1 - Introduction to the VR-Exchange API

Table of Contents

• 1.1 Introduction
• 1.2 The Portal Application
• 1.3 Brokers

1.1 Introduction

The VR-Exchange API has two primary components, the Broker API and the Portal API. The Broker API lets you create brokers for use with VR-Exchange or extend the brokers provided by MAK. The Portal API allows brokers to send messages to, and receive updates from, the Portal. All VR-Exchange API code is placed under the namespace MAKVrExchange. Each broker's API code is placed under its own namespace, as follows:

• HLA Broker API: MAKVrExchange::DtHlaBroker
• TENA Broker API: MAKVrExchange::DtTenaBroker
• DIS Broker API: MAKVrExchange::DtDisBroker.

1.2 The Portal Application

The portal is a separate application, or process, which is independent of the brokers. The Portal application executable is vrx.exe. It has the following functions:

• Create and manage the message queue
• Start and stop brokers (based on the connection configurations)
• Manage broker errors and lifetimes
• Displays basic shared memory queue information
• Display discovered and published objects and interactions
• Allow you to configure connections.

The display of message traffic through the GUI is a convenience for users. It is not required for operation of VR-Exchange. Therefore, if you add new broker types or messages, you do not have to rebuild the GUI.

1.3 Brokers

Brokers must be able to receive and send data in the exercises for which they are translating. Therefore, they behave much like HLA federates, DIS simulations, or TENA range resources. Brokers connect to an exercise the same way a VR-Link application would connect to TENA, DIS, or HLA (they do this using VR-Link libraries). Brokers publish objects and send interactions. While it is possible to write whole simulators that act as brokers, this is not recommended, because brokers must all run on the same machine to communicate and they require a VR-Exchange license to run. These conditions might limit their effectiveness as simulation applications.

Note

Many of the terms and concepts in the Portal API, such as publishers, reflected objects, and callbacks are identical to or very similar to those in VR-Link. Please refer to VR-Link documentation for detailed discussions of these subjects.

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