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)

Converting between quaternions and matrices

Since both matrices and quaternions can be used to encode rotation data, it will be useful to be able to convert between them. To make converting between the two easier, you have to start thinking about rotation in terms of basis vectors, which are the vectors that represent the x, y, and z axes.

The upper 3 x 3 sub-matrix of a 4 x 4 matrix contains three basis vectors. The first column is the right vector, the second is the up vector, and the third is the forward vector. Using only the forward and up vectors, the lookRotation function can be used to convert a matrix into a quaternion.

To convert a quaternion into a matrix, simply multiply the world basis vectors, which are the x, y, and z axes of the world, by the quaternion. Store the resulting vectors in the appropriate components of the matrix:

  1. Implement the quatToMat4 function in quat.cpp. Don't forget to add the function declaration to quat.h:
    mat4 quatToMat4(const...