(*
* 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 uCollisions;
interface
uses uFloat, uTypes, uUtils;
const cMaxGearArrayInd = 1023;
const cMaxGearHitOrderInd = 1023;
type PGearArray = ^TGearArray;
TGearArray = record
ar: array[0..cMaxGearArrayInd] of PGear;
cX: array[0..cMaxGearArrayInd] of LongInt;
cY: array[0..cMaxGearArrayInd] of LongInt;
Count: Longword
end;
type PGearHitOrder = ^TGearHitOrder;
TGearHitOrder = record
ar: array[0..cMaxGearHitOrderInd] of PGear;
order: array[0..cMaxGearHitOrderInd] of LongInt;
Count: Longword
end;
type TLineCollision = record
hasCollision: Boolean;
cX, cY: LongInt; //for visual effects only
end;
procedure initModule;
procedure freeModule;
procedure AddCI(Gear: PGear);
procedure DeleteCI(Gear: PGear);
function CheckGearsCollision(Gear: PGear): PGearArray;
function CheckAllGearsCollision(SourceGear: PGear): PGearArray;
function CheckGearsLineCollision(Gear: PGear; oX, oY, tX, tY: hwFloat): PGearArray;
function CheckAllGearsLineCollision(SourceGear: PGear; oX, oY, tX, tY: hwFloat): PGearArray;
function UpdateHitOrder(Gear: PGear; Order: LongInt): boolean;
procedure ClearHitOrderLeq(MinOrder: LongInt);
procedure ClearHitOrder();
function TestCollisionXwithGear(Gear: PGear; Dir: LongInt): Word;
function TestCollisionYwithGear(Gear: PGear; Dir: LongInt): Word;
function TestCollisionXKick(Gear: PGear; Dir: LongInt): Word;
function TestCollisionYKick(Gear: PGear; Dir: LongInt): Word;
function TestCollisionX(Gear: PGear; Dir: LongInt): Word;
function TestCollisionY(Gear: PGear; Dir: LongInt): Word;
function TestCollisionXwithXYShift(Gear: PGear; ShiftX: hwFloat; ShiftY: LongInt; Dir: LongInt): Word; inline;
function TestCollisionXwithXYShift(Gear: PGear; ShiftX: hwFloat; ShiftY: LongInt; Dir: LongInt; withGear: boolean): Word;
function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt): Word; inline;
function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt; withGear: boolean): Word;
function TestRectangleForObstacle(x1, y1, x2, y2: LongInt; landOnly: boolean): boolean;
function CheckCoordInWater(X, Y: LongInt): boolean; inline;
// returns: negative sign if going downhill to left, value is steepness (noslope/error = _0, 45 = _0_5)
function CalcSlopeBelowGear(Gear: PGear): hwFloat;
function CalcSlopeNearGear(Gear: PGear; dirX, dirY: LongInt): hwFloat;
function CalcSlopeTangent(Gear: PGear; collisionX, collisionY: LongInt; var outDeltaX, outDeltaY: LongInt; TestWord: LongWord): boolean;
implementation
uses uConsts, uLandGraphics, uVariables;
type TCollisionEntry = record
X, Y, Radius: LongInt;
cGear: PGear;
end;
const MAXRECTSINDEX = 1023;
var Count: Longword;
cinfos: array[0..MAXRECTSINDEX] of TCollisionEntry;
ga: TGearArray;
ordera: TGearHitOrder;
procedure AddCI(Gear: PGear);
begin
if (Gear^.CollisionIndex >= 0) or (Count > MAXRECTSINDEX) or
((Count > MAXRECTSINDEX-200) and ((Gear^.Kind = gtMine) or (Gear^.Kind = gtSMine) or (Gear^.Kind = gtKnife))) then
exit;
with cinfos[Count] do
begin
X:= hwRound(Gear^.X);
Y:= hwRound(Gear^.Y);
