Unity2018.4.16 光照烘焙场景和预制
xzhuan原创稿件,转载请注明出处!光照烘焙 作为常用优化手段之一
通过把物体光照的明暗信息保存到纹理上, 实时绘制时不再进行光照计算, 而是采用预先生成的光照纹理(lightmap)来表示明暗效果。
优点：
1.省去光照计算, 提高绘制速度
2.对于一些过度复杂的光照(如光线追踪, 辐射度, AO等算法), 实时计算不太现实. 如果预先计算好保存到纹理上, 这样无疑可以大大提高模型的光影效果
3.保存下来的lightmap还可以进行二次处理, 如做一下模糊, 让阴影边缘更加柔和
缺点：
1.模型额外多了一层纹理, 这样相当于增加了资源的管理成本(异步装载, 版本控制, 文件体积等). 当然, 也可以选择把明暗信息写回原纹理, 但这样限制比较多, 如纹理坐标范围, 物体实例个数...
2.模型需要隔外一层可以展开到一张纹理平面的UV(范围只能是, 不能重合). 如果原模型本身就是这样, 可以结省掉. 但对于大多数模型来说, 可能会采用WRAP/MIRROR寻址, 这只能再做一层, 再说不能强制每个模型只用一张纹理吧? 所以, lightmap的UV需要美术多做一层, 程序展开算法这里不提及....
3.静态的光影效果与对动态的光影没法很好的结合. 如果光照方向改变了的话, 静态光影效果是无法进行变换的. 而且对于静态的阴影, 没法直接影响到动态的模型. 这一点, 反而影响了真实度
unity中操作流程如下
1.模型 勾选Generate Lightmap UVs选项
2.模型 勾选Static静态属性
3.光源设置
4.打开光照设置
5.将实时光照（RealTime Lighting）下实时全局光照（RealTime Global ILLumination）后的复选框取消勾选，也就只进行烘焙全局光照计算。接着将混合光照（Mixed Lighting）的光照模式（Lighting Mode）后的下拉框中的选项改为烘焙间接光（Baked Indirect），最后再将光照贴图设置（Lightmapping Setings）下的光照运算器（Lightmaper）后的下拉框选项改为渐进式（Progressive），如下图所示。还需要勾选环境遮蔽(Ambient Occlusion)，也就是AO，如下第二张图所示，这个选项会在物体或物体间内转角或内转折处产生软阴影，例如墙内凹角，对于表现细节很有帮助
不自动烘焙和 可选雾效效果
6.扩展代码PrefabLightmapData.cs
#if UNITY_EDITORusing UnityEditor;using System.IO;#endifusing UnityEngine;using System.Collections.Generic;public class PrefabLightmapData : MonoBehaviour{ struct RendererInfo { public Renderer renderer; public int lightmapIndex; public Vector4 lightmapOffsetScale; } RendererInfo[] m_RendererInfo; Texture2D[] m_Lightmaps; Texture2D[] m_Lightmaps2; const string LIGHTMAP_RESOURCE_PATH = "Assets/Resources/Lightmaps/"; struct Texture2D_Remap { public int originalLightmapIndex; public Texture2D originalLightmap; public Texture2D lightmap0; public Texture2D lightmap1; } static List<Texture2D_Remap> sceneLightmaps = new List<Texture2D_Remap>(); void Awake() { ApplyLightmaps(m_RendererInfo, m_Lightmaps, m_Lightmaps2); } static void ApplyLightmaps(RendererInfo[] rendererInfo, Texture2D[] lightmaps, Texture2D[] lightmaps2) { bool existsAlready = false; int counter = 0; int[] lightmapArrayOffsetIndex; if (rendererInfo == null || rendererInfo.Length == 0) return; var settingslightmaps = LightmapSettings.lightmaps; var combinedLightmaps = new List<LightmapData>(); lightmapArrayOffsetIndex = new int; for (int i = 0; i < lightmaps.Length; i++) { existsAlready = false; for (int j = 0; j < settingslightmaps.Length; j++) { if (lightmaps == settingslightmaps.lightmapColor) { lightmapArrayOffsetIndex = j; existsAlready = true; } } if (!existsAlready) { lightmapArrayOffsetIndex = counter + settingslightmaps.Length; var newLightmapData = new LightmapData(); newLightmapData.lightmapColor = lightmaps; newLightmapData.lightmapDir = lightmaps2; combinedLightmaps.Add(newLightmapData); ++counter; } } var combinedLightmaps2 = new LightmapData; settingslightmaps.CopyTo(combinedLightmaps2, 0); if (counter > 0) { for (int i = 0; i < combinedLightmaps.Count; i++) { combinedLightmaps2 = new LightmapData(); combinedLightmaps2.lightmapColor = combinedLightmaps.lightmapColor; combinedLightmaps2.lightmapDir = combinedLightmaps.lightmapDir; } } ApplyRendererInfo(rendererInfo, lightmapArrayOffsetIndex); LightmapSettings.lightmaps = combinedLightmaps2; } static void ApplyRendererInfo(RendererInfo[] infos, int[] arrayOffsetIndex) { for (int i = 0; i < infos.Length; i++) { var info = infos; info.renderer.lightmapIndex = arrayOffsetIndex; info.renderer.lightmapScaleOffset = info.lightmapOffsetScale; } }#if UNITY_EDITOR static void AAA() { string filename = "Assets/Scene/Login/Lightmap-0_comp_light.exr"; AssetDatabase.ImportAsset(filename, ImportAssetOptions.ForceUpdate); Debug.Log(filename); AssetImporter i = AssetImporter.GetAtPath(filename); if (i == null) { Debug.Log("i is nil"); } var importer = AssetImporter.GetAtPath(filename) as TextureImporter; importer.isReadable = true; AssetDatabase.ImportAsset(filename, ImportAssetOptions.ForceUpdate); } static void UpdateLightmaps() { PrefabLightmapData[] prefabs = FindObjectsOfType<PrefabLightmapData>(); foreach (var instance in prefabs) { ApplyLightmaps(instance.m_RendererInfo, instance.m_Lightmaps, instance.m_Lightmaps2); } Debug.Log("Prefab lightmaps updated"); } static void GenerateLightmapInfo() { Debug.ClearDeveloperConsole(); if (Lightmapping.giWorkflowMode != Lightmapping.GIWorkflowMode.OnDemand) { Debug.LogError("ExtractLightmapData