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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

Linetest Oriented Bounding Box

Rays and Line segments are similar. The slab test for raycasting and the slap test to see if a Line and OBB intersect are almost the same. The only thing a linetest does different from a Raycast is it normalizes the result of the t value to the length of the line segment.

Because the two tests are so similar, we are going to build the linetest using the existing Raycast against the OBB function. Comparing the squared value of t against the squared length of the line segment is more efficient than normalizing t to the length of the Line.

Getting ready

We are going to implement a function to check if a Line segment and an OBB intersect. This function will return a Boolean result. The linetest function is going to build a ray out of the line and use the existing Raycast against the OBB function.

How to do it…

Follow these steps to implement line testing against an OBB:

  1. Declare the Linetest function in Geometry3D.h:
    bool Linetest(const OBB& obb, const Line...
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