Radius:= Gear^.Radius;
ChangeRoundInLand(X, Y, Radius - 1, true, ((CurrentHedgehog <> nil) and (Gear = CurrentHedgehog^.Gear)) or ((Gear^.Kind = gtCase) and (Gear^.State and gstFrozen = 0)), Gear^.Kind = gtHedgehog);
cGear:= Gear
end;
Gear^.CollisionIndex:= Count;
inc(Count);
end;
procedure DeleteCI(Gear: PGear);
begin
if Gear^.CollisionIndex >= 0 then
begin
with cinfos[Gear^.CollisionIndex] do
ChangeRoundInLand(X, Y, Radius - 1, false, ((CurrentHedgehog <> nil) and (Gear = CurrentHedgehog^.Gear)) or ((Gear^.Kind = gtCase) and (Gear^.State and gstFrozen = 0)), Gear^.Kind = gtHedgehog);
cinfos[Gear^.CollisionIndex]:= cinfos[Pred(Count)];
cinfos[Gear^.CollisionIndex].cGear^.CollisionIndex:= Gear^.CollisionIndex;
Gear^.CollisionIndex:= -1;
dec(Count)
end;
end;
function CheckCoordInWater(X, Y: LongInt): boolean; inline;
begin
CheckCoordInWater:= (Y > cWaterLine)
or ((WorldEdge = weSea) and ((X < LongInt(leftX)) or (X > LongInt(rightX))));
end;
function CheckGearsCollision(Gear: PGear): PGearArray;
var mx, my, tr: LongInt;
i: Longword;
begin
CheckGearsCollision:= @ga;
ga.Count:= 0;
if Count = 0 then
exit;
mx:= hwRound(Gear^.X);
my:= hwRound(Gear^.Y);
tr:= Gear^.Radius + 2;
for i:= 0 to Pred(Count) do
with cinfos[i] do
if (Gear <> cGear) and
(sqr(mx - x) + sqr(my - y) <= sqr(Radius + tr)) then
begin
ga.ar[ga.Count]:= cinfos[i].cGear;
ga.cX[ga.Count]:= hwround(Gear^.X);
ga.cY[ga.Count]:= hwround(Gear^.Y);
inc(ga.Count)
end
end;
function CheckAllGearsCollision(SourceGear: PGear): PGearArray;
var mx, my, tr: LongInt;
Gear: PGear;
begin
CheckAllGearsCollision:= @ga;
ga.Count:= 0;
mx:= hwRound(SourceGear^.X);
my:= hwRound(SourceGear^.Y);
tr:= SourceGear^.Radius + 2;
Gear:= GearsList;
while Gear <> nil do
begin
if (Gear <> SourceGear) and
(sqr(mx - hwRound(Gear^.x)) + sqr(my - hwRound(Gear^.y)) <= sqr(Gear^.Radius + tr))then
begin
ga.ar[ga.Count]:= Gear;
ga.cX[ga.Count]:= hwround(SourceGear^.X);
ga.cY[ga.Count]:= hwround(SourceGear^.Y);
inc(ga.Count)
end;
Gear := Gear^.NextGear
end;
end;
function LineCollisionTest(oX, oY, dirX, dirY, dirNormSqr, dirNormBound: hwFloat;
width: LongInt; Gear: PGear):
TLineCollision; inline;
var toCenterX, toCenterY, r,
b, bSqr, c, desc, t: hwFloat;
realT: extended;
begin
LineCollisionTest.hasCollision:= false;
toCenterX:= (oX - Gear^.X);
toCenterY:= (oY - Gear^.Y);
r:= int2hwFloat(Gear^.Radius + width + 2);
// Early cull to avoid multiplying large numbers
if hwAbs(toCenterX) + hwAbs(toCenterY) > dirNormBound + r then
exit;
b:= dirX * toCenterX + dirY * toCenterY;
c:= hwSqr(toCenterX) + hwSqr(toCenterY) - hwSqr(r);
if (b > _0) and (c > _0) then
exit;
bSqr:= hwSqr(b);
desc:= bSqr - dirNormSqr * c;
if desc.isNegative then exit;
t:= -b - hwSqrt(desc);
if t.isNegative then t:= _0;
if t < dirNormSqr then
with LineCollisionTest do
begin
hasCollision:= true;
realT := hwFloat2Float(t) / hwFloat2Float(dirNormSqr);
cX:= round(hwFloat2Float(oX) + realT * hwFloat2Float(dirX));
cY:= round(hwFloat2Float(oY) + realT * hwFloat2Float(dirY));
end;
end;
