Object Oriented Design

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Object Oriented Design
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Goals

• Using OpenGL as case study turning a blob anti
  pattern into an Object-Oriented Architecture
• A Quick Introduction to OpenGL
• Provide pointers to resources

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Why OpenGL?

• Serves as great design case to explore a variety
  of OOD issues.
• Extremely useful to build 2D/3D games
• Provides access to sophisticated graphics
  supported by hardware acceleration
• E.g., ATI Radeon, GeForce
• Results in complex but efficient rendering
• Already these cards can draw a multi thousands 3D
  polygon object with light sources, etc. faster
  than a 32 x 32 pixel desktop icon.

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OpenGL Architecture
http//developer.apple.com/techpubs/macosx/Carbon/
graphics/OpenGL/OpenGL/chap2/index.html
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Anti Patterns OpenGL the Mega Blob

• a class with 60 or more attributes and
  operations usually indicates the presence of the
  Blob
• OpenGL gt 300 http//gl4java.sourceforge.net/docs/
  html/
• What can we do make this enormous functionality
  more accessible through OOD?

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Lets make a Game Engine

• Refactoring
• Bottom up to make OpenGL functionality available
• Top down to capture needs by a variety of games
• We use some ideas from our 2D editor design

Game 1
Game 2
Game n
Game Engine Chris Schenk Luke Swanson
OpenGL
Hardware
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Examples

• Create a subclass of the OpenGLWindow class and
  extend the display, reshape, idle and init
  methods.
• OpenGL for MCL
• Triangles, cubes, sprites, textures
• OpenGL for Java

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Trade offs

• This is not an OpenGL course
• Keep OpenGL specific lectures to a minimum
• Read the books for more depth
• Game Engine will have to be very simple stressing
  simplicity over depth and performance

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OpenGL Resources

• The OpenGL Red Book
• The must have Programming Guide
• http//fly.cc.fer.hr/unreal/theredbook/
• The OpenGL Blue Book
• The Reference Manual
• http//www.eecs.tulane.edu/www/graphics/doc/OpenGL
  -Man-Pages/opengl_index_spec.html
• Real-Time Rendering
• A truly wonderful book covering a lot of ground
  on how to make efficient 3D
• http//www.amazon.com/exec/obidos/ASIN/1568811012
  
• http//www.opengl.org/

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Homework

• Download and install GL4Java
• http//www.jausoft.com/gl4java.html
• After installation run the demos
• Due October 31
• Read OpenGL Red book chapter 1 and 2
• http//fly.cc.fer.hr/unreal/theredbook/
• Due November 5