QtAgOpenGPS

Ag Precision Mapping and Section Control Software

What is QtAgOpenGPS?

QtAgOpenGPS is a direct port of Brian Tischler's AgOpenGPS, which was originally written in C#. This port aims to follow AgOpenGPS closely, and not introduce any new algorithms or significant architecture modifications, except as required to work with Qt and C++. Currently it's not quite up to the latest commits on Brian's C# AOG, but nearly so.

Quoting the README.me for AgOpenGPS:

"This project is for my personal use only, and has no commercial value whatsoever. This software is not for sale, is incomplete, is in development to show concepts only and is mostly non functional. Any use of this software is not recommended and is intended for simulation only.

This software reads NMEA strings for the purpose of recording and mapping position information for Agricultural use. Also it has up to 8 Section Control to control implements application of product preventing over-application.

Also ouputs angle delta and distance from reference line for AB line and Contour guidance."

Eventually the other utilities in AOG will be ported, including the NMEA simulator.

This application is distributed here in source code form only. I will post demo binaries outside of this tree somewhere.

Copyright

Much of the code is copied straight from the AOG C Sharp sources and is therefore copyright Brian Tischler. Everything else is copyright Michael Torrie ([email protected]) and Muhktimar ([email protected]).

License

AOG was originally licensed under the GPLv3, so this port was also licensed under the GPLv3. AOG has since been relicensed to the MIT license, which is still compatible with the GPLv3, so this project remains GPLv3 for now.

Requirements

QtAOG requires Qt 5.9 or newer to build, on any Qt-supported platform that supports OpenGL ES 2 or newer, or DirectX on Windows.

Why this Port?

This port is mainly for my own entertainment, to allow me to run AOG on Linux, including SBCs like the Raspberry Pi. But I think the most desirable target will be Android some day.

Notes on the Port

This port is as close to a 1:1 transliteration of the C# code as possible, using Qt to drive the GUI, and C++ and Qt together to replace the C# GUI components. Being such a direct translation, the code has a very C# feel to it, even in C++. There are lots of classes that are only instantiated once, and the formgps.h is very large, and the coupling between the various classes is extremely tight. In fact there are a lot of forward references to the main FormGPS class. Since formgps.h is required by just about class in the project, changes to formgps.h require a rebuild of every single object file.

Earlier I changed the case of methods to be more standard C++. I've started to undo that and make the method calls as close to AOG's original names as possible.

Mmost variables, functions, and methods, retain the AOG names, unless architectural differences require moving code into different sections. For example, the OpenGL code runs in a different thread than the main GUI loop, the logic to set UI state has been pulled out of the function that does the actual drawing. Also since QtQuick itself uses OpenGL heavily, there's no point in having an "intializeGL" routine; rather each time we draw the frame we have to set all the variables including the model view and perspective matrices. Of course in OpenGL ES we must manage those matrices ourselves anyway.

AgIO has not yet been ported, so once UDP functionality is working, AgIO will be required for now. It does not yet run under Wine on Linux. The simulator works, though.

Status of the Port

As of Jan 4, 2023, the backend code is now tracking pretty closely to the progress being made on AgOpenGPS/isoxml branch, at least as of Dec 20, 2023. UDP is not yet working.

David Wedel is working on the QML gui which we plan to get working during the month of January.

UI is still mostly non-present, but works with the built-in simulator. For testing purposes, a job and field is automatically started, and a demo AB line is defined at 5 degrees. You should be able to copy Boundary.txt, Sections.txt, ABLines.txt, etc from AgOpenGPS into the QtAgOpenGS/Fields/TestField folder and work with previously-saved data.

Coverage works, boundaries work, u-turn works, automatic u-turn works (but has no button to enable it). AB Line following works. Headland mode works.

Bugs and TODOs

• GL font drawing has issues, but only with the AB Line number display.
  A lot of UI stuff currently drawn with GL should be drawn with QML widgets instead.
• Dashed lines are not possible in OpenGL ES, but I think a shader script can do it. Also there's no easy way to do thick lines in opengl ES either.
• Hook in the GUI that David Wedel is contributing.

---

Compiling from source

(As tested on a fresh Ubuntu 22.0.4 installation)

• sudo apt update
• sudo apt upgrade
  • (reboot if necessary)
• sudo apt install git libxcb-cursor0 -y

Install QT Creator

Look here: https://www.qt.io/offline-installers in the "QT Creator" section.

• Download the file "QT Creator x.x.x for Linux 64-bit"
• Set it to be executable
  • chmod +x qt-creator-opensource-linux-x86_64-12.0.1.run
  • run it to install, log in (yes, you have to register first) and accept the default path in your home profile if that's your thing
  • accept the defaults
  • That'll do, pig

Grab the source

• mkdir github
• cd github
• git clone https://github.com/torriem/QtAgOpenGPS.git
  • (if you want to switch branch away from main)
  • git branch -r
  • (if you see something you like)
  • git pull origin branchname
  • git checkout -b branchname

Dependencies

• sudo apt install qtcreator qtbase5-dev qml-module-qtquick-controls qml-module-qtquick-controls2 qml-module-qt-labs-folderlistmodel qml-module-qtquick-dialogs qml-module-qtquick-extras qml-module-qtquick-dialogs qml-module-qtquick-extras qt5-qmake cmake libqt5serialbus5-dev libqt5serialport5-dev qtdeclarative5-dev qttools5-dev qml-module-qtquick-shapes -y
• (ensure you are in the github/QtAgOpenGPS folder)
• qmake
• make
• (open a beer)
• (drink beer)
• ./QtAgOpenGPS &

Contributing to source

Creating scalable UI's

• This is very important. Creating a GUI that works on a phone screen as well as a giant desktop isn't easy. I thought I'd write this up because I don't want to convert your code to something that looks ok on a phone (and because it's more fun writing this than converting all my existing code to scalable like I need to).

Every width, length, anchor margin that is coded to a number MUST have the scale factor calculated in.

• My first 6 months of code was written like:

  • width: 500
  • height: 100
  • anchors.left: 10
  • anchors.top: 10
  • etc etc

• Now if all you're going to do is use your application on is your computer, no issue. BUT try that on a phone and you'll regret ever trying to code.

• The correct way is(as I learned yesterday):

  • width: 500 * theme.scaleWidth
  • height: 100 * theme.scaleHeight
  • anchors.left: 10 * theme.scaleWidth
  • anchors.top: 10 * theme.scaleHeight

• "theme.scaleWidth/scaleHeight" change based on screen size, so the GUI will look the same on a phone, just smaller.

• Now if your width: parent.width / 2(or whatever), no scale factor is necessary, since parent will scale correctly.

• But if you go width: parent.width / 2 + 10, you must change to width: parent.width / 2 + (10 * theme.scaleWidth) to figure in the scale factor.

• Obviously the width related sizes need theme.scaleWidth and the height related sizes need theme.scaleHeight

anchors.margins is off limits!

• If you go anchors.margins: 10, then what do you set your scale factor to?? Is it a width setting, or a height?
  The answer is neither. So don't use it. Instead, go:
  • anchors.left: 10 * theme.scaleWidth
  • anchors.top: 10 * theme.scaleHeight
  • anchors.right: 10 * theme.scaleWidth
  • anchors.bottom: 10 * theme.scaleHeight

Easy, right? If you have questions, PLEASE ask someone, instead of writing 3000 lines of code with no scaling!