First iteration on semnatic tags

Docs/index.md

@@ -143,6 +143,8 @@ CARLA forum</a>
         — Add new content to CARLA.  
     [__Create a sensor__](tuto_D_create_sensor.md)
         — Develop a new sensor to be used in CARLA.  
+    [__Create semantic tags_](tuto_D_create_semantic_tags.md)
+        — Define new semantic tags for semantic segmentation.  
     [__Customize vehicle suspension__](tuto_D_customize_vehicle_suspension.md)
         — Modify the suspension system of a vehicle.  
     [__Make a release__](tuto_D_make_release.md)

Docs/ref_sensors.md

@@ -1583,8 +1583,7 @@ The following tags are currently available:
 <br>
 
 !!! Note
-    **Adding new tags**:
-    It requires some C++ coding. Add a new label to the `ECityObjectLabel` enum in "Tagger.h", and its corresponding filepath check inside `GetLabelByFolderName()` function in "Tagger.cpp".
+    Read [this](tuto_D_create_semantic_tags.md) tutorial to create new semantic tags. 
 
 #### Basic camera attributes
 

Docs/tuto_D_create_semantic_tags.md

@@ -0,0 +1,57 @@
+# Create semantic tags
+
+Learn how to define customized tags for semantic segmentation. These can additionally be used to filter the bounding boxes that [carla.World](python_api.md#carla.World) retrieves.  
+
+*   [__Create a new semantic tag__](#add-a-4-wheeled-vehicle)  
+*   [__Add a tag to carla.CityObjectLabel__](#add-a-2-wheeled-vehicle)  
+
+---
+
+## Create a new semantic tag
+
+### 1. Create the tag ID
+
+__Open `ObjectLabel.h`__ in `LibCarla/source/carla/rpc`. Add your new tag by the end of the enum using the same formatting as the rest.  
+
+![object_label_h](img/tuto_D_create_semantic_tags/01_objectlabel_tag.jpg)
+
+!!! Note
+    Tags do not have to appear in order. However, it is good practice to list them in order. 
+
+### 2. Create the UE folder for assets
+
+__Open the Unreal Engine Editor__ and go to `Carla/Static`. Create a new folder named as your tag. 
+
+![ue_folder](img/tuto_D_create_semantic_tags/02_ue_folder.jpg)
+
+!!! Note
+    The UE folder and the tag do not necessarily have to be named the same. However, it is good practice to do so.  
+
+### 3. Create two-way correspondence between UE and the code tag
+
+__3.1. Open `Tagger.cpp`__ in `Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Game`. Go to __`GetLabelByFolderName`__ Add the your tag by the end of the list.  
+
+![tagger_cpp](img/tuto_D_create_semantic_tags/03_tagger_cpp.jpg)
+
+__3.2. Go to `GetTagAsString`__ in the same `Tagger.cpp`. Add the new tag by the end of the switch.  
+
+![tagger_cpp_02](img/tuto_D_create_semantic_tags/04_tagger_cpp_02.jpg)
+
+### 4. Add the color code
+
+__Open `CityScapesPalette.h`__ in `LibCarla/source/carla/image`. Add the color code of your new tag by the end of the array. 
+
+![city_scapes_palette_h](img/tuto_D_create_semantic_tags/05_city_scapes_palette_h.jpg)
+
+!!! Warning
+    The position in the array must correspond with the tag ID, in this case, `23u`. 
+
+### 5. Add the tagged elements
+
+The new semantic tag is ready to be used. Only the elements stored inside the UE folder of a tag are tagged as such. Move or import the corresponding elements to the new folder, in order for the to be tagged properly. 
+
+---
+
+## Add a tag to carla.CityObjectLabel
+
+This step is not directly related with semantic segmentation. However, these tags can be used to filter the bounding box query in [carla.World](python_api.md#carla.World). In order to do this, the tag must be added to the [carla.CityObjectLabel]() enum in the PythonAPI. 

mkdocs.yml

@@ -62,6 +62,7 @@ nav:
 - Tutorials (developers):
   - 'Contribute with assets': 'tuto_D_contribute_assets.md'
   - 'Create a sensor': 'tuto_D_create_sensor.md'
+  - 'Create semantic tags': 'tuto_D_create_semantic_tags.md'
   - 'Customize vehicle suspension': 'tuto_D_customize_vehicle_suspension.md'
   - 'Generate detailed colliders': 'tuto_D_generate_colliders.md'
   - 'Make a release': 'tuto_D_make_release.md'