Edit the latest contribution to 2d_skeletons.rst and format the document

tutorials/animation/2d_skeletons.rst

@@ -6,77 +6,102 @@
 Introduction
 ------------
 
-When working with 3D, skeletal deforms are common for characters and creatures and most 3D modelling
-applications support it. For 2D, as this function is not used as often, it's difficult to
-find mainstream software aimed for this.
+When working with 3D, skeletal deforms are common for characters and creatures
+and most 3D modelling applications support it. For 2D, as this function is not
+used as often, it's difficult to find mainstream software aimed for this.
 
-One option is to create animations in third-party software such as Spine or Dragonbones. From Godot 3.1
-onwards, though, this functionality is supported built-in.
+One option is to create animations in third-party software such as Spine or
+Dragonbones. From Godot 3.1 onwards, though, this functionality is supported
+built-in.
 
-Why would you want to do skeletal animations directly in Godot? The answer is that there are many advantages to it:
+Why would you want to do skeletal animations directly in Godot? The answer is
+that there are many advantages to it:
 
-* Better integration with the engine, so less hassle importing and editing from an external tool.
-* Ability to control particle systems, shaders, sounds, call scripts, colors, transparency, etc. in animations.
-* The built-in skeletal system in Godot is very efficient and designed for performance.
+* Better integration with the engine, so less hassle importing and editing from
+  an external tool.
+* Ability to control particle systems, shaders, sounds, call scripts, colors,
+  transparency, etc. in animations.
+* The built-in skeletal system in Godot is very efficient and designed for
+  performance.
 
 The following tutorial will, then, explain 2D skeletal deformations.
 
 Setup
 -----
 
-.. seealso:: Before starting, it is advised to go through the :ref:`doc_cutout_animation` tutorial
-             to gain a general understanding of animating within Godot.
+.. seealso::
 
-For this tutorial, we will be using a single image to construct our character. Download it from :download:`gBot_pieces.png <img/gBot_pieces.png>`
-or save the image below.
+   Before starting, we recommend you to go through the
+   :ref:`doc_cutout_animation` tutorial to gain a general understanding of
+   animating within Godot.
+
+For this tutorial, we will be using a single image to construct our character.
+Download it from :download:`gBot_pieces.png <img/gBot_pieces.png>` or save the
+image below.
 
 .. image:: img/gBot_pieces.png
 
-It is also advised to download the final character image :download:`gBot_complete.png <img/gBot_complete.png>`
-to have a good reference for putting the different pieces together.
+It is also advised to download the final character image
+:download:`gBot_complete.png <img/gBot_complete.png>` to have a good reference
+for putting the different pieces together.
 
 .. image:: img/gBot_complete.png
 
 Creating the polygons
 ---------------------
 
-Create a new scene for your model (if it's going to be an animated character, you may want to use a ``KinematicBody2D``).
-For ease of use, an empty 2D node is created as a root for the polygons.
+Create a new scene for your model (if it's going to be an animated character,
+you may want to use a ``KinematicBody2D``). For ease of use, an empty 2D node is
+created as a root for the polygons.
 
-Begin with a ``Polygon2D`` node. There is no need to place it anywhere in the scene for now, so simply create it like this:
+Begin with a ``Polygon2D`` node. There is no need to place it anywhere in the
+scene for now, so simply create it like this:
 
 .. image:: img/skel2d1.png
 
-Select it and assign the texture with the character pieces you have downloaded before:
+Select it and assign the texture with the character pieces you have downloaded
+before:
 
 .. image:: img/skel2d2.png
 
-Drawing a polygon directly is not advised. Instead, open the "UV" dialog for the polygon:
+Drawing a polygon directly is not advised. Instead, open the "UV" dialog for the
+polygon:
 
 .. image:: img/skel2d3.png
 
-Head over to the *Points* mode, select the pencil and draw a polygon around the desired piece:
+Head over to the *Points* mode, select the pencil and draw a polygon around the
+desired piece:
 
 .. image:: img/skel2d4.png
 
-Duplicate the polygon node, rename it properly, enter the "UV" dialog again and replace the old polygon with another one in the new desired piece. In duplicated nodes with similar shape, you can move the previous polygon (instead of drawing new one). After moving the polygon, remember to update the UV by selecting Edit>” Polygon->UV” in Polygon 2D UV Editor. 
+Duplicate the polygon node and give it a proper name. Then, enter the "UV"
+dialog again and replace the old polygon with another one in the new desired
+piece.
 
