[MLA-1824] make SensorComponent return ISensor[]

Project/Assets/ML-Agents/Examples/Basic/Scripts/BasicSensorComponent.cs

@@ -15,9 +15,9 @@ public class BasicSensorComponent : SensorComponent
         /// Creates a BasicSensor.
         /// </summary>
         /// <returns></returns>
-        public override ISensor CreateSensor()
+        public override ISensor[] CreateSensors()
         {
-            return new BasicSensor(basicController);
+            return new ISensor[] { new BasicSensor(basicController) };
         }
     }
 

Project/Assets/ML-Agents/TestScenes/TestCompressedTexture/TestTextureSensorComponent.cs

@@ -23,14 +23,14 @@ public string SensorName
 
 
     /// <inheritdoc/>
-    public override ISensor CreateSensor()
+    public override ISensor[] CreateSensors()
     {
         m_Sensor = new TestTextureSensor(TestTexture, SensorName, CompressionType);
         if (ObservationStacks != 1)
         {
-            return new StackingSensor(m_Sensor, ObservationStacks);
+            return new ISensor[] { new StackingSensor(m_Sensor, ObservationStacks) };
         }
-        return m_Sensor;
+        return new ISensor[] { m_Sensor };
     }
 }
 

com.unity.ml-agents.extensions/Runtime/Match3/Match3Sensor.cs

@@ -4,6 +4,14 @@
 
 namespace Unity.MLAgents.Extensions.Match3
 {
+
+    /// <summary>
+    /// Delegate that provides integer values at a given (x,y) coordinate.
+    /// </summary>
+    /// <param name="x"></param>
+    /// <param name="y"></param>
+    public delegate int GridValueProvider(int x, int y);
+
     /// <summary>
     /// Type of observations to generate.
     ///
@@ -32,66 +40,68 @@ public enum Match3ObservationType
 
     /// <summary>
     /// Sensor for Match3 games. Can generate either vector, compressed visual,
-    /// or uncompressed visual observations. Uses AbstractBoard.GetCellType()
-    /// and AbstractBoard.GetSpecialType() to determine the observation values.
+    /// or uncompressed visual observations. Uses a GridValueProvider to determine the observation values.
     /// </summary>
     public class Match3Sensor : ISensor, IBuiltInSensor
     {
         private Match3ObservationType m_ObservationType;
-        private AbstractBoard m_Board;
         private ObservationSpec m_ObservationSpec;
-        private int[] m_SparseChannelMapping;
         private string m_Name;
 
         private int m_Rows;
         private int m_Columns;
-        private int m_NumCellTypes;
-        private int m_NumSpecialTypes;
-
-        private int SpecialTypeSize
-        {
-            get { return m_NumSpecialTypes == 0 ? 0 : m_NumSpecialTypes + 1; }
-        }
+        private GridValueProvider m_GridValues;
+        private int m_OneHotSize;
 
         /// <summary>
-        /// Create a sensor for the board with the specified observation type.
+        /// Create a sensor for the GridValueProvider with the specified observation type.
         /// </summary>
-        /// <param name="board"></param>
-        /// <param name="obsType"></param>
-        /// <param name="name"></param>
-        public Match3Sensor(AbstractBoard board, Match3ObservationType obsType, string name)
+        /// <remarks>
+        /// Use Match3Sensor.CellTypeSensor() or Match3Sensor.SpecialTypeSensor() instead of calling
+        /// the constructor directly.
+        /// </remarks>
+        /// <param name="board">The abstract board. This is only used to get the size.</param>
+        /// <param name="gvp">The GridValueProvider, should be either board.GetCellType or board.GetSpecialType.</param>
+        /// <param name="oneHotSize">The number of possible values that the GridValueProvider can return.</param>
+        /// <param name="obsType">Whether to produce vector or visual observations</param>
+        /// <param name="name">Name of the sensor.</param>
+        public Match3Sensor(AbstractBoard board, GridValueProvider gvp, int oneHotSize, Match3ObservationType obsType, string name)
         {
-            m_Board = board;
             m_Name = name;
             m_Rows = board.Rows;
             m_Columns = board.Columns;
-            m_NumCellTypes = board.NumCellTypes;
-            m_NumSpecialTypes = board.NumSpecialTypes;
+            m_GridValues = gvp;
+            m_OneHotSize = oneHotSize;
 
             m_ObservationType = obsType;
             m_ObservationSpec = obsType == Match3ObservationType.Vector
-                ? ObservationSpec.Vector(m_Rows * m_Columns * (m_NumCellTypes + SpecialTypeSize))
-                : ObservationSpec.Visual(m_Rows, m_Columns, m_NumCellTypes + SpecialTypeSize);
-
-            // See comment in GetCompressedObservation()
-            var cellTypePaddedSize = 3 * ((m_NumCellTypes + 2) / 3);
-            m_SparseChannelMapping = new int[cellTypePaddedSize + SpecialTypeSize];
-            // If we have 4 cell types and 2 special types (3 special size), we'd have
-            // [0, 1, 2, 3, -1, -1, 4, 5, 6]
-            for (var i = 0; i < m_NumCellTypes; i++)
-            {
-                m_SparseChannelMapping[i] = i;
-            }
+                ? ObservationSpec.Vector(m_Rows * m_Columns * oneHotSize)
+                : ObservationSpec.Visual(m_Rows, m_Columns, oneHotSize);
+        }
 
