Unity2018.4.16 光照烘焙场景和预制

Ylisar · 发表于 2021-4-14 15:03

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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[0,1], 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

#if UNITY_EDITORusing UnityEditor;using System.IO;#endifusing UnityEngine;using System.Collections.Generic;[DisallowMultipleComponent, ExecuteInEditMode]public class PrefabLightmapData : MonoBehaviour{ [System.Serializable] struct RendererInfo { public Renderer renderer; public int lightmapIndex; public Vector4 lightmapOffsetScale; } [SerializeField] RendererInfo[] m_RendererInfo; [SerializeField] Texture2D[] m_Lightmaps; [SerializeField] Texture2D[] m_Lightmaps2; const string LIGHTMAP_RESOURCE_PATH = "Assets/Resources/Lightmaps/"; [System.Serializable] 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[lightmaps.Length]; for (int i = 0; i < lightmaps.Length; i++) { existsAlready = false; for (int j = 0; j < settingslightmaps.Length; j++) { if (lightmaps == settingslightmaps[j].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.Length + counter]; settingslightmaps.CopyTo(combinedLightmaps2, 0); if (counter > 0) { for (int i = 0; i < combinedLightmaps.Count; i++) { combinedLightmaps2[i + settingslightmaps.Length] = new LightmapData(); combinedLightmaps2[i + settingslightmaps.Length].lightmapColor = combinedLightmaps.lightmapColor; combinedLightmaps2[i + settingslightmaps.Length].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.lightmapIndex]; info.renderer.lightmapScaleOffset = info.lightmapOffsetScale; } }#if UNITY_EDITOR [MenuItem("Assets/Test")] 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); } [MenuItem("Assets/Update Scene with Prefab Lightmaps")] 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"); } [MenuItem("Assets/Bake Prefab Lightmaps")] 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[renderer.lightmapIndex].lightmapColor; Texture2D lightmap2 = LightmapSettings.lightmaps[renderer.lightmapIndex].lightmapDir; int sceneLightmapIndex = AddLightmap(scenePath, resourcePath, renderer.lightmapIndex, lightmap, lightmap2); info.lightmapIndex = lightmaps.IndexOf(sceneLightmaps[sceneLightmapIndex].lightmap0); if (info.lightmapIndex == -1) { info.lightmapIndex = lightmaps.Count; lightmaps.Add(sceneLightmaps[sceneLightmapIndex].lightmap0); lightmaps2.Add(sceneLightmaps[sceneLightmapIndex].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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Unity2018.4.16 光照烘焙场景和预制

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