(*
 * Hedgewars, a free turn based strategy game
 * Copyright (c) 2004-2015 Andrey Korotaev <unC0Rr@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *)

{$INCLUDE "options.inc"}

unit uLand;
interface
uses SDLh, uLandTemplates, uConsts, uTypes, uAILandMarks;

procedure initModule;
procedure freeModule;
procedure DrawBottomBorder;
procedure GenMap;
procedure GenPreview(out Preview: TPreview);
procedure GenPreviewAlpha(out Preview: TPreviewAlpha);

implementation
uses uConsole, uStore, uRandom, uLandObjects, uIO, uLandTexture,
     uVariables, uUtils, uCommands, adler32, uDebug, uLandPainted, uTextures,
     uLandGenMaze, uPhysFSLayer, uScript, uLandGenPerlin,
     uLandGenTemplateBased, uLandUtils, uRenderUtils;

var digest: shortstring;
    maskOnly: boolean;


procedure PrettifyLandAlpha();
begin
    if (cReducedQuality and rqBlurryLand) <> 0 then
        PrettifyAlpha2D(LandPixels, LAND_HEIGHT div 2, LAND_WIDTH div 2)
    else
        PrettifyAlpha2D(LandPixels, LAND_HEIGHT, LAND_WIDTH);
end;

procedure DrawBorderFromImage(Surface: PSDL_Surface);
var tmpsurf: PSDL_Surface;
    //r, rr: TSDL_Rect;
    x, yd, yu: LongInt;
    targetMask: Word;
begin
    tmpsurf:= LoadDataImage(ptCurrTheme, 'Border', ifCritical or ifIgnoreCaps or ifColorKey);

    // if mask only, all land gets filled with landtex and therefore needs borders
    if maskOnly then
        targetMask:= lfLandMask
    else
        targetMask:= lfBasic;

    for x:= 0 to LAND_WIDTH - 1 do
    begin
        yd:= LAND_HEIGHT - 1;
        repeat
            while (yd > 0) and ((Land[yd, x] and targetMask) = 0) do dec(yd);

            if (yd < 0) then
                yd:= 0;

            while (yd < LAND_HEIGHT) and ((Land[yd, x] and targetMask) <> 0) do
                inc(yd);
            dec(yd);
            yu:= yd;

            while (yu > 0  ) and ((Land[yu, x] and targetMask) <> 0) do dec(yu);
            while (yu < yd ) and ((Land[yu, x] and targetMask) =  0) do inc(yu);

            if (yd < LAND_HEIGHT - 1) and ((yd - yu) >= 16) then
                copyToXYFromRect(tmpsurf, Surface, x mod tmpsurf^.w, 16, 1, 16, x, yd - 15);
            if (yu > 0) then
                copyToXYFromRect(tmpsurf, Surface, x mod tmpsurf^.w, 0, 1, Min(16, yd - yu + 1), x, yu);
            yd:= yu - 1;
        until yd < 0;
    end;
    SDL_FreeSurface(tmpsurf);
end;


procedure DrawShoppaBorder;
var x, y, s, i: Longword;
    c1, c2, c: Longword;
begin
    c1:= AMask;
    c2:= AMask or RMask or GMask;

    // vertical
    s:= LAND_HEIGHT;

    for x:= 0 to LAND_WIDTH - 1 do
        for y:= 0 to LAND_HEIGHT - 1 do
            if Land[y, x] = 0 then
                if s < y then
                    begin
                    for i:= max(s, y - 8) to y - 1 do
                        begin
                        if ((x + i) and 16) = 0 then c:= c1 else c:= c2;

                        if (cReducedQuality and rqBlurryLand) = 0 then
                            LandPixels[i, x]:= c
                        else
                            LandPixels[i div 2, x div 2]:= c
                        end;
                    s:= LAND_HEIGHT
                    end
                else
            else
                begin
                if s > y then s:= y;
                if s + 8 > y then
                    begin
                    if ((x + y) and 16) = 0 then c:= c1 else c:= c2;

                    if (cReducedQuality and rqBlurryLand) = 0 then
                        LandPixels[y, x]:= c
                    else
                        LandPixels[y div 2, x div 2]:= c
                    end;
                end;

    // horizontal
    s:= LAND_WIDTH;

    for y:= 0 to LAND_HEIGHT - 1 do
        for x:= 0 to LAND_WIDTH - 1 do
            if Land[y, x] = 0 then
                if s < x then
                    begin
                    for i:= max(s, x - 8) to x - 1 do
                        begin
                        if ((y + i) and 16) = 0 then c:= c1 else c:= c2;

