JJBB/Assets/Project/Script/Common/Utilities/Editor/LightmapSeperate.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using UnityEditor.SceneManagement;
using Object = UnityEngine.Object;

public class LightmapSeperate
{
    public const string lightmapFormat = "Assets/Res_newMS/LightmapParameters/Lightmap{0}.giparams";
    public const int textureSize = 1024;
    public const float atlasFillRatio = 1f;

    [MenuItem("Scene/Bake Scene 烘培当前场景", false, 1)]
    public static void SeperateLightmaps()
    {
        var resolution = LightmapEditorSettings.bakeResolution;
        var allMaterials = new List<LightmapSizeData>();
        var meshRenderers = Object.FindObjectsOfType<MeshRenderer>();
        for (var i = 0; i < meshRenderers.Length; i++)
        {
            var meshRenderer = meshRenderers[i];
            if (meshRenderer.gameObject.isStatic)
            {
                var serialized = new SerializedObject(meshRenderer);
                var property = serialized.FindProperty("m_ScaleInLightmap");
                if (property != null && property.floatValue > 0.5f)
                {
                    property.floatValue = 0.5f;
                    serialized.ApplyModifiedProperties();
                }
                var mainMaterial = meshRenderer.sharedMaterial;
                if (mainMaterial == null)
                    Debug.LogError("物体没有材质 " + meshRenderer.transform.GetHierarchyName());
                else
                {
                    var lightmapSize = allMaterials.GetItem(mainMaterial, ListGetMode.create);
                    lightmapSize.AddMeshRenderer(meshRenderer, resolution);
                }
            }
        }
        for (var i = allMaterials.Count - 1; i >= 0; i--)
            if (!allMaterials[i].IsBakable())
            {
                allMaterials[i].SetLightmapParameters(null);
                allMaterials.RemoveAt(i);
            }
        // 试图合并光照贴图
        allMaterials.Sort((a, b) => -a.totalSize.CompareTo(b.totalSize));
        for (var i = allMaterials.Count - 1; i >= 0; i--)
        {
            var material = allMaterials[i];
            if (material.rendererList.Count < 1)
            {
                allMaterials.RemoveAt(i);
                material.SetLightmapParameters(null);
            }
        }

        var lightmapList = new List<LightmapParamData>();
        while (allMaterials.Count > 0)
        {
            var lightmapData = new LightmapParamData();
            lightmapList.Add(lightmapData);
            lightmapData.AddLightmap(allMaterials, 0);
            var index = allMaterials.FindIndex(a => a.totalSize + lightmapData.totalSize < textureSize * textureSize * atlasFillRatio);
            while (index >= 0)
            {
                lightmapData.AddLightmap(allMaterials, index);
                index = allMaterials.FindIndex(a => a.totalSize + lightmapData.totalSize < textureSize * textureSize * atlasFillRatio);
            }
        }
        var source = AssetDatabase.LoadAssetAtPath<LightmapParameters>(string.Format(lightmapFormat, 0));
        for (var i = 0; i < lightmapList.Count; i++)
        {
            LightmapParameters target;
            if (i == 0)
                target = source;
            else
            {
                var path = string.Format(lightmapFormat, i);
                target = AssetDatabase.LoadAssetAtPath<LightmapParameters>(path);
                if (target == null)
                {
                    target = Object.Instantiate(source);
                    target.bakedLightmapTag = i;
                    EditorUtility.SetDirty(target);
                    AssetDatabase.CreateAsset(target, path);
                }
            }
            var lightmap = lightmapList[i];
            lightmap.SetLightmapParameters(target);
        }
        EditorSceneManager.MarkAllScenesDirty();
        AssetDatabase.Refresh();
        // 配置标准化烘培参数
        LightmapEditorSettings.maxAtlasHeight = textureSize;
#if UNITY_2018
        LightmapEditorSettings.maxAtlasSize = textureSize;
#endif
        Lightmapping.BakeAsync();
    }

    public class LightmapParamData
    {
        public readonly List<LightmapSizeData> lightmapSizeList = new List<LightmapSizeData>();
        public float totalSize { get; private set; }

        public void AddLightmap(List<LightmapSizeData> list, int index)
        {
            var item = list[index];
            list.RemoveAt(index);
            totalSize += item.totalSize;
            lightmapSizeList.Add(item);
        }

        public void SetLightmapParameters(LightmapParameters lightmapParameters)
        {
            for (var i = 0; i < lightmapSizeList.Count; i++)
            {
                var lightmap = lightmapSizeList[i];
                lightmap.SetLightmapParameters(lightmapParameters);
            }
        }
    }

    public class LightmapSizeData : ListItemBase<Material>
    {
        public readonly List<MeshRenderer> rendererList = new List<MeshRenderer>();
        public float totalSize { get; private set; }

        public void AddMeshRenderer(MeshRenderer meshRenderer, float resolution)
        {
            var serializedObject = new SerializedObject(meshRenderer);
            var serializedProperty = serializedObject.FindProperty("m_ScaleInLightmap");
            if (serializedProperty != null)
            {
                var bounds = meshRenderer.bounds;
                var size = bounds.size.x * bounds.size.y + bounds.size.y * bounds.size.z +
                           bounds.size.z * bounds.size.x;
                rendererList.Add(meshRenderer);
                var scale = resolution * serializedProperty.floatValue;
                totalSize += size * scale * scale;
            }
        }

        public bool IsBakable()
        {
            // Unity当前版本无法有效拿到Fallback里面继承的通道
            // 当前条件下，使用Forward通道的，都会参加烘培，所以暂时用这个流程替代
            return id.FindPass("META") > -1 || id.FindPass("FORWARD") > -1;
        }

        public void SetLightmapParameters(LightmapParameters lightmapParameters)
        {
            for (var i = 0; i < rendererList.Count; i++)
            {
                var meshRenderer = rendererList[i];
                var serializedObject = new SerializedObject(meshRenderer);
                var serializedProperty = serializedObject.FindProperty("m_LightmapParameters");
                serializedProperty.objectReferenceValue = lightmapParameters;
                serializedObject.ApplyModifiedProperties();
            }
        }
    }
}