Developing Games With Ruby
Developing Games With Ruby
For those who write code for living
About the Book
Once there was a boy who fell in love with this magical device that could bring things to life inside a glaring screen. He spent endless hours exploring imaginary worlds, fighting strange creatures, shooting pixelated spaceships, racing boxy cars. The boy kept pondering. "How is this made? I want to create my own worlds...".
Then he discovered programming. "I can finally do it!" - he thought. And he tried. And failed. Then he tried harder. He failed again and again. He was too naive to realize that those worlds he was trying to create were too sophisticated, and his knowledge was too limited. He gave up creating those worlds.
What he didn't give up is writing code for this magical device. He realized he isn't smart enough to create worlds, yet he found out he could create simpler things like small applications - web, desktop, server side or whatnot. Few years later he found himself getting paid to make those.
Applications got increasingly bigger, they spanned across multiple servers, integrated with each other, became pats of huge infrastructures. The boy, now a grown man, was all into it. It was fun and challenging enough to spend over 10000 hours learning and building what others wanted him to build.
Some of these things were useful, some where boring and pointless. Some were never finished. There were things he was proud of, there were others that he wouldn't want to talk about, nonetheless everything he built made him a better builder. Yet he never found the time, courage or reason to build what he really wanted to build since he was a little boy - his own worlds.
Until one day he realized that no one can stop him from following his dream. He felt that equipped with his current knowledge and experience he will be able to learn to create worlds of his own. And he went for it.
This boy must live in many software developers, who dream about creating games, but instead sell their software craftsmanship skills to those who need something else. This boy is me, and you. And it's time to set him free.
Welcome to the world of game development that was waiting for you all these years.
A word from the author
Hey! Are you a game developer? I am building Game Hero - an online community for indie game developers. You are welcome to join and share your work!
Table of Contents
- A Boy Who Wanted To Create Worlds
- Why Ruby?
- What You Should Know Before Reading This Book
What Are We Going To Build?
- Game Development Library
- Theme And Mechanics
Preparing The Tools
- Getting Gosu to run on Mac Os X
- Getting The Sample Code
- Other Tools
- Hello World
- Screen Coordinates And Depth
- Main Loop
- Moving Things With Keyboard
- Images And Animation
- Music And Sound
- Using Tilesets
- Integrating With Texture Packer
- Combining Tiles Into A Map
- Using Tiled To Create Maps
- Loading Tiled Maps With Gosu
- Generating Random Map With Perlin Noise
- Player Movement With Keyboard And Mouse
- Game Coordinate System
Prototyping The Game
- Switching Between Game States
- Implementing Menu State
- Implementing Play State
- Implementing World Map
- Implementing Floating Camera
- Implementing The Tank
- Implementing Bullets And Explosions
- Running The Prototype
Optimizing Game Performance
- Profiling Ruby Code To Find Bottlenecks
- Advanced Profiling Techniques
- Optimizing Inefficient Code
- Profiling On Demand
- Adjusting Game Speed For Variable Performance
- Frame Skipping
Refactoring The Prototype
- Game Programming Patterns
- What Is Wrong With Current Design
- Decoupling Using Component Pattern
- Adding Enemy Objects
- Adding Bounding Boxes And Detecting Collisions
- Catching Bullets
- Implementing Turn Speed Penalties
- Implementing Terrain Speed Penalties
Implementing Health And Damage
- Adding Health Component
- Inflicting Damage With Bullets
Creating Artificial Intelligence
- Designing AI Using Finite State Machine
- Implementing AI Vision
- Controlling Tank Gun
- Implementing AI Input
- Implementing Tank Motion States
- Wiring Tank Motion States Into Finite State Machine
Making The Prototype Playable
- Drawing Water Beyond Map Boundaries
- Generating Tree Clusters
- Generating Random Objects
- Implementing A Radar
- Dynamic Sound Volume And Panning
- Giving Enemies Identity
- Respawning Tanks And Removing Dead Ones
- Displaying Explosion Damage Trails
- Debugging Bullet Physics
- Making Camera Look Ahead
- Reviewing The Changes
Dealing With Thousands Of Game Objects
- Spatial Partitioning
- Implementing A Quadtree
- Integrating ObjectPool With QuadTree
- Moving Objects In QuadTree
- Implementing Base Powerup
- Implementing Powerup Graphics
- Implementing Powerup Sounds
- Implementing Repair Damage Powerup
- Implementing Health Boost
- Implementing Fire Rate Boost
- Implementing Tank Speed Boost
- Spawning Powerups On Map
- Respawning Powerups After Pickup
Implementing Heads Up Display
- Design Considerations
- Rendering Text With Custom Font
- Implementing HUD Class
Implementing Game Statistics
- Tracking Kills, Deaths and Damage
- Making Damage Personal
- Tracking Damage From Chain Reactions
- Displaying Game Score
Building Advanced AI
- Improving Tank Navigation
- Implementing Demo State To Observe AI
- Visual AI Debugging
- Making AI Collect Powerups
- Seeking Health Powerups After Heavy Damage
- Evading Collisions And Getting Unstuck
Wrapping It Up
- Lessons Learned
- Special Thanks
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