Refactored layers system to work better as DefinitionNode

It now features undo/redo of layer creation and removal

src/definition/CloudLayerDefinition.cpp

@@ -6,7 +6,8 @@
 #include "PackStream.h"
 #include "FloatNode.h"
 
-CloudLayerDefinition::CloudLayerDefinition(DefinitionNode *parent) : DefinitionNode(parent, "layer", "cloudlayer") {
+CloudLayerDefinition::CloudLayerDefinition(DefinitionNode *parent, const std::string &name)
+    : DefinitionNode(parent, name, "cloudlayer") {
     type = CIRRUS;
     altitude = 0.5;
     scaling = 0.5;
@@ -20,13 +21,13 @@ CloudLayerDefinition::~CloudLayerDefinition() {
 }
 
 CloudLayerDefinition *CloudLayerDefinition::newCopy(const CloudLayerDefinition &other, DefinitionNode *parent) {
-    CloudLayerDefinition *layer = new CloudLayerDefinition(parent);
+    CloudLayerDefinition *layer = new CloudLayerDefinition(parent, other.getName());
     other.copy(layer);
     return layer;
 }
 
 CloudLayerDefinition *CloudLayerDefinition::newCopy(DefinitionNode *parent) const {
-    CloudLayerDefinition *layer = new CloudLayerDefinition(parent);
+    CloudLayerDefinition *layer = new CloudLayerDefinition(parent, getName());
     copy(layer);
     return layer;
 }

src/definition/CloudLayerDefinition.h

@@ -12,7 +12,7 @@ namespace definition {
 
 class DEFINITIONSHARED_EXPORT CloudLayerDefinition : public DefinitionNode {
   public:
-    CloudLayerDefinition(DefinitionNode *parent);
+    CloudLayerDefinition(DefinitionNode *parent, const std::string &name);
     virtual ~CloudLayerDefinition();
 
     inline const NoiseState &getNoiseState() const {

src/definition/CloudsDefinition.cpp

@@ -2,8 +2,8 @@
 
 #include "CloudLayerDefinition.h"
 
-static DefinitionNode *_layerConstructor(Layers *parent) {
+static DefinitionNode *_layerConstructor(Layers *parent, const std::string &name) {
-    return new CloudLayerDefinition(parent);
+    return new CloudLayerDefinition(parent, name);
 }
 
 CloudsDefinition::CloudsDefinition(DefinitionNode *parent) : Layers(parent, "clouds", _layerConstructor) {
@@ -13,9 +13,8 @@ void CloudsDefinition::applyPreset(CloudsPreset preset) {
     clear();
 
     if (preset == CLOUDS_PRESET_PARTLY_CLOUDY) {
-        CloudLayerDefinition *layer = new CloudLayerDefinition(this);
+        CloudLayerDefinition layer(NULL, "Strato-cumulus");
-        layer->type = CloudLayerDefinition::STRATOCUMULUS;
+        layer.type = CloudLayerDefinition::STRATOCUMULUS;
-        layer->setName("Strato-cumulus");
         addLayer(layer);
     }
 }

src/definition/DefinitionDiff.cpp

@@ -4,3 +4,6 @@
 
 DefinitionDiff::DefinitionDiff(const DefinitionNode *node) : type_name(node->getTypeName()), path(node->getPath()) {
 }
+
+DefinitionDiff::~DefinitionDiff() {
+}

src/definition/DefinitionDiff.h

@@ -14,6 +14,7 @@ namespace definition {
 class DEFINITIONSHARED_EXPORT DefinitionDiff {
   public:
     DefinitionDiff(const DefinitionNode *node);
+    virtual ~DefinitionDiff();
 
     inline const std::string &getTypeName() const {
         return type_name;

src/definition/DefinitionNode.cpp

@@ -248,5 +248,7 @@ void DefinitionNode::addDiff(const DefinitionDiff *diff) {
 
     if (root && root->diffs) {
         root->diffs->addDiff(this, diff);
+    } else {
+        delete diff;
     }
 }

src/definition/DiffManager.cpp

@@ -4,6 +4,7 @@
 #include "DefinitionNode.h"
 #include "DefinitionDiff.h"
 #include "DefinitionWatcher.h"
+#include "Logs.h"
 
 DiffManager::DiffManager(DefinitionNode *tree) : tree(tree) {
     undone = 0;
@@ -46,16 +47,21 @@ void DiffManager::addDiff(DefinitionNode *node, const DefinitionDiff *diff) {
 
 void DiffManager::undo() {
     if (undone < (int)diffs.size()) {
-        undone++;
+        const DefinitionDiff *diff = diffs[diffs.size() - undone - 1];
-        const DefinitionDiff *diff = diffs[diffs.size() - undone];
 
         // Obtain the node by path and reverse apply diff on it
         DefinitionNode *node = tree->findByPath(diff->getPath());
-        node->applyDiff(diff, true);
+        if (node) {
+            undone++;
 
