Transcript Tetris: SAS/AF® Considerations

Tetris: SAS/AF Considerations
Richard A. DeVenezia
Independent Consultant
SAS is a registered trademark or trademark of SAS Institute Inc. in the USA and other countries. ® indicates USA registration.
Other brand and product names are registered trademarks or Trademarks of their respective companies.
Slide imagery Copyright © 2005, SAS Institute Inc. All rights reserved.
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Overview

SAS/AF - Dead or Alive ?
• Built to last

Gaming Tradition
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Tradition
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Topics to be Covered

Invention

Pieces

Game Play

Movement Keys

Layout

Timing Loop
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Inventor

Alexey Pajitnov

1985

World wide craze
• More dangerous than a Rubik’s Cube

Still popular
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Pieces

Arrangement of four squares or blocks
• Seven shapes
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Drawing a block

DATA Step - DSGI

45 degree lines
• left side, then bottom side
• color varies by linear interpolation
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Saving a block

goptions device=GIF xpixels=30 ypixels=30;

rc = graph (‘CLEAR’, “E”); ...
...
rc = gset ('COLREP', cindex, acolor);
rc = gset ('LINCOLOR', cindex);
rc = gdraw ('LINE', 2, x1,x2, y1,y2);
...
rc = graph (‘UPDATE’); * creates E.GIF;

PIECE.CLASS uses 4 block images
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.GIF to .IMAGE

sashelp.fsp.imgdat
Image Data Model
_readFilePath(file)
_writeCatalog(ent)

Images in same catalog as
game
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Game Play

Pieces drop by gravity

Player can move, rotate or drop pieces
• Within the grid

Can’t move?
• Locked piece
• Check for completed rows

Game over?
• Any part of locked piece outside the grid
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Piece Class

Adapts to piece type A,B,C,...
• arrays define geometry
private
{ ., .,
, 1, 2,
, ., .,
num D [ 4, 3, 3 ] / ( initialValue =
.
3
4
, ., 1, .
, ., 2, .
, 4, 3, .
, 4, ., .
, 3, 2, 1
, ., ., .
, .,
, .,
, .,
});
3, 44
2, .
1, .
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.

One array per piece
• 4 states of rotation
• 4 blocks per piece
• values define block layout
Piece Class - attributes

Track state
block[4] - image viewers
field
- grid (locked blocks)
piece
- A,B,C...
state
- rotation state 1..4
side
- dimension of side (px)
gravity - how much to drop (px)
timeout - when gravity next occurs
baseSleep - event checking interval
x,y,row,col - position of piece on field

Where, when, how, what is going on
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Piece Class - methods

Attribute driven methods
setcam* - x,y,row,col

Behaviors
right - move blocks of piece
left
down
drop
rotate
lock

Misc
blockRowOf(y), topOfRow(n) - support geometry tests
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
HOLD ON, WAIT a SECOND!

Piece.wait()
• Important and essential
• Wait for player to do something

Does what needs doing while the player does
nothing
• Drop a little (gravity)
• Play a blip sound
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I’m Waiting...

EVENT() returns 1
• when the player stops doing nothing

SLEEP()
• yields gracefully, but unresponding
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The Waiting Game
wait: method return=num
dt = datetime();
do until EVENT();
do while (dt<timeout and not EVENT());
SLEEP(10,0.001); * 10 milli seconds;
dt = datetime();
end;
if (dt>=timeout) then do;
... move down, play sound, timeout+X
... return 1 if locked, -1 if game over
end;
end;
return 0; * event needs servicing;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
What caused the event?

A Text Entry Control
• Field where user types in
4
left

5
6
rotate right
2
drop
Has overrides
kbd.keyFeedback = ‘Yes’
kbd. _setInstanceMethod ('_onKey',
'Playmethods', 'onkey');
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Playmethods.scl:onKey

Dispatches keypress handlers
piece = _self_.piece;
select (upcase(_self_.text));
when ('4') piece.left();
when ('5') piece.rotate();
when ('6') piece.right();
when ('2') piece.drop();
when ('D') piece.drop();
when ('Q') field.gameover = 1;
otherwise ;
end;

AND...
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AND...

Re-enters the wait method
wait:
rc = piece.wait();
if rc > 0 then do;
... is game over ?
... if not, lock the piece and
randomly select a new one
_self_.piece =
_new_ Piece (field, byte(41x + ranuni(0)*7);
goto wait;
end;
* code reaches here if EVENT() is pending;
endmethod;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
BUT...

Pending event (by design) is a keyPress

SAS/AF Executor, event handling
• Invokes onKey of Text Entry
SAS/AF
event supervisor
Text Entry
key pressed
Control
Loop
piece.wait()
for event()
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Text Entry
onKey()
Conclusion

SAS/AF is very much alive
• A gem with many little seen facets

Tetris is still fun

Install SAS/Tetris from
www.devenezia.com/downloads/sas/af
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
About the Speaker
Speaker Richard A. DeVenezia
Independent Consultant
Location 9949 East Steuben Road
Remsen, NY 13438
Telephone (315) 831-8802
E-Mail [email protected]
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.