hedgewars/uLandGraphics.pas
author nemo
Fri, 23 Mar 2012 18:20:59 -0400
changeset 6810 5337f554480e
parent 6700 e04da46ee43c
child 6982 8d41d22a291d
permissions -rw-r--r--
This has bugged me for a while. Since we are missing the source SVGs for this theme, removed the leaves crudely in GIMP. Also added some basic roots. Someone more artistic is encouraged to try and improve it.

(*
 * Hedgewars, a free turn based strategy game
 * Copyright (c) 2004-2012 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 *)

{$INCLUDE "options.inc"}

unit uLandGraphics;
interface
uses uFloat, uConsts, uTypes;

type PRangeArray = ^TRangeArray;
     TRangeArray = array[0..31] of record
                                   Left, Right: LongInt;
                                   end;

function  addBgColor(OldColor, NewColor: LongWord): LongWord;
function  SweepDirty: boolean;
function  Despeckle(X, Y: LongInt): Boolean;
procedure Smooth(X, Y: LongInt);
function  CheckLandValue(X, Y: LongInt; LandFlag: Word): boolean;
function  DrawExplosion(X, Y, Radius: LongInt): Longword;
procedure DrawHLinesExplosions(ar: PRangeArray; Radius: LongInt; y, dY: LongInt; Count: Byte);
procedure DrawTunnel(X, Y, dX, dY: hwFloat; ticks, HalfWidth: LongInt);
procedure FillRoundInLand(X, Y, Radius: LongInt; Value: Longword);
procedure ChangeRoundInLand(X, Y, Radius: LongInt; doSet: boolean);
function  LandBackPixel(x, y: LongInt): LongWord;
procedure DrawLine(X1, Y1, X2, Y2: LongInt; Color: Longword);

function TryPlaceOnLand(cpX, cpY: LongInt; Obj: TSprite; Frame: LongInt; doPlace: boolean; indestructible: boolean): boolean;

implementation
uses SDLh, uLandTexture, uVariables, uUtils, uDebug;

function addBgColor(OldColor, NewColor: LongWord): LongWord;
// Factor ranges from 0 to 100% NewColor
var
    oRed, oBlue, oGreen, oAlpha, nRed, nBlue, nGreen, nAlpha: byte;
begin
    oAlpha := (OldColor shr AShift);
    nAlpha := (NewColor shr AShift);
    // shortcircuit
    if (oAlpha = 0) or (nAlpha = $FF) then
        begin
        addBgColor:= NewColor;
        exit
        end; 
    // Get colors
    oRed   := (OldColor shr RShift);
    oGreen := (OldColor shr GShift);
    oBlue  := (OldColor shr BShift);

    nRed   := (NewColor shr RShift);
    nGreen := (NewColor shr GShift);
    nBlue  := (NewColor shr BShift);

    // Mix colors
    nRed   := min(255,((nRed*nAlpha) div 255) + ((oRed*oAlpha*byte(255-nAlpha)) div 65025));
    nGreen := min(255,((nGreen*nAlpha) div 255) + ((oGreen*oAlpha*byte(255-nAlpha)) div 65025));
    nBlue  := min(255,((nBlue*nAlpha) div 255) + ((oBlue*oAlpha*byte(255-nAlpha)) div 65025)); 
    nAlpha := min(255, oAlpha + nAlpha);

    addBgColor := (nAlpha shl AShift) or (nRed shl RShift) or (nGreen shl GShift) or (nBlue shl BShift);
end;

procedure FillCircleLines(x, y, dx, dy: LongInt; Value: Longword);
var i: LongInt;
begin
if ((y + dy) and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if (Land[y + dy, i] and lfIndestructible) = 0 then
            Land[y + dy, i]:= Value;
if ((y - dy) and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if (Land[y - dy, i] and lfIndestructible) = 0 then
            Land[y - dy, i]:= Value;
if ((y + dx) and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if (Land[y + dx, i] and lfIndestructible) = 0 then
            Land[y + dx, i]:= Value;
if ((y - dx) and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if (Land[y - dx, i] and lfIndestructible) = 0 then
            Land[y - dx, i]:= Value;
end;

procedure ChangeCircleLines(x, y, dx, dy: LongInt; doSet: boolean);
var i: LongInt;
begin
if not doSet then
    begin
    if ((y + dy) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
            if (Land[y + dy, i] > 0) and (Land[y + dy, i] < 256) then
                dec(Land[y + dy, i]); // check > 0 because explosion can erase collision data
    if ((y - dy) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
            if (Land[y - dy, i] > 0) and (Land[y - dy, i] < 256) then
                dec(Land[y - dy, i]);
    if ((y + dx) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
            if (Land[y + dx, i] > 0) and (Land[y + dx, i] < 256) then
                dec(Land[y + dx, i]);
    if ((y - dx) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
            if (Land[y - dx, i] > 0) and (Land[y - dx, i] < 256) then
                dec(Land[y - dx, i]);
    end
else
    begin
    if ((y + dy) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
            if (Land[y + dy, i] < 256) then
                inc(Land[y + dy, i]);
    if ((y - dy) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
            if (Land[y - dy, i] < 256) then
                inc(Land[y - dy, i]);
    if ((y + dx) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
            if (Land[y + dx, i] < 256) then
                inc(Land[y + dx, i]);
    if ((y - dx) and LAND_HEIGHT_MASK) = 0 then
        for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
            if (Land[y - dx, i] < 256) then
                inc(Land[y - dx, i]);
    end
end;