requires that you have baked you lightmaps and Auto mode is disabled."); return; } Lightmapping.Bake(); string lightMapPath = System.IO.Path.Combine(Directory.GetCurrentDirectory(), LIGHTMAP_RESOURCE_PATH); if (!Directory.Exists(lightMapPath)) Directory.CreateDirectory(lightMapPath); sceneLightmaps = new List<Texture2D_Remap>(); //var scene = UnityEngine.SceneManagement.SceneManager.GetActiveScene(); var sceneName = Path.GetFileNameWithoutExtension(EditorApplication.currentScene); var resourcePath = LIGHTMAP_RESOURCE_PATH + sceneName; var scenePath = System.IO.Path.GetDirectoryName(EditorApplication.currentScene) + "/" + sceneName + "/"; PrefabLightmapData[] prefabs = FindObjectsOfType<PrefabLightmapData>(); foreach (var instance in prefabs) { var gameObject = instance.gameObject; var rendererInfos = new List<RendererInfo>(); var lightmaps = new List<Texture2D>(); var lightmaps2 = new List<Texture2D>(); GenerateLightmapInfo(scenePath, resourcePath, gameObject, rendererInfos, lightmaps, lightmaps2); instance.m_RendererInfo = rendererInfos.ToArray(); instance.m_Lightmaps = lightmaps.ToArray(); instance.m_Lightmaps2 = lightmaps2.ToArray(); var targetPrefab = PrefabUtility.GetPrefabParent(gameObject) as GameObject; if (targetPrefab != null) { //Prefab PrefabUtility.ReplacePrefab(gameObject, targetPrefab); } ApplyLightmaps(instance.m_RendererInfo, instance.m_Lightmaps, instance.m_Lightmaps2); } Debug.Log("Update to prefab lightmaps finished"); } static void GenerateLightmapInfo(string scenePath, string resourcePath, GameObject root, List<RendererInfo> rendererInfos, List<Texture2D> lightmaps, List<Texture2D> lightmaps2) { var renderers = root.GetComponentsInChildren<MeshRenderer>(); foreach (MeshRenderer renderer in renderers) { if (renderer.lightmapIndex != -1) { RendererInfo info = new RendererInfo(); info.renderer = renderer; info.lightmapOffsetScale = renderer.lightmapScaleOffset; Texture2D lightmap = LightmapSettings.lightmaps.lightmapColor; Texture2D lightmap2 = LightmapSettings.lightmaps.lightmapDir; int sceneLightmapIndex = AddLightmap(scenePath, resourcePath, renderer.lightmapIndex, lightmap, lightmap2); info.lightmapIndex = lightmaps.IndexOf(sceneLightmaps.lightmap0); if (info.lightmapIndex == -1) { info.lightmapIndex = lightmaps.Count; lightmaps.Add(sceneLightmaps.lightmap0); lightmaps2.Add(sceneLightmaps.lightmap1); } rendererInfos.Add(info); } } } static int AddLightmap(string scenePath, string resourcePath, int originalLightmapIndex, Texture2D lightmap, Texture2D lightmap2) { int newIndex = -1; for (int i = 0; i < sceneLightmaps.Count; i++) { if (sceneLightmaps.originalLightmapIndex == originalLightmapIndex) { return i; } } if (newIndex == -1) { var lightmap_Remap = new Texture2D_Remap(); lightmap_Remap.originalLightmapIndex = originalLightmapIndex; lightmap_Remap.originalLightmap = lightmap; var filename = scenePath + "Lightmap-" + originalLightmapIndex; lightmap_Remap.lightmap0 = GetLightmapAsset(filename + "_comp_light.exr", resourcePath + "_light", originalLightmapIndex, lightmap); if (lightmap2 != null) { lightmap_Remap.lightmap1 = GetLightmapAsset(filename + "_comp_dir.png", resourcePath + "_dir", originalLightmapIndex, lightmap2); } sceneLightmaps.Add(lightmap_Remap); newIndex = sceneLightmaps.Count - 1; } return newIndex; } static Texture2D GetLightmapAsset(string filename, string resourcePath, int originalLightmapIndex, Texture2D lightmap) { AssetDatabase.ImportAsset(filename, ImportAssetOptions.ForceUpdate); var importer = AssetImporter.GetAtPath(filename) as TextureImporter; importer.isReadable = true; AssetDatabase.ImportAsset(filename, ImportAssetOptions.ForceUpdate); var assetLightmap = AssetDatabase.LoadAssetAtPath<Texture2D>(filename); var assetPath = resourcePath + "-" + originalLightmapIndex + ".asset"; var newLightmap = Instantiate<Texture2D>(assetLightmap); AssetDatabase.CreateAsset(newLightmap, assetPath); newLightmap = AssetDatabase.LoadAssetAtPath<Texture2D>(assetPath); importer.isReadable = false; AssetDatabase.ImportAsset(filename, ImportAssetOptions.ForceUpdate); return newLightmap; }#endif}
7.模型挂载PrefabLightmapData.cs代码
烘焙场景和预制 Assets/Update Scene with Prefab Lightmaps
烘焙预制Assets/Bake Prefab Lightmaps
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