Add History object to handle history

scripts/vr-edit/modules/feedback.js

@@ -23,6 +23,8 @@ Feedback = (function () {
         CREATE_SOUND = SoundCache.getSound(Script.resolvePath("../assets/audio/create.wav")),
         EQUIP_SOUND = SoundCache.getSound(Script.resolvePath("../assets/audio/equip.wav")),
         ERROR_SOUND = SoundCache.getSound(Script.resolvePath("../assets/audio/error.wav")),
+        UNDO_SOUND = DROP_SOUND,  // TODO
+        REDO_SOUND = DROP_SOUND,  // TODO
 
         FEEDBACK_PARAMETERS = {
             DROP_TOOL:       { sound: DROP_SOUND,   volume: 0.3, haptic: 0.75  },
@@ -35,6 +37,8 @@ Feedback = (function () {
             EQUIP_TOOL:      { sound: EQUIP_SOUND,  volume: 0.3, haptic: 0.6   },
             APPLY_PROPERTY:  { sound: null,         volume: 0,   haptic: 0.3   },
             APPLY_ERROR:     { sound: ERROR_SOUND,  volume: 0.2, haptic: 0.7   },
+            UNDO_ACTION:     { sound: UNDO_SOUND,   volume: 0.2, haptic: 0.2   },  // TODO
+            REDO_ACTION:     { sound: REDO_SOUND,   volume: 0.2, haptic: 0.2   },  // TODO
             GENERAL_ERROR:   { sound: ERROR_SOUND,  volume: 0.2, haptic: 0.7   }
         },
 
@@ -68,6 +72,8 @@ Feedback = (function () {
         EQUIP_TOOL: "EQUIP_TOOL",
         APPLY_PROPERTY: "APPLY_PROPERTY",
         APPLY_ERROR: "APPLY_ERROR",
+        UNDO_ACTION: "UNDO_ACTION",
+        REDO_ACTION: "REDO_ACTION",
         GENERAL_ERROR: "GENERAL_ERROR",
         play: play
     };

scripts/vr-edit/modules/history.js

@@ -0,0 +1,99 @@
+//
+//  history.js
+//
+//  Created by David Rowe on 12 Sep 2017.
+//  Copyright 2017 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+/* global History */
+
+History = (function () {
+    // Provides undo facility.
+    // Global object.
+
+    "use strict";
+
+    var history = [
+            /*
+            {
+                undoData: {
+                    setProperties: [
+                        {
+                            entityID: <entity ID>,
+                            properties: { <name>: <value>, <name>: <value>, ... }
+                        }
+                    ],
+                    createEntities: [
+                        {
+                            entityID: <entity ID>,
+                            properties: { <name>: <value>, <name>: <value>, ... }
+                        }
+                    ],
+                    deleteEntities: [
+                        {
+                            entityID: <entity ID>,
+                            properties: { <name>: <value>, <name>: <value>, ... }
+                        }
+                    ]
+                },
+                redoData: {
+                    ""
+                }
+            }
+            */
+        ],
+        MAX_HISTORY_ITEMS = 100,
+        undoPosition = -1;  // The next history item to undo; the next history item to redo = undoIndex + 1.
+
+    function push(undoData, redoData) {
+        // Wipe any redo history after current undo position.
+        if (undoPosition < history.length - 1) {
+            history.splice(undoPosition + 1, history.length - undoPosition - 1);
+        }
+
+        // Limit the number of history items.
+        if (history.length >= MAX_HISTORY_ITEMS) {
+            history.splice(0, history.length - MAX_HISTORY_ITEMS + 1);
+        }
+
+        history.push({ undoData: undoData, redoData: redoData });
+        undoPosition += 1;
+    }
+
+    function hasUndo() {
+        return undoPosition > -1;
+    }
+
+    function hasRedo() {
+        return undoPosition < history.length - 1;
+    }
+
+    function undo() {
+        if (undoPosition > -1) {
+
+            // TODO
+
+            undoPosition -= 1;
+        }
+    }
+
+    function redo() {
+        if (undoPosition < history.length - 1) {
+
+            // TODO
+
+            undoPosition += 1;
+        }
+    }
+
+    return {
+        push: push,
+        hasUndo: hasUndo,
+        hasRedo: hasRedo,
+        undo: undo,
+        redo: redo
+    };
+}());

scripts/vr-edit/vr-edit.js

@@ -83,6 +83,7 @@
     Script.include("./modules/hand.js");
     Script.include("./modules/handles.js");
     Script.include("./modules/highlights.js");
+    Script.include("./modules/history.js");
     Script.include("./modules/laser.js");
     Script.include("./modules/selection.js");
     Script.include("./modules/toolIcon.js");
@@ -1535,6 +1536,23 @@
             }
             break;
 
+        case "undoAction":
+            if (History.hasUndo()) {
+                Feedback.play(dominantHand, Feedback.UNDO_ACTION)
+                History.undo();
+            } else {
+                Feedback.play(dominantHand, Feedback.GENERAL_ERROR);
+            }
+            break;
+        case "redoAction":
+            if (History.hasRedo()) {
+                Feedback.play(dominantHand, Feedback.REDO_ACTION)
+                History.redo();
+            } else {
+                Feedback.play(dominantHand, Feedback.GENERAL_ERROR);
+            }
+            break;
+
         default:
             log("ERROR: Unexpected command in onUICommand(): " + command + ", " + parameter);
         }