Add generated sources

README.md

@@ -1,24 +1,36 @@
 # enroute flight navigation
 
-**enroute flight navigation** is a mobile flight navigation app for Android and other devices. The app is free, open source and 100% non-commercial. We do not collect user data. **enroute flight navigation** is a project of [Akaflieg Freiburg](https://akaflieg-freiburg.de), a flight club based in Freiburg, Germany. You can find more information on the [homepage](https://akaflieg-freiburg.github.io/enroute).
+**enroute flight navigation** is a mobile flight navigation app for Android and
+  other devices. The app is free, open source and 100% non-commercial. We do not
+  collect user data. **enroute flight navigation** is a project of [Akaflieg
+  Freiburg](https://akaflieg-freiburg.de), a flight club based in Freiburg,
+  Germany. You can find more information on the
+  [homepage](https://akaflieg-freiburg.github.io/enroute).
 
 ## 1. Compilation
 
-**enroute flight navigation** is a fairly large, but fairly standard Qt application that can be build on a standard Linux system. The build relies on **cmake**. The author uses Fedora Linux. Builds on Windows or MacOS hosts has never been attempted.
+**enroute flight navigation** is a fairly large, but fairly standard Qt
+application that can be build on a standard Linux system. The build relies on
+**cmake**. The author uses Fedora Linux. Builds on Windows or MacOS hosts has
+never been attempted.
 
-The CMake scripts download substantial amounts of data during the build process.
+The GIT repository includes the following submodules, which are all tied in in
+3rdParty.
 
 * Google's Material Design Icon set
 
 * Google's Roboto Fonts
 
 * Nitroshare's QHTTPEngine
 
-* For Android only: precompiled version of the openSSL libraries for various architectures.
+* For Android only: precompiled version of the openSSL libraries for various
+  architectures.
 
 ### 1.1 Building a desktop app
 
-On a standard Linux system, the following commands will build a desktop version of the app. The commands produce a single binary at **./src/enroute** that links to Qt dynamically, but contains all the data required to run.
+On a standard Linux system, the following commands will build a desktop version
+of the app. The commands produce a single binary at **./src/enroute** that links
+to Qt dynamically, but contains all the data required to run.
 
 ```shell
 # Create build directory
@@ -35,7 +47,9 @@ make -j5
 ./src/enroute
 ```
 
-We include a script, **buildscript-linux-debug.sh** that will build a debug binary of **enroute** with LLVM's address-sanitizer and undefined-sanitizer included. The CLANG compiler set must be available.
+We include a script, **buildscript-linux-debug.sh** that will build a debug
+binary of **enroute** with LLVM's address-sanitizer and undefined-sanitizer
+included. The CLANG compiler set must be available.
 
 ```shell
 # Go to the main 'enroute' directory
@@ -55,24 +69,44 @@ The author uses Qt Creator to build Android apps.
 
 ### 1.3 Dependencies
 
-* **Qt development libraries**, version ≥ 5.12 for the desktop app and version ≥ 5.14 for the Android app.
+* **Qt development libraries**, version ≥ 5.12 for the desktop app and version ≥
+    5.14 for the Android app.
 
-* **CMake**, version ≥ 3.13 for the desktop app and version ≥ 3.15 for the Android app.
+* **CMake**, version ≥ 3.13 for the desktop app and version ≥ 3.15 for the
+    Android app.
 
-* Command line utilities: **curl**, **git**, **tar** (used to download data at configuration stage), **Doxygen**, **dot** (to build documentation,) **inkscape** (used to generate PNG versions of icons from SVG sources) and **python3** (used to compile lists of files during the configuration stage)
+* Command line utilities: **curl**, **git**, **tar** (used to download data at
+  configuration stage), **Doxygen**, **dot** (to build documentation,)
+  **inkscape** (used to generate PNG versions of icons from SVG sources) and
+  **python3** (used to compile lists of files during the configuration stage)
 
 # 2. Other cmake targets
 
-To aid development, the **cmake** scripts include a number of non-obvious targets.
+To aid development, the **cmake** scripts include a number of non-obvious
+targets.
 
 ## 2.1 Target: DistributeQtSource
 
-To comply with legal regulations, we need to make a copy of the Qt sources available on the internet. This target does that automatically. Run the following command on one of Stefan Kebekus' machines:
+To comply with legal regulations, we need to make a copy of the Qt sources
+available on the internet. This target does that automatically. Run the
+following command on one of Stefan Kebekus' machines:
 
 ```bash
 make DistributeQtSource
 ```
 
-This will download the sources for the precise Qt version used for building this binary and will make them available at [https://cplx.vm.uni-freiburg.de/storage/QtSources](https://cplx.vm.uni-freiburg.de/storage/QtSources).
+This will download the sources for the precise Qt version used for building this
+binary and will make them available at
+[https://cplx.vm.uni-freiburg.de/storage/QtSources](https://cplx.vm.uni-freiburg.de/storage/QtSources).
 
 
+## 2.2 Target: generatedSources
+
+This subdirectories of generatedSources contain source files that have been
+generated from other sources, for instance icons in PNG format that have been
+generated from scalable vector graphics. We include these generated sources in
+our GIT repository because the tools required to build them are not universally
+available on all platforms.
+
+There exists a special CMake target, **generatedSources** that re-builds the
+source files in this directory.