-        for (auto watcher : watchers[node]) {
+            node->applyDiff(diff, true);
-            // FIXME Reverse diff
+
-            watcher->nodeChanged(node, diff);
+            for (auto watcher : watchers[node]) {
+                // FIXME Reverse diff
+                watcher->nodeChanged(node, diff);
+            }
+        } else {
+            Logs::error() << "Can't find node to undo diff : " << diff->getPath() << std::endl;
         }
     }
 }
@@ -63,14 +69,19 @@ void DiffManager::undo() {
 void DiffManager::redo() {
     if (undone > 0) {
         const DefinitionDiff *diff = diffs[diffs.size() - undone];
-        undone--;
 
         // Obtain the node by path and re-apply diff on it
         DefinitionNode *node = tree->findByPath(diff->getPath());
-        node->applyDiff(diff);
+        if (node) {
+            undone--;
 
-        for (auto watcher : watchers[node]) {
+            node->applyDiff(diff);
-            watcher->nodeChanged(node, diff);
+
+            for (auto watcher : watchers[node]) {
+                watcher->nodeChanged(node, diff);
+            }
+        } else {
+            Logs::error() << "Can't find node to redo diff : " << diff->getPath() << std::endl;
         }
     }
 }

src/definition/DiffManager.h

@@ -19,6 +19,13 @@ class DEFINITIONSHARED_EXPORT DiffManager {
     DiffManager(DefinitionNode *tree);
     ~DiffManager();
 
+    /**
+     * Get the total number of diff stored.
+     */
+    inline int getDiffCount(int include_undone = true) {
+        return include_undone ? diffs.size() : diffs.size() - undone;
+    }
+
     /**
      * Add a watcher for a specific node.
      *

src/definition/Layers.cpp

@@ -2,15 +2,15 @@
 
 #include "PackStream.h"
 #include "Logs.h"
+#include "LayersDiff.h"
 
 Layers::Layers(DefinitionNode *parent, const std::string &name, LayerConstructor layer_constructor)
     : DefinitionNode(parent, name, "layers" + name), layer_constructor(layer_constructor) {
     max_layer_count = 100;
-    null_layer = layer_constructor(this);
+    null_layer = layer_constructor(this, "#NULL#");
 }
 
 Layers::~Layers() {
-    clear();
     delete null_layer;
 }
 
@@ -28,16 +28,12 @@ void Layers::load(PackStream *stream) {
     int layer_count;
     stream->read(&layer_count);
 
-    if (layer_count > max_layer_count) {
-        layer_count = max_layer_count;
-    }
     clear();
     for (int i = 0; i < layer_count; i++) {
-        int position = addLayer();
+        DefinitionNode *layer = layer_constructor(this, stream->readString());
-        if (position >= 0) {
+        layer->load(stream);
-            layers[position]->setName(stream->readString());
+        addLayer(*layer);
-            layers[position]->load(stream);
+        delete layer;
-        }
     }
 }
 
@@ -53,24 +49,18 @@ void Layers::copy(DefinitionNode *destination_) const {
     null_layer->copy(destination->null_layer);
 
     for (auto layer : layers) {
-        int position = destination->addLayer();
+        destination->addLayer(*layer);
-        DefinitionNode *new_layer = destination->getLayer(position);
-        layer->copy(new_layer);
     }
 }
 
-Layers *Layers::newCopy() const {
-    Layers *result = new Layers(NULL, getName(), layer_constructor);
-    copy(result);
-    return result;
-}
-
 void Layers::setMaxLayerCount(int max_layer_count) {
     this->max_layer_count = max_layer_count;
-    // TODO Delete overlimit layers ?
+    for (int i = getLayerCount(); i > max_layer_count; i--) {
+        removeLayer(i - 1);
+    }
 }
 
-int Layers::count() const {
+int Layers::getLayerCount() const {
     return layers.size();
 }
 
@@ -84,82 +74,79 @@ DefinitionNode *Layers::getLayer(int position) const {
     }
 }
 
