week5.asciidoc

Nature of Code: Week 5

Topics for this week include:

• What is Box2D and why would we use it

• The Box2D World

• Vectors in Box2D

• Hello Box2D World

• Things that don’t move in Box2D

• Custom Geometry in Box2D

• Joints in Box2D

• Apply forces in Box2D

• Collision events in Box2D

• Midterm Homework assignment

What is Box2D?

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• Read along: The Nature of Code: Chapter 5

• Box2D web site

• JBox2D web site

• PBox2D github repo

What are the core elements of the Box2D world?

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• Read along: The Nature of Code: Chapter 5, Section 3

• Box2D manual

Box2D coordinate system and Box2D vectors

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• Read along: The Nature of Code: Chapter 5, Section 4

Task	Function
Convert location from World to Pixels	Vec2 coordWorldToPixels(Vec2 world)
Convert location from World to Pixels	Vec2 coordWorldToPixels(float worldX, float worldY)
Convert location from Pixels to World	Vec2 coordPixelsToWorld(Vec2 screen)
Convert location from Pixels to World	Vec2 coordPixelsToWorld(float pixelX, float pixelY)
Scale a dimension (such as height, width, or radius) from Pixels to World	float scalarPixelsToWorld(float val)
Scale a dimension from World to Pixels	float scalarWorldToPixels(float val)

A first Box2D sketch

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• Read along: The Nature of Code: Chapter 5, Section 5

• Example 5.1: Simple Processing Sketch with no Box2D

• Example 5.1: Simple Processing Sketch with Box2D added!

Static Objects in Box2D

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• Read along: The Nature of Code: Chapter 5, Section 8

• Example 5.2: Boxes falling on platforms

• Example 5.3: ChainShape surface

• Exercise 5.3: Noise Chain

• Exercise 5.3: Sine Chain

Complex Shapes in Box2D

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• Read along: The Nature of Code: Chapter 5, Section 10

• Example 5.4: Custom Polygons)

• Example 5.5: Attaching multiple shapes to one body

Box2D Joints

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• Read along: Nature of Code 5.11

• Example 5.6: Distance Joint

• Example 5.7: Revolute Joint

• Example 5.8: Mouse Joint

• Kinematic Body Demo

Applying Forces in Box2D

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• Read along: Nature of Code 5.12

• Exercise 5.10: Wind

• Exercise 5.10: Attract Mouse

• Exercise 5.10: Gravitational Attraction

Triggering Collision Events in Box2D

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• Read along: Nature of Code 5.13

• Example 5.9: Collision Listening

• Collision Deletion Demo

• Another Collision listening demo

Homework Week 5

For this week, you should begin working on your midterm project. As an experiment, I’d like to try seeding a little online discussion about midterm ideas. Please visit the following link and make a post and comment on other posts:

• http://natureofcode.com/itp/midterm.html

If you are struggling for ideas, here are some links to midterm projects from last year:

• Dollee’s Mon Mon Monsters

• Mark’s Plop Plop Fizz Fizz

• Natalie’s Trees

• Ben’s Genetic Verlet Physics

• Peter’s Name Swarm

• Nick’s Cosmic Crossfire

• Jannae’s Collide

• Mark’s Waiting Game airport project