Learn how to update the game-math library to provide new capabilities including the addition of graphics and set methods for column matrices, points, vectors, and lines. Also study sample programs that illustrate the use of the new capabilities and learn how to draw on off-screen images.
Table of contents
Preface
This module is one in a collection of modules designed for teaching
GAME2302 Mathematical Applications for Game Development at Austin
Community College in Austin, TX.
What you have learned
In the previous module, I presented and explained two sample programs and a
sample game-programming math library named
GM2D01 , which were intended to
implement concepts fromKjell's tutorial in Java code.
The library named
GM2D01 is purely mathematical. By that, I
mean that the library doesn't provide any mechanism for rendering objects of the
ColMatrix ,
Line ,
Point , or
Vector classes in a visual graphics context. That capability
will be added to the version that I will present in this module.
What you will learn
In this module, you will learn how to update the math library to provide a
number of new capabilities including the addition of graphics and various
set methods. You will also learn that the addition of
set methods exposes certain vulnerabilities, and you will learn how to protectagainst those vulnerabilities. Finally, you will learn how to draw on
off-screen images.
Viewing tip
I recommend that you open another copy of this module in a separate
browser window and use the following links to easily find and view the Figuresand Listings while you are reading about them.
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Figure 1 . Screen output from both sample programs.
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Figure 2 . Graphic output from Exercise 1.
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Figure 3 . Graphic output from Exercise 2.
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Figure 4 . Graphic output from Exercise 3.
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Figure 5 . Text output from Exercise 3.
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Figure 6 . Graphic output from Exercise 4.
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Figure 7 . Graphic output from Exercise 5.
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Figure 8 . Graphic output from Exercise 6.
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Figure 9 . Graphic output from Exercise 7.
Listings
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Listing 1 . Beginning of the class named PointLine03 and the class named GUI.
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Listing 2 . Beginning of the constructor for the GUI class.
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Listing 3 . Create two off-screen images.
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Listing 4 . Remaining code in the constructor.
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Listing 5 . Beginning of the drawOffscreen method.
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Listing 6 . Define four lines that will be used to draw borders.
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Listing 7 . Draw a visual manifestation of each line.
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Listing 8 . The draw method of the GM2D02.Line class.
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Listing 9 . Draw a visual manifestation of a GM2D02.Point object.
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Listing 10 . The draw method of the GM2D02.Point class.
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Listing 11 . Draw the vertices of a hexagon.
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Listing 12 . Draw six lines connecting the vertices of the hexagon.
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Listing 13 . Instantiate three objects of type GM2D02.Vector.
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Listing 14 . Call the draw method to draw the vector.
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Listing 15 . The draw method of the GM2D02.Vector class.
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Listing 16 . Three visual manifestations of the same vector.
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Listing 17 . Draw the blue vector.
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Listing 18 . The MyCanvas class and the overridden paint method.
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Listing 19 . The setData method of the ColMatrix class.
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Listing 20 . Updated constructor for the Point class in GM2D02.
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Listing 21 . The drawOffscreen method of the program named PointLine04.
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Listing 22 . Instantiate a point at the upper-left corner.
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Listing 23 . Instantiate a moveable Point object.
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Listing 24 . Instantiate a moveable Line object.
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Listing 25 . Relocate the Line to three more locations.
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Listing 26 . Source code for the game-math library class named GM2D02.
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Listing 27 . Source code for the program named PointLine03.
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Listing 28 . Source code for the program named PointLine04.
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Listing 29 . Code for generating random values in Java.