-int Layers::findLayer(DefinitionNode *layer) const {
+bool Layers::applyDiff(const DefinitionDiff *diff, bool backward) {
-    int i = 0;
+    auto layer_diff = (LayersDiff *)diff;
-    for (auto it : layers) {
+    LayersDiff::LayersDiffOp op = layer_diff->getOp();
-        if (it == layer) {
+    int layer_count = getLayerCount();
-            return i;
+
+    if ((not backward and op == LayersDiff::LAYER_ADDED) or (backward and op == LayersDiff::LAYER_REMOVED)) {
+        if (layer_count >= max_layer_count) {
+            Logs::warning() << "Add layer ignored because limit of " << max_layer_count << " reached" << std::endl;
+            return false;
+        } else {
+            int position = layer_diff->getLayer1();
+            if (position < 0 or position > layer_count) {
+                Logs::error() << "Add layer ignored because requested position was incorrect" << std::endl;
+                return false;
+            } else {
+                DefinitionNode *layer = layer_constructor(this, "temp");
+                layer_diff->restoreSavedLayer(layer);
+                if (position == layer_count) {
+                    layers.push_back(layer);
+                } else {
+                    layers.insert(layers.begin() + position, layer);
+                }
+                addChild(layer);
+                return true;
+            }
+        }
+    } else if ((not backward and op == LayersDiff::LAYER_REMOVED) or (backward and op == LayersDiff::LAYER_ADDED)) {
+        int position = layer_diff->getLayer1();
+        if (position < 0 or position >= layer_count) {
+            Logs::warning() << "Removing unknown layer " << position << " on " << layer_count << " from '" << getName()
+                            << "'" << std::endl;
+            return false;
+        } else {
+            DefinitionNode *removed = layers[position];
+            removeChild(removed);
+            layers.erase(layers.begin() + position);
+            delete removed;
+            return true;
         }
-        i++;
     }
-    Logs::warning() << "Layer " << layer << " (" << layer->getName() << " not found, on a total of "
+    return false;
-                    << (int)layers.size() << std::endl;
-    return -1;
 }
 
-int Layers::addLayer(DefinitionNode *layer) {
+void Layers::generateInitDiffs(std::vector<const DefinitionDiff *> *diffs) const {
-    if ((int)layers.size() < max_layer_count) {
+    int i = 0;
-        layers.push_back(layer);
+    for (auto layer: layers) {
-        addChild(layer);
+        auto diff = new LayersDiff(this, LayersDiff::LAYER_ADDED, i++);
-        return layers.size() - 1;
+        diff->saveLayer(*layer);
-    } else {
+        diffs->push_back(diff);
-        Logs::warning() << "Add layer ignored because limit of " << max_layer_count << " reached" << std::endl;
-        delete layer;
-        return -1;
     }
 }
 
-int Layers::addLayer() {
+void Layers::addLayer(const DefinitionNode &tocopy) {
-    return addLayer(layer_constructor(this));
+    auto diff = new LayersDiff(this, LayersDiff::LAYER_ADDED, getLayerCount());
+    diff->saveLayer(tocopy);
+    addDiff(diff);
+}
+
+void Layers::addLayer(const std::string &name) {
+    auto layer = layer_constructor(this, name);
+    addLayer(*layer);
+    delete layer;
 }
 
 void Layers::removeLayer(int position) {
-    if (position >= 0 and position < (int)layers.size()) {
+    auto diff = new LayersDiff(this, LayersDiff::LAYER_REMOVED, position);
-        DefinitionNode *removed = layers[position];
+    diff->saveLayer(*getLayer(position));
-        removeChild(removed);
+    addDiff(diff);
-        layers.erase(layers.begin() + position);
-        delete removed;
-    } else {
-        Logs::warning() << "Removing unknown layer " << position << " on " << (int)layers.size() << " from '"
-                        << getName() << "'" << std::endl;
-    }
-}
-
-void Layers::removeLayer(DefinitionNode *layer) {
-    removeLayer(findLayer(layer));
-}
-
-void Layers::moveLayer(int old_position, int new_position) {
-    if (old_position >= 0 and old_position < (int)layers.size() and new_position >= 0 and
-        new_position < (int)layers.size()) {
-        DefinitionNode *layer = layers[old_position];
-        layers.erase(layers.begin() + old_position);
-        layers.insert(layers.begin() + new_position, layer);
-    }
-}
-
-void Layers::moveLayer(DefinitionNode *layer, int new_position) {
-    moveLayer(findLayer(layer), new_position);
 }
 
 void Layers::clear() {
-    while (layers.size() > 0) {
+    int n = getLayerCount();
-        removeLayer(0);
+    for (int i = n - 1; i >= 0; i--) {
-    }
+        removeLayer(i);
-}
-
-DefinitionNode *Layers::findChildByName(const std::string name) {
-    DefinitionNode *result = DefinitionNode::findChildByName(name);
-    if (result) {
-        return result;
-    } else {
-        int position = addLayer();
-        if (position >= 0) {
-            result = getLayer(position);
-            result->setName(name);
-            return result;
-        } else {
-            return NULL;
-        }
     }
 }

src/definition/Layers.h

@@ -8,7 +8,7 @@
 namespace paysages {
 namespace definition {
 
-typedef DefinitionNode *(*LayerConstructor)(Layers *parent);
+typedef DefinitionNode *(*LayerConstructor)(Layers *parent, const std::string &name);
 
 /**
  * @brief Layers of definitions, ideally all of the same type.
@@ -21,31 +21,49 @@ class DEFINITIONSHARED_EXPORT Layers : public DefinitionNode {
     virtual void save(PackStream *stream) const override;
     virtual void load(PackStream *stream) override;
     virtual void copy(DefinitionNode *destination) const override;
-    Layers *newCopy() const;
 
-    void setMaxLayerCount(int max_layer_count);
+    virtual bool applyDiff(const DefinitionDiff *diff, bool backward = false) override;
-
+    virtual void generateInitDiffs(std::vector<const DefinitionDiff *> *diffs) const override;
-    int count() const;
-    DefinitionNode *getLayer(int position) const;
-    int findLayer(DefinitionNode *layer) const;
 
