本示例基于 Unity2018.4.11f1，示例下载在本篇博客结尾处。
一、创建游戏物体（示例中创建了 Unity 中五个基本物体）
二、创建脚本 CreateMouseRay - 将该脚本挂载到摄像机上（挂载到其他游戏物体上也可以，建议挂载到相机上）
三、创建Shader和材质球（如下图）
四、本实例涉及到的其他技术点：
- 基于鼠标位置，创建从相机指向鼠标的射线（Scene视图可见）
五、实现思路：
- 创建一个物体，该物体带有边缘效果的材质球，取消碰撞器，隐藏该物体
- 基于鼠标创建射线，得到射线检测到的物体
- 将射线检测到的物体的坐标、旋转、缩放，赋值给第 1 步创建的物体，并取消该物体的隐藏，更换材质球
- 检测到的物体不同（可以通过name判断）时，更新边缘效果物体的 Transform，返还刚刚被选中物体的材质球
- 射线检测不到物体时隐藏边缘效果物体，返还刚刚被选中物体的材质球
六、脚本 和 Shader
C#脚本 CreateMouseRay
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CreateMouseRay : MonoBehaviour
{
// 鼠标位置在世界坐标系中的 实例
private Transform mousePoint;
// 高亮物体
private Transform highLightObj;
// 物体本身的材质球
private Material oldMaterial;
// 当前射线检测到的物体
private GameObject nowObj;
void Start()
{
// 鼠标的屏幕坐标转成世界坐标的点
mousePoint = GameObject.CreatePrimitive(PrimitiveType.Sphere).GetComponent<Transform>();
Destroy(mousePoint.GetComponent<Collider>());
mousePoint.localScale = Vector3.one * 0.1f;
// 用于边缘效果展示的物体
highLightObj = GameObject.CreatePrimitive(PrimitiveType.Sphere).GetComponent<Transform>();
Destroy(highLightObj.GetComponent<Collider>());
highLightObj.GetComponent<MeshRenderer>().material = Resources.Load<Material>("MT_Silhouette");
highLightObj.gameObject.SetActive(false);
}
void Update()
{
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
RaycastHit raycastHit = new RaycastHit();
if (Physics.Raycast(ray, out raycastHit))
{
if (!nowObj || nowObj.name != raycastHit.transform.name)
{
if (nowObj)
{
// 换回原来的材质
nowObj.GetComponent<MeshRenderer>().material = oldMaterial;
}
// 射线当前检测到的物体
nowObj = raycastHit.transform.gameObject;
// 更换材质球
oldMaterial = raycastHit.transform.GetComponent<MeshRenderer>().material;
nowObj.GetComponent<MeshRenderer>().material = Resources.Load<Material>("MT_HighLinght");
// 显示选中效果
highLightObj.position = raycastHit.transform.position;
highLightObj.rotation = raycastHit.transform.rotation;
highLightObj.localScale = raycastHit.transform.localScale;
highLightObj.GetComponent<MeshFilter>().mesh = raycastHit.collider.GetComponent<MeshFilter>().mesh;
highLightObj.gameObject.SetActive(true);
}
}
else
{
if (highLightObj.gameObject.activeSelf)
{
// 隐藏选中效果
highLightObj.gameObject.SetActive(false);
// 换回原来的材质
nowObj.GetComponent<MeshRenderer>().material = oldMaterial;
// 置空射线检测到的物体
nowObj = null;
}
}
Debug.DrawRay(Camera.main.transform.position, GetMousePositionOnWorld() - Camera.main.transform.position, Color.red);
mousePoint.position = GetMousePositionOnWorld();
}
private Vector3 GetMousePositionOnWorld()
{
Vector3 mousePos = Input.mousePosition;
// Z 值不能为零，Z 值为零该方法返回值为相机的世界坐标
// 鼠标坐标值转换为世界坐标时，该方法返回值的 Z 值为：相机的 Z 值加上下面一行代码的赋值
// 例如：相机 Z 值为-10，经过下面一行代码赋值后，该方法返回值的 Z 值为 0
mousePos.z = 10;
return Camera.main.ScreenToWorldPoint(mousePos);
}
}
Shader
//======= Copyright (c) Valve Corporation, All rights reserved. ===============
//
// Purpose: Used to show the outline of the object
//
//=============================================================================
// UNITY_SHADER_NO_UPGRADE
Shader "Silhouette"
{
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
Properties
{
g_vOutlineColor( "Outline Color", Color ) = ( .5, .5, .5, 1 )
g_flOutlineWidth( "Outline width", Range ( .001, 0.03 ) ) = .005
g_flCornerAdjust( "Corner Adjustment", Range( 0, 2 ) ) = .5
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
CGINCLUDE
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
#pragma target 5.0
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
#include "UnityCG.cginc"
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
float4 g_vOutlineColor;
float g_flOutlineWidth;
float g_flCornerAdjust;
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
struct VS_INPUT
{
float4 vPositionOs : POSITION;
float3 vNormalOs : NORMAL;
};
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
struct PS_INPUT
{
float4 vPositionOs : TEXCOORD0;
float3 vNormalOs : TEXCOORD1;
float4 vPositionPs : SV_POSITION;
};
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