                        if (cReducedQuality and rqBlurryLand) = 0 then
                            LandPixels[y, i]:= c
                        else
                            LandPixels[y div 2, i div 2]:= c
                        end;
                    s:= LAND_WIDTH
                    end
                else
            else
                begin
                if s > x then s:= x;
                if s + 8 > x then
                    begin
                    if ((x + y) and 16) = 0 then c:= c1 else c:= c2;

                    if (cReducedQuality and rqBlurryLand) = 0 then
                        LandPixels[y, x]:= c
                    else
                        LandPixels[y div 2, x div 2]:= c
                    end;
                end
end;

procedure ColorizeLandFast(mapsurf: PSDL_Surface);
var ltexsurf: PSDL_Surface;
    i: LongInt;
    ltlnp, srcp, dstp, stopp: Pointer;
    c: SizeInt;
begin
    ltexsurf:= LoadDataImage(ptCurrTheme, 'LandTex', ifCritical or ifIgnoreCaps);

    // pointer to current line of ltexsurf pixels. will be moved from line to line
    ltlnp:= ltexsurf^.pixels;
    // pointer to mapsurf pixels. will jump forward after every move()
    dstp:= mapsurf^.pixels;

    // time to get serious
    SDL_LockSurface(mapsurf);
    SDL_LockSurface(ltexsurf);

    // for now only fill a row with the height of landtex. do vertical copies within mapsurf after

    // do this loop for each line of ltexsurf (unless we run out of map height first)
    for i:= 1 to min(ltexsurf^.h, mapsurf^.h) do
        begin
        // amount of pixels to write in first move()
        c:= ltexsurf^.pitch;

        // protect from odd cases where landtex wider than map
        if c > mapsurf^.pitch then
            c:= mapsurf^.pitch;

        // write line of landtex to mapsurf
        move(ltlnp^, dstp^, c);

        // fill the rest of the line by copying left-to-right until full

        // new src is start of line that we've just written to
        srcp:= dstp;
        // set stop pointer to start of next pixel line of mapsurf
        stopp:= dstp + mapsurf^.pitch;
        // move dst pointer to after what we've just written
        inc(dstp, c);

        // loop until dstp went past end of line
        while dstp < stopp do
            begin
            // copy all from left of dstp to right of it (or just fill the gap if smaller)
            c:= min(dstp-srcp, stopp-dstp);
            move(srcp^, dstp^, c);
            inc(dstp, c);
            end;

        // move to next line in ltexsurf
        inc(ltlnp, ltexsurf^.pitch);
        end;

    // we don't need ltexsurf itself anymore -> cleanup
    ltlnp:= nil;
    SDL_UnlockSurface(ltexsurf);
    SDL_FreeSurface(ltexsurf);
    ltexsurf:= nil;

    // from now on only copy pixels within mapsurf

    // copy all the already written lines at once for that get number of written bytes so far
    // already written pixels are between start and current dstp
    srcp:= mapsurf^.pixels;

    // first byte after end of pixels
    stopp:= srcp + (mapsurf^.pitch * mapsurf^.h);

    while dstp < stopp do
        begin
        // copy all from before dstp to after (or just fill the gap if smaller)
        c:= min(dstp-srcp, stopp-dstp);
        // worried about size of c with humongous maps? don't be:
        //  the OS wouldn't have allowed allocation of object with size > max of SizeInt anyway
        move(srcp^, dstp^, c);
        inc(dstp, c);
        end;

    // cleanup
    srcp:= nil;
    dstp:= nil;
    stopp:= nil;
    SDL_UnlockSurface(mapsurf);

    // freed in freeModule() below
    LandBackSurface:= LoadDataImage(ptCurrTheme, 'LandBackTex', ifIgnoreCaps or ifColorKey);
    if (LandBackSurface <> nil) and GrayScale then Surface2GrayScale(LandBackSurface);
end;

procedure ColorizeLand(Surface: PSDL_Surface);
var tmpsurf: PSDL_Surface;
    r: TSDL_Rect;
    y: LongInt; // stupid SDL 1.2 uses stupid SmallInt for y which limits us to 32767.  But is even worse if LandTex is large, can overflow on 32767 map.
begin
    tmpsurf:= LoadDataImage(ptCurrTheme, 'LandTex', ifCritical or ifIgnoreCaps);
    r.y:= 0;
    y:= 0;
    while y < LAND_HEIGHT do
        begin
        r.x:= 0;
        while r.x < LAND_WIDTH do
            begin
            copyToXY(tmpsurf, Surface, r.x, r.y);
            //SDL_UpperBlit(tmpsurf, nil, Surface, @r);
            inc(r.x, tmpsurf^.w)
            end;
        inc(y, tmpsurf^.h);
        r.y:= y
        end;
    SDL_FreeSurface(tmpsurf);

    // freed in freeModule() below
    LandBackSurface:= LoadDataImage(ptCurrTheme, 'LandBackTex', ifIgnoreCaps or ifColorKey);
    if (LandBackSurface <> nil) and GrayScale then Surface2GrayScale(LandBackSurface);
end;


procedure GenDrawnMap;
begin
    ResizeLand(4096, 2048);
    uLandPainted.Draw;