     /**
-     * @brief Add a new layer
+     * Set the maximal layer count allowed.
-     *
-     * This method takes ownership of the layer definition. In any case, it will be deleted by
-     * this object (even if the layer could not be added).
-     * @return The position of the new layer, -1 if it couldn't be added.
      */
-    int addLayer(DefinitionNode *layer);
+    void setMaxLayerCount(int max_layer_count);
-    int addLayer();
-    void removeLayer(int position);
-    void removeLayer(DefinitionNode *layer);
-    void moveLayer(int old_position, int new_position);
-    void moveLayer(DefinitionNode *layer, int new_position);
-    void clear();
 
-  protected:
+    /**
-    virtual DefinitionNode *findChildByName(const std::string name) override;
+     * Get the current layer count.
+     */
+    int getLayerCount() const;
+
+    /**
+     * Retrieve a layer by its position.
+     */
+    DefinitionNode *getLayer(int position) const;
+
+    /**
+     * Retrieve a layer by its name.
+     */
+    DefinitionNode *getLayer(const std::string &name) const;
+
+    /**
+     * Add a new empty layer.
+     */
+    void addLayer(const std::string &name);
+
+    /**
+     * Add a new layer, copying another node into it.
+     */
+    void addLayer(const DefinitionNode &tocopy);
+
+    /**
+     * Remove a layer by its position.
+     */
+    void removeLayer(int position);
+
+    /**
+     * Clear this node of all layers.
+     */
+    void clear();
 
   public:
     LayerConstructor layer_constructor;

src/definition/LayersDiff.cpp

@@ -0,0 +1,32 @@
+#include "LayersDiff.h"
+
+#include "PackStream.h"
+#include "Layers.h"
+#include "Logs.h"
+
+LayersDiff::LayersDiff(const Layers *layers, LayersDiffOp op, int layer1)
+    : DefinitionDiff(layers), op(op), layer1(layer1), saved(NULL) {
+}
+
+LayersDiff::~LayersDiff() {
+    if (saved) {
+        delete saved;
+    }
+}
+
+void LayersDiff::saveLayer(const DefinitionNode &src) {
+    if (saved) {
+        delete saved;
+    }
+    saved = new PackStream();
+    saved->write(src.getName());
+    src.save(saved);
+}
+
+void LayersDiff::restoreSavedLayer(DefinitionNode *dest) const {
+    if (saved) {
+        PackStream reader(saved);
+        dest->setName(reader.readString());
+        dest->load(&reader);
+    }
+}

src/definition/LayersDiff.h

@@ -0,0 +1,47 @@
+#ifndef LAYERSDIFF_H
+#define LAYERSDIFF_H
+
+#include "definition_global.h"
+
+#include "DefinitionDiff.h"
+
+namespace paysages {
+namespace definition {
+
+class DEFINITIONSHARED_EXPORT LayersDiff : public DefinitionDiff {
+  public:
+    typedef enum { LAYER_ADDED, LAYER_REMOVED } LayersDiffOp;
+
+  public:
+    LayersDiff(const Layers *layers, LayersDiffOp op, int layer1);
+    virtual ~LayersDiff();
+
+    inline LayersDiffOp getOp() const {
+        return op;
+    }
+    inline int getLayer1() const {
+        return layer1;
+    }
+
+    /**
+     * Save a layer state into the diff.
+     */
+    void saveLayer(const DefinitionNode &src);
+
+    /**
+     * Restore the saved layer into a node.
+     */
+    void restoreSavedLayer(DefinitionNode *dest) const;
+
+  private:
+    // Operation to apply
+    LayersDiffOp op;
+    // Position of first layer changed
+    int layer1;
+    // Serialized layer data
+    PackStream *saved;
+};
+}
+}
+
+#endif // LAYERSDIFF_H

src/definition/TextureLayerDefinition.cpp

@@ -8,8 +8,8 @@
 #include "TerrainDefinition.h"
 #include "Color.h"
 
-TextureLayerDefinition::TextureLayerDefinition(DefinitionNode *parent)
+TextureLayerDefinition::TextureLayerDefinition(DefinitionNode *parent, const std::string &name)
-    : DefinitionNode(parent, "texture", "texturelayer") {
+    : DefinitionNode(parent, name, "texturelayer") {
     terrain_zone = new Zone;
     _displacement_noise = new NoiseGenerator;
     _detail_noise = new NoiseGenerator;

src/definition/TextureLayerDefinition.h

@@ -20,7 +20,7 @@ class DEFINITIONSHARED_EXPORT TextureLayerDefinition : public DefinitionNode {
     } TextureLayerPreset;
 
   public:
-    TextureLayerDefinition(DefinitionNode *parent);
+    TextureLayerDefinition(DefinitionNode *parent, const std::string &name);
     virtual ~TextureLayerDefinition();
 
     virtual void save(PackStream *stream) const override;

src/definition/TexturesDefinition.cpp

@@ -2,53 +2,53 @@
 
 #include "TextureLayerDefinition.h"
 
