ProceduralGrid.cs

using UnityEngine;
using System.Collections;

[RequireComponent (typeof(MeshFilter), typeof(MeshRenderer))]
public class ProceduralGrid : MonoBehaviour {

	Mesh mesh;
	Vector3[] vertices;
	int[] triangles;

	//grid settings
	public float cellSize = 1;
	public Vector3 gridOffset;
	public int gridSize;

	// Use this for initialization
	void Awake () {
		mesh = GetComponent<MeshFilter> ().mesh;
	}
	
	void Start() {
		MakeContiguousProceduralGrid ();
		UpdateMesh ();
	}

	void MakeDiscreteProceduralGrid(){
		//set array sizes
		vertices = new Vector3[gridSize * gridSize * 4];
		triangles = new int[gridSize * gridSize * 6];

		//set tracker integers
		int v = 0;
		int t = 0;

		//set vertex offset
		float vertexOffset = cellSize * 0.5f;

		for (int x = 0; x < gridSize; x++) {
			for (int y = 0; y < gridSize; y++) {
				Vector3 cellOffset = new Vector3(x * cellSize, 0, y * cellSize);
				
				//populate the vertices and triangles arrays
				vertices [v] = new Vector3 (-vertexOffset, x+y, -vertexOffset) + cellOffset + gridOffset;
				vertices [v+1] = new Vector3 (-vertexOffset, x+y,  vertexOffset) + cellOffset + gridOffset;
				vertices [v+2] = new Vector3 ( vertexOffset, x+y, -vertexOffset) + cellOffset + gridOffset;
				vertices [v+3] = new Vector3 ( vertexOffset, x+y,  vertexOffset) + cellOffset + gridOffset;

				triangles [t] = v;
				triangles [t+1] = triangles [t+4] = v+1;
				triangles [t+2] = triangles [t+3] = v+2;
				triangles [t+5] = v+3;

				v += 4;
				t += 6;
			}
		}
	}

	void MakeContiguousProceduralGrid(){
		//set array sizes
		vertices = new Vector3[(gridSize + 1) * (gridSize + 1)];
		triangles = new int[gridSize * gridSize * 6];

		//set tracker integers
		int v = 0;
		int t = 0;

		//set vertex offset
		float vertexOffset = cellSize * 0.5f;

		//create vertex grid
		for (int x = 0; x <= gridSize; x++) {
			for (int y = 0; y <= gridSize; y++) {
				vertices [v] = new Vector3 ((x * cellSize) - vertexOffset, (x + y) * 0.2f, (y * cellSize) - vertexOffset);
				v++;
			}
		}

		//reset vertex tracker
		v = 0;

		//setting each cell's triangles
		for (int x = 0; x < gridSize; x++) {
			for (int y = 0; y < gridSize; y++) {
				triangles [t] = v;
				triangles [t+1] = triangles [t+4] = v+1;
				triangles [t+2] = triangles [t+3] = v + (gridSize +1);
				triangles [t+5] = v + (gridSize + 1) + 1;
				v++;
				t += 6;
			}
			v++;
		}
	}

	void UpdateMesh(){
		mesh.Clear ();

		mesh.vertices = vertices;
		mesh.triangles = triangles;
		mesh.RecalculateNormals ();
	}
}