Fix PutShipOnRoute function (#5250)

Gliese852 · web-flow · commit c8f6b39e02f4 · 2021-10-04T18:44:17.000-04:00
* Fix PutShipOnRoute function

After placing the ship on the route, the possibility of a collision is
checked.  In case of a possible collision, its position is changed to
avoid this. It turns out that this calculation worked incorrectly,
because the FromVectors function creates a matrix using vectors as
columns, and in the further calculation it is assumed that vectors are
rows.

Also removed unnecessary Frame object retrieval by FrameId

The choice of trajectory correction method depends only on whether we
can calculate the tangent to the sphere of the effective radius of the
obstructor from the target. We cannot do this if the target is within
this sphere. All other conditions are unnecessary.
diff --git a/src/lua/LuaSpace.cpp b/src/lua/LuaSpace.cpp
@@ -253,43 +253,41 @@ static int l_space_put_ship_on_route(lua_State *l)
 	ship->SetFuel((0.001 * pp.getMass() - ss.static_mass) / st->fuelTankMass);
 
 	ship->UpdateFrame();
-	Frame *shipFrame = Frame::GetFrame(ship->GetFrame());
-	Frame *targFrame = Frame::GetFrame(targetbody->GetFrame());
-
 	// check for collision at spawn position
 	const vector3d shippos = ship->GetPosition();
 	const vector3d targpos = targetbody->GetPositionRelTo(ship->GetFrame());
 	const vector3d relpos = targpos - shippos;
 	const vector3d reldir = relpos.NormalizedSafe();
 	const double targdist = relpos.Length();
-	Body *body = shipFrame->GetBody();
+	Body *body = Frame::GetFrame(ship->GetFrame())->GetBody();
 	const double erad = MaxEffectRad(body, ship->GetPropulsion());
 	const int coll = CheckCollision(ship, reldir, targdist, targpos, 0, erad);
 	if (coll) {
 		// need to correct positon, to avoid collision
-		if (Frame::GetFrame(shipFrame->GetNonRotFrame()) != Frame::GetFrame(targFrame->GetNonRotFrame()) && targpos.Length() > erad) {
-			// the ship is not in the target's frame or target is above the effective radius of obstructor - rotate the ship's position
+		if (targpos.Length() > erad) {
+			// target is above the effective radius of obstructor - rotate the ship's position
 			// around the target position, so that the obstructor's "effective radius" does not cross the path
 			// direction obstructor -> target
 			const vector3d z = targpos.Normalized();
 			// the axis around which the position of the ship will rotate
 			const vector3d y = z.Cross(shippos).NormalizedSafe();
 			// just the third axis of this basis
 			const vector3d x = y.Cross(z);
+
 			// this is the basis in which the position of the ship will rotate
-			const matrix3x3d corrCS = matrix3x3d::FromVectors(x, y, z);
+			const matrix3x3d corrCS = matrix3x3d::FromVectors(x, y, z).Transpose();
 			const double len = targpos.Length();
 			// two possible positions of the ship, when flying around the obstructor to the right or left
 			// rotate (in the given basis) the direction from the target to the obstructor, so that it passes tangentially to the obstructor
 			const vector3d safe1 = corrCS.Transpose() * (matrix3x3d::RotateY(+asin(erad / len)) * corrCS * -targpos).Normalized() * targdist;
 			const vector3d safe2 = corrCS.Transpose() * (matrix3x3d::RotateY(-asin(erad / len)) * corrCS * -targpos).Normalized() * targdist;
-			// choose the one that is closer to the current position oh the ship
+			// choose the one that is closer to the current position of the ship
 			if ((safe1 + relpos).Length() < (safe2 + relpos).Length())
 				ship->SetPosition(safe1 + targpos);
 			else
 				ship->SetPosition(safe2 + targpos);
 		} else {
-			// we are in target's frame, and target below the effective radius of planet. Position the ship direct above the target
+			// target below the effective radius of obstructor. Position the ship direct above the target
 			ship->SetPosition(targpos + targpos.Normalized() * targdist);
 		}
 		// update velocity direction
