add experimental texture support

Author: bertt

README.md

@@ -20,6 +20,8 @@ Features:
 
 - Shading PbrMetallicRoughness and PbrSpecularGlossiness;
 
+- Automatic 3DCityDB v5 texture support per tile/glTF (texture > shader > default);
+
 - Query parameter support;
 
 - Cesium: LOD support and Outlines support (using CESIUM_primitive_outline);
@@ -155,6 +157,19 @@ Sample command for running pg2b3dm:
 $ pg2b3dm -h localhost -U postgres -c geom_triangle --shaderscolumn shaders -t delaware_buildings -d postgres -g 100,0 
 ```
 
+## 3DCityDB v5 textures
+
+When the source database matches the 3DCityDB v5 schema, pg2b3dm automatically checks if texture data is present in
+`citydb.surface_data_mapping` + `citydb.surface_data` + `citydb.tex_image` and then resolves textures per tile/glTF.
+
+Rules:
+
+- Per-tile behavior: one tile can be textured while another tile from the same run is not textured.
+- Priority: if both textures and shaders are available in a tile, textures are used and shaders are ignored.
+- Fallback in textured tiles: geometries without valid texture coordinates/image use the default material.
+
+No extra CLI option is required for this workflow.
+
 Database password will be asked to create the database connection, unless:
 
 - Trusted authentication is enabled;

dataprocessing/dataprocessing_citygml.md

@@ -173,11 +173,49 @@ Result: The exported 3D Tiles will now have different colors based on the CityGM
 
 ---
 
-## 5. Conclusion  
+## 6. Textures in 3DCityDB v5
+
+For 3DCityDB v5 input (`citydb.geometry_data` or a view carrying `geometry_data.id`), pg2b3dm now automatically detects
+texture data and applies textures per tile.
+
+Relevant texture tables and columns:
+
+- `citydb.surface_data_mapping.texture_mapping` (texture coordinates)
+- `citydb.surface_data.tex_image_id`
+- `citydb.tex_image.image_data` (image bytes)
+
+Example query:
+
+```sql
+SELECT
+    gmdt.id,
+    gmdt.geometry,
+    gmdt.geometry_properties,
+    sdm.texture_mapping,
+    ti.image_uri,
+    ti.image_data
+FROM citydb.geometry_data gmdt
+JOIN citydb.surface_data_mapping sdm
+    ON gmdt.id = sdm.geometry_data_id
+JOIN citydb.surface_data sd
+    ON sd.id = sdm.surface_data_id
+JOIN citydb.tex_image ti
+    ON ti.id = sd.tex_image_id
+WHERE sdm.texture_mapping IS NOT NULL
+  AND ti.image_data IS NOT NULL;
+```
+
+Priority rule during export:
+
+- If textures and shaders are both available in the same tile, textures are used.
+- Tiles without texture data keep existing shader/default behavior.
+
+---
+
+## 7. Conclusion  
 
 3DCityDB v5 streamlines the process of:
 - Storing and querying CityGML 3.0 models in PostgreSQL/PostGIS  
 - Converting them into web-ready 3D Tiles for efficient visualization  
-- Supporting semantic 3D city models suitable for digital twin and urban planning applications  
-
-Future improvements may include the direct handling of texture data to enrich the visual quality of the exported 3D Tiles.
+- Supporting semantic 3D city models suitable for digital twin and urban planning applications
+- Exporting both shader-based and texture-based visualizations.

