Main/Assets/Editor/SplitTerrain/Uitls/LightMapUtil.cs

using System;
using System.IO;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;

namespace Thousandto.Editor.Test
{
    public static class LightMapUtil
    {
        public static void CalcLightmapInfo(Renderer render)
        {
        }

        //如果不存在uv2，则使用uv代替
        public static Vector2[] GetMeshUV2(Mesh m)
        {
            var uv2 = m.uv2;
            if (uv2 == null || uv2.Length == 0)
                uv2 = m.uv;

            return uv2;
        }

        /// <summary>
        /// 计算该renderer在lightmap贴图中的包围范围
        /// </summary>
        /// <param name="uv">uv2光照uv</param>
        /// <param name="r"></param>
        /// <returns>(minx, miny, maxX, maxY)</returns>
        public static Vector4 GetBounds(Vector2[] uv, Renderer r)
        {
            if (uv != null)
            {
                var __uv = new Vector2[uv.Length];
                Array.Copy(uv, __uv, uv.Length);
                uv = __uv;
                var minx = float.MaxValue;
                var miny = float.MaxValue;
                var maxx = float.MinValue;
                var maxy = float.MinValue;
                for (var _j = 0; _j < uv.Length; ++_j)
                {
                    var _uv = uv[_j];
                    if (_uv.x < minx)
                    {
                        minx = _uv.x;
                    }
                    if (_uv.y < miny)
                    {
                        miny = _uv.y;
                    }
                    if (_uv.x > maxx)
                    {
                        maxx = _uv.x;
                    }
                    if (_uv.y > maxy)
                    {
                        maxy = _uv.y;
                    }
                }
                var bounds = new Vector4(minx, miny, maxx, maxy);
                return bounds;
            }

            return Vector4.zero;
        }

        public static float GetScaleInLightmap(Renderer rd)
        {
            UnityEditor.SerializedObject so = new UnityEditor.SerializedObject(rd);
            var sp = so.FindProperty("m_ScaleInLightmap");
            return sp.floatValue;
        }

        //烘焙场景时，可以指定GameObject的bake tag，相同tag的物件的光照信息会生成到同以一张贴图中
        public static void SetRenderLightmapParameters(Renderer renderer, string giparamsFile = "Assets/GameAssets/Resources/Scene/AAA.giparams")
        {
            SerializedObject so = new SerializedObject(renderer);
            var sp = so.FindProperty("m_LightmapParameters");
            sp.objectReferenceValue = AssetDatabase.LoadAssetAtPath(giparamsFile, typeof(LightmapParameters));
            so.ApplyModifiedProperties();
        }

        //创建LightmapParameters资源文件
        public static void CreateLightmapParameterFile(string path, int bakeTag)
        {
            LightmapParameters lp = new LightmapParameters();
            lp.bakedLightmapTag = bakeTag;
            AssetDatabase.CreateAsset(lp, path);
            AssetDatabase.ImportAsset(path);
        }

        //从整lightmap贴图中扣指定物件的光照贴图
        public static Texture2D PickLightmap(GameObject go, out Vector4 sourceBounds, out Vector4 scaleBounds, out Rect pickRect)
        {
            pickRect = new Rect();
            sourceBounds = Vector4.zero;
            scaleBounds = Vector4.zero;
            if (go == null)
                return null;

            var meshFilter = go.GetComponent<MeshFilter>();
            var renderer = go.GetComponent<Renderer>();
            if (meshFilter == null || renderer == null)
                return null;

            var tex = GetFullLightmap(renderer);
            if (tex == null)
                return null;
            var uv2s = GetMeshUV2(meshFilter.sharedMesh);
            //var bounds = GetBounds(uv2s, renderer);
            sourceBounds = LightMapUtil.GetBounds(uv2s, renderer);
            scaleBounds = CalcBoundWithLightmapScaleOffset(sourceBounds, renderer.lightmapScaleOffset);