-static DefinitionNode *_layer_constructor(Layers *parent) {
+static DefinitionNode *_layer_constructor(Layers *parent, const std::string &name) {
-    return new TextureLayerDefinition(parent);
+    return new TextureLayerDefinition(parent, name);
 }
 
 TexturesDefinition::TexturesDefinition(DefinitionNode *parent) : Layers(parent, "textures", _layer_constructor) {
 }
 
 void TexturesDefinition::applyPreset(TexturesPreset preset) {
-    TextureLayerDefinition *layer;
+    TextureLayerDefinition layer(NULL, "temp");
     clear();
 
-    layer = getTextureLayer(addLayer());
+    layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_MUD);
-    layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_MUD);
+    layer.setName("Mud");
-    layer->setName("Mud");
+    addLayer(layer);
 
     if (preset == TEXTURES_PRESET_FULL) {
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_ROCK);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_ROCK);
+        layer.setName("Ground");
-        layer->setName("Ground");
+        addLayer(layer);
 
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_GRASS);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_GRASS);
+        layer.setName("Grass");
-        layer->setName("Grass");
+        addLayer(layer);
 
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_SAND);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_SAND);
+        layer.setName("Sand");
-        layer->setName("Sand");
+        addLayer(layer);
 
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_SNOW);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_SNOW);
+        layer.setName("Snow");
-        layer->setName("Snow");
+        addLayer(layer);
     } else if (preset == TEXTURES_PRESET_IRELAND) {
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_ROCK);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_ROCK);
+        layer.setName("Ground");
-        layer->setName("Ground");
+        addLayer(layer);
 
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_GRASS);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_GRASS);
+        layer.setName("Grass");
-        layer->setName("Grass");
+        addLayer(layer);
     } else if (preset == TEXTURES_PRESET_ALPS) {
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_ROCK);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_ROCK);
+        layer.setName("Ground");
-        layer->setName("Ground");
+        addLayer(layer);
 
-        layer = getTextureLayer(addLayer());
+        layer.applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_SNOW);
-        layer->applyPreset(TextureLayerDefinition::TEXTURES_LAYER_PRESET_SNOW);
+        layer.setName("Snow");
-        layer->setName("Snow");
+        addLayer(layer);
     } else if (preset == TEXTURES_PRESET_CANYON) {
         /* TODO */
     }
@@ -56,7 +56,7 @@ void TexturesDefinition::applyPreset(TexturesPreset preset) {
 
 double TexturesDefinition::getMaximalDisplacement() {
     double result = 0.0;
-    int n = count();
+    int n = getLayerCount();
     for (int i = 0; i < n; i++) {
         result += getTextureLayer(i)->displacement_height;
     }

src/definition/TimeManager.cpp

@@ -17,7 +17,7 @@ void TimeManager::moveForward(Scenery *scenery, double amount) {
     scenery->getAtmosphere()->setDayTime(scenery->getAtmosphere()->propDayTime()->getValue() + amount);
 
     // Move the clouds
-    int n = scenery->getClouds()->count();
+    int n = scenery->getClouds()->getLayerCount();
     for (int i = 0; i < n; i++) {
         CloudLayerDefinition *cloud = scenery->getClouds()->getCloudLayer(i);
         cloud->propXOffset()->addValue(-wind_x * amount * 100.0);

src/definition/definition_global.h

@@ -26,6 +26,7 @@ class SurfaceMaterial;
 class Zone;
 class WaterDefinition;
 class Layers;
+class LayersDiff;
 class CloudsDefinition;
 class CloudLayerDefinition;
 class AtmosphereDefinition;

src/interface/commandline/tests.cpp

@@ -52,14 +52,15 @@ static void testGroundShadowQuality() {
     scenery.getAtmosphere()->applyPreset(AtmosphereDefinition::ATMOSPHERE_PRESET_CLEAR_SUNSET);
     scenery.getAtmosphere()->setDayTime(16, 45);
     scenery.getTextures()->clear();
-    TextureLayerDefinition *texture = scenery.getTextures()->getTextureLayer(scenery.getTextures()->addLayer());
+    TextureLayerDefinition texture(NULL, "test");
-    texture->displacement_height = 0.3;
+    texture.displacement_height = 0.3;
-    texture->displacement_scaling = 2.0;
+    texture.displacement_scaling = 2.0;
-    texture->displacement_offset = 0.0;
+    texture.displacement_offset = 0.0;
-    texture->material->setColor(0.6, 0.55, 0.57, 1.0);
+    texture.material->setColor(0.6, 0.55, 0.57, 1.0);
-    texture->material->reflection = 0.006;
+    texture.material->reflection = 0.006;
-    texture->material->shininess = 6.0;
+    texture.material->shininess = 6.0;
-    texture->validate();
+    texture.validate();
+    scenery.getTextures()->addLayer(texture);
     scenery.getCamera()->setLocation(Vector3(10.0, 10.0, -10.0));
     scenery.getCamera()->setTarget(VECTOR_ZERO);
     scenery.validate();

src/render/software/CloudsRenderer.cpp

@@ -20,7 +20,7 @@ CloudsRenderer::CloudsRenderer(SoftwareRenderer *parent) : parent(parent) {
     enabled = true;
     fake_renderer = new BaseCloudLayerRenderer(parent);
 
