function SurfaceSheet2Atlas(surf: PSDL_Surface; spriteWidth: Integer; spriteHeight: Integer): PTexture;

uses GLunit, uUtils, uVariables, uConsts, uDebug, uConsole, uAtlas, SysUtils;

var

  logFile: TextFile;

function CropSurface(source: PSDL_Surface; rect: PSDL_Rect): PSDL_Surface;

var

    fmt: PSDL_PixelFormat;

    srcP, dstP: PByte;

    copySize: Integer;

    i: Integer;

const

    pixelSize = 4;

begin

    //writeln(stdout, 'Cropping from ' + IntToStr(source^.w) + 'x' + IntToStr(source^.h) + ' -> ' + IntToStr(rect^.w) + 'x' + IntToStr(rect^.h));

    fmt:= source^.format;

    CropSurface:= SDL_CreateRGBSurface(source^.flags, rect^.w, rect^.h, 

        fmt^.BitsPerPixel, fmt^.Rmask, fmt^.Gmask, fmt^.Bmask, fmt^.Amask);

    if SDL_MustLock(source) then

        SDLTry(SDL_LockSurface(source) >= 0, true);

    if SDL_MustLock(CropSurface) then

        SDLTry(SDL_LockSurface(CropSurface) >= 0, true);

    srcP:= source^.pixels;

    dstP:= CropSurface^.pixels;

    inc(srcP, pixelSize * rect^.x);

    inc(srcP, source^.pitch * rect^.y);

    copySize:= rect^.w * pixelSize;

    for i:= 0 to Pred(rect^.h) do

    begin

        Move(srcP^, dstP^, copySize);

        inc(srcP, source^.pitch);

        inc(dstP, CropSurface^.pitch);

    end;

    if SDL_MustLock(source) then

        SDL_UnlockSurface(source);

    if SDL_MustLock(CropSurface) then

        SDL_UnlockSurface(CropSurface);

end;

function TransparentLine(p: PByte; stride: Integer; length: Integer): boolean;

var

    i: Integer;

begin

    TransparentLine:= false;

    for i:=0 to pred(length) do

    begin

        if p^ <> 0 then

            exit;

        inc(p, stride);

    end;

    TransparentLine:= true;

end;

function AutoCrop(source: PSDL_Surface; var cropinfo: TCropInformation): PSDL_Surface;

var

    l,r,t,b, i: Integer;

    pixels, p: PByte;

    scanlineSize: Integer;

    rect: TSDL_Rect;

const

    pixelSize = 4;

begin

    l:= source^.w; 

    r:= 0; 

    t:= source^.h;

    b:= 0;

    if SDL_MustLock(source) then

        SDLTry(SDL_LockSurface(source) >= 0, true);

    pixels:= source^.pixels;

    scanlineSize:= source^.pitch;

    inc(pixels, 3); // advance to alpha value

    // check top

    p:= pixels;

    for i:= 0 to Pred(source^.h) do

    begin

        if not TransparentLine(p, pixelSize, source^.w) then

        begin

            t:= i;

            break;

        end;

        inc(p, scanlineSize);

    end;

    // check bottom

    p:= pixels;

    inc(p, scanlineSize * source^.h);

    for i:= 0 to Pred(source^.h - t) do

    begin

        dec(p, scanlineSize);

        if not TransparentLine(p, pixelSize, source^.w) then

        begin

            b:= i;

            break;

        end;

    end;

    // check left

    p:= pixels;

    for i:= 0 to Pred(source^.w) do

    begin

        if not TransparentLine(p, scanlineSize, source^.h) then

        begin

            l:= i;

            break;

        end;

        inc(p, pixelSize);

    end;

    // check right

    p:= pixels;

    inc(p, scanlineSize);

    for i:= 0 to Pred(source^.w - l) do

    begin

        dec(p, pixelSize);

        if not TransparentLine(p, scanlineSize, source^.h) then

        begin

            r:= i;

            break;

        end;

    end;

    if SDL_MustLock(source) then

        SDL_UnlockSurface(source);

    rect.x:= l;

    rect.y:= t;

    rect.w:= source^.w - r - l;    

    rect.h:= source^.h - b - t;

    cropInfo.l:= l;

    cropInfo.r:= r;

    cropInfo.t:= t;

    cropInfo.b:= b;

    cropInfo.x:= Trunc(source^.w / 2 - l + r);

    cropInfo.y:= Trunc(source^.h / 2 - t + b);

    if (l = source^.w) or (t = source^.h) then

    begin

        result:= nil;

        exit;

    end;

    if (l <> 0) or (r <> 0) or (t <> 0) or (b <> 0) then

        result:= CropSurface(source, @rect)

