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Game Physics Cookbook

You're reading from   Game Physics Cookbook Discover over 100 easy-to-follow recipes to help you implement efficient game physics and collision detection in your games

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Product type Paperback
Published in Mar 2017
Publisher Packt
ISBN-13 9781787123663
Length 480 pages
Edition 1st Edition
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Author (1):
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Gabor Szauer Gabor Szauer
Author Profile Icon Gabor Szauer
Gabor Szauer
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Toc

Table of Contents (19) Chapters Close

Preface 1. Vectors FREE CHAPTER 2. Matrices 3. Matrix Transformations 4. 2D Primitive Shapes 5. 2D Collisions 6. 2D Optimizations 7. 3D Primitive Shapes 8. 3D Point Tests 9. 3D Shape Intersections 10. 3D Line Intersections 11. Triangles and Meshes 12. Models and Scenes 13. Camera and Frustum 14. Constraint Solving 15. Manifolds and Impulses 16. Springs and Joints A. Advanced Topics Index

Circle to circle

Determining if two circles intersect is extremely simple. If the length of a line going from the center of circle A to the center of circle B is less than the sum of the two circles, radii, they intersect. Of course, we want to avoid the expensive square root operation performed when finding the length of a line. To avoid this, we can compare the square length of the line against the square sum of the two circles, radii:

Circle to circle

Getting ready

We are going to implement a function to detect the collision between two circles. To avoid the expensive square root operation involved in finding the distance between two circles, we're going to find the square distance. Because we're comparing the square distance, we also have to square the sum of the circles, radii.

How to do it…

Follow these steps to implement a collision detection function between two circles:

  1. Declare the CircleCircle collision function in Geometry2D.h:
    bool CircleCircle(const Circle& c1, const Circle&amp...
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