Game Audio Programming 3: Principles and Practices

Guy Somberg

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780367354138
• eBook ISBN: 9781000169645
• Topic: Informatica
• Subtopic: Grafica per computer

Welcome to the third volume of Game Audio Programming: Principles and Practices—the first series of its kind dedicated to the art and science of game audio programming. This volume contains 14 chapters from some of the top game audio programmers and sound designers in the industry. Topics range across game genres (ARPG, RTS, FPS, etc.), and from low-level topics such as DSP to high-level topics like using influence maps for audio.

The techniques in this book are targeted at game audio programmers of all abilities, from newbies who are just getting into audio programming to seasoned veterans. All of the principles and practices in this book have been used in real shipping games, so they are all very practical and immediately applicable. There are chapters about split-screen audio, dynamic music improvisation, dynamic mixing, ambiences, DSPs, and more.

This book continues the tradition of collecting modern, up-to-date knowledge and wisdom about game audio programming. So, whether you've been a game audio programmer for one year or ten years, or even if you've just been assigned the task and are trying to figure out what it's all about, this book is for you!

Key Features

• Cutting-edge advanced game audio programming concepts with examples from real game audio engines
• Includes both high-level and low-level topics
• Practical code examples, math, and diagrams that you can apply directly to your game audio engine.

Guy Somberg has been programming audio engines for his entire career. From humble beginnings writing a low-level audio mixer for slot machines, he quickly transitioned to writing game audio engines for all manner of games. He has written audio engines that shipped AAA games like Hellgate: London, Bioshock 2, The Sims 4, and Torchlight 3, as well as smaller titles like Minion Master, Tales from the Borderlands, and Game of Thrones. Guy has also given several talks at the Game Developer Conference, the Audio Developer Conference, and CppCon. When he's not programming or writing game audio programming books, he can be found at home reading, playing video games, and playing the flute.

CHAPTER 1

Sound Effect Categories

Florian Füsslin

Crytek GmbH

CONTENTS

1.1 Preamble

1.1.1 Interactive Media

1.1.2 The Big Three

1.2 The World

1.2.1 Environment

1.2.2 Weather

1.2.3 Particle Effects

1.2.4 Physics

1.3 Characters

1.3.1 Movement

1.3.2 Interactions

1.4 Feedback

1.4.1 Menu

1.4.2 Interface

1.4.3 Experience

1.5 Wrap-Up

1.5.1 Sound Effects Category Check List

1.6 Conclusion

1.1 Preamble

In the last two years, I have lectured on the subject of Game Audio at various universities and audio schools. While giving those talks, I realized that I ended up explaining terminology in greater detail than I had anticipated. The general split of game audio production into dialog, music, and sound effects makes sense to everyone. When I tried to break it into smaller pieces, however, there were many follow-up questions on sound effects in particular. Some people had either never heard of some sound effect categories or didn’t associate anything with them. I consulted with colleagues in the game industry about this observation, and it turns out that even within this group of audio specialists, definitions and terminologies of sound effect categories vary. This chapter felt like a great opportunity to tackle the topic, and provide an overview of a potential project structure, common complexity, and possible challenges. It can function as a basis for a nomenclature for the project naming convention, and can build the foundation for communication and collaboration between audio designers and audio programmers. The goal is to enable you to handle all sound effect requirements and requests coming your way in a structured fashion.

1.1.1 Interactive Media

Most of the terminology around sound effects has been adopted from film and audio post production, thinking in scenes and stems. Atmospheres set the mood and background of a scene; foley effects support on-screen sounds to add details and enhance drama; designed special effect sounds create emotional reactions and support the actions. We have full control of audio in this kind of linear media environment, so all of our sound effects will play back exactly once and can be perfectly designed, timed, balanced, and mixed to fit that particular scene.

But because games are interactive with player input, we have a lot less control. Therefore, we have to think in sources (where is the sound emitter), situations (when is it playing), and conditions (what states it is in). We need a lot more assets to cover all potential scenarios and multiple variations to avoid repetition. In theory, every sound could play at any time and be the most important sound playing at that moment, which requires a constant shift in priorities and adjustment of the mix in real time. With this complexity, game audio needs to develop new sub-categories within the sound effects group.

