The `Math_INF` and `Math_NAN` defines were just aliases for those
constants, so we might as well use them directly.
Some portions of the code were already using `INFINITY` directly.
* Lua table syntax uses named indexing: `{ mykey = myvalue }`
* Python style syntax uses string indexing: `{ "mykey" : myvalue }`
* Both are incompatible since a StringName key wont fetch a String key, hence confusing.
* This PR proposes always using String for indexing at a very minimal performance cost. Always indexing with StringNames will be faster, but they are considerably more expensive to create.
* Deprecates GDNative in favor of a simpler, lower level interface.
* New extension system allows registering core engine classes.
* Simple header interface in gdnative_interace.h
The order of numbers is not changed except for Transform2D. All logic is done inside of their structures (and not in Variant).
For the number of decimals printed, they now use String::num_real which works best with real_t, except for Color which is fixed at 4 decimals (this is a reliable number of float digits when converting from 16-bpc so it seems like a good choice)
This PR and commit adds a new IK system for 2D with the Skeleton2D node
that adds several new IK solvers, a way to control bones in a Skeleton2D
node similar to that in Skeleton3D. It also adds additional changes
and functionality.
This work was sponsored by GSoC 2020 and TwistedTwigleg.
Full list of changes:
* Adds a SkeletonModifier2D resource
* This resource is the base where all IK code is written and executed
* Has a function for clamping angles, since it is so commonly used
* Modifiers are unique when duplicated so it works with instancing
* Adds a SkeletonModifierStack2D resource
* This resource manages a series of SkeletonModification2Ds
* This is what the Skeleton2D directly interfaces with to make IK possible
* Adds SkeletonModifier2D resources for LookAt, CCDIK, FABRIK, Jiggle, and TwoBoneIK
* Each modification is in its own file
* There is also a SkeletonModifier2D resource that acts as a stack for using multiple stacks together
* Adds a PhysicalBone2D node
* Works similar to the PhysicalBone3D node, but uses a RigidBody2D node
* Changes to Skeleton2D listed below:
* Skeleton2D now holds a single SkeletonModificationStack2D for IK
* Skeleton2D now has a local_pose_override, which overrides the Bone2D position similar to how the overrides work in Skeleton3D
* Changes to Bone2D listed below:
* The default_length property has been changed to length. Length is the length of the bone to its child bone node
* New bone_angle property, which is the angle the bone has to its first child bone node
* Bone2D caches its transform when not modified by IK for IK interpolation purposes
* Bone2D draws its own editor gizmo, though this is stated to change in the future
* Changes to CanvasItemEditor listed below:
* Bone2D gizmo drawing code removed
* The 2D IK code is removed. Now Bone2D is the only bone system for 2D
* Transform2D now has a looking_at function for rotating to face a position
* Two new node notifications: NOTIFICATION_EDITOR_PRE_SAVE and NOTIFICATION_EDITOR_POST_SAVE
* These notifications only are called in the editor right before and after saving a scene
* Needed for not saving the IK position when executing IK in the editor
* Documentation for all the changes listed above.
