Jackson is a very heavy library; it supports loads of features that we
don't need, and historically has caused issues due to long class loading
times (a little over 2 seconds to load AprilTagFieldLayout). This often
manifests as a help request in the form of "my robot disables when I do
X, but doesn't disable when doing X in subsequent attempts until code
restart." While SC has brought down Jackson loading times significantly,
with AprilTagFieldLayout loads taking only 330 milliseconds, that's
still a rather long delay, and while libraries should handle any JSON
loading ahead of time to prevent delays in auto/teleop, it would still
be good to make the worst case better to reduce user frustration.
Benchmarks indicate using [Avaje
Jsonb](https://github.com/avaje/avaje-jsonb) to load AprilTagFieldLayout
only takes ~70 ms, a fair chunk of which isn't actually in Avaje Jsonb
(~4 ms is spent on using getResourceAsStream to retrieve the JSON file,
~8 ms is spent on just loading the AprilTag class and its dependencies).
Note that all times listed are end-to-end, meaning nothing else was done
except for the operation being benchmarked, and doing arithmetic on them
can be flawed due to some classes being loaded twice, i.e.,
getResourceAsStream and `new AprilTag()` likely load some of the same
JDK classes and so subtracting both from the Avaje Jsonb load time is
likely slightly incorrect because class loading is being double counted.
For our purposes, it's likely accurate enough and is mostly just for
contextualization.
Benchmarks were run on a Raspberry Pi CM5 with 2 GB of RAM. Source code
for the
[results](https://github.com/user-attachments/files/26471452/benchmark.txt)
can be found in the "Fastjson2" commit
(2456d15ca8ebd17635e607cd40bf8816e77869a1).
Avaje Jsonb uses code generation via annotation processors to generate
the classes needed to do JSON serde and uses service providers to find
them, which will require downstream changes in robot projects, as the
different service providers in each library must be merged together for
Avaje Jsonb to function. We will use the Gradle shadow plugin, as its
already used by the installer and therefore adds zero additional
dependencies.
Currently the major DataLog backend API (reading and writing) is split between wpiutil and glass. In the interest of allowing code that wants to use these APIs to not need to link to glass and declutter wpiutil, all of those APIs are moved to a new library named "datalog".
Signed-off-by: Jade Turner <spacey-sooty@proton.me>
Co-authored-by: Jade Turner <spacey-sooty@proton.me>
Co-authored-by: Gold856 <117957790+Gold856@users.noreply.github.com>
Explicitly list required components when using FindJava and FindJNI
Consolidate find_package calls for Java, JNI, and OpenCV into the root CMakeLists.txt file
Remove references to main_lib_dest
Install missing generated headers
Flatten some if statements
Use LinkMacOSGUI macro instead of hand rolling it
Stop installing OpenCV libraries and an extra ntcorejni library; OpenCV JAR will still be installed to make it easy to use
Only print platform version on Windows
Prevent GUI modules from being built when wpimath is off, which would otherwise cause a build failure
Simplify build configuration checks
Clean up fieldImages JAR creation
Place built JARs in the same subdir as installed JARs
Remove unnecessary JAR includes
Remove extra directories in target_include_directories
Improve CMake docs
To reduce the need for users to manually perform unit conversions, this allows Measure objects from wpiunits to be passed into most places in wpimath that currently expect doubles in terms of SI units like meters.
For example, users would need to know that unit conversion is required - and what the correct units are. Using units would be more difficult to write code for than just hardcoding a value or using Units.inchesToMeters.
Now, using units has no more developer overhead than using raw numbers.
The CMake enable/disable flags as currently structured are a confusing mix of
WITH, WITHOUT, and USE with odd defaults. This changes the flags to consistently
use WITH and default the build options to everything enabled.
The wpimath library is a new library designed to separate the reusable math functionality
from the common utility library (wpiutil) and the hardware-dependent library (wpilibc/j).
Package names / include file names were NOT changed to minimize breakage. In a future year
it would be good to revamp these for a more uniform user experience and to reduce the risk
of accidental naming conflicts.
While theoretically all of this functionality could be placed into wpiutil, several pieces
of this library (e.g. DARE) are very time-consuming to compile, so it's nice to avoid this
expense for users who only want cscore or ntcore. It also allows for easy future separation
of build tasks vs number of workers on memory-constrained machines.
This moves the following functionality from wpiutil into wpimath:
- Eigen
- ejml
- Drake
- DARE
- wpiutil.math package (Matrix etc)
- units
And the following functionality from wpilibc/j into wpimath:
- Geometry
- Kinematics
- Spline
- Trajectory
- LinearFilter
- MedianFilter
- Feed-forward controllers
Add EJML as the Java library for linear algebra for use in wpilib. This is equivalent to Eigen for C++.
The EJML dependency is downloaded in cmake and pulled in via maven in the gradle build.