procedure FillRoundInLand(X, Y, Radius: LongInt; Value: Longword);
var dx, dy, d: LongInt;
begin
dx:= 0;
dy:= Radius;
d:= 3 - 2 * Radius;
while (dx < dy) do
    begin
    FillCircleLines(x, y, dx, dy, Value);
    if (d < 0) then
        d:= d + 4 * dx + 6
    else
        begin
        d:= d + 4 * (dx - dy) + 10;
        dec(dy)
        end;
    inc(dx)
    end;
if (dx = dy) then
    FillCircleLines(x, y, dx, dy, Value);
end;

procedure ChangeRoundInLand(X, Y, Radius: LongInt; doSet: boolean);
var dx, dy, d: LongInt;
begin
dx:= 0;
dy:= Radius;
d:= 3 - 2 * Radius;
while (dx < dy) do
    begin
    ChangeCircleLines(x, y, dx, dy, doSet);
    if (d < 0) then
        d:= d + 4 * dx + 6
    else
        begin
        d:= d + 4 * (dx - dy) + 10;
        dec(dy)
        end;
    inc(dx)
    end;
if (dx = dy) then
    ChangeCircleLines(x, y, dx, dy, doSet)
end;

procedure FillLandCircleLines0(x, y, dx, dy: LongInt);
var i, t: LongInt;
begin
t:= y + dy;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfIndestructible) = 0) and (not disableLandBack or (Land[t, i] > 255))  then
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= 0
            else
                LandPixels[t div 2, i div 2]:= 0;

t:= y - dy;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfIndestructible) = 0) and (not disableLandBack or (Land[t, i] > 255))  then
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= 0
            else
                LandPixels[t div 2, i div 2]:= 0;

t:= y + dx;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfIndestructible) = 0) and (not disableLandBack or (Land[t, i] > 255))  then
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= 0
            else
                LandPixels[t div 2, i div 2]:= 0;

t:= y - dx;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfIndestructible) = 0) and (not disableLandBack or (Land[t, i] > 255))  then
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= 0
            else
                LandPixels[t div 2, i div 2]:= 0;

end;

function FillLandCircleLinesBG(x, y, dx, dy: LongInt): Longword;
var i, t, by, bx: LongInt;
    cnt: Longword;
begin
cnt:= 0;
t:= y + dy;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if (Land[t, i] and lfIndestructible) = 0 then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                begin
                by:= t; bx:= i;
                end
            else
                begin
                by:= t div 2; bx:= i div 2;
                end;
            if ((Land[t, i] and lfBasic) <> 0) and (((LandPixels[by,bx] and AMask) shr AShift) = 255) and (not disableLandBack) then
                begin
                inc(cnt);
                LandPixels[by, bx]:= LandBackPixel(i, t)
                end
            else if ((Land[t, i] and lfObject) <> 0) or (((LandPixels[by,bx] and AMask) shr AShift) < 255) then 
                LandPixels[by, bx]:= 0
            end;

t:= y - dy;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if (Land[t, i] and lfIndestructible) = 0 then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                begin
                by:= t; bx:= i;
                end
            else
                begin
                by:= t div 2; bx:= i div 2;
                end;
            if ((Land[t, i] and lfBasic) <> 0) and (((LandPixels[by,bx] and AMask) shr AShift) = 255) and (not disableLandBack) then
                begin
                inc(cnt);
                LandPixels[by, bx]:= LandBackPixel(i, t)
                end
            else if ((Land[t, i] and lfObject) <> 0) or (((LandPixels[by,bx] and AMask) shr AShift) < 255) then 
                LandPixels[by, bx]:= 0
            end;

t:= y + dx;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if (Land[t, i] and lfIndestructible) = 0 then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                begin
                by:= t; bx:= i;
                end
            else
                begin
                by:= t div 2; bx:= i div 2;
                end;
            if ((Land[t, i] and lfBasic) <> 0) and (((LandPixels[by,bx] and AMask) shr AShift) = 255) and (not disableLandBack) then
                begin
                inc(cnt);
                LandPixels[by, bx]:= LandBackPixel(i, t)
                end
            else if ((Land[t, i] and lfObject) <> 0) or (((LandPixels[by,bx] and AMask) shr AShift) < 255) then 
                LandPixels[by, bx]:= 0
            end;
t:= y - dx;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if (Land[t, i] and lfIndestructible) = 0 then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                begin
                by:= t; bx:= i;
                end
            else
                begin
                by:= t div 2; bx:= i div 2;
                end;
            if ((Land[t, i] and lfBasic) <> 0) and (((LandPixels[by,bx] and AMask) shr AShift) = 255) and (not disableLandBack) then
                begin
                inc(cnt);
                LandPixels[by, bx]:= LandBackPixel(i, t)
                end
            else if ((Land[t, i] and lfObject) <> 0) or (((LandPixels[by,bx] and AMask) shr AShift) < 255) then 
                LandPixels[by, bx]:= 0
            end;
FillLandCircleLinesBG:= cnt;
end;

procedure FillLandCircleLinesEBC(x, y, dx, dy: LongInt);
var i, t: LongInt;
begin
t:= y + dy;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfBasic) <> 0) or ((Land[t, i] and lfObject) <> 0) then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= cExplosionBorderColor
            else
                LandPixels[t div 2, i div 2]:= cExplosionBorderColor;

