``````(*
SEAN PALMER

> there is simple method of masking color 0 so it won't be displayed.
> An assembly language routine based around this:

Procedure PutImg(x, y : Integer; Var Img);
Type
AList = Array[1..\$FFFF] of Byte; {1-based Arrays are slower than 0-based}
Var
APtr    : ^AList; {I found a very fast way to do this: With}
j, i,
Width,
Height,
Counter : Word;
begin
Aptr    := @Img;
Width   := (Aptr^ SHL 8) + Aptr^ + 1; {these +1's that 1-based Arrays }
Height  := (Aptr^ SHL 8) + Aptr^ + 1; { require make For slower code}
Counter := 5;
For j := y to (y + height - 1) do
begin  {try pre-calculating the offset instead}
For i := x to (x + width - 1) do
begin
Case Aptr^[Counter] of {CASE is probably not the way to do this}
0:; { do nothing }
else _mcgaScreen[j, i] := Aptr^[Counter]; { plot it }
end;
Inc(Counter);
end;
end;
end;

ok, here's my try:
*)

Type
pWord = ^Word;

Procedure putImg(x, y : Integer; Var image);
Var
anImg : Record
img : Array [0..\$FFF7] of Byte;
end Absolute image;

aScrn : Record
scrn : Array [0..\$FFF7] of Byte;
end Absolute \$A000 : 0000;

width,
height,
counter,
offs, src : Word;

begin
width  := pWord(@anImg)^;
height := pWord(@anImg)^;
offs   := y * 320 + x;
src    := 4;   {skip width, height}
With aScrn, anImg do
Repeat
counter := width;
Repeat
if img[src] <> 0 then
scrn[offs] := img[src];
inc(src);
inc(offs);
dec(counter);
Until counter = 0;
inc(offs, 320 - width);
dec(height);
Until height = 0;
end;

{
Those Arrays-pretending-to-be-Records above so they'll work With the With
statement should end up making BP keep the address in Registers, making it
faster. In any Case it won't be slower than yours. I'd appreciate you
timing them and letting me know the results. Actually, let me know if it
even compiles and works... 8)

But Really, man, if you're writing Graphics routines you Really have to
go For assembly. Pascal don't cut it. (c doesn't either...)
}

``````