-            for (var i = m_NumCellTypes; i < cellTypePaddedSize; i++)
-            {
-                m_SparseChannelMapping[i] = -1;
-            }
+        /// <summary>
+        /// Create a sensor that encodes the board cells as observations.
+        /// </summary>
+        /// <param name="board">The abstract board.</param>
+        /// <param name="obsType">Whether to produce vector or visual observations</param>
+        /// <param name="name">Name of the sensor.</param>
+        /// <returns></returns>
+        public static Match3Sensor CellTypeSensor(AbstractBoard board, Match3ObservationType obsType, string name)
+        {
+            return new Match3Sensor(board, board.GetCellType, board.NumCellTypes, obsType, name);
+        }
 
-            for (var i = 0; i < SpecialTypeSize; i++)
-            {
-                m_SparseChannelMapping[cellTypePaddedSize + i] = i + m_NumCellTypes;
-            }
+        /// <summary>
+        /// Create a sensor that encodes the cell special types as observations.
+        /// </summary>
+        /// <param name="board">The abstract board.</param>
+        /// <param name="obsType">Whether to produce vector or visual observations</param>
+        /// <param name="name">Name of the sensor.</param>
+        /// <returns></returns>
+        public static Match3Sensor SpecialTypeSensor(AbstractBoard board, Match3ObservationType obsType, string name)
+        {
+            var specialSize = board.NumSpecialTypes == 0 ? 0 : board.NumSpecialTypes + 1;
+            return new Match3Sensor(board, board.GetSpecialType, specialSize, obsType, name);
         }
 
         /// <inheritdoc/>
@@ -103,14 +113,14 @@ public ObservationSpec GetObservationSpec()
         /// <inheritdoc/>
         public int Write(ObservationWriter writer)
         {
-            if (m_Board.Rows != m_Rows || m_Board.Columns != m_Columns || m_Board.NumCellTypes != m_NumCellTypes)
-            {
-                Debug.LogWarning(
-                    $"Board shape changes since sensor initialization. This may cause unexpected results. " +
-                    $"Old shape: Rows={m_Rows} Columns={m_Columns}, NumCellTypes={m_NumCellTypes} " +
-                    $"Current shape: Rows={m_Board.Rows} Columns={m_Board.Columns}, NumCellTypes={m_Board.NumCellTypes}"
-                );
-            }
+            // if (m_Board.Rows != m_Rows || m_Board.Columns != m_Columns || m_Board.NumCellTypes != m_NumCellTypes)
+            // {
+            //     Debug.LogWarning(
+            //         $"Board shape changes since sensor initialization. This may cause unexpected results. " +
+            //         $"Old shape: Rows={m_Rows} Columns={m_Columns}, NumCellTypes={m_NumCellTypes} " +
+            //         $"Current shape: Rows={m_Board.Rows} Columns={m_Board.Columns}, NumCellTypes={m_Board.NumCellTypes}"
+            //     );
+            // }
 
             if (m_ObservationType == Match3ObservationType.Vector)
             {
@@ -119,22 +129,13 @@ public int Write(ObservationWriter writer)
                 {
                     for (var c = 0; c < m_Columns; c++)
                     {
-                        var val = m_Board.GetCellType(r, c);
-                        for (var i = 0; i < m_NumCellTypes; i++)
+                        var val = m_GridValues(r, c);
+
+                        for (var i = 0; i < m_OneHotSize; i++)
                         {
                             writer[offset] = (i == val) ? 1.0f : 0.0f;
                             offset++;
                         }
-
-                        if (m_NumSpecialTypes > 0)
-                        {
-                            var special = m_Board.GetSpecialType(r, c);
-                            for (var i = 0; i < SpecialTypeSize; i++)
-                            {
-                                writer[offset] = (i == special) ? 1.0f : 0.0f;
-                                offset++;
-                            }
-                        }
                     }
                 }
 
@@ -148,22 +149,12 @@ public int Write(ObservationWriter writer)
                 {
                     for (var c = 0; c < m_Columns; c++)
                     {
-                        var val = m_Board.GetCellType(r, c);
-                        for (var i = 0; i < m_NumCellTypes; i++)
+                        var val = m_GridValues(r, c);
+                        for (var i = 0; i < m_OneHotSize; i++)
                         {
                             writer[r, c, i] = (i == val) ? 1.0f : 0.0f;
                             offset++;
                         }
-
-                        if (m_NumSpecialTypes > 0)
-                        {
-                            var special = m_Board.GetSpecialType(r, c);
-                            for (var i = 0; i < SpecialTypeSize; i++)
-                            {
-                                writer[offset] = (i == special) ? 1.0f : 0.0f;
-                                offset++;
-                            }
-                        }
                     }
                 }
 
