Glow, Blur in 2d with no opengl or d3d ? possible ?

[jasonf]

Ready code?... Nope. But the code is very simple.

procedure outline( destinationpixels, sourcepixels, transparent, outlinecolour)

For x = 0 to sourcewidth

For y = 0 to sourceheight

  if sourcepixels( x,y ) = transparent and 
    &#40; sourcepixels&#40; x-1, y &#41; <> transparent or 
    sourcepixels&#40; x+1, y &#41; <> transparent or
    sourcepixels&#40; x, y-1 &#41; <> transparent or
    sourcepixels&#40; x, y+1 &#41; <> transparent &#41; then
    destinationpixels&#40; x,y &#41; = outlinecolour
  end if

next y

next x

end procedure

procedure makeglow( destinationpixels, sourcepixels, transparentcolour, outlinecolour , outlinedarknessfactor, outlinesteps )

outline( destinationpixels, sourcepixels, transparent,outlinecolour )


for i = 1 to outlinesteps

   tempsource = copydestinationtotempdestination( destinationpixels )

   outlinecolour = outlinecolour - outlinedarknessfactor

   outline( destinationpixels, tempsource, transparent, outlinecolour )

next i

end procedure

sorry, I can't write it in pascal at the moment, I don't have access to a pascal IDE.. so I've done it in Pseudocode.

[arthurprs]

Ready code?... Nope. But the code is very simple.

procedure outline( destinationpixels, sourcepixels, transparent, outlinecolour)

For x = 0 to sourcewidth

For y = 0 to sourceheight

  if sourcepixels( x,y ) = transparent and 
    &#40; sourcepixels&#40; x-1, y &#41; <> transparent or 
    sourcepixels&#40; x+1, y &#41; <> transparent or
    sourcepixels&#40; x, y-1 &#41; <> transparent or
    sourcepixels&#40; x, y+1 &#41; <> transparent &#41; then
    destinationpixels&#40; x,y &#41; = outlinecolour
  end if

next y

next x

end procedure

procedure makeglow( destinationpixels, sourcepixels, transparentcolour, outlinecolour , outlinedarknessfactor, outlinesteps )

outline( destinationpixels, sourcepixels, transparent,outlinecolour )


for i = 1 to outlinesteps

   tempsource = copydestinationtotempdestination( destinationpixels )

   outlinecolour = outlinecolour - outlinedarknessfactor

   outline( destinationpixels, tempsource, transparent, outlinecolour )

next i

end procedure

sorry, I can't write it in pascal at the moment, I don't have access to a pascal IDE.. so I've done it in Pseudocode.

It looks like a MIX of Basic and Pascal

[jasonf]

well, yeah, it's a kind-of mix of both.. needless to say, it won't compile.

Can you see what I'm trying to show you though?


You see, writing a glow function is pretty much library dependent so I can't just write the code. You'll need access to the surface memory so you can manipulate it. Different libraries expose the underlying surface in different ways, some give an array of pixels you can use.

If you're using the Jedi-SDL library then you're going to have a different mechanism to access the surface memory than with DelphiX.

Once you've written a function which works for your library, you'll only want to call it whenever your main image (the one which you're generating the glow for) changes.. otherwise, you'll eat processor cycles re-generating the same glow for every frame.

[arthurprs]

well, yeah, it's a kind-of mix of both.. needless to say, it won't compile.

Can you see what I'm trying to show you though?


You see, writing a glow function is pretty much library dependent so I can't just write the code. You'll need access to the surface memory so you can manipulate it. Different libraries expose the underlying surface in different ways, some give an array of pixels you can use.

If you're using the Jedi-SDL library then you're going to have a different mechanism to access the surface memory than with DelphiX.

Once you've written a function which works for your library, you'll only want to call it whenever your main image (the one which you're generating the glow for) changes.. otherwise, you'll eat processor cycles re-generating the same glow for every frame.

I will try the code =)

I will post results later.

[arthurprs]

[pascal]
function Tform1.outline( src : TBitmap ; transparentcolor , outlinecolor : TColor ): Tbitmap;
var
x, y: Integer;
begin

result:= TBitmap.Create;
zprofiler.Mark(1,True);
Result.Assign(src);
zprofiler.Mark(1,False);

for x := 1 to src.Width - 2 do
for y := 1 to src.Height - 2 do
begin
if (src.Canvas.Pixels[ x,y ] = transparentcolor) and
( (src.Canvas.Pixels[ x-1, y ] <> transparentcolor) or
(src.Canvas.Pixels[ x+1, y ] <> transparentcolor) or
(src.Canvas.Pixels[ x, y-1 ] <> transparentcolor) or
(src.Canvas.Pixels[ x, y+1 ] <> transparentcolor) ) then
Result.Canvas.Pixels[ x,y ] := outlinecolor;
end;
end;

function Tform1.makeglow(src : Tbitmap ; transparentcolor , glowcolor : TColor; outlinedarknessfactor, outlinesteps: Integer): TBitmap;
var
count : Integer;
begin
Result := TBitmap.Create;
Result.Assign(src);
for count:= 0 to outlinesteps-1 do
begin
Result := outline( Result, transparentcolor, glowcolor);
glowcolor := glowcolor + outlinedarknessfactor; // << this is wrong i know
end;
end;

procedure TForm1.Image1Click(Sender: TObject);
begin
image2.Picture.Bitmap:= makeglow(Image1.Picture.Bitmap, RGB(255,0,255), RGB(0,100,250), 100, 3);
end;
[/pascal]

;] it appers to have worked



But the code is toooooo slow
i think im making something wrong

EDIT: Reuploaded the img cuz jpeg is a TRASH to show details

[JernejL]

Ofcourse it is slow on cpu! that's why people do such effects with graphic cards!

[arthurprs]

Ofcourse it is slow on cpu! that's why people do such effects with graphic cards!

How can i make gpu do the work ?

[JernejL]

by using opengl or d3d to do the fancy rendering.

[wagenheimer]

There are some example of how to do this on Asphyre without using shaders?

[Robert Kosek]

The general idea given, in the example of blurred vector/line games, was that you render to a small rendertarget, render normally, and then stretch the rendertarget over the screen with anti-aliasing on. Of course you must give it a transparency value and correct blendmode. It gives a pretty good result from what I understand.

Without shaders that is pretty much the best you can do. At least efficiently.