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BOOK: Professional XNA Game Programming: For Xbox 360 and Windows ISBN: 978-0-470-12677-6
This is the forum to discuss the Wrox book Professional XNA Game Programming: For Xbox 360 and Windows by Benjamin Nitschke; ISBN: 9780470126776
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Old May 25th, 2007, 09:32 PM
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I am looking at the RenderBall / RenderPaddles methods and trying to get a handle on the numbers. At first they look a little random, was wondering if anyone could explain why they are used?

                (int)((0.05f + 0.9f * ballPosition.X) * 1024) - GameBallRect.Width/2,
                (int)((0.02f + 0.96f * ballPosition.Y) * 768) - GameBallRect.Height/2,

Where is 0.05, 0.9, 0.96 coming from? I assume this is adjusting for screen scaling in some way. Normally code would use a constant that describes a number vice using real numbers inside a method.

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Old June 3rd, 2007, 09:45 AM
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I'm stumped on this one too, would be gratefull if anyone could explain this.

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Old June 5th, 2007, 01:19 AM
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I wondered about it, too. I think the .05f comes from the paddle positions being located at .05 and at (1-.05) in the X direction. That leaves 0.90 for the distance between the paddles. Haven't worked out the Y axis, but it looks to be something similar (1.0 = 0.02 + 0.96 + 0.02)


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