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)

glTF – loading the bind pose

You are now ready to load the bind pose from a glTF file, but there is a problem. glTF files don't store the bind pose. Instead, for each skin that a glTF file contains, it stores a matrix array that holds the inverse bind pose matrix for each joint that affects the skin.

Storing the inverse bind pose matrices like this is good for optimization, which will make more sense in the next chapter, but for now, it is something we have to deal with. So, how do you get the bind pose?

To get the bind pose, load the rest pose and convert each transform in the rest pose into a world space transform. This makes sure that if a skin didn't provide an inverse bind pose matrix for a joint, a good default value is available.

Next, loop through each skinned mesh in the .gltf file. For each skinned mesh, invert the inverse bind pose matrix of each joint. Inverting the inverse bind pose matrix results in the bind pose matrix. Convert the bind pose...