src/b3dm.tileset/CityDbRepository.cs

@@ -0,0 +1,105 @@
+using System;
+using Npgsql;
+
+namespace B3dm.Tileset;
+
+public static class CityDbRepository
+{
+    public static bool Is3dCityDbV5OrHigher(NpgsqlConnection conn)
+    {
+        const string sql = @"
+SELECT COUNT(*) = 10
+FROM (
+    VALUES
+      ('geometry_data','id'),
+      ('geometry_data','geometry'),
+      ('surface_data_mapping','geometry_data_id'),
+      ('surface_data_mapping','surface_data_id'),
+      ('surface_data_mapping','texture_mapping'),
+      ('surface_data','id'),
+      ('surface_data','tex_image_id'),
+      ('tex_image','id'),
+      ('tex_image','image_data'),
+      ('tex_image','mime_type')
+) req(table_name, column_name)
+JOIN information_schema.columns c
+  ON c.table_schema = 'citydb'
+ AND c.table_name = req.table_name
+ AND c.column_name = req.column_name";
+
+        return ExecuteBooleanScalar(conn, sql);
+    }
+
+    public static bool HasTextureData(NpgsqlConnection conn)
+    {
+        const string sql = @"
+SELECT EXISTS (
+    SELECT 1
+    FROM citydb.surface_data_mapping sdm
+    JOIN citydb.surface_data sd ON sd.id = sdm.surface_data_id
+    JOIN citydb.tex_image ti ON ti.id = sd.tex_image_id
+    WHERE sdm.texture_mapping IS NOT NULL
+      AND ti.image_data IS NOT NULL
+    LIMIT 1
+)";
+
+        return ExecuteBooleanScalar(conn, sql);
+    }
+
+    public static bool HasColumn(NpgsqlConnection conn, string tableName, string columnName)
+    {
+        var schemaAndTable = GetSchemaAndTable(tableName);
+        if (schemaAndTable == null) {
+            return false;
+        }
+
+        const string sql = @"
+SELECT EXISTS (
+    SELECT 1
+    FROM information_schema.columns
+    WHERE table_schema = @schema
+      AND table_name = @table
+      AND column_name = @column
+)";
+
+        return ExecuteBooleanScalar(conn, sql, cmd => {
+            cmd.Parameters.AddWithValue("schema", schemaAndTable.Value.Schema);
+            cmd.Parameters.AddWithValue("table", schemaAndTable.Value.Table);
+            cmd.Parameters.AddWithValue("column", columnName);
+        });
+    }
+
+    private static (string Schema, string Table)? GetSchemaAndTable(string tableName)
+    {
+        if (string.IsNullOrWhiteSpace(tableName)) {
+            return null;
+        }
+
+        var value = tableName.Trim();
+        var parts = value.Split('.', 2, StringSplitOptions.RemoveEmptyEntries);
+        if (parts.Length == 1) {
+            return ("public", StripQuotes(parts[0]));
+        }
+
+        return (StripQuotes(parts[0]), StripQuotes(parts[1]));
+    }
+
+    private static string StripQuotes(string value)
+    {
+        return value.Trim().Trim('"');
+    }
+
+    private static bool ExecuteBooleanScalar(NpgsqlConnection conn, string sql, Action<NpgsqlCommand> addParameters = null)
+    {
+        conn.Open();
+        try {
+            using var cmd = new NpgsqlCommand(sql, conn);
+            addParameters?.Invoke(cmd);
+            var value = cmd.ExecuteScalar();
+            return value is bool result && result;
+        }
+        finally {
+            conn.Close();
+        }
+    }
+}

src/b3dm.tileset/GeometryRepository.cs

@@ -38,9 +38,9 @@ public static double[] GetGeometriesBoundingBox(NpgsqlConnection conn, string ge
         return result;
     }
 
-    public static List<GeometryRecord> GetGeometrySubset(NpgsqlConnection conn, string geometry_table, string geometry_column, double[] bbox, int source_epsg, int target_srs, string shaderColumn = "", string attributesColumns = "", string query = "", string radiusColumn = "", bool keepProjection = false)
+    public static List<GeometryRecord> GetGeometrySubset(NpgsqlConnection conn, string geometry_table, string geometry_column, double[] bbox, int source_epsg, int target_srs, string shaderColumn = "", string attributesColumns = "", string query = "", string radiusColumn = "", bool keepProjection = false, string idColumn = "", bool includeTextures = false)
     {
-        var sqlselect = GetSqlSelect(geometry_column, shaderColumn, attributesColumns, radiusColumn, target_srs);
+        var sqlselect = GetSqlSelect(geometry_column, shaderColumn, attributesColumns, radiusColumn, target_srs, idColumn);
         var sqlFrom = "FROM " + geometry_table;
 
         // todo: fix unit test when there is no z
@@ -49,7 +49,10 @@ public static List<GeometryRecord> GetGeometrySubset(NpgsqlConnection conn, stri
         var sqlWhere = GetWhere(geometry_column, points.fromPoint, points.toPoint, query, source_epsg, keepProjection);