function CheckGearsLineCollision(Gear: PGear; oX, oY, tX, tY: hwFloat): PGearArray;
var dirX, dirY, dirNormSqr, dirNormBound: hwFloat;
test: TLineCollision;
i: Longword;
begin
CheckGearsLineCollision:= @ga;
ga.Count:= 0;
if Count = 0 then
exit;
dirX:= (tX - oX);
dirY:= (tY - oY);
dirNormBound:= _1_5 * (hwAbs(dirX) + hwAbs(dirY));
dirNormSqr:= hwSqr(dirX) + hwSqr(dirY);
if dirNormSqr.isNegative then
exit;
for i:= 0 to Pred(Count) do
with cinfos[i] do if Gear <> cGear then
begin
test:= LineCollisionTest(
oX, oY, dirX, dirY, dirNormSqr, dirNormBound, Gear^.Radius, cGear);
if test.hasCollision then
begin
ga.ar[ga.Count] := cGear;
ga.cX[ga.Count] := test.cX;
ga.cY[ga.Count] := test.cY;
inc(ga.Count)
end
end
end;
function CheckAllGearsLineCollision(SourceGear: PGear; oX, oY, tX, tY: hwFloat): PGearArray;
var dirX, dirY, dirNormSqr, dirNormBound: hwFloat;
test: TLineCollision;
Gear: PGear;
begin
CheckAllGearsLineCollision:= @ga;
ga.Count:= 0;
dirX:= (tX - oX);
dirY:= (tY - oY);
dirNormBound:= _1_5 * (hwAbs(dirX) + hwAbs(dirY));
dirNormSqr:= hwSqr(dirX) + hwSqr(dirY);
if dirNormSqr.isNegative then
exit;
Gear:= GearsList;
while Gear <> nil do
begin
if SourceGear <> Gear then
begin
test:= LineCollisionTest(
oX, oY, dirX, dirY, dirNormSqr, dirNormBound, SourceGear^.Radius, Gear);
if test.hasCollision then
begin
ga.ar[ga.Count] := Gear;
ga.cX[ga.Count] := test.cX;
ga.cY[ga.Count] := test.cY;
inc(ga.Count)
end
end;
Gear := Gear^.NextGear
end;
end;
function UpdateHitOrder(Gear: PGear; Order: LongInt): boolean;
var i: LongInt;
begin
UpdateHitOrder:= true;
for i:= 0 to ordera.Count - 1 do
if ordera.ar[i] = Gear then
begin
if Order <= ordera.order[i] then UpdateHitOrder:= false;
ordera.order[i]:= Max(ordera.order[i], order);
exit;
end;
if ordera.Count > cMaxGearHitOrderInd then
UpdateHitOrder:= false
else
begin
ordera.ar[ordera.Count]:= Gear;
ordera.order[ordera.Count]:= Order;
Inc(ordera.Count);
end
end;
procedure ClearHitOrderLeq(MinOrder: LongInt);
var i, freeIndex: LongInt;
begin;
freeIndex:= 0;
i:= 0;
while i < ordera.Count do
begin
if ordera.order[i] <= MinOrder then
Dec(ordera.Count)
else
begin
if freeIndex < i then
begin
ordera.ar[freeIndex]:= ordera.ar[i];
ordera.order[freeIndex]:= ordera.order[i];
end;
Inc(freeIndex);
end;
Inc(i)
end
end;
procedure ClearHitOrder();
begin
ordera.Count:= 0;
end;
function TestCollisionXwithGear(Gear: PGear; Dir: LongInt): Word;
var x, y, i: LongInt;
begin
// Special case to emulate the old intersect gear clearing, but with a bit of slop for pixel overlap
if (Gear^.CollisionMask = lfNotCurHogCrate) and (Gear^.Kind <> gtHedgehog) and (Gear^.Hedgehog <> nil) and (Gear^.Hedgehog^.Gear <> nil) and
((hwRound(Gear^.Hedgehog^.Gear^.X) + Gear^.Hedgehog^.Gear^.Radius + 16 < hwRound(Gear^.X) - Gear^.Radius) or
(hwRound(Gear^.Hedgehog^.Gear^.X) - Gear^.Hedgehog^.Gear^.Radius - 16 > hwRound(Gear^.X) + Gear^.Radius)) then
Gear^.CollisionMask:= lfAll;
x:= hwRound(Gear^.X);
if Dir < 0 then
x:= x - Gear^.Radius
else
x:= x + Gear^.Radius;
if (x and LAND_WIDTH_MASK) = 0 then
begin
y:= hwRound(Gear^.Y) - Gear^.Radius + 1;