            return PickTexture(tex, scaleBounds, out pickRect);
        }

        public static Vector4 CalcBoundWithLightmapScaleOffset(Vector4 sourceBounds, Vector4 lightmapScaleOffset)
        {
            var scaleBounds = new Vector4(sourceBounds.x * lightmapScaleOffset.x + lightmapScaleOffset.z,
                                     sourceBounds.y * lightmapScaleOffset.y + lightmapScaleOffset.w,
                                     sourceBounds.z * lightmapScaleOffset.x + lightmapScaleOffset.z,
                                     sourceBounds.w * lightmapScaleOffset.y + lightmapScaleOffset.w);

            return scaleBounds;
        }

        public static Texture2D PickTexture(Texture2D sourceTex, Vector4 bounds, out Rect pickRect)
        {
            pickRect = new Rect();
            var blockW = ((bounds.z - bounds.x) * sourceTex.width);
            var blockH = ((bounds.w - bounds.y) * sourceTex.height);
            var startX = Mathf.RoundToInt(bounds.x * sourceTex.width);
            var startY = Mathf.RoundToInt(bounds.y * sourceTex.height);

            if(blockW - (int)blockW > 0.11f)
            {
                blockW += 1;
            }
            if(blockH - (int)blockH > 0.11f)
            {
                blockH += 1;
            }

            int w = (int)blockW;
            int h = (int)blockH;
            //startY = (tex.height - startY - blockH);
            if (blockH == 0 || blockW == 0)
                return null;

            if (startX + w > sourceTex.width)
                w--;
            if (startY + h > sourceTex.height)
                h--;

            pickRect.x = startX;
            pickRect.y = startY;
            pickRect.width = w;
            pickRect.height = h;

            var colors = sourceTex.GetPixels(startX, startY, w, h);
            Texture2D tex2d = new Texture2D(w, h);
            tex2d.SetPixels(colors);
            tex2d.Apply();
            return tex2d;
        }

        //从整lightmap贴图中扣指定物件的光照贴图
        public static Texture2D PickLightmap(Renderer renderer, out Vector4 bound, out Vector4 scaleBound, out Rect pickRect)
        {
            GameObject go = renderer.gameObject;
            return PickLightmap(go, out bound, out scaleBound, out pickRect);
        }

        public static Texture2D GetFullLightmap(Renderer rd)
        {
            int lightmapIndex = rd.lightmapIndex;
            var lightmaps = LightmapSettings.lightmaps;
            if(lightmaps.Length == 0)
            {
                UnityEngine.Debug.LogError("No lightmap in current scene: " + EditorSceneManager.GetActiveScene().name);
                return null;
            }
            if(lightmapIndex == -1)
            {
                UnityEngine.Debug.LogError("lightmapIndex is -1 : " + rd.name);
                return null;
            }

            if(lightmapIndex >= lightmaps.Length)
            {
                UnityEngine.Debug.LogError("Renderer index out of range: " + lightmapIndex + " name: " + rd.name);
                return null;
            }

            var tex = lightmaps[lightmapIndex].lightmapColor;
            var path = AssetDatabase.GetAssetPath(tex);
            if(File.Exists(path))
            {
                TextureImporter ti = AssetImporter.GetAtPath(path) as TextureImporter;
                if (!ti.isReadable)
                {
                    ti.isReadable = true;
                    ti.SaveAndReimport();
                }
            }
            return tex;
        }

        public static Texture2D CreateEmptyTexture(int width, int height, TextureFormat format)
        {
            Texture2D tex = new Texture2D(width, height, TextureFormat.RGBA32, false);
            Color[] color = new Color[width * height];
            for (int i = 0; i < color.Length; ++i)
            {
                color[i] = new Color(0, 0, 0, 0);
            }
            tex.SetPixels(color);

            return tex;
        }

        [MenuItem("Test/Create/LightmapParameters")]
        static void TestCreate()
        {
            CreateLightmapParameterFile("Assets/GameAssets/Resources/Scene/1.giparams", 1);
        }
    }
}