Vic's QBasic Programming Tutorial
Basic Tutorial III.V (3.5)
GAME TEQUINIQUES REVISTITED!!
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Ok! OK!!!
I have had enought E-mails about people not understanding my game tutorial...
So, I figured it was probly my fault for not explaining it good enough...
This tutorial works hand in hand with tutor #3 so make sure you read it
first...
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First of all, I will once again I will cover How to move a sprite...
I will cover it a few times now...
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OK! here we go!
Every Sprite has a X value and a Y value...
Let me draw a grid for you to get the picture better...
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1 | | | | | | | | | | | | |
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2 | | | | | | | | | | | | |
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3 | | | | | | | | | | | | |
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4 | | | | | | | | | | | | |
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5 | | | | | | | | | | | | |
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Do you remember your times table?? Its exactly like that...
Ok, Imagine that We wanted to put sprite at this point (where the XX is)
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1 | | | | | | | | | | | | |
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2 | | | | | | | | | | | | |
| | | | | XX | | | | | | | |
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3 | | | | | | | | | | | | |
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4 | | | | | | | | | | | | |
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5 | | | | | | | | | | | | |
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Believe it or not, the X value would be 5 and the Y value would equal 2...
So its like this...
X = 5
Y = 2
Remebmer from the graphics tutorial??
X goes left to right, and Y goes up and down...
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Ok, You most likely get that...
If you don't, just think about it for a while...
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Now, What if we wanted to move that XX one space to the RIGHT? What would
its X value be now??
Let me show you this...
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1 | | | | | | | | | | | | |
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2 | | | | | | | | | | | | |
| | | | | XX | ZZ | | | | | | |
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3 | | | | | | | | | | | | |
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4 | | | | | | | | | | | | |
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5 | | | | | | | | | | | | |
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The XX is where the sprite is now, and ZZ is where we want the sprite to
go, which is one space to the right...
So, The X value of the XX is 5 remember, if we want it to be one place to
the right, (where the ZZ is) what should the next X value be? 6 right?
So, if we want the sprite to move one space to the right what should we do?
This is what it used to equall...
X = 5
Y = 2
Now, it equalls
X = 6
Y = 2
Remember,
X = left to right and
Y = up and down,
So, now, if we wanted to move the sprite down one, we would change the Y
value...
So the coordinates would equal
X = 6
Y = 3
So it would now be here... (where the AA is)
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1 | | | | | | | | | | | | |
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2 | | | | | | | | | | | | |
| | | | | XX | ZZ | | | | | | |
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3 | | | | | | | | | | | | |
| | | | | | AA | | | | | | |
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4 | | | | | | | | | | | | |
| | | | | | | | | | | | |
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5 | | | | | | | | | | | | |
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If we were to put this into a formula, what would it look like?
If we wanted to move the sprite ONE (1) space to the right what should
we put???
X = X + 1
Imagine X was equal to 5... Now what does X equal?
6 right??? YES! That would be one space to the right...
If we wanted to move the sprite one down what would we do?
Y = Y + 1
So, if Y was equal to 2 Y would now equal 3!!! One space down...
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I don't know how I can make this any clearer...
IF you still don't understand it, just keep looking at others source code...
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