         var sql = sqlselect + sqlFrom + " where " + sqlWhere;
 
-        var geometries = GetGeometries(conn, shaderColumn, attributesColumns, sql, radiusColumn);
+        var geometries = GetGeometries(conn, shaderColumn, attributesColumns, sql, radiusColumn, idColumn);
+        if (includeTextures) {
+            EnrichWithTextures(conn, geometries);
+        }
         return geometries;
     }
 
@@ -85,10 +88,13 @@ public static string GetWhere(string geometry_column, Point from, Point to, stri
         return where;
     }
 
-    public static string GetSqlSelect(string geometry_column, string shaderColumn, string attributesColumns, string radiusColumn, int target_srs)
+    public static string GetSqlSelect(string geometry_column, string shaderColumn, string attributesColumns, string radiusColumn, int target_srs, string idColumn = "")
     {
         var g = GetGeometryColumn(geometry_column, target_srs);
         var sqlselect = $"SELECT ST_AsBinary({g})";
+        if (idColumn != String.Empty) {
+            sqlselect = $"{sqlselect}, {idColumn} ";
+        }
         if (shaderColumn != String.Empty) {
             sqlselect = $"{sqlselect}, {shaderColumn} ";
         }
@@ -107,7 +113,7 @@ public static string GetGeometryColumn(string geometry_column, int target_srs)
         return $"st_transform({geometry_column}, {target_srs})";
     }
 
-    public static List<GeometryRecord> GetGeometries(NpgsqlConnection conn, string shaderColumn, string attributesColumns, string sql, string radiusColumn)
+    public static List<GeometryRecord> GetGeometries(NpgsqlConnection conn, string shaderColumn, string attributesColumns, string sql, string radiusColumn, string idColumn = "")
     {
         var geometries = new List<GeometryRecord>();
         conn.Open();
@@ -116,11 +122,18 @@ public static List<GeometryRecord> GetGeometries(NpgsqlConnection conn, string s
         var attributesColumnIds = new Dictionary<string, int>();
         var shadersColumnId = int.MinValue;
         var radiusColumnId = int.MinValue;
+        var idColumnId = int.MinValue;
 
         if (attributesColumns != String.Empty) {
             var attributesColumnsList = attributesColumns.Split(',').ToList();
             attributesColumnIds = FindFields(reader, attributesColumnsList);
         }
+        if (idColumn != String.Empty) {
+            var fld = FindField(reader, idColumn);
+            if (fld.HasValue) {
+                idColumnId = fld.Value;
+            }
+        }
         if (shaderColumn != String.Empty) {
             var fld = FindField(reader, shaderColumn);
             if (fld.HasValue) {
@@ -140,6 +153,10 @@ public static List<GeometryRecord> GetGeometries(NpgsqlConnection conn, string s
 
             var geom = Geometry.Deserialize<WkbSerializer>(stream);
             var geometryRecord = new GeometryRecord(batchId) { Geometry = geom };
+            if (idColumn != string.Empty && idColumnId >= 0) {
+                var id = reader.GetFieldValue<object>(idColumnId);
+                geometryRecord.SourceId = Convert.ToInt64(id);
+            }
 
             if (shaderColumn != string.Empty) {
                 var json = GetJson(reader, shadersColumnId);
@@ -164,6 +181,82 @@ public static List<GeometryRecord> GetGeometries(NpgsqlConnection conn, string s
         return geometries;
     }
 
+    private static void EnrichWithTextures(NpgsqlConnection conn, List<GeometryRecord> geometries)
+    {
+        var sourceIds = geometries
+            .Where(g => g.SourceId.HasValue)
+            .Select(g => g.SourceId!.Value)
+            .Distinct()
+            .ToArray();
+
+        if (sourceIds.Length == 0) {
+            return;
+        }
+
+        var geometriesById = geometries
+            .Where(g => g.SourceId.HasValue)
+            .GroupBy(g => g.SourceId!.Value)
+            .ToDictionary(g => g.Key, g => g.First());
+
+        const string sql = @"
+SELECT g.id,
+       g.geometry_properties::text AS geometry_properties,
+       sdm.texture_mapping::text AS texture_mapping,
+       ti.mime_type,
+       ti.image_data
+FROM citydb.geometry_data g
+JOIN citydb.surface_data_mapping sdm
+  ON sdm.geometry_data_id = g.id
+JOIN citydb.surface_data sd
+  ON sd.id = sdm.surface_data_id
+JOIN citydb.tex_image ti
+  ON ti.id = sd.tex_image_id
+WHERE g.id = ANY(@ids)
+  AND sdm.texture_mapping IS NOT NULL
+  AND ti.image_data IS NOT NULL
+ORDER BY g.id, sdm.surface_data_id";
+
