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Jon Lennart Aasenden
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 Posted: Thu Mar 24, 2005 11:55 am Post subject: 15 & 16 BPP color conversion LUT? |
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Hi.
I have heard that you can build a conversion LUT for 15 & 16 BPP colors,
making it very fast to convert 24bit RGB values. Could anyone point me in
the right direction?
Is there somewhere i can download some code, or could someone show me how
its done?
Jon Lennart Aasenden
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Boris Novgorodov
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| Posted: Sat Mar 26, 2005 6:34 am Post subject: Re: 15 & 16 BPP color conversion LUT? |
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| Quote: | I have heard that you can build a conversion LUT for 15 & 16 BPP colors,
making it very fast to convert 24bit RGB values. Could anyone point me in
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LUT15:array[0..32767] of TColor;
function ColorFrom15(Col15: Word): TColor;
asm
mov ecx,eax
and ecx,$1F //Blue
imul ecx,541052 //Scaling
mov edx,eax
and ecx,$FF0000 //Blue Mask
and edx,$3E0 //Green
imul edx,135263
and eax,$7C00
shr edx,11
imul eax,135263 //Red
and edx,$FF00 //Green Mask
shr eax,24
or eax,ecx
or eax,edx
end;
function ColorFrom16(Col16: Word): TColor;
asm
mov ecx,eax
and ecx,$1F
imul ecx,541052
and ecx,$FF0000
mov edx,eax
and edx,$7E0
imul edx,135263
shr edx,12
and eax,$F800
and edx,$FF00
imul eax,135263
shr eax,24
or eax,ecx
or eax,edx
end;
procedure TForm1.Button1Click(Sender: TObject);
var
w: Word;
r: TRect;
begin
for w := 0 to 32767 do
LUT15[w] := ColorFrom15(w);
for w := 0 to 32767 do begin
Canvas.Brush.Color := LUT15[w];
r.Top := (w div 256) * 3;
r.Left := (w mod 256) * 2;
r.Right := r.Left + 2;
r.Bottom := r.Top + 3;
Canvas.FillRect(r);
end;
end;
--
Regards
Boris Novgorodov
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Jon Lennart Aasenden
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| Posted: Sat Mar 26, 2005 12:03 pm Post subject: Re: 15 & 16 BPP color conversion LUT? |
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Wowy!
eh.. do you have that without assembler?
Im working on a project that is 100% native pascal.
It would mean a lot.
Thank you for a great example!
Jon Lennart Aasenden
"Boris Novgorodov" <mbo (AT) mail (DOT) ru> wrote
| Quote: | I have heard that you can build a conversion LUT for 15 & 16 BPP colors,
making it very fast to convert 24bit RGB values. Could anyone point me
in
LUT15:array[0..32767] of TColor;
function ColorFrom15(Col15: Word): TColor;
asm
mov ecx,eax
and ecx,$1F //Blue
imul ecx,541052 //Scaling
mov edx,eax
and ecx,$FF0000 //Blue Mask
and edx,$3E0 //Green
imul edx,135263
and eax,$7C00
shr edx,11
imul eax,135263 //Red
and edx,$FF00 //Green Mask
shr eax,24
or eax,ecx
or eax,edx
end;
function ColorFrom16(Col16: Word): TColor;
asm
mov ecx,eax
and ecx,$1F
imul ecx,541052
and ecx,$FF0000
mov edx,eax
and edx,$7E0
imul edx,135263
shr edx,12
and eax,$F800
and edx,$FF00
imul eax,135263
shr eax,24
or eax,ecx
or eax,edx
end;
procedure TForm1.Button1Click(Sender: TObject);
var
w: Word;
r: TRect;
begin
for w := 0 to 32767 do
LUT15[w] := ColorFrom15(w);
for w := 0 to 32767 do begin
Canvas.Brush.Color := LUT15[w];
r.Top := (w div 256) * 3;
r.Left := (w mod 256) * 2;
r.Right := r.Left + 2;
r.Bottom := r.Top + 3;
Canvas.FillRect(r);
end;
end;
--
Regards
Boris Novgorodov
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Boris Novgorodov
Guest
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| Posted: Sun Mar 27, 2005 12:49 pm Post subject: Re: 15 & 16 BPP color conversion LUT? |
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| Quote: | eh.. do you have that without assembler?
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function ColorFrom15(w:word):TColor;
begin
Result := (((w and $1F) * 541052) and $FF0000) or
(((((w and $3E0) shr 5) * 541052) shr  and $FF00) or
((((w and $7C00) shr 10) * 541052) shr 16);
end;
function ColorFrom16(w:word):TColor;
Result := (((w and $1F) * 541052) and $FF0000) or
(((((w and $7E0) shr 5) * 266231) shr and $FF00) or
((((w and $F800) shr 11) * 541052) shr 16);
--
Regards
Boris Novgorodov
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