    MaxHedgehogs:= 48;
    hasGirders:= true;
    playHeight:= 2048;
    playWidth:= 4096;
    leftX:= ((LAND_WIDTH - playWidth) div 2);
    rightX:= (playWidth + ((LAND_WIDTH - playWidth) div 2)) - 1;
    topY:= LAND_HEIGHT - playHeight;
end;

function SelectTemplate: LongInt;
var l: LongInt;
begin
    if (cReducedQuality and rqLowRes) <> 0 then
        SelectTemplate:= SmallTemplates[getrandom(Succ(High(SmallTemplates)))]
    else
    begin
        if cTemplateFilter = 0 then
            begin
            l:= getRandom(GroupedTemplatesCount);
            repeat
                inc(cTemplateFilter);
                dec(l, TemplateCounts[cTemplateFilter]);
            until l < 0;
            end else getRandom(1);

        case cTemplateFilter of
        0: OutError('Ask unC0Rr about what you did wrong', true);
        1: SelectTemplate:= SmallTemplates[getrandom(TemplateCounts[cTemplateFilter])];
        2: SelectTemplate:= MediumTemplates[getrandom(TemplateCounts[cTemplateFilter])];
        3: SelectTemplate:= LargeTemplates[getrandom(TemplateCounts[cTemplateFilter])];
        4: SelectTemplate:= CavernTemplates[getrandom(TemplateCounts[cTemplateFilter])];
        5: SelectTemplate:= WackyTemplates[getrandom(TemplateCounts[cTemplateFilter])];
// For lua only!
        6: begin
           SelectTemplate:= min(LuaTemplateNumber,High(EdgeTemplates));
           GetRandom(2) // burn 1
           end
        end
    end;

    WriteLnToConsole('Selected template #'+inttostr(SelectTemplate)+' using filter #'+inttostr(cTemplateFilter));
end;

procedure LandSurface2LandPixels(Surface: PSDL_Surface);
var x, y: LongInt;
    p: PLongwordArray;
begin
if checkFails(Surface <> nil, 'Assert (LandSurface <> nil) failed', true) then exit;

if SDL_MustLock(Surface) then
    if SDLCheck(SDL_LockSurface(Surface) >= 0, 'SDL_LockSurface', true) then exit;

p:= Surface^.pixels;
for y:= 0 to LAND_HEIGHT - 1 do
    begin
    for x:= 0 to LAND_WIDTH - 1 do
    if Land[y, x] <> 0 then
        if (cReducedQuality and rqBlurryLand) = 0 then
            LandPixels[y, x]:= p^[x]// or AMask
        else
            LandPixels[y div 2, x div 2]:= p^[x];// or AMask;

    p:= PLongwordArray(@(p^[Surface^.pitch div 4]));
    end;

if SDL_MustLock(Surface) then
    SDL_UnlockSurface(Surface);
end;


procedure GenLandSurface;
var tmpsurf: PSDL_Surface;
    x,y: Longword;
begin
    AddProgress();

    tmpsurf:= SDL_CreateRGBSurface(SDL_SWSURFACE, LAND_WIDTH, LAND_HEIGHT, 32, RMask, GMask, BMask, AMask);

    if checkFails(tmpsurf <> nil, 'Error creating pre-land surface', true) then exit;
    ColorizeLandFast(tmpsurf);
    if gameFlags and gfShoppaBorder = 0 then DrawBorderFromImage(tmpsurf);
    AddOnLandObjects(tmpsurf);

    LandSurface2LandPixels(tmpsurf);
    SDL_FreeSurface(tmpsurf);

    if gameFlags and gfShoppaBorder <> 0 then DrawShoppaBorder;

    for x:= leftX+2 to rightX-2 do
        for y:= topY+2 to LAND_HEIGHT-3 do
            if (Land[y, x] = 0) and
               (((Land[y, x-1] = lfBasic) and ((Land[y+1,x] = lfBasic)) or (Land[y-1,x] = lfBasic)) or
               ((Land[y, x+1] = lfBasic) and ((Land[y-1,x] = lfBasic) or (Land[y+1,x] = lfBasic)))) then
            begin
                if (cReducedQuality and rqBlurryLand) = 0 then
                    begin
                    if (Land[y, x-1] = lfBasic) and (LandPixels[y, x-1] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y, x-1]

                    else if (Land[y, x+1] = lfBasic) and (LandPixels[y, x+1] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y, x+1]

                    else if (Land[y-1, x] = lfBasic) and (LandPixels[y-1, x] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y-1, x]

                    else if (Land[y+1, x] = lfBasic) and (LandPixels[y+1, x] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y+1, x];

