[游戏开发]Unity如何体面的做3D物体描边轮廓

C#

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering;

public class Outline : PostEffectsBase
{
    public bool inBufferMode = false;
    
    [Range(0, 1)]
    public float _OutlineWidth;
    public Color _OutlineColor;
    public float _SimpleDistance;

    public Material writeMaterial;

    CommandBuffer commandBuffer = null;

    public List<Renderer> outlinedObjects = new List<Renderer>();

    public bool Initialized
    {
        get { return commandBuffer != null; }
    }

    private void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            bool hitSelectable = Physics.Raycast(ray, out var hit) && hit.transform.CompareTag("Selectable");
            if (hitSelectable)
            {
                Renderer[] renderers = hit.transform.GetComponentsInChildren<Renderer>();
                foreach (Renderer renderer in renderers) 
                {
                    if (outlinedObjects.Contains(renderer))
                    {
                        outlinedObjects.Remove(renderer);
                    }
                    else
                    {
                        outlinedObjects.Add(renderer);
                    }
                }
            }
            else
            {
                outlinedObjects.Clear();
            }
        }
    }

    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        if (Material != null) 
        {
            Material.SetFloat("_OutlineWidth", _OutlineWidth);
            Material.SetColor("_OutlineColor", _OutlineColor);
            Material.SetFloat("_SimpleDistance", _SimpleDistance);
        }

        commandBuffer = new CommandBuffer();
        commandBuffer.name = "Outline";

        //setup stuff
        int selectionBuffer = Shader.PropertyToID("_SelectionBuffer");
        commandBuffer.GetTemporaryRT(selectionBuffer, source.descriptor);

        //render selection buffer
        commandBuffer.SetRenderTarget(selectionBuffer);
        commandBuffer.ClearRenderTarget(true, true, Color.clear);
        if (outlinedObjects != null && outlinedObjects.Count > 0)
        {
            for (int i = 0; i < outlinedObjects.Count; i++) 
            {
                commandBuffer.DrawRenderer(outlinedObjects[i], writeMaterial);
            }
        }
        
        if (inBufferMode)
        {
            commandBuffer.Blit(selectionBuffer, destination);
        }
        else
        {
            //apply everything in commandbuffer
            commandBuffer.Blit(source, destination, Material);
        }

        //clean up 
        commandBuffer.ReleaseTemporaryRT(selectionBuffer);

        //execute and clean up commandbuffer itself
        Graphics.ExecuteCommandBuffer(commandBuffer);
        commandBuffer.Dispose();
    }
}

Shader:

Shader "LSQ/Render Pipeline/Command Buffer/Outline"
{
    Properties
    {
        [HideInInspector]_MainTex ("Texture", 2D) = "white" {}
        _OutlineWidth ("OutlineWidth", Range(0, 1)) = 1
        _OutlineColor ("OutlineColor", Color) = (1, 1, 1, 1)
        _SimpleDistance ("SimpleDistance", float) = 0.01
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            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;
            
            float _OutlineWidth;
            float4 _OutlineColor;
            float _SimpleDistance;
            sampler2D _SelectionBuffer;

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

            fixed4 frag (v2f i) : SV_Target
            {
                //sample directions
                #define DIV_SQRT_2 0.70710678118
                float2 directions[8] = 
                {
                    float2(1, 0), float2(0, 1), float2(-1, 0), float2(0, -1),
                    float2(DIV_SQRT_2, DIV_SQRT_2), float2(-DIV_SQRT_2, DIV_SQRT_2),
                    float2(-DIV_SQRT_2, -DIV_SQRT_2), float2(DIV_SQRT_2, -DIV_SQRT_2)
                };

                float aspect = _ScreenParams.x * (_ScreenParams.w - 1); //width times 1/height
                float2 sampleDistance = float2(_OutlineWidth / aspect, _OutlineWidth) * _SimpleDistance;
                
                //generate outline
                float maxAlpha = 0;
                for(uint index = 0; index < 8; index++)
                {
                    float2 sampleUV = i.uv + directions[index] * sampleDistance;
                    maxAlpha = max(maxAlpha, tex2D(_SelectionBuffer, sampleUV).a);
                }
                //remove core
                float border = max(0, maxAlpha - tex2D(_SelectionBuffer, i.uv).a);
                
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv);
                col = lerp(col, _OutlineColor, border);
                return col;
            }
            ENDCG
        }
    }
}