+        conn.Open();
+        var cmd = new NpgsqlCommand(sql, conn);
+        cmd.Parameters.AddWithValue("ids", sourceIds);
+        var reader = cmd.ExecuteReader();
+
+        while (reader.Read()) {
+            var sourceId = Convert.ToInt64(reader.GetFieldValue<object>(0));
+            if (!geometriesById.TryGetValue(sourceId, out var geometryRecord)) {
+                continue;
+            }
+
+            if (string.IsNullOrWhiteSpace(geometryRecord.GeometryProperties)) {
+                geometryRecord.GeometryProperties = reader.IsDBNull(1) ? String.Empty : reader.GetString(1);
+            }
+
+            var textureMapping = reader.IsDBNull(2) ? String.Empty : reader.GetString(2);
+            var textureMimeType = reader.IsDBNull(3) ? String.Empty : reader.GetString(3);
+            var textureImageData = reader.GetFieldValue<byte[]>(4);
+
+            var texture = new GeometryTexture() {
+                TextureMapping = textureMapping,
+                TextureMimeType = textureMimeType,
+                TextureImageData = textureImageData
+            };
+
+            if (texture.IsValid()) {
+                geometryRecord.Textures.Add(texture);
+            }
+
+            // keep legacy fields for backward compatibility with older call paths
+            if (string.IsNullOrWhiteSpace(geometryRecord.TextureMapping) && geometryRecord.TextureImageData.Length == 0) {
+                geometryRecord.TextureMapping = textureMapping;
+                geometryRecord.TextureMimeType = textureMimeType;
+                geometryRecord.TextureImageData = textureImageData;
+            }
+        }
+
+        reader.Close();
+        conn.Close();
+    }
+
     private static int? FindField(NpgsqlDataReader reader, string fieldName)
     {
         var schema = reader.GetSchemaTable();
@@ -221,4 +314,4 @@ private static (Point fromPoint, Point toPoint) GetPoints(double[] bbox)
         return (fromPoint, toPoint);
     }
 
-}
+}

src/b3dm.tileset/OctreeTiler.cs

@@ -80,7 +80,7 @@ public List<Tile3D> GenerateTiles3D(BoundingBox3D bbox, int level, Tile3D tile,
             }
 
             var bbox1 = new double[] { bbox.XMin, bbox.YMin, bbox.XMax, bbox.YMax, bbox.ZMin, bbox.ZMax };
-            var geometries = GeometryRepository.GetGeometrySubset(conn, inputTable.TableName, inputTable.GeometryColumn, bbox1, inputTable.EPSGCode, target_srs, inputTable.ShadersColumn, inputTable.AttributeColumns, where, inputTable.RadiusColumn, tilingSettings.KeepProjection);
+            var geometries = GeometryRepository.GetGeometrySubset(conn, inputTable.TableName, inputTable.GeometryColumn, bbox1, inputTable.EPSGCode, target_srs, inputTable.ShadersColumn, inputTable.AttributeColumns, where, inputTable.RadiusColumn, tilingSettings.KeepProjection, inputTable.IdColumn, inputTable.UseTexturePipeline);
 
             if (geometries.Count > 0) {
 

src/b3dm.tileset/QuadtreeTiler.cs

@@ -98,7 +98,7 @@ public List<Tile> GenerateTiles(BoundingBox bbox, Tile tile, List<Tile> tiles, i
 
             byte[] bytes = null;
 
-            var geometries = GeometryRepository.GetGeometrySubset(conn, inputTable.TableName, inputTable.GeometryColumn, tile.BoundingBox, source_epsg, target_srs, inputTable.ShadersColumn, inputTable.AttributeColumns, where, inputTable.RadiusColumn, keepProjection);
+            var geometries = GeometryRepository.GetGeometrySubset(conn, inputTable.TableName, inputTable.GeometryColumn, tile.BoundingBox, source_epsg, target_srs, inputTable.ShadersColumn, inputTable.AttributeColumns, where, inputTable.RadiusColumn, keepProjection, inputTable.IdColumn, inputTable.UseTexturePipeline);
             // var scale = new double[] { 1, 1, 1 };
             if (geometries.Count > 0) {
 

src/b3dm.tileset/settings/InputTable.cs

@@ -4,13 +4,17 @@ public class InputTable
 {
     public string TableName { get; set; }   
     public string GeometryColumn { get; set; }
+    public string IdColumn { get; set; } = string.Empty;
     public string RadiusColumn { get; set; } = string.Empty;
     public string ShadersColumn { get; set; } = string.Empty;
     public string Query { get; set; } = string.Empty;
 
     public string LodColumn { get; set; } = string.Empty;
     public string AttributeColumns { get; set; } = string.Empty;
     public int EPSGCode { get; set; }
+    public bool Is3dCityDbV5OrHigher { get; set; }
+    public bool HasTextureData { get; set; }
+    public bool UseTexturePipeline { get; set; }
 
     public string GetQueryClause()
     {