                    if (((LandPixels[y,x] and AMask) shr AShift) > 10) then
                        LandPixels[y,x]:= (LandPixels[y,x] and (not AMask)) or (128 shl AShift)
                    end;
                Land[y,x]:= lfObject
            end
            else if (Land[y, x] = 0) and
                    (((Land[y, x-1] = lfBasic) and (Land[y+1,x-1] = lfBasic) and (Land[y+2,x] = lfBasic)) or
                    ((Land[y, x-1] = lfBasic) and (Land[y-1,x-1] = lfBasic) and (Land[y-2,x] = lfBasic)) or
                    ((Land[y, x+1] = lfBasic) and (Land[y+1,x+1] = lfBasic) and (Land[y+2,x] = lfBasic)) or
                    ((Land[y, x+1] = lfBasic) and (Land[y-1,x+1] = lfBasic) and (Land[y-2,x] = lfBasic)) or
                    ((Land[y+1, x] = lfBasic) and (Land[y+1,x+1] = lfBasic) and (Land[y,x+2] = lfBasic)) or
                    ((Land[y-1, x] = lfBasic) and (Land[y-1,x+1] = lfBasic) and (Land[y,x+2] = lfBasic)) or
                    ((Land[y+1, x] = lfBasic) and (Land[y+1,x-1] = lfBasic) and (Land[y,x-2] = lfBasic)) or
                    ((Land[y-1, x] = lfBasic) and (Land[y-1,x-1] = lfBasic) and (Land[y,x-2] = lfBasic))) then

                begin

                if (cReducedQuality and rqBlurryLand) = 0 then

                    begin

                    if (Land[y, x-1] = lfBasic) and (LandPixels[y,x-1] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y, x-1]

                    else if (Land[y, x+1] = lfBasic) and (LandPixels[y,x+1] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y, x+1]

                    else if (Land[y+1, x] = lfBasic) and (LandPixels[y+1,x] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y+1, x]

                    else if (Land[y-1, x] = lfBasic) and (LandPixels[y-1,x] and AMask <> 0) then
                        LandPixels[y, x]:= LandPixels[y-1, x];

                    if (((LandPixels[y,x] and AMask) shr AShift) > 10) then
                        LandPixels[y,x]:= (LandPixels[y,x] and (not AMask)) or (64 shl AShift)
                    end;
                Land[y,x]:= lfObject
            end;

    AddProgress();
end;

procedure MakeFortsPreview;
var gap: LongInt;
    h1, h2, w1, w2, x, y, lastX, wbm, bmref: LongWord;
const fortHeight = 960;
      fortWidth  = 704;
      bmHeight = 53;
      bmWidth = 64;
begin
ResizeLand(4096,2048);

lastX:= LAND_WIDTH-1;

gap:= (1024 - fortWidth) + 60 + 20 * cFeatureSize;

h2:= LAND_HEIGHT-1;
h1:= h2 - fortHeight;
w2:= (LAND_WIDTH - gap) div 2;
w1:= w2 - fortWidth;
wbm:= h1 + bmHeight;

// generate 2 forts in center
for y:= h1 to h2 do
    for x:= w1 to w2 do
        begin
        if x mod 4 <> 0 then
            begin
            if (y <= wbm) and ((x - w1) mod (bmWidth * 2) >= bmWidth) then
                continue;
            Land[y,x]:= lfBasic;
            Land[y,lastX-x]:= lfBasic;
            end;
        end;

w2:= w1 - gap;
w1:= max(0, w2 - fortWidth);
wbm:= h1 + bmHeight;
bmref:= w2 + bmWidth;

for y:= h1 to h2 do
    for x:= w1 to w2 do
        begin
        if ((y - x) mod 2) = 0 then
            begin
            // align battlement on inner edge, because real outer edge could be offscreen
            if (y <= wbm) and ((LAND_WIDTH + x - bmref) mod (bmWidth * 2) >= bmWidth) then
                continue;
            Land[y,x]:= lfBasic;
            Land[y,lastX-x]:= lfBasic;
            end;
        end;
end;

procedure MakeFortsMap;
var tmpsurf: PSDL_Surface;
    sectionWidth, i, t, p: integer;
    mirror: boolean;
    pc: PClan;
begin

// make the gaps between forts adjustable if fort map was selected
if cMapGen = mgForts then
    sectionWidth:= 1024 + 60 + 20 * cFeatureSize
else
    sectionWidth:= 1024 * 300;

// mix up spawn/fort order of clans
for i:= 0 to ClansCount - 1 do
    begin
    t:= GetRandom(ClansCount);
    p:= GetRandom(ClansCount);
    if t <> p then
        begin
        pc:= SpawnClansArray[t];
        SpawnClansArray[t]:= SpawnClansArray[p];
        SpawnClansArray[p]:= pc;
        end;
    end;

// figure out how much space we need
playWidth:= sectionWidth * ClansCount;

