Draw grid on the terrain in Unity
Jan 23, 2015
Drawing grid on the terrain is used in lot of game genres – RTS, Simulation, Tower defense, etc. It can be done very easily in Unity.
Here is some very simple extensible solution with following features:
Respect terrain height Option to have different texture in different parts (eg. to distinguish free and taken cells) Configurable (you can resize grid in editor or real-time and set cell size)
在許多游戲類型的RTS、仿真、塔防御等游戲中都使用了繪圖網格，可以很容易地在Unity中完成。
下面是一些非常簡單的可擴展的解決方案，具有以下特性:
根據地形高度選項在不同的部分有不同的紋理 (例如. 區分free 和 taken cells)可配置 (可在編輯器或 real-time 中調整網格大小並設置單元格尺寸)
代碼:
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class TerrainGrid : MonoBehaviour {
public float cellSize = 1;
public int gridWidth = 10;
public int gridHeight = 10;
public float yOffset = 0.5f;
public Material cellMaterialValid;
public Material cellMaterialInvalid;
private GameObject[] _cells;
private float[] _heights;
void Start() {
_cells = new GameObject[gridHeight * gridWidth];
_heights = new float[(gridHeight + 1) * (gridWidth + 1)];
for (int z = 0; z < gridHeight; z++) {
for (int x = 0; x < gridWidth; x++) {
_cells[z * gridWidth + x] = CreateChild();
}
}
}
void Update () {
UpdateSize();
UpdatePosition();
UpdateHeights();
UpdateCells();
}
GameObject CreateChild() {
GameObject go = new GameObject();
go.name = "Grid Cell";
go.transform.parent = transform;
go.transform.localPosition = Vector3.zero;
go.AddComponent<MeshRenderer>();
go.AddComponent<MeshFilter>().mesh = CreateMesh();
return go;
}
void UpdateSize() {
int newSize = gridHeight * gridWidth;
int oldSize = _cells.Length;
if (newSize == oldSize)
return;
GameObject[] oldCells = _cells;
_cells = new GameObject[newSize];
if (newSize < oldSize) {
for (int i = 0; i < newSize; i++) {
_cells[i] = oldCells[i];
}
for (int i = newSize; i < oldSize; i++) {
Destroy(oldCells[i]);
}
}
else if (newSize > oldSize) {
for (int i = 0; i < oldSize; i++) {
_cells[i] = oldCells[i];
}
for (int i = oldSize; i < newSize; i++) {
_cells[i] = CreateChild();
}
}
_heights = new float[(gridHeight + 1) * (gridWidth + 1)];
}
void UpdatePosition() {
RaycastHit hitInfo;
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
Physics.Raycast(ray, out hitInfo, Mathf.Infinity, LayerMask.GetMask("Terrain"));
Vector3 position = hitInfo.point;
position.x -= hitInfo.point.x % cellSize + gridWidth * cellSize / 2;
position.z -= hitInfo.point.z % cellSize + gridHeight * cellSize / 2;
position.y = 0;
transform.position = position;
}
void UpdateHeights() {
RaycastHit hitInfo;
Vector3 origin;
for (int z = 0; z < gridHeight + 1; z++) {
for (int x = 0; x < gridWidth + 1; x++) {
origin = new Vector3(x * cellSize, 200, z * cellSize);
Physics.Raycast(transform.TransformPoint(origin), Vector3.down, out hitInfo, Mathf.Infinity, LayerMask.GetMask("Terrain"));
_heights[z * (gridWidth + 1) + x] = hitInfo.point.y;
}
}
}
void UpdateCells() {
for (int z = 0; z < gridHeight; z++) {
for (int x = 0; x < gridWidth; x++) {
GameObject cell = _cells[z * gridWidth + x];
MeshRenderer meshRenderer = cell.GetComponent<MeshRenderer>();
MeshFilter meshFilter = cell.GetComponent<MeshFilter>();
meshRenderer.material = IsCellValid(x, z) ? cellMaterialValid : cellMaterialInvalid;
UpdateMesh(meshFilter.mesh, x, z);
}
}
}
bool IsCellValid(int x, int z) {
RaycastHit hitInfo;
Vector3 origin = new Vector3(x * cellSize + cellSize/2, 200, z * cellSize + cellSize/2);
Physics.Raycast(transform.TransformPoint(origin), Vector3.down, out hitInfo, Mathf.Infinity, LayerMask.GetMask("Buildings"));
return hitInfo.collider == null;
}
Mesh CreateMesh() {
Mesh mesh = new Mesh();
mesh.name = "Grid Cell";
mesh.vertices = new Vector3[] { Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero };
mesh.triangles = new int[] { 0, 1, 2, 2, 1, 3 };
mesh.normals = new Vector3[] { Vector3.up, Vector3.up, Vector3.up, Vector3.up };
mesh.uv = new Vector2[] { new Vector2(1, 1), new Vector2(1, 0), new Vector2(0, 1), new Vector2(0, 0) };
return mesh;
}
void UpdateMesh(Mesh mesh, int x, int z) {
mesh.vertices = new Vector3[] {
MeshVertex(x, z),
MeshVertex(x, z + 1),
MeshVertex(x + 1, z),
MeshVertex(x + 1, z + 1),
};
}
Vector3 MeshVertex(int x, int z) {
return new Vector3(x * cellSize, _heights[z * (gridWidth + 1) + x] + yOffset, z * cellSize);
}
}
Because we want to have different kind of cells we have two options – one is using separate game object for every cell and second option is using one game object containing mesh with lot of submeshes. I chose first option because of simplicity and flexibility.
因為我們想要有不同種類的格子, 我們有兩個選擇-一個是為每個格子使用單獨的游戲對象和第二個選項是使用一個包涵網格的游戲對象, 其中含有大量的網格集合。我選擇的第一個選項, 因為簡單和靈活性。
For every cell we create corresponding mesh. In example above you can see that it's very simple square mesh from just 2 triangles (line 131). Y coordinate of each square's vertex is calculated by doing raycast on the terrain (precalculated for every cell in UpdateHeights method every frame) and adding yOffset value. For better result you can experiment with square mesh with much more triangles (eg. 24).
對於每個單元格, 我們創建相應的網格。在上面的例子中, 你可以看到, 它是非常簡單的正方形網格從2個三角形 (131 行)。每個正方形頂點的 Y 坐標是通過在地形上進行 raycast (每幀調用UpdateHeights 對於每個單元格) 和增加 yOffset 值來計算的。為更好的結果, 你可以試驗的正方形網格更多的三角形 (例如 24)。
To every mesh of the cell we assign material based on IsCellValid method which is doing raycast through the center of the cell and checking "Buildings" layer for some colliders, if there is any the cellMaterialInvalid is used (red in screenshot), otherwise cellMaterialValid is used (green).
對單元格的每個網格我們分配材料基於 IsCellValid 方法,這個方法是通過方格中心並且檢查 "Buildings" 層數,做 raycast 為有些碰撞, 如果有任何 cellMaterialInvalid 使用 (截圖的中紅色), 否則cellMaterialValid 使用 (綠色)。
Number of cells are managed in UpdateSize method which is checking for size changes and doing corresponding action – adding new or deleting cells.
In method UpdatePosition the grid is moved so it's center is always under mouse cursor.
This is just an example and for real use you will probably have to modify position and resizing behaviour.
單元格的數量在 UpdateSize 方法中進行管理, 它正在檢查大小更改並執行相應操作–添加新或刪除單元格。
在方法 UpdatePosition 中, 網格被移動, 因此它的中心總是在鼠標光標下面。
這只是一個例子, 對於實際使用, 您可能需要修改位置和調整行為。
原文地址 <http://rene.klacan.sk/unity3d/games/2015/01/23/draw-grid-on-the-terrain-in-unity/>