ce2_cpp_flownode_tutorial

Document Author:

Kevin “vloktboky” Kirst

RenEvo Software & Designs

Email: kkirst@gmail.com

CryENGINE™ 2 SDK

Table of Contents

Introduction .......................................................................................................... 1

Requirements ................................................................................................... 1

Terminology...................................................................................................... 2

Creating a Custom Flow Node ............................................................................. 3

Frequently Asked Questions........................................................................... 17

Appendix B......................................................................................................... 18

MyFlowNodes.cpp .......................................................................................... 18

Example_RaceGraph.xml............................................................................... 21

1

Introduction

The Flow-Graph is an amazing tool for designers and programmers alike. Built

the Flow-Graph. (I will explain this terminology for you further on.) However, for

those of you who find yourself in need of something unique and original to

achieve the desired effect for your mods or maps, there is hope. Creating a

custom Flow Node is not as difficult as it sounds! In fact, there are two ways to

achieve this:

1. Defining Ports within an entity’s Lua script and placing that entity on your

2. Defining Nodes in C++ and using your custom GameDll.dll with the Editor.

Requirements

Before continuing on with this tutorial, please ensure you have the following on

your computer and have an understanding on how to use them:

 CryENGINE™ 2 SDK

 CryENGINE™ 2 SDK C++ Source Solution

 Sandbox 2™ with Flow-Graph knowledge

2

Terminology

Graph

A Graph is a series of Nodes which are Linked together via their Ports. The

Graph is the final result which defines a behavior, such as opening a door and

turning on a light when someone enters a proximity trigger or triggers a remote

button.

Link

A Node is a container of Output and Input Ports and makes up a Graph. A node

is typically used to represent either an entity or an action (component). In the

behavior “When you push a button, open door,” both the button and the door are

represented as nodes.

Port

A Port is like a doorway for a Node. Links between two different ports embody

the described behavior. There are two different types of ports:

 Input – “Walking in” to the door. These ports are represented on the left-

Given a node “Soldier” that is used to describe a soldier with health, the node

may have an input port IsDamaged and output ports Yes and No. When you call

the IsDamaged input port via a link, either the Yes or No output ports may be

called depending on the soldier’s health. This creates a Split and can be used to

separate the behavior based on the result. For example, you could link the Yes

3

Creating a Custom Flow Node

Hopefully we’re all familiar with the concept of a stopwatch.

This wonderful tool aids us in determining the duration of time

between two events. Although you may be asking yourself,

“What purpose would I have for making a stopwatch in

Sandbox?” I feel this is a concept simple enough for our first

component node. And if you ever wanted to know how long it

would take a player to run from point A to point B on your map,

now you can figure that out!

You may have noticed I called this a component node. What I mean by this is no

Input Ports

 Start – (Void) This will be a functional port that we will call when we want

 Stop – (Void) This will be a functional port that we will call when we want

 Timeout – (Float) This will be a data port that we will use to specify how

Output Ports

 Done – (Float) We will signal this port when the stopwatch has stopped.