// note: LAND_WIDTH might be bigger than specified below (rounded to next power of 2)
ResizeLand(playWidth, 2048);

// For now, defining a fort is playable area as 3072x1200 - there are no tall forts.  The extra height is to avoid triggering border with current code, also if user turns on a border, it will give a bit more maneuvering room.
playHeight:= 1200;

// center playable area in land array
leftX:= ((LAND_WIDTH - playWidth) div 2);
rightX:= ((playWidth + (LAND_WIDTH - playWidth) div 2) - 1);
topY:= LAND_HEIGHT - playHeight;

WriteLnToConsole('Generating forts land...');

for i := 0 to ClansCount - 1 do
    begin

    // face in random direction
    mirror:= (GetRandom(2) = 0);
    // make first/last fort face inwards
    if (WorldEdge <> weWrap) or (ClansCount = 2) then
        mirror:= (i <> 0) and (mirror or (i = ClansCount - 1));

    if mirror then
        begin
        // not critical because if no R we can fallback to mirrored L
        tmpsurf:= LoadDataImage(ptForts, SpawnClansArray[i]^.Teams[0]^.FortName + 'R', ifAlpha or ifColorKey or ifIgnoreCaps);
        // fallback
        if tmpsurf = nil then
            begin
            tmpsurf:= LoadDataImage(ptForts, SpawnClansArray[i]^.Teams[0]^.FortName + 'L', ifAlpha or ifCritical or ifColorKey or ifIgnoreCaps);
            BlitImageAndGenerateCollisionInfo(leftX + sectionWidth * i + ((sectionWidth - tmpsurf^.w) div 2), LAND_HEIGHT - tmpsurf^.h, tmpsurf^.w, tmpsurf, 0, true);
            end
        else
            BlitImageAndGenerateCollisionInfo(leftX + sectionWidth * i + ((sectionWidth - tmpsurf^.w) div 2), LAND_HEIGHT - tmpsurf^.h, tmpsurf^.w, tmpsurf);
        SDL_FreeSurface(tmpsurf);
        end
    else
        begin
        tmpsurf:= LoadDataImage(ptForts, SpawnClansArray[i]^.Teams[0]^.FortName + 'L', ifAlpha or ifCritical or ifColorKey or ifIgnoreCaps);
        BlitImageAndGenerateCollisionInfo(leftX + sectionWidth * i + ((sectionWidth - tmpsurf^.w) div 2), LAND_HEIGHT - tmpsurf^.h, tmpsurf^.w, tmpsurf);
        SDL_FreeSurface(tmpsurf);
        end;

    end;
end;

procedure LoadMapConfig;
var f: PFSFile;
    s: shortstring;
begin
s:= cPathz[ptMapCurrent] + '/map.cfg';

WriteLnToConsole('Fetching map HH limit');

f:= pfsOpenRead(s);
if f <> nil then
    begin
    pfsReadLn(f, s);
    if not pfsEof(f) then
        begin
        pfsReadLn(f, s);
        val(s, MaxHedgehogs)
        end;

    pfsClose(f)
    end;

if (MaxHedgehogs = 0) then
    MaxHedgehogs:= 18;
end;

// Loads Land[] from an image, allowing overriding standard collision
procedure LoadMask;
var tmpsurf: PSDL_Surface;
    p: PLongwordArray;
    x, y, cpX, cpY: Longword;
    mapName: shortstring;
begin
tmpsurf:= LoadDataImage(ptMapCurrent, 'mask', ifAlpha or ifColorKey or ifIgnoreCaps);
if tmpsurf = nil then
    begin
    mapName:= ExtractFileName(cPathz[ptMapCurrent]);
    tmpsurf:= LoadDataImage(ptMissionMaps, mapName + '/mask', ifAlpha or ifColorKey or ifIgnoreCaps);
    end;


if (tmpsurf <> nil) and (tmpsurf^.format^.BytesPerPixel = 4) then
    begin
    if LAND_WIDTH = 0 then
        begin
        LoadMapConfig;
        ResizeLand(tmpsurf^.w, tmpsurf^.h);
        playHeight:= tmpsurf^.h;
        playWidth:= tmpsurf^.w;
        leftX:= (LAND_WIDTH - playWidth) div 2;
        rightX:= (playWidth + ((LAND_WIDTH - playWidth) div 2)) - 1;
        topY:= LAND_HEIGHT - playHeight;
        end;
    disableLandBack:= true;

    cpX:= (LAND_WIDTH - tmpsurf^.w) div 2;
    cpY:= LAND_HEIGHT - tmpsurf^.h;
    if SDL_MustLock(tmpsurf) then
        SDLCheck(SDL_LockSurface(tmpsurf) >= 0, 'SDL_LockSurface', true);