            Land[t, i]:= Land[t, i] or lfDamaged;
            //Despeckle(i, t);
            LandDirty[t div 32, i div 32]:= 1;
            end;

t:= y - dy;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dx, 0) to Min(x + dx, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfBasic) <> 0) or ((Land[t, i] and lfObject) <> 0) then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= cExplosionBorderColor
            else
                LandPixels[t div 2, i div 2]:= cExplosionBorderColor;
            Land[t, i]:= Land[t, i] or lfDamaged;
            //Despeckle(i, t);
            LandDirty[t div 32, i div 32]:= 1;
            end;

t:= y + dx;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfBasic) <> 0) or ((Land[t, i] and lfObject) <> 0) then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= cExplosionBorderColor
            else
               LandPixels[t div 2, i div 2]:= cExplosionBorderColor;

            Land[t, i]:= Land[t, i] or lfDamaged;
            //Despeckle(i, t);
            LandDirty[t div 32, i div 32]:= 1;
            end;

t:= y - dx;
if (t and LAND_HEIGHT_MASK) = 0 then
    for i:= Max(x - dy, 0) to Min(x + dy, LAND_WIDTH - 1) do
        if ((Land[t, i] and lfBasic) <> 0) or ((Land[t, i] and lfObject) <> 0) then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[t, i]:= cExplosionBorderColor
            else
                LandPixels[t div 2, i div 2]:= cExplosionBorderColor;

            Land[t, i]:= Land[t, i] or lfDamaged;
            //Despeckle(i, y - dy);
            LandDirty[t div 32, i div 32]:= 1;
            end;
end;

function DrawExplosion(X, Y, Radius: LongInt): Longword;
var dx, dy, ty, tx, d: LongInt;
    cnt: Longword;
begin

// draw background land texture
    begin
    cnt:= 0;
    dx:= 0;
    dy:= Radius;
    d:= 3 - 2 * Radius;

    while (dx < dy) do
        begin
        inc(cnt, FillLandCircleLinesBG(x, y, dx, dy));
        if (d < 0) then
            d:= d + 4 * dx + 6
        else
            begin
            d:= d + 4 * (dx - dy) + 10;
            dec(dy)
            end;
        inc(dx)
        end;
    if (dx = dy) then
        inc(cnt, FillLandCircleLinesBG(x, y, dx, dy));
    end;

// draw a hole in land
if Radius > 20 then
    begin
    dx:= 0;
    dy:= Radius - 15;
    d:= 3 - 2 * dy;

    while (dx < dy) do
        begin
        FillLandCircleLines0(x, y, dx, dy);
        if (d < 0) then
            d:= d + 4 * dx + 6
        else
            begin
            d:= d + 4 * (dx - dy) + 10;
            dec(dy)
            end;
        inc(dx)
        end;
    if (dx = dy) then
        FillLandCircleLines0(x, y, dx, dy);
    end;

  // FillRoundInLand after erasing land pixels to allow Land 0 check for mask.png to function
    FillRoundInLand(X, Y, Radius, 0);

// draw explosion border
    begin
    inc(Radius, 4);
    dx:= 0;
    dy:= Radius;
    d:= 3 - 2 * Radius;
    while (dx < dy) do
        begin
        FillLandCircleLinesEBC(x, y, dx, dy);
        if (d < 0) then
            d:= d + 4 * dx + 6
        else
            begin
            d:= d + 4 * (dx - dy) + 10;
            dec(dy)
            end;
        inc(dx)
        end;
    if (dx = dy) then
        FillLandCircleLinesEBC(x, y, dx, dy);
    end;

tx:= Max(X - Radius - 1, 0);
dx:= Min(X + Radius + 1, LAND_WIDTH) - tx;
ty:= Max(Y - Radius - 1, 0);
dy:= Min(Y + Radius + 1, LAND_HEIGHT) - ty;
UpdateLandTexture(tx, dx, ty, dy);
DrawExplosion:= cnt
end;

procedure DrawHLinesExplosions(ar: PRangeArray; Radius: LongInt; y, dY: LongInt; Count: Byte);
var tx, ty, by, bx,  i: LongInt;
begin
for i:= 0 to Pred(Count) do
    begin
    for ty:= Max(y - Radius, 0) to Min(y + Radius, LAND_HEIGHT) do
        for tx:= Max(0, ar^[i].Left - Radius) to Min(LAND_WIDTH, ar^[i].Right + Radius) do
            begin
            if (Land[ty, tx] and lfIndestructible) = 0 then
                begin
                if (cReducedQuality and rqBlurryLand) = 0 then
                    begin
                    by:= ty; bx:= tx;
                    end
                else
                    begin
                    by:= ty div 2; bx:= tx div 2;
                    end;
                if ((Land[ty, tx] and lfBasic) <> 0) and (((LandPixels[by,bx] and AMask) shr AShift) = 255) and (not disableLandBack) then
                    LandPixels[by, bx]:= LandBackPixel(tx, ty)
                else if ((Land[ty, tx] and lfObject) <> 0) or (((LandPixels[by,bx] and AMask) shr AShift) < 255) then 
                    LandPixels[by, bx]:= 0
                end
            end;
    inc(y, dY)
    end;

