マウスでクリックした位置に三角形ポリゴンを作成するサンプル

ゲーム実行中にマウスでクリックした位置に三角形ポリゴンを動的に作成するサンプルコード。ここからもうちょっと進化させたものを作る予定ですけどこの状態のものも需要が有るかも？と思い公開しておきます。

プロジェクトファイルはこちらでダウンロード出来ます。

using UnityEngine;
using System.Collections;

public class ClickPointCreateTriangle : MonoBehaviour {
	
	public Material cubeMaterial;
	GameObject[] cubeList;
	int cubeIndex = 0;
	
	void CubePosReset() {
		Vector3 cubePos = new Vector3(0, 0, -100f);
		for (int i=0; i<cubeList.Length; i++) {
			cubeList[i].transform.position = cubePos;
		}
		cubeIndex = 0;
	}
	
	GameObject CreateCube (Vector3 pos) {
		GameObject cube = GameObject.CreatePrimitive(PrimitiveType.Cube);
		cube.renderer.material = cubeMaterial;
		cube.transform.position = pos;
		float s = 0.02f;
		cube.transform.localScale = new Vector3(s, s, s);
		return cube;
	}

	void CreateTriangle ()
	{
		string objectName = "Triangle";
		Mesh mesh = new Mesh ();
		
		Vector3[] vertices = new Vector3[3];
		for (int i=0; i<vertices.Length; i++) {
			vertices [i] = cubeList [i].transform.position;
		}
		mesh.vertices = vertices;
		
		int[] triangles = new int[3];
		Vector3 v1 = mesh.vertices [1] - mesh.vertices [0];
		Vector3 v2 = mesh.vertices [2] - mesh.vertices [1];
		Vector3 crossVec = Vector3.Cross (v1, v2);
		if (Vector3.Dot (Camera.mainCamera.transform.position, crossVec) > 0) {
			triangles [0] = 0;
			triangles [1] = 1;
			triangles [2] = 2;
		} else {
			triangles [0] = 0;
			triangles [1] = 2;
			triangles [2] = 1;
		}
		mesh.triangles = triangles;

		mesh.uv = new Vector2[]{
			new Vector2 (0.0f, 1.0f),
			new Vector2 (1.0f, 1.0f),
			new Vector2 (0.0f, 0.0f)
		};		

		mesh.RecalculateNormals ();	// 法線の再計算
		mesh.RecalculateBounds ();	// バウンディングボリュームの再計算
		mesh.Optimize ();
		
		GameObject newGameobject = new GameObject (objectName);
		
		MeshRenderer meshRenderer = newGameobject.AddComponent<MeshRenderer> ();
		meshRenderer.material = new Material (Shader.Find ("Diffuse"));
		
		
		MeshFilter meshFilter = newGameobject.AddComponent<MeshFilter> ();
		meshFilter.mesh = mesh;
	}

	void Start ()
	{
		cubeList = new GameObject[3];
		Vector3 cubePos = new Vector3 (0, 0, -100f);
		for (int i=0; i<cubeList.Length; i++) {
			cubeList [i] = CreateCube (cubePos);
		}
		CubePosReset ();
	}
	
	void Update ()
	{
		if (Input.GetMouseButtonUp (0)) {
			if (cubeIndex <= cubeList.Length - 1) {
				Vector3 mousePos = Input.mousePosition;
				mousePos.z = 1f;
				cubeList [cubeIndex++].transform.position = Camera.mainCamera.ScreenToWorldPoint (mousePos);
				if (cubeIndex == cubeList.Length) {
					CreateTriangle ();
					CubePosReset ();
				}
			}
		}
	}
}