+When you duplicate nodes and the next piece has a similar shape, you can edit
+the previous polygon instead of drawing a new one.
+
+After moving the polygon, remember to update the UV by selecting Edit -> Polygon
+-> UV” in the Polygon 2D UV Editor.
 
 .. image:: img/skel2d5.png
 
-Keep doing this until all pieces have been mapped.
+Keep doing this until you mapped all pieces.
 
 .. image:: img/skel2d6.png
 
-You will notice that pieces for nodes appear in the same layout as they do in the original texture.
-This is because (by default) when you draw a polygon, the UV and points are the same.
+You will notice that pieces for nodes appear in the same layout as they do in
+the original texture. This is because by default, when you draw a polygon, the
+UV and points are the same.
 
-Rearrange the pieces and build the character. This should be pretty quick. There is no need to change pivots,
-so don't bother making sure rotation pivots for each piece are right; you can leave them be for now.
+Rearrange the pieces and build the character. This should be pretty quick. There
+is no need to change pivots, so don't bother making sure rotation pivots for
+each piece are right; you can leave them be for now.
 
 .. image:: img/skel2d7.png
 
-Ah, the visual order of the pieces is not correct yet, as some are covering wrong pieces. Rearrange the order of the nodes to fix this:
+Ah, the visual order of the pieces is not correct yet, as some are covering
+wrong pieces. Rearrange the order of the nodes to fix this:
 
 .. image:: img/skel2d8.png
 
@@ -85,42 +110,52 @@ And there you go! It was definitely much easier than in the cutout tutorial.
 Creating the skeleton
 ---------------------
 
-Create a ``Skeleton2D`` node as a child of the root node. This will be the base of our skeleton:
+Create a ``Skeleton2D`` node as a child of the root node. This will be the base
+of our skeleton:
 
 .. image:: img/skel2d9.png
 
-Create a ``Bone2D`` node as a child of the skeleton. Put it on the hip (usually skeletons start here).
-The bone will be pointing to the right, but you can ignore this for now.
+Create a ``Bone2D`` node as a child of the skeleton. Put it on the hip (usually
+skeletons start here). The bone will be pointing to the right, but you can
+ignore this for now.
 
 .. image:: img/skel2d10.png
 
-Keep creating bones in hierarchy and naming them accordingly. 
+Keep creating bones in hierarchy and naming them accordingly.
 
 .. image:: img/skel2d11.png
 
-At the end of this chain, there will be a *jaw* node. It is, again, very short and pointing to the right.
-This is normal for bones without children. The length of *tip* bones can be changed with a property in the inspector:
+At the end of this chain, there will be a *jaw* node. It is, again, very short
+and pointing to the right. This is normal for bones without children. The length
+of *tip* bones can be changed with a property in the inspector:
 
 .. image:: img/skel2d12.png
 
-In this case, we don't need to rotate the bone (coincidentally the jaw points right in the sprite), but in case you need to, feel free to do it.
-Again, this is only really needed for tip bones as nodes with children don't usually need a length or a specific rotation.
+In this case, we don't need to rotate the bone (coincidentally the jaw points
+right in the sprite), but in case you need to, feel free to do it. Again, this
+is only really needed for tip bones as nodes with children don't usually need a
+length or a specific rotation.
 
 Keep going and build the whole skeleton:
 
 .. image:: img/skel2d13.png
 
-You will notice that all bones raise an annoying warning about a missing rest pose. This means that it's time to set one.
-Go to the *skeleton* node and create a rest pose. This pose is the default one, you can come back to it anytime you want (which is very handy for animating):
+You will notice that all bones raise an annoying warning about a missing rest
+pose. This means that it's time to set one. Go to the *skeleton* node and create
+a rest pose. This pose is the default one, you can come back to it anytime you
+want (which is very handy for animating):
 
 .. image:: img/skel2d14.png
 
-The warnings will go away. If you modify the skeleton (add/remove bones) you will need to set the rest pose again.
+The warnings will go away. If you modify the skeleton (add/remove bones) you
+will need to set the rest pose again.
 
 Deforming the polygons
 ----------------------
 
-Select the previously created polygons and assign the skeleton node to their ``Skeleton`` property. This will ensure that they can eventually be deformed by it.
+Select the previously created polygons and assign the skeleton node to their
+``Skeleton`` property. This will ensure that they can eventually be deformed by
+it.
 
