What is the best way to navigate through a grid based level using Raycasting ?

Questions & Answers
1

I have a level with tiles of 1 unit each. How do I make sure that the player(lavender) never goes into the walls and always stays in the middle of the walkable area(steel blue) ?
I have tried to put nodes(red) which, if hit by a raycast ray will allow the turn to happen, but this method fails when the player is at a high speed.

Check the level image here:

32248-tt.png
32248-tt.png791×604 19.1 KB

Check my code here:

	RaycastHit hit;
	Ray wRay;
	Ray aRay;
	Ray sRay;
	Ray dRay;

void Update () {
transform.position += transform.forward * speed * Time.deltaTime;

if (Input.GetKey (KeyCode.W)) {
			wRay.origin = transform.position;
			wRay.direction = Vector3.left;
			if (Physics.Raycast(wRay, out hit, 2f) && hit.transform.tag == "turnallowed")
			{
					gameObject.transform.rotation = Quaternion.Euler(0,270,0);
			}
			Debug.DrawRay(transform.position, Vector3.left, Color.red);
		}


		if (Input.GetKey (KeyCode.A)) {
			aRay.origin = transform.position;
			aRay.direction = Vector3.back;
			if (Physics.Raycast(aRay, out hit, 2f) && hit.transform.tag == "turnallowed")
			{
				gameObject.transform.rotation = Quaternion.Euler(0,180,0);
			}
			Debug.DrawRay(transform.position, Vector3.back, Color.blue);
		}


		if (Input.GetKey (KeyCode.S)) {
			sRay.origin = transform.position;
			sRay.direction = Vector3.right;
			if (Physics.Raycast(sRay, out hit, 2f) && hit.transform.tag == "turnallowed")
			{
				gameObject.transform.rotation = Quaternion.Euler(0,90,0);
			}
			Debug.DrawRay(transform.position, Vector3.right, Color.white);
		}

		if (Input.GetKey (KeyCode.D)) {
			dRay.origin = transform.position;
			dRay.direction = Vector3.forward;
			if (Physics.Raycast(aRay, out hit, 2f) && hit.transform.tag == "turnallowed")
			{
				gameObject.transform.rotation = Quaternion.Euler(0,0,0);
			}
			Debug.DrawRay(transform.position, Vector3.forward, Color.green);
		}

}
3

The best way IMHO would be to keep an occupied flag in the grid itself…

class Cell {
  public bool occupied;
}

class Grid {
  public Cell[,] cells = new Cell[10,10];
}

class Move {
  void Update() {
    if (Input.GetKeyDown(Keycode.W)) { //move left
      if (Grid.cells[currentX +1, currentY].occupied)
        //false move
    } //etc...
  }
}

This is a very short example, but i think you get the idea

2

Why are you having a grid based level when you are accelerating?

Why not just have the raycasts look for walls and if there is a wall you cant use that button to move the way the raycast is raying?