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 matrices into transforms

External file formats might store transformation data as matrices. glTF, for example, can store the transform of a node as the position, rotation, and scale, or as a single 4x4 matrix. To make the transform code robust, you need to be able to convert matrices to transforms.

Converting a matrix to a transform is more difficult than converting a transform to a matrix. Extracting the rotation of the matrix is simple; you have already implemented a function to turn a 4x4 matrix into a quaternion. Extracting the position is also simple; copy the last column of the matrix into a vector. Extracting the scale is more difficult.

Recall that the order of operations for a transform is to scale, rotate, and then translate. This means that if you had three matrices—S, R, and T—that represent scale, rotation, and translation, respectively, they would combine into a transform matrix, M, as follows:

M = SRT

To find the scale, first, ignore...