    if allOK then
    begin
        p:= tmpsurf^.pixels;
        for y:= 0 to Pred(tmpsurf^.h) do
            begin
            for x:= 0 to Pred(tmpsurf^.w) do
                SetLand(Land[cpY + y, cpX + x], p^[x]);
            p:= PLongwordArray(@(p^[tmpsurf^.pitch div 4]));
            end;

        if SDL_MustLock(tmpsurf) then
            SDL_UnlockSurface(tmpsurf);
        if not disableLandBack then
            begin
            // freed in freeModule() below
            LandBackSurface:= LoadDataImage(ptCurrTheme, 'LandBackTex', ifIgnoreCaps or ifColorKey);
            if (LandBackSurface <> nil) and GrayScale then
                Surface2GrayScale(LandBackSurface)
            end;
    end;
end;
if (tmpsurf <> nil) then
    SDL_FreeSurface(tmpsurf);
tmpsurf:= nil;
end;

procedure LoadMap;
var tmpsurf: PSDL_Surface;
    mapName: shortstring = '';
begin
WriteLnToConsole('Loading land from file...');
AddProgress;
tmpsurf:= LoadDataImage(ptMapCurrent, 'map', ifAlpha or ifColorKey or ifIgnoreCaps);
if tmpsurf = nil then
    begin
    mapName:= ExtractFileName(cPathz[ptMapCurrent]);
    tmpsurf:= LoadDataImage(ptMissionMaps, mapName + '/map', ifAlpha or ifCritical or ifColorKey or ifIgnoreCaps);
    if not allOK then exit;
    end;
// (bare) Sanity check. Considering possible LongInt comparisons as well as just how much system memoery it would take
if checkFails((tmpsurf^.w < $40000000) and (tmpsurf^.h < $40000000) and (QWord(tmpsurf^.w) * tmpsurf^.h < 6*1024*1024*1024), 'Map dimensions too big!', true)
        then exit;

ResizeLand(tmpsurf^.w, tmpsurf^.h);
LoadMapConfig;

playHeight:= tmpsurf^.h;
playWidth:= tmpsurf^.w;
leftX:= (LAND_WIDTH - playWidth) div 2;
rightX:= (playWidth + ((LAND_WIDTH - playWidth) div 2)) - 1;
topY:= LAND_HEIGHT - playHeight;

if not checkFails(tmpsurf^.format^.BytesPerPixel = 4, 'Map should be 32bit', true) then
    BlitImageAndGenerateCollisionInfo(
        (LAND_WIDTH - tmpsurf^.w) div 2,
        LAND_HEIGHT - tmpsurf^.h,
        tmpsurf^.w,
        tmpsurf);

SDL_FreeSurface(tmpsurf);

if allOK then LoadMask;
end;

procedure DrawBottomBorder; // broken out from other borders for doing a floor-only map, or possibly updating bottom during SD
var x, w, c, y: Longword;
begin
for w:= 0 to 23 do
    for x:= leftX to rightX do
        begin
        y:= Longword(cWaterLine) - 1 - w;
        Land[y, x]:= lfIndestructible;
        if (x + y) mod 32 < 16 then
            c:= AMask
        else
            c:= AMask or RMask or GMask; // FF00FFFF

        if (cReducedQuality and rqBlurryLand) = 0 then
            LandPixels[y, x]:= c
        else
            LandPixels[y div 2, x div 2]:= c
        end
end;

procedure GenMap;
var x, y, w, c, c2: Longword;
    map, mask: shortstring;
begin
    hasBorder:= false;
    maskOnly:= false;

    LoadThemeConfig;

    // is this not needed any more? lets hope setlength sets also 0s
    //if ((GameFlags and gfForts) <> 0) or (Pathz[ptMapCurrent] <> '') then
    //    FillChar(Land,SizeOf(TCollisionArray),0);*)

    if cPathz[ptMapCurrent] <> '' then
        begin
        map:= cPathz[ptMapCurrent] + '/map.png';
        mask:= cPathz[ptMapCurrent] + '/mask.png';
        if (not(pfsExists(map)) and pfsExists(mask)) then
            begin
            maskOnly:= true;
            LoadMask;
            GenLandSurface
            end
        else LoadMap;
        end
    else
        begin
        WriteLnToConsole('Generating land...');
        case cMapGen of
            mgRandom: GenTemplated(EdgeTemplates[SelectTemplate]);
            mgMaze  : begin ResizeLand(4096,2048); GenMaze; end;
            mgPerlin: begin ResizeLand(4096,2048); GenPerlin; end;
            mgDrawn : GenDrawnMap;
            mgForts : begin GameFlags:= (GameFlags or gfForts or gfDivideTeams); MakeFortsMap(); end;
        else
            OutError('Unknown mapgen', true);
        end;
        if cMapGen <> mgForts then
            GenLandSurface
        end;

    AddProgress;

