May 2022 – Göthel Software Blog

Chase, Scatter and Phantoms – Sisyphus alike Ghost Fate

2022-05-312023-10-09 Sven

Earlier this year, we required a true distraction from the chaos of this world and a sad tragedy in our closer circle. What would have been more rewarding for a little recovery than indulging oneself with game theory, paying homage to Toru Iwatani‘s classic Puckman? Both my sons loved the idea and we added this work to our little cs-class. My older one was eager to learn how the math behind the ghosts works. Euclidian geometry, Pythagoras, points and vectors .. plus the strategy of choosing targets WoW! We completed the little fun endeavor using C++17 and the SDL2 library, resulting in a working nostalgic re-implementation.

At the bottom of this article I have placed a little video recording, partially demonstrating the results. Continue reading “Chase, Scatter and Phantoms – Sisyphus alike Ghost Fate” →

Rational Expressions with frictionless Fractions and implemented Time

2022-05-292022-05-30 Sven

Natural numbers are defined as the sequence of numbers fully defined by their initial value, its successor and the successor of its successor and so forth. Despite the beauty of their intrinsic Dedekind–Peano axioms, they are also fully proven by induction.

${\begin{alignedat}{3}0&:=&&\quad \ \,\{\}&&=\emptyset \\1&:=0'&&=\{0\}&&=\{\emptyset \}\\2&:=1'&&=\{0,1\}&&=\{\emptyset ,\{\emptyset \}\}\\3&:=2'&&=\{0,1,2\}&&=\{\emptyset ,\{\emptyset \},\{\emptyset ,\{\emptyset \}\}\}\\&\vdots &&&&\\(n+1)&:=n'&&=\{0,1,\ldots ,n\}&&=n\cup \{n\}\end{alignedat}}$ Continue reading “Rational Expressions with frictionless Fractions and implemented Time” →

Identifiable C++ Function Pointer of any kind in Direct-BT (Part 2)

2022-05-222023-01-03 Sven

Earlier I started elaborating on Direct-BT C++ implementation details, covering communication channels and data structures suitable for concurrency.

This part shall cover Jaulib’s jau::function<R(A…)>, used to manage callback lists e.g. in BTManager or simply utilizing them to delegate functionality like in jau::service_runner. Continue reading “Identifiable C++ Function Pointer of any kind in Direct-BT (Part 2)” →

Direct-BT C++ Implementation Details (Part 1)

2022-05-222023-04-19 Sven2 Comments

This is the first article covering Direct-BT‘s implementation details including jaulib.

See Direct-BT, Bluetooth Server and Client Programming in C++ and Java (Part 1) for a little introduction to Direct-BT.

Standard and Proprietary Communication Channels

As described, we were required to utilize the host Bluetooth implementation in the GNU/Linux kernel, i.e. BlueZ/Kernel directly without D-Bus to achieve best performance and access the native HCI, L2CAP/GATT and SMP communication channels directly. Continue reading “Direct-BT C++ Implementation Details (Part 1)” →

Direct-BT, Bluetooth Server and Client Programming in C++ and Java (Part 1)

2022-05-222022-05-22 Sven1 Comment

This is the first article covering Direct-BT using version 2.7.1 and may give you a little introduction into this project.

See Direct-BT C++ Implementation Details (Part 1) for some insight view.

Overview

Direct-BT provides direct Bluetooth LE and BREDR programming, offering robust high-performance support for embedded & desktop with zero overhead via C++ and Java.

It supports a fully event driven workflow from adapter management, device discovery to GATT programming, using its platform agnostic HCI, L2CAP, SMP and GATT protocol implementation.

Multiple Bluetooth adapter are handled, as well as multiple concurrent connections per adapter.

Peripheral server device programming is supported as well as the central client, which is also used for Java and C++ self unit testing across two or more Bluetooth adapter. Continue reading “Direct-BT, Bluetooth Server and Client Programming in C++ and Java (Part 1)” →