Align actor to sloped floor

[Cherno]

I have an idea in my head that involves using model actors for vehicles like tanks, and a 3d landscape with uneven ground, so lots of slopes.

Of course, the vehicles should align themselves to the floor, has anyone ever attempted something like this?

My idea would be to use A_SetPitch and A_SetRoll with an angle that is computed by using GetZAt at two points, one at the front and one at the back of the vehicle.

[RiboNucleic Asshat]

I believe Nashgore: Vengeance Edition contains code for aligning an actor to the slope of a plane. You can find the relevant code in NashGoreStatics.zc:

---

Code: Select all

	//===========================================================================
	//
	// AlignToPlane
	// Original code written by ZZYZX
	//
	//===========================================================================

	static void AlignToPlane(Actor self, double pitchAdjust = 0, bool ceiling = false)
	{
		if (!self) return;
		double ceilingAdjust = 0;
		Vector3 fnormal;
		if (!ceiling)
		{
			fnormal = self.CurSector.FloorPlane.Normal;
		}
		else
		{
			fnormal = self.CurSector.CeilingPlane.Normal;
			ceilingAdjust = 180.0;
		}
		Vector2 fnormalp1 = (fnormal.x != 0 || fnormal.y != 0) ? (fnormal.x, fnormal.y).Unit() : (0, 0);
		Vector2 fnormalp2 = ((fnormal.x, fnormal.y).Length(), fnormal.z);
		double dang = self.Angle;
		double fang = atan2(fnormalp1.y, fnormalp1.x);
		double fpitch = atan2(fnormalp2.x, fnormalp2.y);
		double ddiff1 = sin(fang - (dang - pitchAdjust));
		double ddiff2 = cos(fang - dang);
		self.Pitch = (fpitch * ddiff2 - pitchAdjust) + ceilingAdjust;
		self.Roll = -fpitch * ddiff1 + ceilingAdjust;
		self.Angle = dang + ceilingAdjust;
	}

You could study this and adapt it to your needs. Possibly ask ZZYZX about it too.

[Nash]

Do note that that is useless for vehicles because its sample point is the middle of the actor. For vehicles, you need at least 4 sample points (one at each wheel).

[Cherno]

Thanks for the tip. Now I have to figure out the math