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UNDERGROUND.ISO
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scroll4.pas
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Pascal/Delphi Source File
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1995-07-28
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1KB
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27 lines
Uses Crt,Gif,ModeXLib;
Var x, {current offset in x-direction}
x_dir, {specifies scroll direction for x}
y, {current offset for y-direction}
y_dir:word; {specifies scroll direction for y}
Begin
Init_ModeX; {enable Mode X}
double; {160 byte mode on (640*400 pixels total}
LoadGif('640400'); {load image}
p13_2_ModeX(vram_pos,rest div 4); {rest of image in video RAM}
x:=1; {x-beginning with column 1}
x_dir:=1; {x-direction 1 byte per pass}
y:=160; {y-beginning with line 1}
y_dir:=160; {y-direction +160 bytes per pass}
Repeat
Inc(x,x_dir); {x-movement}
Inc(y,y_dir); {y-movement}
WaitRetrace; {wait for retrace}
SetStart(y+x); {and write new start in register}
if (x >= 80) {x-border reached -> turn x-direction around}
or (x <= 1) Then x_dir:=-x_dir;
if (y >= 200*160) {y-border reached -> turn y-direction around}
or (y <= 160) Then y_dir:=-y_dir;
Until KeyPressed; {run until key is pressed}
TextMode(3);
End.