Book Image

C++ Game Animation Programming - Second Edition

By : Michael Dunsky, Gabor Szauer
4.5 (2)
Book Image

C++ Game Animation Programming - Second Edition

4.5 (2)
By: Michael Dunsky, Gabor Szauer

Overview of this book

If you‘re fascinated by the complexities of animating video game characters and are curious about the transformation of model files into 3D avatars and NPCs that can explore virtual worlds, then this book is for you. In this new edition, you’ll learn everything you need to know about game animation, from a simple graphical window to a large crowd of smoothly animated characters. First, you’ll learn how to use modern high-performance graphics, dig into the details of how virtual characters are stored, and load the models and animations into a minimalistic game-like application. Then, you’ll get an overview of the components of an animation system, how to play the animations and combine them, and how to blend from one animation into another. You’ll also get an introduction to topics that will make your programming life easier, such as debugging your code or stripping down the graphical output. By the end of this book, you’ll have gained deep insights into all the parts of game animation programming and how they work together, revealing the magic that brings life to the virtual worlds on your screen.
Table of Contents (22 chapters)
1
Part 1:Building a Graphics Renderer
7
Part 2: Mathematics Roundup
10
Part 3: Working with Models and Animations
15
Part 4: Advancing Your Code to the Next Level

Using quaternions for smooth rotations

Spherical Linear Interpolation, or SLERP for short, uses mathematics to rotate from the position of one quaternion to the position of another quaternion. Figure 7.10 shows an example of SLERP. The red line is the path for the interpolation between the quaternions with orientations <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math"><mml:msub><mml:mrow><mml:mi>φ</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math"><mml:msub><mml:mrow><mml:mi>φ</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>.

Figure 7.10: Spherical Linear Interpolation between two quaternions

Doing the same transition with Euler angles works in one dimension. But for a full three-dimensional path between two quaternions, there is no simple mathematical solution to go from one combined rotation to another while maintaining a steady path in all the directions of the movement.

Note

Rotating from orientation <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math"><mml:msub><mml:mrow><mml:mi>φ</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math"><mml:msub><mml:mrow><mml:mi>φ</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> has a second solution: the other way around the circle, starting on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math"><mml:msub><mml:mrow><mml:mi>φ</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:math> and going “downward.” It is not guaranteed that Spherical Linear Interpolation will use the shortest path between two quaternions; this must be checked in the implementation...