    else result:= source;

end;

var 

    x0, y0, x1, y1, tmp: Real;

    p: PChar;

const 

    texelOffset = 0.0;

    aw:=texture^.atlas^.w;

    ah:=texture^.atlas^.h;

    if texture^.isRotated then

        w:=r^.h;

        h:=r^.w;

    end else

        w:=r^.w;

        h:=r^.h;        

    x0:= (texture^.x + {r^.x} +     texelOffset)/aw;

    x1:= (texture^.x + {r^.x} + w - texelOffset)/aw;

    y0:= (texture^.y + {r^.y} +     texelOffset)/ah;

    y1:= (texture^.y + {r^.y} + h - texelOffset)/ah;

    if (texture^.isRotated) then

    begin

        tb^[0].X:= x0;

        tb^[0].Y:= y0;

        tb^[3].X:= x1;

        tb^[3].Y:= y0;

        tb^[2].X:= x1;

        tb^[2].Y:= y1;

        tb^[1].X:= x0;

        tb^[1].Y:= y1

    end else

    begin

        tb^[0].X:= x0;

        tb^[0].Y:= y0;

        tb^[1].X:= x1;

        tb^[1].Y:= y0;

        tb^[2].X:= x1;

        tb^[2].Y:= y1;

        tb^[3].X:= x0;

        tb^[3].Y:= y1;

    end;

    with texture^ do

    begin

        vb[0].X:= texture^.cropInfo.l;

        vb[0].Y:= texture^.cropInfo.t;

        vb[1].X:= texture^.cropInfo.l + w;

        vb[1].Y:= texture^.cropInfo.t;

        vb[2].X:= texture^.cropInfo.l + w;

        vb[2].Y:= texture^.cropInfo.t + h;

        vb[3].X:= texture^.cropInfo.l;

        vb[3].Y:= texture^.cropInfo.t + h;

    end;

    r.x:= 0;

    r.y:= 0;

    r.w:= texture^.w;

    r.h:= texture^.h;

    ComputeTexcoords(texture, @r, @texture^.tb);

NewTexture^.nextFrame:=nil;

NewTexture^.cropInfo.l:= 0;

NewTexture^.cropInfo.r:= 0;

NewTexture^.cropInfo.t:= 0;

NewTexture^.cropInfo.b:= 0;

NewTexture^.cropInfo.x:= width div 2;

NewTexture^.cropInfo.y:= height div 2;

function SurfaceSheet2Atlas(surf: PSDL_Surface; spriteWidth: Integer; spriteHeight: Integer): PTexture;

var

    subSurface: PSDL_Surface;

    framesX, framesY: Integer;

    last, current: PTexture;

    r: TSDL_Rect;

    x, y: Integer;

begin

    SurfaceSheet2Atlas:= nil;

    r.x:= 0;

    r.y:= 0;

    r.w:= spriteWidth;

    r.h:= spriteHeight;

    last:= nil;

    framesX:= surf^.w div spriteWidth;

    framesY:= surf^.h div spriteHeight;

    for x:=0 to Pred(framesX) do

    begin

        r.y:= 0;

        for y:=0 to Pred(framesY) do

        begin

            subSurface:= CropSurface(surf, @r);

            current:= Surface2Atlas(subSurface, false);

            if last = nil then

            begin

                SurfaceSheet2Atlas:= current;

                last:= current;

            end else

            begin

                last^.nextFrame:= current;

                last:= current;

            end;

            inc(r.y, spriteHeight);

        end;

        inc(r.x, spriteWidth);

    end;

    SDL_FreeSurface(surf);

end;

    cropped: PSDL_Surface;

    cropInfo: TCropInformation;

    cropped:= AutoCrop(surf, cropInfo);

    if cropped <> surf then

    begin

        SDL_FreeSurface(surf);

        surf:= cropped;

    end;

    if surf = nil then

    begin

        new(Surface2Atlas);

        Surface2Atlas^.w:= 0;

        Surface2Atlas^.h:= 0;

        Surface2Atlas^.x:=0 ;

        Surface2Atlas^.y:=0 ;

        Surface2Atlas^.isRotated:= false;

        Surface2Atlas^.surface:= nil;

        Surface2Atlas^.shared:= false;

        Surface2Atlas^.nextFrame:= nil;

        Surface2Atlas^.cropInfo:= cropInfo;

        exit;

    end;

    if (surf^.w <= 512) and (surf^.h <= 512) then

        Surface2Atlas^.cropInfo:= cropInfo;

Surface2Atlas^.nextFrame:= nil;

Surface2Atlas^.cropInfo:= cropInfo;

    exit;