关于Unity里自发光材质的烘焙，一个是要加上Meta Pass，一个是要设置材质的Lightmap Flags设置为BakedEmissive
以下为烘焙自发光成功与失败的对比
第一点加上meta pass，以下为URP管线下通用Meta Pass，加载自定义的shader后面，把参数换成自己的参数名就好：
// This pass it not used during regular rendering, only for lightmap baking.Pass{Name "Meta"Tags{"LightMode" = "Meta"}Cull OffHLSLPROGRAM#pragma only_renderers gles gles3 glcore d3d11#pragma target 2.0#pragma vertex vert_Meta#pragma fragment frag_Meta#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/MetaInput.hlsl"TEXTURE2D(_BaseMap);SAMPLER(sampler_BaseMap);TEXTURE2D(_MetallicGlossMap);SAMPLER(sampler_MetallicGlossMap);TEXTURE2D(_Emissionmap);SAMPLER(sampler_Emissionmap);struct a2v_Meta{float4 positionOS : POSITION;float3 normalOS: NORMAL;float2 uv0: TEXCOORD0;float2 uv1: TEXCOORD1;float2 uv2: TEXCOORD2;#ifdef _TANGENT_TO_WORLDfloat4 tangentOS: TANGENT;#endif};struct v2f_Meta{float4 positionCS : SV_POSITION;float2 uv : TEXCOORD0;};v2f_Meta vert_Meta(a2v_Meta input){v2f_Meta output = (v2f_Meta)0;output.positionCS = MetaVertexPosition(input.positionOS, input.uv1, input.uv2, unity_LightmapST, unity_DynamicLightmapST);output.uv = TRANSFORM_TEX(input.uv0, _BaseMap);return output;}half4 frag_Meta(v2f_Meta input) : SV_Target{SurfaceData surfaceData;half4 albedoAlpha = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, input.uv);surfaceData.albedo = albedoAlpha.rgb * _BaseColor.rgb;surfaceData.alpha = albedoAlpha.a * _BaseColor.a;half4 metallicGlossOcclusion = SAMPLE_TEXTURE2D(_MetallicGlossMap, sampler_MetallicGlossMap, input.uv);surfaceData.metallic = _Metallic * metallicGlossOcclusion.r;surfaceData.smoothness = _Smoothness * metallicGlossOcclusion.a;surfaceData.specular = _SpecularColor.rgb;surfaceData.emission = SAMPLE_TEXTURE2D(_Emissionmap, sampler_Emissionmap, input.uv).rgb * _Emission.rgb;surfaceData.clearCoatMask = 0.0h;surfaceData.clearCoatSmoothness = 0.0h;BRDFData brdfData;InitializeBRDFData(surfaceData.albedo, surfaceData.metallic, surfaceData.specular, surfaceData.smoothness, surfaceData.alpha, brdfData);MetaInput metaInput;metaInput.Albedo = brdfData.diffuse + brdfData.specular * brdfData.roughness * 0.5;metaInput.SpecularColor = surfaceData.specular;metaInput.Emission = surfaceData.emission;return MetaFragment(metaInput);}ENDHLSL}
第二点设置材质的Lightmap Flags，可以用代码mat.globalIlluminationFlags = MaterialGlobalIlluminationFlags.BakedEmissive来设置，或者在Debug模式下，把材质的LightmapFlags改为4
做了个小工具，便于美术在材质面板上，点击右上角的齿轮，就可以很轻松的设置哪些材质需要自发光烘焙
以下是代码，放进工程里就好
using UnityEngine;using UnityEditor;public class MaterialBakedEmissionTool : MonoBehaviour{// Start is called before the first frame update[MenuItem("CONTEXT/Material/Set Baked Emission")]public static void SetBakedEmission(MenuCommand menuCommand){var mat = menuCommand.context as Material;if (mat != null){mat.globalIlluminationFlags = MaterialGlobalIlluminationFlags.BakedEmissive;}}[MenuItem("CONTEXT/Material/Reset Baked Emission")]public static void ResetBakedEmission(MenuCommand menuCommand){var mat = menuCommand.context as Material;if (mat != null){mat.globalIlluminationFlags = MaterialGlobalIlluminationFlags.None;}}}
