added ship control

Game.cpp

@@ -492,23 +492,11 @@ void Game::processTickCount() {
 
                 Environment::shipVelocity = velocity * delta / 100;
 
-                Vector3f direction = { diffx, 0, -diffy };
+                Vector3f dir = { -diffx, 0, diffy };
+                float angle = atan2(dir.v[0], -dir.v[2]); // [-pi, pi]
+                Vector4f quat = { 0, sin(angle * 0.5f), 0, cos(angle * 0.5f) };
+                rotateShipMat = QuatToMatrix(quat);
 
-                Vector3f origin = { 0,0, -1 };
-
-                float dir_module = sqrtf(diffx * diffx + diffy * diffy);
-
-                float scalar = direction.v[0] * origin.v[0] + direction.v[1] * origin.v[1]+ direction.v[2] * origin.v[2];
-
-                float angle = acos(scalar / dir_module);
-
-                Vector4f quat = {
-                    0,
-                    1 * sin(angle / 2),
-                    0,
-                    cos(angle / 2)
-
-                };
 
                 rotateShipMat = QuatToMatrix(quat);