PS_INPUT MainVs( VS_INPUT i )
{
PS_INPUT o;
o.vPositionOs.xyzw = i.vPositionOs.xyzw;
o.vNormalOs.xyz = i.vNormalOs.xyz;
#if UNITY_VERSION >= 540
o.vPositionPs = UnityObjectToClipPos( i.vPositionOs.xyzw );
#else
o.vPositionPs = mul( UNITY_MATRIX_MVP, i.vPositionOs.xyzw );
#endif
return o;
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
PS_INPUT Extrude( PS_INPUT vertex )
{
PS_INPUT extruded = vertex;
// Offset along normal in projection space
float3 vNormalVs = mul( ( float3x3 )UNITY_MATRIX_IT_MV, vertex.vNormalOs.xyz );
float2 vOffsetPs = TransformViewToProjection( vNormalVs.xy );
vOffsetPs.xy = normalize( vOffsetPs.xy );
// Calculate position
#if UNITY_VERSION >= 540
extruded.vPositionPs = UnityObjectToClipPos( vertex.vPositionOs.xyzw );
#else
extruded.vPositionPs = mul( UNITY_MATRIX_MVP, vertex.vPositionOs.xyzw );
#endif
extruded.vPositionPs.xy += vOffsetPs.xy * extruded.vPositionPs.w * g_flOutlineWidth;
return extruded;
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
[maxvertexcount(18)]
void ExtrudeGs( triangle PS_INPUT inputTriangle[3], inout TriangleStream<PS_INPUT> outputStream )
{
float3 a = normalize(inputTriangle[0].vPositionOs.xyz - inputTriangle[1].vPositionOs.xyz);
float3 b = normalize(inputTriangle[1].vPositionOs.xyz - inputTriangle[2].vPositionOs.xyz);
float3 c = normalize(inputTriangle[2].vPositionOs.xyz - inputTriangle[0].vPositionOs.xyz);
inputTriangle[0].vNormalOs = inputTriangle[0].vNormalOs + normalize( a - c) * g_flCornerAdjust;
inputTriangle[1].vNormalOs = inputTriangle[1].vNormalOs + normalize(-a + b) * g_flCornerAdjust;
inputTriangle[2].vNormalOs = inputTriangle[2].vNormalOs + normalize(-b + c) * g_flCornerAdjust;
PS_INPUT extrudedTriangle0 = Extrude( inputTriangle[0] );
PS_INPUT extrudedTriangle1 = Extrude( inputTriangle[1] );
PS_INPUT extrudedTriangle2 = Extrude( inputTriangle[2] );
outputStream.Append( inputTriangle[0] );
outputStream.Append( extrudedTriangle0 );
outputStream.Append( inputTriangle[1] );
outputStream.Append( extrudedTriangle0 );
outputStream.Append( extrudedTriangle1 );
outputStream.Append( inputTriangle[1] );
outputStream.Append( inputTriangle[1] );
outputStream.Append( extrudedTriangle1 );
outputStream.Append( extrudedTriangle2 );
outputStream.Append( inputTriangle[1] );
outputStream.Append( extrudedTriangle2 );
outputStream.Append( inputTriangle[2] );
outputStream.Append( inputTriangle[2] );
outputStream.Append( extrudedTriangle2 );
outputStream.Append(inputTriangle[0]);
outputStream.Append( extrudedTriangle2 );
outputStream.Append( extrudedTriangle0 );
outputStream.Append( inputTriangle[0] );
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
fixed4 MainPs( PS_INPUT i ) : SV_Target
{
return g_vOutlineColor;
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
fixed4 NullPs( PS_INPUT i ) : SV_Target
{
return float4( 1.0, 0.0, 1.0, 1.0 );
}
ENDCG
SubShader
{
Tags { "RenderType"="Outline" "Queue" = "Geometry-1" }
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
// Render the object with stencil=1 to mask out the part that isn't the silhouette
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
Pass
{
Tags { "LightMode" = "Always" }
ColorMask 0
Cull Off
ZWrite Off
Stencil
{
Ref 1
Comp always
Pass replace
}
CGPROGRAM
#pragma vertex MainVs
#pragma fragment NullPs
ENDCG
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
// Render the outline by extruding along vertex normals and using the stencil mask previously rendered. Only render depth, so that the final pass executes
// once per fragment (otherwise alpha blending will look bad).
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
Pass
{
Tags { "LightMode" = "Always" }
Cull Off
ZWrite On
Stencil
{
Ref 1
Comp notequal
Pass keep
Fail keep
}
CGPROGRAM
#pragma vertex MainVs
#pragma geometry ExtrudeGs
#pragma fragment MainPs
ENDCG
}
}
}
点击下载示例文件，解压后为 unitypackage 文件 https://files.cnblogs.com/files/kao-la-bao-bei/Select.rar