Pl2 EXOS 3.DOC
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EXERCISES NR° 3
the LineAs
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1) Exercise nr°1:
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Create a program that changes the shape of the MOUSE cursor.
Indications:
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. You may give the cursor any shape you want.
. Simply refer to the chapter on LineAs to
find answers to your questions if you run into
problems...
2) Exercise nr°2:
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Create a program using the H-LINE and LINE routines that
draws a grid on the screen.
(Preferably large squares)
Indications:
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.The program must work in MEDIUM resolution
.Pay attention to respect the graphic constraints of this
resolution (For the coordinates).
3) Exercise nr°3:
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Write a program that draws a large rectangle, approximately
in the middle of the screen.
Also modify the PAT and use the program from the previous exercise
to draw the rectangle on a grid surface.
Indications:
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.Your program must modify the PAT, you may choose the filling pattern.
.The program must work in MEDIUM resolution (because the program of the
previous exercise is designed for this resolution).
.Instead of completing the previous program, use the
PEXEC function of GEMDOS to load the grid program and draw the
rectangle upon the program's return.
4) Exercise nr°4:
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Create a program that moves a SPRITE from the left to the
right of the screen and then from the right back to its starting point on the
left. (In Medium resolution)
Indications:
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.Do not use MASK (data = 0) for the SPRITE, it will
greatly simplify the task...
.The design of the SPRITE is left to your imagination.
.You must use DRAW SPRITE to display the SPRITE on the screen
and UNDRAW SPRITE when you need to erase it to display it further
on the screen.
.The SPRITE must be in VDI format
5) Exercise nr°5:
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Write a program that works in LOW resolution and displays
points of any of the 16 available colors randomly on the screen.
The entire screen will be filled with color dots assigned
at random.
Once this is done, rotate the color palette.
Indications:
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.To display the points on the screen, use the PUT PIXEL routine.
You can create a macro instruction from this routine
to simplify the work...
.To get random colors for each of these points, use
the RANDOM macro instruction.
(See the chapter on GEMDOS)
.For a rotation of colors, use the PALETTE macro instruction
(See the chapter on GEMDOS) and you can call it
providing various parameters the data defining
the colors of which you have rotated by one unit each time.
6) Exercise nr°6:
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Create a program that draws a diamond on the screen.
Also modify the PAT according to your tastes.
The program must first display the diamond without CLIPPING then
it must display the same diamond using CLIPPING in such
way that only the left half of the diamond remains visible.
Indications:
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.To draw the diamond use the FILLED POLYGON routine.
.If you encounter problems, refer to the chapter on
LineAs and look closely at the explanations of routine $A006
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PIECHOCKI Laurent
8,impasse Bellevue Corrections in the file:CORRIG_3.DOC
57980 TENTELING ------------
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