inc(Radius, 4);
dec(y, Count * dY);

for i:= 0 to Pred(Count) do
    begin
    for ty:= Max(y - Radius, 0) to Min(y + Radius, LAND_HEIGHT) do
        for tx:= Max(0, ar^[i].Left - Radius) to Min(LAND_WIDTH, ar^[i].Right + Radius) do
            if ((Land[ty, tx] and lfBasic) <> 0) or ((Land[ty, tx] and lfObject) <> 0) then
                begin
                 if (cReducedQuality and rqBlurryLand) = 0 then
                    LandPixels[ty, tx]:= cExplosionBorderColor
                else
                    LandPixels[ty div 2, tx div 2]:= cExplosionBorderColor;

                Land[ty, tx]:= Land[ty, tx] or lfDamaged;
                LandDirty[ty div 32, tx div 32]:= 1;
                end;
    inc(y, dY)
    end;


UpdateLandTexture(0, LAND_WIDTH, 0, LAND_HEIGHT)
end;

//
//  - (dX, dY) - direction, vector of length = 0.5
//
procedure DrawTunnel(X, Y, dX, dY: hwFloat; ticks, HalfWidth: LongInt);
var nx, ny, dX8, dY8: hwFloat;
    i, t, tx, ty, by, bx, stX, stY, ddy, ddx: Longint;
    despeckle : Boolean;
begin  // (-dY, dX) is (dX, dY) rotated by PI/2
stY:= hwRound(Y);
stX:= hwRound(X);

despeckle:= HalfWidth > 1;

nx:= X + dY * (HalfWidth + 8);
ny:= Y - dX * (HalfWidth + 8);

dX8:= dX * 8;
dY8:= dY * 8;
for i:= 0 to 7 do
    begin
    X:= nx - dX8;
    Y:= ny - dY8;
    for t:= -8 to ticks + 8 do
    begin
    X:= X + dX;
    Y:= Y + dY;
    tx:= hwRound(X);
    ty:= hwRound(Y);
    if ((ty and LAND_HEIGHT_MASK) = 0)
    and ((tx and LAND_WIDTH_MASK) = 0)
    and (((Land[ty, tx] and lfBasic) <> 0) or ((Land[ty, tx] and lfObject) <> 0)) then
        begin
        if despeckle then 
            begin
            Land[ty, tx]:= Land[ty, tx] or lfDamaged;
            LandDirty[ty div 32, tx div 32]:= 1
            end;
        if (cReducedQuality and rqBlurryLand) = 0 then
            LandPixels[ty, tx]:= cExplosionBorderColor
        else
            LandPixels[ty div 2, tx div 2]:= cExplosionBorderColor
        end
    end;
    nx:= nx - dY;
    ny:= ny + dX;
    end;

for i:= -HalfWidth to HalfWidth do
    begin
    X:= nx - dX8;
    Y:= ny - dY8;
    for t:= 0 to 7 do
        begin
        X:= X + dX;
        Y:= Y + dY;
        tx:= hwRound(X);
        ty:= hwRound(Y);
        if ((ty and LAND_HEIGHT_MASK) = 0) and ((tx and LAND_WIDTH_MASK) = 0) and (((Land[ty, tx] and lfBasic) <> 0)
        or ((Land[ty, tx] and lfObject) <> 0)) then
            begin
            Land[ty, tx]:= Land[ty, tx] or lfDamaged;
            if despeckle then
                LandDirty[ty div 32, tx div 32]:= 1;
            if (cReducedQuality and rqBlurryLand) = 0 then
                LandPixels[ty, tx]:= cExplosionBorderColor
            else
                LandPixels[ty div 2, tx div 2]:= cExplosionBorderColor
            end
        end;
    X:= nx;
    Y:= ny;
    for t:= 0 to ticks do
        begin
        X:= X + dX;
        Y:= Y + dY;
        tx:= hwRound(X);
        ty:= hwRound(Y);
        if ((ty and LAND_HEIGHT_MASK) = 0) and ((tx and LAND_WIDTH_MASK) = 0) and ((Land[ty, tx] and lfIndestructible) = 0) then
            begin
            if (cReducedQuality and rqBlurryLand) = 0 then
                begin
                by:= ty; bx:= tx;
                end
            else
                begin
                by:= ty div 2; bx:= tx div 2;
                end;
            if ((Land[ty, tx] and lfBasic) <> 0) and (((LandPixels[by,bx] and AMask) shr AShift) = 255) and (not disableLandBack) then
                LandPixels[by, bx]:= LandBackPixel(tx, ty)
            else if ((Land[ty, tx] and lfObject) <> 0) or (((LandPixels[by,bx] and AMask) shr AShift) < 255) then
                LandPixels[by, bx]:= 0;
            Land[ty, tx]:= 0;
            end
        end;
    for t:= 0 to 7 do
    begin
    X:= X + dX;
    Y:= Y + dY;
    tx:= hwRound(X);
    ty:= hwRound(Y);
    if ((ty and LAND_HEIGHT_MASK) = 0) and ((tx and LAND_WIDTH_MASK) = 0) and (((Land[ty, tx] and lfBasic) <> 0)
    or ((Land[ty, tx] and lfObject) <> 0)) then
        begin
        Land[ty, tx]:= Land[ty, tx] or lfDamaged;
        if despeckle then
            LandDirty[ty div 32, tx div 32]:= 1;
        if (cReducedQuality and rqBlurryLand) = 0 then
            LandPixels[ty, tx]:= cExplosionBorderColor
        else
            LandPixels[ty div 2, tx div 2]:= cExplosionBorderColor
        end
        end;
    nx:= nx - dY;
    ny:= ny + dX;
    end;

