotClamp = 1.0f;
-    result = acosf(dotClamp);
-
-    // Alternative implementation, more costly
-    //float v1Length = sqrtf((v1.x*v1.x) + (v1.y*v1.y));
-    //float v2Length = sqrtf((v2.x*v2.x) + (v2.y*v2.y));
-    //result = -acosf((v1.x*v2.x + v1.y*v2.y)/(v1Length*v2Length));
+    float dot = v1.x*v2.x + v1.y*v2.y;
+    float det = v1.x*v2.y - v1.y*v2.x;
+    result = -atan2f(det, dot);
     
     return result;
 }