Unity3D研究院之Lightmap支持GPU Instancing（一百零七）

        struct v2f
        {
            float2 uv0 : TEXCOORD0;
            float2 uv1 : TEXCOORD1;
            float4 pos : SV_POSITION;
            UNITY_VERTEX_INPUT_INSTANCE_ID
        };

        v2f vert(appdata IN)
        {
            v2f o;
            UNITY_SETUP_INSTANCE_ID(IN);
            UNITY_TRANSFER_INSTANCE_ID(IN, o); 
            o.uv0 = TRANSFORM_TEX(IN.uv0, _MainTex);
            o.pos = UnityObjectToClipPos(IN.pos);
            
            //IN.uv1.xy表示每个mesh的uv2
            //unity_LightmapST.xy表示LightmapScaleOffset.xy也就是Tiling x Tiling y
            //unity_LightmapST.zw表示LightmapScaleOffset.zw Offset x Offset y
            o.uv1 = IN.uv1.xy * unity_LightmapST.xy + unity_LightmapST.zw;
            return o;
        }

        fixed4 frag(v2f IN) : SV_Target
        {
            UNITY_SETUP_INSTANCE_ID(IN);
            fixed4 col;
            col.rgb = DecodeLightmap(UNITY_SAMPLE_TEX2D(unity_Lightmap, IN.uv1.xy));
            return col;
        }

Shader "Mobile/Custom" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        //---add---
        _LightmapST("_LightmapST",Vector)=(0,0,0,0)
        //---add---
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_instancing
            #include "UnityCG.cginc"
            
            sampler2D _MainTex;
            float4 _MainTex_ST;

            struct appdata
            {
                float3 pos : POSITION;
                float3 uv0 : TEXCOORD0;
                float3 uv1 : TEXCOORD1;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f
            {
                float2 uv0 : TEXCOORD0;
                //---add---
                float2 uv1 : TEXCOORD1;
                //---add---
                float4 pos : SV_POSITION;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };
            
            //将MeshRenderer中的LightmapScaleOffset分别传入_LightmapST中
            UNITY_INSTANCING_BUFFER_START(Props)
            UNITY_DEFINE_INSTANCED_PROP(fixed4, _LightmapST)
            UNITY_INSTANCING_BUFFER_END(Props)
            
            v2f vert(appdata IN)
            {
                v2f o;
                UNITY_SETUP_INSTANCE_ID(IN);
                UNITY_TRANSFER_INSTANCE_ID(IN, o); 
                
                o.uv0 = TRANSFORM_TEX(IN.uv0, _MainTex);
                 
                //---add---
                //取出每一个物体的LightmapScaleOffset重新算UV2
                fixed4 l =  UNITY_ACCESS_INSTANCED_PROP(Props, _LightmapST);
                o.uv1 = IN.uv1.xy * l.xy + l.zw;
                //---add---
                o.pos = UnityObjectToClipPos(IN.pos);
                return o;
            }
            fixed4 frag(v2f IN) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(IN);
             
                fixed4 col;
                //在这里采样lightmap
                col.rgb = DecodeLightmap(UNITY_SAMPLE_TEX2D(unity_Lightmap, IN.uv1.xy));
                return col;
            }

            ENDCG
        }
    }
}

using System.Collections.Generic;
using UnityEngine;
public class Custom : MonoBehaviour
{
   
    public Material material;
    public Texture2D lightmapTexture;

    MeshFilter meshfilter;
    List<Matrix4x4> materix = new List<Matrix4x4>();
    List<Vector4> lightmapOffset = new List<Vector4>();
    MaterialPropertyBlock block;

    void Start()
    {
        //获取节点下的所有MeshRenderer
        foreach (var item in GetComponentsInChildren<MeshRenderer>())
        {
            //隐藏它
            item.gameObject.SetActive(false);
            if (meshfilter == null)
            {
                //取出第一个mesh，因为我们是做例子可以肯定保证下面的mesh都是一样的
                meshfilter = item.GetComponent<MeshFilter>();
            }
            //保存每个物体的矩阵以及lightmapScaleOffset
            materix.Add(item.localToWorldMatrix);
            lightmapOffset.Add(item.lightmapScaleOffset);
           

        }
        //启动LIGHTMAP_ON宏
        material.EnableKeyword("LIGHTMAP_ON");
        //为了避免GC所以只new一次MaterialPropertyBlock
        block = new MaterialPropertyBlock();
        //设置具体用哪张烘焙贴图
        block.SetTexture("unity_Lightmap", lightmapTexture);
        //将每个物体的lightmapScaleOffset传入shader中
        block.SetVectorArray("_LightmapST", lightmapOffset.ToArray());

    }

    void Update()
    {
        //一次绘制
        Graphics.DrawMeshInstanced(meshfilter.sharedMesh, 0, material, materix, block);
    }

}

    void Start()
    {
        foreach (var item in GetComponentsInChildren<MeshRenderer>())
        {
            if(meshfilter == null)
            {
                meshfilter = item.GetComponent<MeshFilter>();
            }
            materix.Add(item.localToWorldMatrix);
            lightmapOffset.Add(item.lightmapScaleOffset);
            item.gameObject.SetActive(false);

        }
        material.EnableKeyword("LIGHTMAP_ON");
        block = new MaterialPropertyBlock();
        block.SetTexture("unity_Lightmap", lightmapTexture);
        //unity2019可以在这直接传入unity_LightmapST
        block.SetVectorArray("unity_LightmapST", lightmapOffset.ToArray());
    }

    void Update()
    {
        //一次渲染
        Graphics.DrawMeshInstanced(meshfilter.sharedMesh, 0, material, materix, block);
    }

        Graphics.DrawMeshInstanced(meshfilter.sharedMesh, 0, material, materix, block,ShadowCastingMode.Off,false,0,Camera.main,LightProbeUsage.CustomProvided);