for i:= 0 to 7 do
    begin
    X:= nx - dX8;
    Y:= ny - dY8;
    for t:= -8 to ticks + 8 do
    begin
    X:= X + dX;
    Y:= Y + dY;
    tx:= hwRound(X);
    ty:= hwRound(Y);
    if ((ty and LAND_HEIGHT_MASK) = 0) and ((tx and LAND_WIDTH_MASK) = 0) and (((Land[ty, tx] and lfBasic) <> 0)
    or ((Land[ty, tx] and lfObject) <> 0)) then
        begin
        Land[ty, tx]:= Land[ty, tx] or lfDamaged;
        if despeckle then
            LandDirty[ty div 32, tx div 32]:= 1;
        if (cReducedQuality and rqBlurryLand) = 0 then
            LandPixels[ty, tx]:= cExplosionBorderColor
        else
            LandPixels[ty div 2, tx div 2]:= cExplosionBorderColor
        end
    end;
    nx:= nx - dY;
    ny:= ny + dX;
    end;

tx:= Max(stX - HalfWidth * 2 - 4 - abs(hwRound(dX * ticks)), 0);
ty:= Max(stY - HalfWidth * 2 - 4 - abs(hwRound(dY * ticks)), 0);
ddx:= Min(stX + HalfWidth * 2 + 4 + abs(hwRound(dX * ticks)), LAND_WIDTH) - tx;
ddy:= Min(stY + HalfWidth * 2 + 4 + abs(hwRound(dY * ticks)), LAND_HEIGHT) - ty;

UpdateLandTexture(tx, ddx, ty, ddy)
end;

function TryPlaceOnLand(cpX, cpY: LongInt; Obj: TSprite; Frame: LongInt; doPlace: boolean; indestructible: boolean): boolean;
var X, Y, bpp, h, w, row, col, gx, gy, numFramesFirstCol: LongInt;
    p: PByteArray;
    Image: PSDL_Surface;
begin
numFramesFirstCol:= SpritesData[Obj].imageHeight div SpritesData[Obj].Height;

TryDo(SpritesData[Obj].Surface <> nil, 'Assert SpritesData[Obj].Surface failed', true);
Image:= SpritesData[Obj].Surface;
w:= SpritesData[Obj].Width;
h:= SpritesData[Obj].Height;
row:= Frame mod numFramesFirstCol;
col:= Frame div numFramesFirstCol;

if SDL_MustLock(Image) then
    SDLTry(SDL_LockSurface(Image) >= 0, true);

bpp:= Image^.format^.BytesPerPixel;
TryDo(bpp = 4, 'It should be 32 bpp sprite', true);
// Check that sprite fits free space
p:= @(PByteArray(Image^.pixels)^[ Image^.pitch * row * h + col * w * 4 ]);
case bpp of
    4: for y:= 0 to Pred(h) do
        begin
        for x:= 0 to Pred(w) do
            if (PLongword(@(p^[x * 4]))^) <> 0 then
                if ((cpY + y) <= Longint(topY)) or ((cpY + y) >= LAND_HEIGHT)
                or ((cpX + x) <= Longint(leftX)) or ((cpX + x) >= Longint(rightX)) or (Land[cpY + y, cpX + x] <> 0) then
                    begin
                    if SDL_MustLock(Image) then
                        SDL_UnlockSurface(Image);
                    exit(false)
                    end;
        p:= @(p^[Image^.pitch]);
        end;
    end;

TryPlaceOnLand:= true;
if not doPlace then
    begin
    if SDL_MustLock(Image) then
        SDL_UnlockSurface(Image);
    exit
    end;

// Checked, now place
p:= @(PByteArray(Image^.pixels)^[ Image^.pitch * row * h + col * w * 4 ]);
case bpp of
    4: for y:= 0 to Pred(h) do
        begin
        for x:= 0 to Pred(w) do
            if (PLongword(@(p^[x * 4]))^) <> 0 then
                   begin
                if (cReducedQuality and rqBlurryLand) = 0 then
                    begin
                    gX:= cpX + x;
                    gY:= cpY + y;
                    end
                else
                     begin
                     gX:= (cpX + x) div 2;
                     gY:= (cpY + y) div 2;
                    end;
                if indestructible then
                    Land[cpY + y, cpX + x]:= lfIndestructible
                else if (LandPixels[gY, gX] and AMask) shr AShift = 255 then  // This test assumes lfBasic and lfObject differ only graphically
                    Land[cpY + y, cpX + x]:= lfBasic
                else
                    Land[cpY + y, cpX + x]:= lfObject;
                // For testing only. Intent is to flag this on objects with masks, or use it for an ice ray gun
                if (Theme = 'Snow') or (Theme = 'Christmas') then
                    Land[cpY + y, cpX + x]:= Land[cpY + y, cpX + x] or lfIce;
                    LandPixels[gY, gX]:= PLongword(@(p^[x * 4]))^
                end;
        p:= @(p^[Image^.pitch]);
        end;
    end;
if SDL_MustLock(Image) then
    SDL_UnlockSurface(Image);

x:= Max(cpX, leftX);
w:= Min(cpX + Image^.w, LAND_WIDTH) - x;
y:= Max(cpY, topY);
h:= Min(cpY + Image^.h, LAND_HEIGHT) - y;
UpdateLandTexture(x, w, y, h)
end;

function Despeckle(X, Y: LongInt): boolean;
var nx, ny, i, j, c, xx, yy: LongInt;
    pixelsweep: boolean;
begin
if (cReducedQuality and rqBlurryLand) = 0 then
    begin
    xx:= X;
    yy:= Y;
    end
else
    begin
    xx:= X div 2;
    yy:= Y div 2;
    end;
pixelsweep:= ((Land[Y, X] and $FF00) = 0) and (LandPixels[yy, xx] <> 0);
if (((Land[Y, X] and lfDamaged) <> 0) and ((Land[Y, X] and lfIndestructible) = 0)) or pixelsweep then
    begin
    c:= 0;
    for i:= -1 to 1 do
        for j:= -1 to 1 do
            if (i <> 0) or (j <> 0) then
                begin
                ny:= Y + i;
                nx:= X + j;
                if ((ny and LAND_HEIGHT_MASK) = 0) and ((nx and LAND_WIDTH_MASK) = 0) then
                    begin
                    if pixelsweep then
                        begin
                        if ((cReducedQuality and rqBlurryLand) <> 0) then
                            begin
                            nx:= nx div 2;
                            ny:= ny div 2
                            end;
                        if LandPixels[ny, nx] <> 0 then
                            inc(c);
                        end
                    else if Land[ny, nx] > 255 then
                        inc(c);
                    end
                end;

    if c < 4 then // 0-3 neighbours
        begin
        if ((Land[Y, X] and lfBasic) <> 0) and (not disableLandBack) then
            LandPixels[yy, xx]:= LandBackPixel(X, Y)
        else
            LandPixels[yy, xx]:= 0;

        if not pixelsweep then
            begin
            Land[Y, X]:= 0;
            exit(true)
            end
        end;
    end;
Despeckle:= false
end;

procedure Smooth(X, Y: LongInt);
begin
// a bit of AA for explosions
if (Land[Y, X] = 0) and (Y > LongInt(topY) + 1) and 
    (Y < LAND_HEIGHT-2) and (X > LongInt(leftX) + 1) and (X < LongInt(rightX) - 1) then
    begin
    if ((((Land[y, x-1] and lfDamaged) <> 0) and (((Land[y+1,x] and lfDamaged) <> 0)) or ((Land[y-1,x] and lfDamaged) <> 0))
    or (((Land[y, x+1] and lfDamaged) <> 0) and (((Land[y-1,x] and lfDamaged) <> 0) or ((Land[y+1,x] and lfDamaged) <> 0)))) then
        begin
        if (cReducedQuality and rqBlurryLand) = 0 then
            begin
            if ((LandPixels[y,x] and AMask) shr AShift) < 10 then
                LandPixels[y,x]:= (cExplosionBorderColor and (not AMask)) or (128 shl AShift)
            else
                LandPixels[y,x]:=
                                (((((LandPixels[y,x] and RMask shr RShift) div 2)+((cExplosionBorderColor and RMask) shr RShift) div 2) and $FF) shl RShift) or
                                (((((LandPixels[y,x] and GMask shr GShift) div 2)+((cExplosionBorderColor and GMask) shr GShift) div 2) and $FF) shl GShift) or
                                (((((LandPixels[y,x] and BMask shr BShift) div 2)+((cExplosionBorderColor and BMask) shr BShift) div 2) and $FF) shl BShift) or ($FF shl AShift)
            end;
        if (Land[y, x-1] = lfObject) then
            Land[y,x]:= lfObject
        else if (Land[y, x+1] = lfObject) then
            Land[y,x]:= lfObject
        else
            Land[y,x]:= lfBasic;
        end
    else if ((((Land[y, x-1] and lfDamaged) <> 0) and ((Land[y+1,x-1] and lfDamaged) <> 0) and ((Land[y+2,x] and lfDamaged) <> 0))
    or (((Land[y, x-1] and lfDamaged) <> 0) and ((Land[y-1,x-1] and lfDamaged) <> 0) and ((Land[y-2,x] and lfDamaged) <> 0))
    or (((Land[y, x+1] and lfDamaged) <> 0) and ((Land[y+1,x+1] and lfDamaged) <> 0) and ((Land[y+2,x] and lfDamaged) <> 0))
    or (((Land[y, x+1] and lfDamaged) <> 0) and ((Land[y-1,x+1] and lfDamaged) <> 0) and ((Land[y-2,x] and lfDamaged) <> 0))
    or (((Land[y+1, x] and lfDamaged) <> 0) and ((Land[y+1,x+1] and lfDamaged) <> 0) and ((Land[y,x+2] and lfDamaged) <> 0))
    or (((Land[y-1, x] and lfDamaged) <> 0) and ((Land[y-1,x+1] and lfDamaged) <> 0) and ((Land[y,x+2] and lfDamaged) <> 0))
    or (((Land[y+1, x] and lfDamaged) <> 0) and ((Land[y+1,x-1] and lfDamaged) <> 0) and ((Land[y,x-2] and lfDamaged) <> 0))
    or (((Land[y-1, x] and lfDamaged) <> 0) and ((Land[y-1,x-1] and lfDamaged) <> 0) and ((Land[y,x-2] and lfDamaged) <> 0))) then
        begin
        if (cReducedQuality and rqBlurryLand) = 0 then
            begin
            if ((LandPixels[y,x] and AMask) shr AShift) < 10 then
                LandPixels[y,x]:= (cExplosionBorderColor and (not AMask)) or (64 shl AShift)
            else
                LandPixels[y,x]:=
                                (((((LandPixels[y,x] and RMask shr RShift) * 3 div 4)+((cExplosionBorderColor and RMask) shr RShift) div 4) and $FF) shl RShift) or
                                (((((LandPixels[y,x] and GMask shr GShift) * 3 div 4)+((cExplosionBorderColor and GMask) shr GShift) div 4) and $FF) shl GShift) or
                                (((((LandPixels[y,x] and BMask shr BShift) * 3 div 4)+((cExplosionBorderColor and BMask) shr BShift) div 4) and $FF) shl BShift) or ($FF shl AShift)
            end;
        if (Land[y, x-1] = lfObject) then
            Land[y, x]:= lfObject
        else if (Land[y, x+1] = lfObject) then
            Land[y, x]:= lfObject
        else if (Land[y+1, x] = lfObject) then
            Land[y, x]:= lfObject
        else if (Land[y-1, x] = lfObject) then
        Land[y, x]:= lfObject
        else Land[y,x]:= lfBasic
        end
    end
else if ((cReducedQuality and rqBlurryLand) = 0) and (LandPixels[Y, X] and AMask = 255)
and ((Land[Y, X] and (lfDamaged or lfBasic) = lfBasic) or (Land[Y, X] and (lfDamaged or lfBasic) = lfBasic))
and (Y > LongInt(topY) + 1) and (Y < LAND_HEIGHT-2) and (X > LongInt(leftX) + 1) and (X < LongInt(rightX) - 1) then
    begin
    if ((((Land[y, x-1] and lfDamaged) <> 0) and (((Land[y+1,x] and lfDamaged) <> 0)) or ((Land[y-1,x] and lfDamaged) <> 0))
    or (((Land[y, x+1] and lfDamaged) <> 0) and (((Land[y-1,x] and lfDamaged) <> 0) or ((Land[y+1,x] and lfDamaged) <> 0)))) then
        begin
        LandPixels[y,x]:=
                        (((((LandPixels[y,x] and RMask shr RShift) div 2)+((cExplosionBorderColor and RMask) shr RShift) div 2) and $FF) shl RShift) or
                        (((((LandPixels[y,x] and GMask shr GShift) div 2)+((cExplosionBorderColor and GMask) shr GShift) div 2) and $FF) shl GShift) or
                        (((((LandPixels[y,x] and BMask shr BShift) div 2)+((cExplosionBorderColor and BMask) shr BShift) div 2) and $FF) shl BShift) or ($FF shl AShift)
        end
    else if ((((Land[y, x-1] and lfDamaged) <> 0) and ((Land[y+1,x-1] and lfDamaged) <> 0) and ((Land[y+2,x] and lfDamaged) <> 0))
    or (((Land[y, x-1] and lfDamaged) <> 0) and ((Land[y-1,x-1] and lfDamaged) <> 0) and ((Land[y-2,x] and lfDamaged) <> 0))
    or (((Land[y, x+1] and lfDamaged) <> 0) and ((Land[y+1,x+1] and lfDamaged) <> 0) and ((Land[y+2,x] and lfDamaged) <> 0))
    or (((Land[y, x+1] and lfDamaged) <> 0) and ((Land[y-1,x+1] and lfDamaged) <> 0) and ((Land[y-2,x] and lfDamaged) <> 0))
    or (((Land[y+1, x] and lfDamaged) <> 0) and ((Land[y+1,x+1] and lfDamaged) <> 0) and ((Land[y,x+2] and lfDamaged) <> 0))
    or (((Land[y-1, x] and lfDamaged) <> 0) and ((Land[y-1,x+1] and lfDamaged) <> 0) and ((Land[y,x+2] and lfDamaged) <> 0))
    or (((Land[y+1, x] and lfDamaged) <> 0) and ((Land[y+1,x-1] and lfDamaged) <> 0) and ((Land[y,x-2] and lfDamaged) <> 0))
    or (((Land[y-1, x] and lfDamaged) <> 0) and ((Land[y-1,x-1] and lfDamaged) <> 0) and ((Land[y,x-2] and lfDamaged) <> 0))) then
        begin
        LandPixels[y,x]:=
                        (((((LandPixels[y,x] and RMask shr RShift) * 3 div 4)+((cExplosionBorderColor and RMask) shr RShift) div 4) and $FF) shl RShift) or
                        (((((LandPixels[y,x] and GMask shr GShift) * 3 div 4)+((cExplosionBorderColor and GMask) shr GShift) div 4) and $FF) shl GShift) or
                        (((((LandPixels[y,x] and BMask shr BShift) * 3 div 4)+((cExplosionBorderColor and BMask) shr BShift) div 4) and $FF) shl BShift) or ($FF shl AShift)
        end
    end
end;

function SweepDirty: boolean;
var x, y, xx, yy, ty, tx: LongInt;
    bRes, updateBlock, resweep, recheck: boolean;
begin
bRes:= false;
reCheck:= true;

while recheck do
    begin
    recheck:= false;
    for y:= 0 to LAND_HEIGHT div 32 - 1 do
        begin
        for x:= 0 to LAND_WIDTH div 32 - 1 do
            begin
            if LandDirty[y, x] = 1 then
                begin
                updateBlock:= false;
                resweep:= true;
                ty:= y * 32;
                tx:= x * 32;
                while(resweep) do
                    begin
                    resweep:= false;
                    for yy:= ty to ty + 31 do
                        for xx:= tx to tx + 31 do
                            if Despeckle(xx, yy) then
                                begin
                                bRes:= true;
                                updateBlock:= true;
                                resweep:= true;
                                if (yy = ty) and (y > 0) then
                                    begin
                                    LandDirty[y-1, x]:= 1;
                                    recheck:= true;
                                    end
                                else if (yy = ty+31) and (y < LAND_HEIGHT div 32 - 1) then
                                    begin
                                    LandDirty[y+1, x]:= 1;
                                    recheck:= true;
                                    end;
                                if (xx = tx) and (x > 0) then
                                    begin
                                    LandDirty[y, x-1]:= 1;
                                    recheck:= true;
                                    end
                                else if (xx = tx+31) and (x < LAND_WIDTH div 32 - 1) then
                                    begin
                                    LandDirty[y, x+1]:= 1;
                                    recheck:= true;
                                    end
                                end;
                    end;
                if updateBlock then
                    UpdateLandTexture(tx, 32, ty, 32);
                LandDirty[y, x]:= 2;
                end;
            end;
        end;
     end;

for y:= 0 to LAND_HEIGHT div 32 - 1 do
    for x:= 0 to LAND_WIDTH div 32 - 1 do
        if LandDirty[y, x] <> 0 then
            begin
            LandDirty[y, x]:= 0;
            ty:= y * 32;
            tx:= x * 32;
            for yy:= ty to ty + 31 do
                for xx:= tx to tx + 31 do
                    Smooth(xx,yy)
            end;

SweepDirty:= bRes;
end;


// Return true if outside of land or not the value tested, used right now for some X/Y movement that does not use normal hedgehog movement in GSHandlers.inc
function CheckLandValue(X, Y: LongInt; LandFlag: Word): boolean; inline;
begin
    CheckLandValue:= ((X and LAND_WIDTH_MASK <> 0) or (Y and LAND_HEIGHT_MASK <> 0)) or ((Land[Y, X] and LandFlag) = 0)
end;

function LandBackPixel(x, y: LongInt): LongWord; inline;
var p: PLongWordArray;
begin
    if LandBackSurface = nil then
        LandBackPixel:= 0
    else
        begin
        p:= LandBackSurface^.pixels;
        LandBackPixel:= p^[LandBackSurface^.w * (y mod LandBackSurface^.h) + (x mod LandBackSurface^.w)];// or $FF000000;
        end
end;


procedure DrawLine(X1, Y1, X2, Y2: LongInt; Color: Longword);
var
  eX, eY, dX, dY: LongInt;
  i, sX, sY, x, y, d: LongInt;
begin
eX:= 0;
eY:= 0;
dX:= X2 - X1;
dY:= Y2 - Y1;

if (dX > 0) then
    sX:= 1
else
    if (dX < 0) then
        begin
        sX:= -1;
        dX:= -dX
        end
    else
        sX:= dX;

if (dY > 0) then
    sY:= 1
else
    if (dY < 0) then
        begin
        sY:= -1;
        dY:= -dY
        end
    else
        sY:= dY;

if (dX > dY) then
    d:= dX
else
    d:= dY;

x:= X1;
y:= Y1;

for i:= 0 to d do
    begin
    inc(eX, dX);
    inc(eY, dY);
    if (eX > d) then
        begin
        dec(eX, d);
        inc(x, sX);
        end;
    if (eY > d) then
        begin
        dec(eY, d);
        inc(y, sY);
        end;

    if ((x and LAND_WIDTH_MASK) = 0) and ((y and LAND_HEIGHT_MASK) = 0) then
        Land[y, x]:= Color;
    end
end;

end.