1.1.2 The Big Three

The sound effects for most modern games usually fall into three major categories:

1. World—The game environment including ambiences, weather conditions, particle effects, and physics.
2. Character—All protagonists and antagonists, their movement, and their interactions.
3. Feedback—Audio cues for menu, heads-up display, and enrichment of the user experience.

It’s easy to see how these categories can map to the sounds for games like an FPS or an MMORPG, but they are also applicable to other genres. For example, in a soccer game, the world is the stadium, the character is the ball, and feedback is the situational crowd reaction. In an RTS game, the world is the battlefield, the units are the characters, and feedback is the information about mission status, resources, and production.

These “big three” main categories can function as a starting point for how we structure and manage our audio data in the project or audio middleware. In a soccer game, for example, we would need specific groups and folders for each stadium, but we could treat and structure the crowd globally. This line of thinking works for other categories as well. If our game will always be in sunny daylight for all levels, then we don’t need any weather effects, and we can treat our ambiences globally with no real-time conditions.

In another scenario, we have an open world with different environments ranging from a dense jungle to vast deserts, extreme weather conditions, and a complete 24-hour day/night cycle featuring all four seasons. In this case, we will probably design and structure per environment, including dawn, day, dusk, and night layers. We will repeat this procedure per season, and support extreme weather conditions like seasonal types of rain in the jungle and various sandstorms in the desert. All of this must be driven by parameters so that our environments and conditions can adapt in real time.

There are always exceptions to the rules, and each project has different requirements, which is why it is important to ask the following questions:

Do I need this (sub) category in my project? Do I see this category used globally, or is it specific to one section of the game? Do I have to react to real-time conditions, and if yes, what are they?

With these questions in mind, let’s dive deeper into the sub-categories of the big three.

1.2 The World

The world represents the game environment and consists of the following sub-categories:

• Environment—Ambiences and spot effects.
• Weather—All elements like rain or thunderstorms.
• Particle effects—Fires, sparks, steam, etc.
• Physics—Everything related to rolling, sliding, bending, collision, and destruction.

1.2.1 Environment

Unless you are in space, there is always some noise. It can be a subtle room tone, a rustling forest, or a cold mountain wind. This is called ambience, sound bed, or atmosphere. Even if it is very subtle, it grounds the player in the world and functions as the noise floor and threshold from which we can build our audio mix and dynamic range. This base layer is usually designed as a static loop or a granular loop which is rather sparse and steady to hide its repetition. To reduce the potential monotony, we can add details which don’t need visual support such as blooms or falling dust.

Once we have the base loop, we can build on it. Wind gusts can help to make the ambience feel more dynamic, ideally driven by a parameter like wind_intensity. If our project supports a full day and night cycle, we will want to consider sweeteners for dawn, day, dusk, and night and drive them via a time_of_day parameter. If our game ranges across all seasons, we might use a season parameter to provide variants for spring, summer, autumn, and winter.

In addition to the ambiences, we can use spot effects for positional details to the environment. This can be a constant emitter like a waterfall, a generator, or a windmill, or it can be randomly occurring like an insect flyby, wind gust, or distant rumble. Ideally there is a corresponding visual representation or a landmark we want the player to pay attention to, but even without that, playing these sounds can still enliven and add depth to the player’s environment.

1.2.2 Weather

Weather can be a big part of the perceived environment and ambience. Due to its complex nature and the strong visual component, it makes sense to treat it as a separate sub-category. Rain, for example, can range from a sprinkle to a thunderstorm to a full-blown hurricane and will need to blend between these via a parameter like rain_intensity. Wind can go from a gentle breeze to a full storm all the way to a tornado, agai...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Acknowledgments
• Editor
• Contributors
• Chapter 1. Sound Effect Categories
• Section I DSP
• Section II Voice
• Section III Audio Engines
• Index