// check for land near top
c:= 0;
if (GameFlags and gfBorder) <> 0 then
    hasBorder:= true
else
    for y:= topY to topY + 5 do
        for x:= leftX to rightX do
            if Land[y, x] <> 0 then
                begin
                inc(c);
                if c > LongWord((LAND_WIDTH div 2)) then // avoid accidental triggering
                    begin
                    hasBorder:= true;
                    break;
                    end;
                end;

if hasBorder then
    begin
    if WorldEdge = weNone then
        begin
        for y:= 0 to LAND_HEIGHT - 1 do
            for x:= 0 to LAND_WIDTH - 1 do
                if (y < topY) or (x < leftX) or (x > rightX) then
                    Land[y, x]:= lfIndestructible;
        end
    else if topY > 0 then
        begin
        for y:= 0 to LongInt(topY) - 1 do
            for x:= 0 to LAND_WIDTH - 1 do
                Land[y, x]:= lfIndestructible;
        end;
    // experiment hardcoding cave
    // also try basing cave dimensions on map/template dimensions, if they exist
    for w:= 0 to 5 do // width of 3 allowed hogs to be knocked through with grenade
        begin
        if (WorldEdge <> weBounce) and (WorldEdge <> weWrap) then
            for y:= topY to LAND_HEIGHT - 1 do
                    begin
                    Land[y, leftX + w]:= lfIndestructible;
                    Land[y, rightX - w]:= lfIndestructible;
                    if (y + leftX + w) mod 32 < 16 then
                        c:= AMask
                    else
                        c:= AMask or RMask or GMask; // FF00FFFF
                    if (y + rightX - w) mod 32 < 16 then
                        c2:= AMask
                    else
                        c2:= AMask or RMask or GMask; // FF00FFFF

                    if (cReducedQuality and rqBlurryLand) = 0 then
                        begin
                        LandPixels[y, leftX + w]:= c;
                        LandPixels[y, rightX - w]:= c2;
                        end
                    else
                        begin
                        LandPixels[y div 2, (leftX + w) div 2]:= c;
                        LandPixels[y div 2, (rightX - w) div 2]:= c2;
                        end;
                    end;

        for x:= leftX to rightX do
            begin
            Land[topY + w, x]:= lfIndestructible;
            if (x + w) mod 32 < 16 then
                c:= AMask
            else
                c:= AMask or RMask or GMask; // FF00FFFF

            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[topY + w, x]:= c
            else
                LandPixels[(topY + w) div 2, x div 2]:= c;
            end;
        end;
    end;

if (GameFlags and gfBottomBorder) <> 0 then
    DrawBottomBorder;

if (GameFlags and gfDisableGirders) <> 0 then
    hasGirders:= false;

if (GameFlags and gfForts = 0) and (maskOnly or (cPathz[ptMapCurrent] = '')) then
    AddObjects

else
    AddProgress();

FreeLandObjects;

if not allOK then exit;

if GrayScale then
    begin
    if (cReducedQuality and rqBlurryLand) = 0 then
        for x:= leftX to rightX do
            for y:= topY to LAND_HEIGHT-1 do
                begin
                w:= LandPixels[y,x];
                w:= round(((w shr RShift and $FF) * RGB_LUMINANCE_RED +
                      (w shr BShift and $FF) * RGB_LUMINANCE_GREEN +
                      (w shr GShift and $FF) * RGB_LUMINANCE_BLUE));
                if w > 255 then
                    w:= 255;
                w:= (w and $FF shl RShift) or (w and $FF shl BShift) or (w and $FF shl GShift) or (LandPixels[y,x] and AMask);
                LandPixels[y,x]:= w or (LandPixels[y, x] and AMask)
                end
    else
        for x:= leftX div 2 to rightX div 2 do
            for y:= topY div 2 to LAND_HEIGHT-1 div 2 do
                begin
                w:= LandPixels[y div 2,x div 2];
                w:= ((w shr RShift and $FF) +  (w shr BShift and $FF) + (w shr GShift and $FF)) div 3;
                w:= (w and $FF shl RShift) or (w and $FF shl BShift) or (w and $FF shl GShift) or (LandPixels[y div 2,x div 2] and AMask);
                LandPixels[y,x]:= w or (LandPixels[y div 2, x div 2] and AMask)
                end
    end;

PrettifyLandAlpha();

// adjust world edges for borderless maps
if (WorldEdge <> weNone) and (not hasBorder) then
    InitWorldEdges();

end;

procedure GenPreview(out Preview: TPreview);
var rh, rw, ox, oy, x, y, xx, yy, t, bit, cbit, lh, lw: LongInt;
begin
    WriteLnToConsole('Generating preview...');
    case cMapGen of
        mgRandom: GenTemplated(EdgeTemplates[SelectTemplate]);
        mgMaze: begin ResizeLand(4096,2048); GenMaze; end;
        mgPerlin: begin ResizeLand(4096,2048); GenPerlin; end;
        mgDrawn: GenDrawnMap;
        mgForts: MakeFortsPreview();
    else
        OutError('Unknown mapgen', true);
    end;