 .. image:: img/skel2d15.png
 
@@ -128,56 +163,72 @@ Click the property highlighted above and select the skeleton node:
 
 .. image:: img/skel2d16.png
 
-Again, open the UV editor for the polygon and go to the *Bones* section. 
+Again, open the UV editor for the polygon and go to the *Bones* section.
 
 .. image:: img/skel2d17.png
 
-You will not be able to paint weights yet. For this you need to synchronize the list of bones from the skeleton with the polygon.
-This step is done only once and manually (unless you modify the skeleton by adding/removing/renaming bones).
-It ensures that your rigging information is kept in the polygon, even if a skeleton node is accidentally lost or the skeleton modified. Push the "Sync Bones to Polygon" button to sync the list.
+You will not be able to paint weights yet. For this you need to synchronize the
+list of bones from the skeleton with the polygon. This step is done only once
+and manually (unless you modify the skeleton by adding/removing/renaming bones).
+It ensures that your rigging information is kept in the polygon, even if a
+skeleton node is accidentally lost or the skeleton modified. Push the "Sync
+Bones to Polygon" button to sync the list.
 
 .. image:: img/skel2d18.png
 
-The list of bones will automatically appear. By default, your polygon has no weight assigned to any of them.
-Select the bones you want to assign weight to and paint them:
+The list of bones will automatically appear. By default, your polygon has no
+weight assigned to any of them. Select the bones you want to assign weight to
+and paint them:
 
 .. image:: img/skel2d19.png
 
-Points in white have a full weight assigned, while points in black are not influenced by the bone.
-If the same point is painted white for multiple bones, the influence will be distributed amongst them (so usually there is not that much
-need to use shades in-between unless you want to polish the bending effect).
+Points in white have a full weight assigned, while points in black are not
+influenced by the bone. If the same point is painted white for multiple bones,
+the influence will be distributed amongst them (so usually there is not that
+much need to use shades in-between unless you want to polish the bending
+effect).
 
 .. image:: img/skel2d20.gif
 
-After painting the weights, animating the bones (NOT the polygons!) will have the desired effect of modifying and bending the polygons accordingly.
-As you only need to animate bones in this approach, work becomes much easier!
+After painting the weights, animating the bones (NOT the polygons!) will have
+the desired effect of modifying and bending the polygons accordingly. As you
+only need to animate bones in this approach, work becomes much easier!
 
-But it's not all roses. Trying to animate bones that bend the polygon will often yield unexpected results:
+But it's not all roses. Trying to animate bones that bend the polygon will often
+yield unexpected results:
 
 .. image:: img/skel2d21.gif
 
-This happens because Godot generates internal triangles that connect the points when drawing the polygon. They don't always bend the way you would expect.
-To solve this, you need to set hints in the geometry to clarify how you expect it to deform.
+This happens because Godot generates internal triangles that connect the points
+when drawing the polygon. They don't always bend the way you would expect. To
+solve this, you need to set hints in the geometry to clarify how you expect it
+to deform.
 
 Internal vertices
 -----------------
 
-Open the UV menu for each bone again and go to the *Points* section. Add some internal vertices in the regions where you expect the geometry to bend:
+Open the UV menu for each bone again and go to the *Points* section. Add some
+internal vertices in the regions where you expect the geometry to bend:
 
 .. image:: img/skel2d22.png
 
-Now, go to the *Polygon* section and redraw your own polygons with more detail. Imagine that, as your polygons bend, you need to make sure they deform the least possible,
-so experiment a bit to find the right setup.
+Now, go to the *Polygon* section and redraw your own polygons with more detail.
+Imagine that, as your polygons bend, you need to make sure they deform the least
+possible, so experiment a bit to find the right setup.
 
 .. image:: img/skel2d23.png
 
-Once you start drawing, the original polygon will disappear and you will be free to create your own:
+Once you start drawing, the original polygon will disappear and you will be free
+to create your own:
 
 .. image:: img/skel2d24.png
 
-This amount of detail is usually fine, though you may want to have more fine-grained control over where triangles go. Experiment by yourself until you get the results you like.
+This amount of detail is usually fine, though you may want to have more
+fine-grained control over where triangles go. Experiment by yourself until you
+get the results you like.
 
-**Note:** Don't forget that your newly added internal vertices also need weight painting! Go to the *Bones* section again to assign them to the right bones.
+**Note:** Don't forget that your newly added internal vertices also need weight
+ painting! Go to the *Bones* section again to assign them to the right bones.
 
 Once you are all set, you will get much better results: