unity 快速创建小地图

先写一个纹理遮罩shader

Shader "Unlit/TexMask"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_MaskTex("Mask Texture",2D) = "white"{}
}
SubShader
{
Tags {"Queue"="Transparent" "RenderType"="Transparent" }
LOD 100

Pass
{
Blend SrcAlpha OneMinusSrcAlpha
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog

#include "UnityCG.cginc"

struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};

struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
};

sampler2D _MainTex;
float4 _MainTex_ST;
sampler2D _MaskTex;

v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}

fixed4 frag (v2f i) : SV_Target
{
// sample the texture
fixed4 col = tex2D(_MainTex, i.uv)*tex2D(_MaskTex,i.uv);
// apply fog
UNITY_APPLY_FOG(i.fogCoord, col);
return col;
}
ENDCG
}
}
}

原理就是:初始图片*遮罩图片，需要隐藏的地方，遮罩图片的alpha值为0，需要显示的地方为白色,这里我设置的是一张圆形遮罩，后面就是一张圆形的小地图



2.写一个小地图脚本，用来显示小地图，原理就是在目标头上生成一个摄像机，让摄像机跟随目标，并将看到的俯视图转为小地图的纹理

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class MiniMap : MonoBehaviour {
public Transform target;
private Camera miniMapCamera;
private RenderTexture renderTex;
public Image miniMapTex;
// Use this for initialization
void Start () {
miniMapCamera = new GameObject("MiniMapCamera", typeof(Camera)).GetComponent<Camera>();
renderTex = new RenderTexture((int)miniMapCamera.pixelWidth, (int)miniMapCamera.pixelHeight, 1);
miniMapCamera.targetTexture = renderTex;
miniMapTex.material.SetTexture("_MainTex", renderTex);
}

// Update is called once per frame
void Update () {
miniMapCamera.transform.position = target.position + new Vector3(0, 30, 0);
miniMapCamera.transform.LookAt(target.position);

}
}

3.显示小地图



4.这里功能都写得特别简单粗糙，适当在上面添加一些功能和美术，应该还是蛮好看的