-    CloudLayerDefinition *fake_layer = new CloudLayerDefinition(NULL);
+    CloudLayerDefinition *fake_layer = new CloudLayerDefinition(NULL, "#fake#");
     fake_model = new BaseCloudsModel(fake_layer);
 }
 
@@ -60,7 +60,7 @@ void CloudsRenderer::update() {
     layer_models.clear();
 
     CloudsDefinition *clouds = parent->getScenery()->getClouds();
-    int n = clouds->count();
+    int n = clouds->getLayerCount();
     for (int i = 0; i < n; i++) {
         layer_renderers.push_back(new CloudBasicLayerRenderer(parent));
 
@@ -129,7 +129,7 @@ void CloudsRenderer::setLayerModel(unsigned int layer, BaseCloudsModel *model, b
 Color CloudsRenderer::getColor(const Vector3 &eye, const Vector3 &location, const Color &base) {
     CloudsDefinition *definition = parent->getScenery()->getClouds();
 
-    int n = definition->count();
+    int n = definition->getLayerCount();
     if (not enabled or n < 1) {
         return base;
     }
@@ -152,7 +152,7 @@ Color CloudsRenderer::getColor(const Vector3 &eye, const Vector3 &location, cons
 bool CloudsRenderer::applyLightFilter(LightComponent &light, const Vector3 &at) {
     CloudsDefinition *definition = parent->getScenery()->getClouds();
 
-    int n = definition->count();
+    int n = definition->getLayerCount();
     if (not enabled or n < 1) {
         return true;
     }
@@ -172,7 +172,7 @@ double CloudsRenderer::getHighestAltitude() {
     CloudsDefinition *definition = parent->getScenery()->getClouds();
     double highest = 0.0;
 
-    int n = definition->count();
+    int n = definition->getLayerCount();
     double low, high;
     for (int i = 0; i < n; i++) {
         BaseCloudsModel *layer_model = getLayerModel(i);

src/render/software/TexturesRenderer.cpp

@@ -46,7 +46,7 @@ double TexturesRenderer::getTriplanarNoise(NoiseGenerator *noise, const Vector3
 double TexturesRenderer::getMaximalDisplacement(TexturesDefinition *textures) {
     int i, n;
     double disp = 0.0;
-    n = textures->count();
+    n = textures->getLayerCount();
     for (i = 0; i < n; i++) {
         TextureLayerDefinition *layer = textures->getTextureLayer(i);
 
@@ -129,7 +129,7 @@ Vector3 TexturesRenderer::displaceTerrain(const TerrainRenderer::TerrainResult &
     double offset = 0.0;
     int i, n;
 
-    n = textures->count();
+    n = textures->getLayerCount();
     for (i = 0; i < n; i++) {
         TextureLayerDefinition *layer = textures->getTextureLayer(i);
 
@@ -161,7 +161,7 @@ TexturesRenderer::TexturesResult TexturesRenderer::applyToTerrain(double x, doub
     // TODO Displaced textures had their presence already computed before, store that result and use it
 
     // Find presence of each layer
-    int n = textures->count();
+    int n = textures->getLayerCount();
     int start = 0;
     for (int i = 0; i < n; i++) {
         TexturesLayerResult &layer = result.layers[i];

src/system/FileSystem.cpp

@@ -15,5 +15,8 @@ bool FileSystem::isFile(const std::string &filepath) {
 bool FileSystem::removeFile(const std::string &filepath) {
     if (FileSystem::isFile(filepath)) {
         remove(filepath.c_str());
+        return true;
+    } else {
+        return false;
     }
 }

src/system/PackStream.cpp

@@ -33,6 +33,13 @@ PackStream::PackStream(const PackStream *other) {
     stream->setVersion(QDataStream::Qt_5_2);
 }
 
+PackStream::PackStream(const std::string &buffer_content) {
+    file = NULL;
+    buffer = new QByteArray(buffer_content.c_str(), buffer_content.size());
+    stream = new QDataStream(buffer, QIODevice::ReadOnly);
+    stream->setVersion(QDataStream::Qt_5_2);
+}
+
 bool PackStream::bindToFile(const std::string &filepath, bool write) {
     if (not file) {
         file = new QFile(QString::fromStdString(filepath));
@@ -90,6 +97,16 @@ void PackStream::writeFromBuffer(const PackStream &other, bool prepend_size) {
     }
 }
 
