Design of Software Application

Before work could begin on the development of a software program that would act as an interface and control system between the Motion Analysis Hardware/Software and the user, a wide range of programming languages and Application Programming Interfaces (API‘s) were researched and considered. In order to create a program that could be incorporated well with the software Motion Analysis provide with their system (EVaRT), we studied the Software Development Kit (SDK) provided by the company in order to ascertain which was the best programming language to use. With the SDK written in C++, and it being one of the most advanced, multipurpose and most popular programming languages in the world, we decided that all core programming would be completed in this language.

Furthermore, our proposed software would run only on a windows platform, we therefore decided to use the Microsoft Foundation Classes (MFC). The Microsoft Foundation Class Library is based around parts of the windows API. The classes in the MFC Library are written as object orientated in the C++ programming language. The MFC Library helps the programmer a vast amount of time by providing predefined code that has already been written. It also provides an overall framework for developing the application program.

There are MFC Library classes for all graphical user interface elements within a common windows application (windows, menus, frames, tool bars, status bars, etc). MFC helps with building interfaces, for handling events such as messages from other applications, for handling keyboard and mouse input, and for creating ActiveX controls.

As our software will act as a visual aid between the user and the motion capture system, it must be capable of displaying 3D graphics. In order for this to occur we must utilise a graphics API to display 2D and 3D computer graphics. After some research we realised there were only two mainstream graphics API‘s which would

be suitable for our purpose, these being OpenGL or DirectX. After much consideration we decided that OpenGL was the best API, as it ties well with the use of the Microsoft Foundation Classes. The basic operation of OpenGL is to accept primitives such as points, lines and polygons, and convert them into pixels. OpenGL is widely used in the gaming industry as well as CAD, virtual reality, scientific visualization, information visualization, and flight simulation.

To get a greater understanding of the program we intend to create and where it fits into the complete system and all software and hardware used please see Fig. 6.1 which represents a flow diagram for the software integration.

User OpenGL Software Application Motion Description MFC Motion Calculation Eagle Hub Gesture Recognition EVaRT

Camera 1 Camera 2 Camera 3 Camera 4 Camera 5 Camera 6 Camera 7

Fig. 6.1: Software integration

Before programming began we designed the layout of the interface window and how the main graphics would be displayed to the user. We developed an interface similar to that of most popular 3D CAD packages, as it allows the user to view the 3D scene from different perspectives via different viewports. We chose to split the main window into four viewports, each representing a different axis. Viewport

A represents the X axis; viewport B represents the Y axis, viewport C represents the Z axis, and viewport D represents the scene from a 3D perspective.

Fig. 6.2 shows the four viewports described above. For testing and display purposes, a 3D cube with different colour faces is shown in the centre of the 3D scene.

Fig. 6.2: Print screen of viewport layout and axis specification.

The main window of our software can be minimised and moved to anywhere on the screen. This feature was implemented in order to use our software on a dual screen setup, making configuration between the EVaRT system and our software easier. Each viewport can also be resized and defined according to the user‘s preference. This is controlled by the vertical drop down menu toolbar to the right of the screenshot displayed in Fig. 6.2. We designed all aspects of our software so the user and or assistant has full control over it‘s appearance in the hope of getting better results from the designer whilst at the modelling stage.

Before the software is able to receive information from the Motion Analysis equipment the user must make connection to the EVaRT system by accessing the

―EVaRT Connect‖ dialogue box. To do this they must access the ―Tools‖ toolbar located on the top bar. Once selected the user is faced with a secondary window which asks for some information specific to making a connection. An EVaRT IP address and Host IP address is required. As our software can be run from a separate computer to that of where EVaRT is running, all information is past through the Ethernet connection. The host IP which is required is of the computer that is running our software and the EVaRT IP is of the computer where the EVaRT system is running. Further information about frame capture is required, the number of frames to receive from the system and the number of frames to record, both of which can be defined by the user dependant on their proposed capture session. Please see Fig. 6.3A and Fig. 6.3B. for the breakdown of this menu system and dialog box respectively.

(A)

( B)

Fig. 6.3A – B: Screenshot of menu system and Evart Connect Dialog box respectively.

As with the main window of our program, the EVaRT Connect box was programmed to be modeless. A modeless window allows the user to continue working with the main application while the modeless window stays open or minimised. This is well suited to our application, as the user must make connection using this box, but also needs to continue working with the window behind, whilst modelling. Please see Appendix B for programming code of

A more detailed flow diagram showing the internal working of our application, and how each file contributes to a process function is show below in Fig. 6.4.