阴影实现 - 面片阴影BlobShadow

最终效果

1) 两个阴影重叠的时候，基本正常

2) 在斜坡上，阴影穿插了进去

3) 跳起来的时候，阴影跟着一起起来了

4) 在平台边缘，镂空的地方也显示了阴影

 

using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

public class BlobShadow : MonoBehaviour
{
    public Transform m_Player;
    public Camera m_Camera; //Player所在的相机, 一般为主相机

    public float m_BlobHeightOffset = 0.01f; //面片高度的修正
    public float m_BlobHalfSize = 0.5f; //面片一半大小

    private Mesh m_ShadowMesh;
    private Material m_ShadowMat;

    private List<Vector3> m_QuadVertList = new List<Vector3>();
    private List<int> m_QuadTriangleList = new List<int>();
    private List<Vector2> m_QuadUVs = new List<Vector2>();

    void Awake()
    {
        if (null == m_Player)
            m_Player = this.transform;
        if (null == m_Camera)
            m_Camera = Camera.main;
    }

    void Start()
    {
        CreateBlobShadowMesh();
        m_ShadowMat = new Material(Shader.Find("My/Shadow/BlobShadow"));
    }

    private void CreateBlobShadowMesh()
    {
        m_ShadowMesh = new Mesh();
        m_ShadowMesh.name = "BlobShadow";
        //m_ShadowMesh.MarkDynamic();

        //四边形四个角占位
        m_QuadVertList.Add(Vector3.zero);
        m_QuadVertList.Add(Vector3.zero);
        m_QuadVertList.Add(Vector3.zero);
        m_QuadVertList.Add(Vector3.zero);

        m_ShadowMesh.SetVertices(m_QuadVertList);

        //映射整张贴图
        m_QuadUVs.Add(new Vector2(0, 0));
        m_QuadUVs.Add(new Vector2(0, 1));
        m_QuadUVs.Add(new Vector2(1, 0));
        m_QuadUVs.Add(new Vector2(1, 1));

        m_ShadowMesh.SetUVs(0, m_QuadUVs);

        //顶点绘制顺序
        m_QuadTriangleList.Add(0);
        m_QuadTriangleList.Add(1);
        m_QuadTriangleList.Add(2);

        m_QuadTriangleList.Add(2);
        m_QuadTriangleList.Add(1);
        m_QuadTriangleList.Add(3);

        m_ShadowMesh.SetTriangles(m_QuadTriangleList, 0, true);
    }

    void Update()
    {
        RenderBlobShadow();
    }

    private void RenderBlobShadow()
    {
        Vector3 center = m_Player.position;

        //四个角
        m_QuadVertList[0] = center + new Vector3(-m_BlobHalfSize, m_BlobHeightOffset, -m_BlobHalfSize);
        m_QuadVertList[1] = center + new Vector3(-m_BlobHalfSize, m_BlobHeightOffset, m_BlobHalfSize);
        m_QuadVertList[2] = center + new Vector3(m_BlobHalfSize, m_BlobHeightOffset, -m_BlobHalfSize);
        m_QuadVertList[3] = center + new Vector3(m_BlobHalfSize, m_BlobHeightOffset, m_BlobHalfSize);

        m_ShadowMesh.Clear(true);
        m_ShadowMesh.SetVertices(m_QuadVertList);
        m_ShadowMesh.SetUVs(0, m_QuadUVs);
        m_ShadowMesh.SetTriangles(m_QuadTriangleList, 0, true);

        Graphics.DrawMesh(m_ShadowMesh, Vector3.zero, Quaternion.identity, m_ShadowMat, 0, m_Camera); //在角色脚底绘制面片
    }

}

 

BlobShadow.shader

Shader "My/Shadow/BlobShadow"
{
    Properties
    {
        _MainTex("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType" = "Transparent" "Queue" = "Transparent-1"}
        LOD 100

        Pass
        {
            Blend Zero SrcColor
            ZWrite Off

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

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

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

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

            fixed4 frag(v2f i) : SV_Target
            {
                fixed4 c = tex2D(_MainTex, i.uv);
                return c;
            }

            ENDCG
        }
    }

}

 

参考

GitHub - xieliujian/UnityDemo_ProjectorShadow: Unity的投影阴影

GitHub - xieliujian/UnityDemo_PlanarShadow: UnityDemo平面阴影