    // strict scaling needed here since preview assumes a rectangle
    rh:= max(LAND_HEIGHT,2048);
    rw:= max(LAND_WIDTH,4096);
    ox:= 0;
    if rw < rh*2 then
        begin
        rw:= rh*2;
        end;
    if rh < rw div 2 then rh:= rw * 2;

    ox:= (rw-LAND_WIDTH) div 2;
    oy:= rh-LAND_HEIGHT;

    lh:= rh div 128;
    lw:= rw div 32;
    for y:= 0 to 127 do
        for x:= 0 to 31 do
        begin
            Preview[y, x]:= 0;
            for bit:= 0 to 7 do
            begin
                t:= 0;
                cbit:= bit * 8;
                for yy:= y * lh to y * lh + 7 do
                    for xx:= x * lw + cbit to x * lw + cbit + 7 do
                        if ((yy-oy) and LAND_HEIGHT_MASK = 0) and ((xx-ox) and LAND_WIDTH_MASK = 0)
                           and (Land[yy-oy, xx-ox] <> 0) then
                            inc(t);
                if t > 8 then
                    Preview[y, x]:= Preview[y, x] or ($80 shr bit);
            end;
        end;
end;


procedure GenPreviewAlpha(out Preview: TPreviewAlpha);
var rh, rw, ox, oy, x, y, xx, yy, t, lh, lw: LongInt;
begin
    WriteLnToConsole('Generating preview...');
    case cMapGen of
        mgRandom: GenTemplated(EdgeTemplates[SelectTemplate]);
        mgMaze: begin ResizeLand(4096,2048); GenMaze; end;
        mgPerlin: begin ResizeLand(4096,2048); GenPerlin; end;
        mgDrawn: GenDrawnMap;
        mgForts: MakeFortsPreview;
    else
        OutError('Unknown mapgen', true);
    end;

    // strict scaling needed here since preview assumes a rectangle
    rh:= max(LAND_HEIGHT, 2048);
    rw:= max(LAND_WIDTH, 4096);
    ox:= 0;
    if rw < rh*2 then
        begin
        rw:= rh*2;
        end;
    if rh < rw div 2 then rh:= rw * 2;

    ox:= (rw-LAND_WIDTH) div 2;
    oy:= rh-LAND_HEIGHT;

    lh:= rh div 128;
    lw:= rw div 256;
    for y:= 0 to 127 do
        for x:= 0 to 255 do
            begin
            t:= 0;

            for yy:= y * lh - oy to y * lh + lh - 1 - oy do
                for xx:= x * lw - ox to x * lw + lw - 1 - ox do
                    if (yy and LAND_HEIGHT_MASK = 0) and (xx and LAND_WIDTH_MASK = 0)
                        and (Land[yy, xx] <> 0) then
                        inc(t);

            Preview[y, x]:= t * 255 div (lh * lw);
            end;
end;

procedure chLandCheck(var s: shortstring);
begin
    AddFileLog('CheckLandDigest: ' + s + ' digest : ' + digest);
    if digest = '' then
        digest:= s
    else
        checkFails(s = digest, 'Different map or critical resources loaded, sorry', true);
end;

procedure chSendLandDigest(var s: shortstring);
var i: LongInt;
begin
    for i:= 0 to LAND_HEIGHT-1 do
        syncedPixelDigest:= Adler32Update(syncedPixelDigest, @Land[i,0], LAND_WIDTH);
    s:= 'M' + IntToStr(syncedPixelDigest); // + cScriptName; script name is no longer needed. scripts are hashed

    ScriptSetString('LandDigest', s);

    chLandCheck(s);
    if allOK then SendIPCRaw(@s[0], Length(s) + 1)
end;

procedure initModule;
begin
    RegisterVariable('landcheck', @chLandCheck, false);
    RegisterVariable('sendlanddigest', @chSendLandDigest, false);

    LandBackSurface:= nil;
    digest:= '';
    maskOnly:= false;
    LAND_WIDTH:= 0;
    LAND_HEIGHT:= 0;
(*
    if (cReducedQuality and rqBlurryLand) = 0 then
        SetLength(LandPixels, LAND_HEIGHT, LAND_WIDTH)
    else
        SetLength(LandPixels, LAND_HEIGHT div 2, LAND_WIDTH div 2);

    SetLength(Land, LAND_HEIGHT, LAND_WIDTH);
    SetLength(LandDirty, (LAND_HEIGHT div 32), (LAND_WIDTH div 32));
*)
end;

procedure freeModule;
begin
    SetLength(Land, 0, 0);
    SetLength(LandPixels, 0, 0);
    SetLength(LandDirty, 0, 0);
end;

end.