+std::string PackStream::getBuffer() {
+    if (file) {
+        Logs::error() << "Try to get buffer on a stream bound to a file: " << file->fileName().toStdString()
+                      << std::endl;
+        return "";
+    } else {
+        return buffer->toStdString();
+    }
+}
+
 void PackStream::read(int *value) {
     if (value and not stream->atEnd()) {
         int output;

src/system/PackStream.h

@@ -25,6 +25,11 @@ class SYSTEMSHARED_EXPORT PackStream {
      */
     PackStream(const PackStream *other);
 
+    /**
+     * Open a reading stream on a buffer content.
+     */
+    PackStream(const std::string &buffer_content);
+
     bool bindToFile(const std::string &filepath, bool write = false);
 
     void write(const int *value);
@@ -41,6 +46,11 @@ class SYSTEMSHARED_EXPORT PackStream {
      */
     void writeFromBuffer(const PackStream &other, bool prepend_size = false);
 
+    /**
+     * Get the contents of the memory buffer, if this stream is not bound to a file.
+     */
+    std::string getBuffer();
+
     void read(int *value);
     void read(double *value);
     void read(char *value, int max_length);

src/tests/Layers_Test.cpp

@@ -2,19 +2,21 @@
 
 #include "Layers.h"
 #include "PackStream.h"
+#include "DiffManager.h"
+#include "IntNode.h"
 
-DefinitionNode *_construc1(Layers *) {
+static DefinitionNode *_construc1(Layers *, const std::string &name) {
-    return new DefinitionNode(NULL, "test");
+    return new DefinitionNode(NULL, name);
 }
 
-DefinitionNode *_construc2(Layers *parent) {
+static DefinitionNode *_construc2(Layers *parent, const std::string &name) {
-    DefinitionNode *result = new DefinitionNode(parent, "test");
+    DefinitionNode *result = new DefinitionNode(parent, name);
     return result;
 }
 
 TEST(Layers, Constructor) {
     Layers layers1(NULL, "test", _construc1);
-    EXPECT_EQ(0, layers1.count());
+    EXPECT_EQ(0, layers1.getLayerCount());
 }
 
 TEST(Layers, NullLayer) {
@@ -27,22 +29,22 @@ TEST(Layers, NullLayer) {
         EXPECT_EQ(NULL, layer->getParent());
         EXPECT_EQ(layer, layer->getRoot());
 
-        EXPECT_EQ("test", layer->getName());
+        EXPECT_EQ("#NULL#", layer->getName());
     }
 
-    EXPECT_EQ(0, layers1.count());
+    EXPECT_EQ(0, layers1.getLayerCount());
 }
 
 TEST(Layers, copy) {
     Layers layers1(NULL, "test", _construc2);
-    layers1.addLayer();
+    layers1.addLayer("test");
-    EXPECT_EQ(1, layers1.count());
+    EXPECT_EQ(1, layers1.getLayerCount());
 
     // Copy with the same constructor
     Layers layers2(NULL, "test", _construc2);
-    EXPECT_EQ(0, layers2.count());
+    EXPECT_EQ(0, layers2.getLayerCount());
     layers1.copy(&layers2);
-    EXPECT_EQ(1, layers2.count());
+    EXPECT_EQ(1, layers2.getLayerCount());
     EXPECT_EQ("test", layers1.getLayer(0)->getName());
     EXPECT_EQ(&layers1, layers1.getLayer(0)->getParent());
     EXPECT_EQ("test", layers2.getLayer(0)->getName());
@@ -54,32 +56,35 @@ TEST(Layers, maxLayerCount) {
     Layers layers1(NULL, "test", _construc1);
     layers1.setMaxLayerCount(2);
 
-    EXPECT_EQ(0, layers1.count());
+    EXPECT_EQ(0, layers1.getLayerCount());
-    layers1.addLayer();
+    layers1.addLayer("t1");
-    EXPECT_EQ(1, layers1.count());
+    EXPECT_EQ(1, layers1.getLayerCount());
-    layers1.addLayer();
+    layers1.addLayer("t2");
-    EXPECT_EQ(2, layers1.count());
+    EXPECT_EQ(2, layers1.getLayerCount());
-    layers1.addLayer();
+    layers1.addLayer("t3");
-    EXPECT_EQ(2, layers1.count());
+    EXPECT_EQ(2, layers1.getLayerCount());
-    layers1.addLayer();
+    layers1.addLayer("t4");
-    EXPECT_EQ(2, layers1.count());
+    EXPECT_EQ(2, layers1.getLayerCount());
     layers1.removeLayer(0);
-    EXPECT_EQ(1, layers1.count());
+    EXPECT_EQ(1, layers1.getLayerCount());
-    layers1.addLayer();
+    layers1.addLayer("t5");
-    EXPECT_EQ(2, layers1.count());
+    EXPECT_EQ(2, layers1.getLayerCount());
-    layers1.addLayer();
+    layers1.addLayer("t6");
-    EXPECT_EQ(2, layers1.count());
+    EXPECT_EQ(2, layers1.getLayerCount());
+
+    layers1.setMaxLayerCount(1);
+    EXPECT_EQ(1, layers1.getLayerCount());
+    layers1.setMaxLayerCount(0);
+    EXPECT_EQ(0, layers1.getLayerCount());
 }
 