@@ -185,17 +176,10 @@ public byte[] GetCompressedObservation()
             // fit in in 2 images, but we'll use 3 here (2 PNGs for the 4 cell type channels, and 1 for
             // the special types). Note that we have to also implement the sparse channel mapping.
             // Optimize this it later.
-            var numCellImages = (m_NumCellTypes + 2) / 3;
+            var numCellImages = (m_OneHotSize + 2) / 3;
             for (var i = 0; i < numCellImages; i++)
             {
-                converter.EncodeToTexture(m_Board.GetCellType, tempTexture, 3 * i);
-                bytesOut.AddRange(tempTexture.EncodeToPNG());
-            }
-
-            var numSpecialImages = (SpecialTypeSize + 2) / 3;
-            for (var i = 0; i < numSpecialImages; i++)
-            {
-                converter.EncodeToTexture(m_Board.GetSpecialType, tempTexture, 3 * i);
+                converter.EncodeToTexture(m_GridValues, tempTexture, 3 * i);
                 bytesOut.AddRange(tempTexture.EncodeToPNG());
             }
 
@@ -223,7 +207,7 @@ internal SensorCompressionType GetCompressionType()
         /// <inheritdoc/>
         public CompressionSpec GetCompressionSpec()
         {
-            return new CompressionSpec(GetCompressionType(), m_SparseChannelMapping);
+            return new CompressionSpec(GetCompressionType());
         }
 
         /// <inheritdoc/>
@@ -265,9 +249,6 @@ internal class OneHotToTextureUtil
         int m_Width;
         private static Color[] s_OneHotColors = { Color.red, Color.green, Color.blue };
 
-        public delegate int GridValueProvider(int x, int y);
-
-
         public OneHotToTextureUtil(int height, int width)
         {
             m_Colors = new Color[height * width];

com.unity.ml-agents.extensions/Runtime/Match3/Match3SensorComponent.cs

@@ -21,10 +21,20 @@ public class Match3SensorComponent : SensorComponent
         public Match3ObservationType ObservationType = Match3ObservationType.Vector;
 
         /// <inheritdoc/>
-        public override ISensor CreateSensor()
+        public override ISensor[] CreateSensors()
         {
             var board = GetComponent<AbstractBoard>();
-            return new Match3Sensor(board, ObservationType, SensorName);
+            var cellSensor = Match3Sensor.CellTypeSensor(board, ObservationType, SensorName + " (cells)");
+            if (board.NumSpecialTypes > 0)
+            {
+                var specialSensor =
+                    Match3Sensor.SpecialTypeSensor(board, ObservationType, SensorName + " (special)");
+                return new ISensor[] { cellSensor, specialSensor };
+            }
+            else
+            {
+                return new ISensor[] { cellSensor };
+            }
         }
 
     }

com.unity.ml-agents.extensions/Runtime/Sensors/ArticulationBodySensorComponent.cs

@@ -16,9 +16,9 @@ public class ArticulationBodySensorComponent  : SensorComponent
         /// Creates a PhysicsBodySensor.
         /// </summary>
         /// <returns></returns>
-        public override ISensor CreateSensor()
+        public override ISensor[] CreateSensors()
         {
-            return new PhysicsBodySensor(RootBody, Settings, sensorName);
+            return new ISensor[] {new PhysicsBodySensor(RootBody, Settings, sensorName)};
         }
 
     }

com.unity.ml-agents.extensions/Runtime/Sensors/GridSensor.cs

@@ -267,9 +267,9 @@ public enum GridDepthType { Channel, ChannelHot };
         private Color DebugDefaultColor = new Color(1f, 1f, 1f, 0.25f);
 
         /// <inheritdoc/>
-        public override ISensor CreateSensor()
+        public override ISensor[] CreateSensors()
         {
-            return this;
+            return new ISensor[] { this };
         }
 
         /// <summary>

com.unity.ml-agents.extensions/Runtime/Sensors/RigidBodySensorComponent.cs

@@ -39,10 +39,10 @@ public class RigidBodySensorComponent : SensorComponent
         /// Creates a PhysicsBodySensor.
         /// </summary>
         /// <returns></returns>
-        public override ISensor CreateSensor()
+        public override ISensor[] CreateSensors()
         {
             var _sensorName = string.IsNullOrEmpty(sensorName) ? $"PhysicsBodySensor:{RootBody?.name}" : sensorName;
-            return new PhysicsBodySensor(GetPoseExtractor(), Settings, _sensorName);
+            return new ISensor[] { new PhysicsBodySensor(GetPoseExtractor(), Settings, _sensorName) };
         }
 
         /// <summary>