Book Image

Hands-On C++ Game Animation Programming

By : Gabor Szauer
Book Image

Hands-On C++ Game Animation Programming

By: Gabor Szauer

Overview of this book

Animation is one of the most important parts of any game. Modern animation systems work directly with track-driven animation and provide support for advanced techniques such as inverse kinematics (IK), blend trees, and dual quaternion skinning. This book will walk you through everything you need to get an optimized, production-ready animation system up and running, and contains all the code required to build the animation system. You’ll start by learning the basic principles, and then delve into the core topics of animation programming by building a curve-based skinned animation system. You’ll implement different skinning techniques and explore advanced animation topics such as IK, animation blending, dual quaternion skinning, and crowd rendering. The animation system you will build following this book can be easily integrated into your next game development project. The book is intended to be read from start to finish, although each chapter is self-contained and can be read independently as well. By the end of this book, you’ll have implemented a modern animation system and got to grips with optimization concepts and advanced animation techniques.
Table of Contents (17 chapters)

Comparing vectors

The last operation that needs to be implemented is vector comparison. Comparison is a component-wise operation; each element must be compared using an epsilon. Another way to measure whether two vectors are the same is to subtract them. If they were equal, subtracting them would yield a vector with no length.

Overload the == and != operators in vec3.cpp. Don't forget to add the function declarations to vec3.h:

bool operator==(const vec3 &l, const vec3 &r) {
    vec3 diff(l - r);
    return lenSq(diff) < VEC3_EPSILON;
bool operator!=(const vec3 &l, const vec3 &r) {
    return !(l == r);

Important note:

Finding the right epsilon value to use for comparison operations is difficult. In this chapter, you declared 0.000001f as the epsilon. This value is the result of some trial and error. To learn more about comparing floating point values, check out