 TEST(Layers, saveLoad) {
     PackStream *stream;
 
     Layers layers1(NULL, "test", _construc1);
-    layers1.addLayer();
+    layers1.addLayer("first");
-    layers1.addLayer();
+    layers1.addLayer("second");
-    ASSERT_EQ(2, layers1.count());
+    ASSERT_EQ(2, layers1.getLayerCount());
-    layers1.getLayer(0)->setName("first");
-    layers1.getLayer(1)->setName("second");
 
     stream = new PackStream();
     stream->bindToFile("/tmp/test_paysages_pack", true);
@@ -93,7 +98,99 @@ TEST(Layers, saveLoad) {
     layers2.load(stream);
     delete stream;
 
-    ASSERT_EQ(2, layers2.count());
+    ASSERT_EQ(2, layers2.getLayerCount());
     EXPECT_EQ("first", layers2.getLayer(0)->getName());
     EXPECT_EQ("second", layers2.getLayer(1)->getName());
 }
+
+static void checkLayerChild(const Layers &layers, int layer, const std::string &name, int value) {
+    ASSERT_EQ(1, layers.getLayerCount());
+    ASSERT_TRUE(layers.getLayer(layer)->findByPath(name));
+    ASSERT_EQ("int", layers.getLayer(layer)->findByPath(name)->getTypeName());
+    EXPECT_EQ(value, ((IntNode *)layers.getLayer(layer)->findByPath(name))->getValue());
+}
+
+class TestLayer : public DefinitionNode {
+  public:
+    TestLayer(Layers *parent, const std::string &name) : DefinitionNode(parent, name) {
+        val = new IntNode(this, "val", 5);
+    }
+    IntNode *val;
+};
+
+static DefinitionNode *_construc3(Layers *parent, const std::string &name) {
+    return new TestLayer(parent, name);
+}
+
+TEST(Layers, undoRedo) {
+    Layers layers(NULL, "layers", _construc3);
+
+    EXPECT_EQ(0, layers.getLayerCount());
+    EXPECT_EQ(0, layers.getDiffManager()->getDiffCount());
+
+    layers.addLayer("testlayer");
+
+    ASSERT_EQ(1, layers.getLayerCount());
+
+    TestLayer *layer = (TestLayer *)layers.getLayer(0);
+
+    EXPECT_EQ(1, layers.getDiffManager()->getDiffCount());
+    checkLayerChild(layers, 0, "val", 5);
+
+    layer->val->setValue(8);
+
+    EXPECT_EQ(2, layers.getDiffManager()->getDiffCount());
+    checkLayerChild(layers, 0, "val", 8);
+
+    layers.removeLayer(0);
+
+    EXPECT_EQ(3, layers.getDiffManager()->getDiffCount());
+    EXPECT_EQ(0, layers.getLayerCount());
+
+    // Start undoing
+    layers.getDiffManager()->undo();
+    checkLayerChild(layers, 0, "val", 8);
+    layers.getDiffManager()->undo();
+    checkLayerChild(layers, 0, "val", 5);
+    layers.getDiffManager()->undo();
+    EXPECT_EQ(0, layers.getLayerCount());
+
+    EXPECT_EQ(3, layers.getDiffManager()->getDiffCount());
+
+    // Start redoing
+    layers.getDiffManager()->redo();
+    checkLayerChild(layers, 0, "val", 5);
+    layers.getDiffManager()->redo();
+    checkLayerChild(layers, 0, "val", 8);
+    layers.getDiffManager()->redo();
+    EXPECT_EQ(0, layers.getLayerCount());
+
+    EXPECT_EQ(3, layers.getDiffManager()->getDiffCount());
+
+    // TODO Test swapping
+}
+
+TEST(Layers, generateInitDiffs) {
+    Layers layers(NULL, "layers", _construc1);
+
+    std::vector<const DefinitionDiff *> diffs;
+    layers.generateInitDiffs(&diffs);
+    EXPECT_EQ(0, (int)diffs.size());
+
+    layers.addLayer("l1");
+    layers.addLayer("l2");
+    layers.addLayer("l3");
+
+    diffs.clear();
+    layers.generateInitDiffs(&diffs);
+    EXPECT_EQ(3, (int)diffs.size());
+
+    Layers layers1(NULL, "layers", _construc1);
+    for (auto diff: diffs) {
+        layers1.applyDiff(diff);
+    }
+    ASSERT_EQ(3, layers1.getLayerCount());
+    EXPECT_EQ("l1", layers1.getLayer(0)->getName());
+    EXPECT_EQ("l2", layers1.getLayer(1)->getName());
+    EXPECT_EQ("l3", layers1.getLayer(2)->getName());
+}