i:= y + Gear^.Radius * 2 - 2;
repeat
if (y and LAND_HEIGHT_MASK) = 0 then
if Land[y, x] and Gear^.CollisionMask <> 0 then
exit(Land[y, x] and Gear^.CollisionMask);
inc(y)
until (y > i);
end;
TestCollisionXwithGear:= 0
end;
function TestCollisionYwithGear(Gear: PGear; Dir: LongInt): Word;
var x, y, i: LongInt;
begin
// Special case to emulate the old intersect gear clearing, but with a bit of slop for pixel overlap
if (Gear^.CollisionMask = lfNotCurHogCrate) and (Gear^.Kind <> gtHedgehog) and (Gear^.Hedgehog <> nil) and (Gear^.Hedgehog^.Gear <> nil) and
((hwRound(Gear^.Hedgehog^.Gear^.Y) + Gear^.Hedgehog^.Gear^.Radius + 16 < hwRound(Gear^.Y) - Gear^.Radius) or
(hwRound(Gear^.Hedgehog^.Gear^.Y) - Gear^.Hedgehog^.Gear^.Radius - 16 > hwRound(Gear^.Y) + Gear^.Radius)) then
Gear^.CollisionMask:= lfAll;
y:= hwRound(Gear^.Y);
if Dir < 0 then
y:= y - Gear^.Radius
else
y:= y + Gear^.Radius;
if (y and LAND_HEIGHT_MASK) = 0 then
begin
x:= hwRound(Gear^.X) - Gear^.Radius + 1;
i:= x + Gear^.Radius * 2 - 2;
repeat
if (x and LAND_WIDTH_MASK) = 0 then
if Land[y, x] and Gear^.CollisionMask <> 0 then
begin
exit(Land[y, x] and Gear^.CollisionMask)
end;
inc(x)
until (x > i);
end;
TestCollisionYwithGear:= 0
end;
function TestCollisionXKick(Gear: PGear; Dir: LongInt): Word;
var x, y, mx, my, i: LongInt;
pixel: Word;
begin
pixel:= 0;
x:= hwRound(Gear^.X);
if Dir < 0 then
x:= x - Gear^.Radius
else
x:= x + Gear^.Radius;
if (x and LAND_WIDTH_MASK) = 0 then
begin
y:= hwRound(Gear^.Y) - Gear^.Radius + 1;
i:= y + Gear^.Radius * 2 - 2;
repeat
if (y and LAND_HEIGHT_MASK) = 0 then
begin
if Land[y, x] and Gear^.CollisionMask <> 0 then
begin
if ((Land[y, x] and Gear^.CollisionMask) and lfNotObjMask) <> 0 then
exit(Land[y, x] and Gear^.CollisionMask)
else
pixel:= Land[y, x] and Gear^.CollisionMask;
end;
end;
inc(y)
until (y > i);
end;
TestCollisionXKick:= pixel;
if pixel <> 0 then
begin
if hwAbs(Gear^.dX) < cHHKick then
exit;
if (Gear^.State and gstHHJumping <> 0)
and (hwAbs(Gear^.dX) < _0_4) then
exit;
mx:= hwRound(Gear^.X);
my:= hwRound(Gear^.Y);
for i:= 0 to Pred(Count) do
with cinfos[i] do
if (Gear <> cGear) and
((mx > x) xor (Dir > 0)) and
(
((cGear^.Kind in [gtHedgehog, gtMine, gtKnife]) and ((Gear^.State and gstNotKickable) = 0)) or
// only apply X kick if the barrel is knocked over
((cGear^.Kind = gtExplosives) and ((cGear^.State and gsttmpflag) <> 0))
) and
(sqr(mx - x) + sqr(my - y) <= sqr(Radius + Gear^.Radius + 2)) then
begin
with cGear^ do
begin
dX:= Gear^.dX;
dY:= Gear^.dY * _0_5;
State:= State or gstMoving;
if Kind = gtKnife then State:= State and (not gstCollision);
Active:= true
end;
DeleteCI(cGear);
exit(0);
end
end
end;
function TestCollisionYKick(Gear: PGear; Dir: LongInt): Word;
var x, y, mx, my, myr, i: LongInt;
pixel: Word;
begin
pixel:= 0;
y:= hwRound(Gear^.Y);
if Dir < 0 then
y:= y - Gear^.Radius
else
y:= y + Gear^.Radius;
if (y and LAND_HEIGHT_MASK) = 0 then
begin
x:= hwRound(Gear^.X) - Gear^.Radius + 1;
i:= x + Gear^.Radius * 2 - 2;
repeat
if (x and LAND_WIDTH_MASK) = 0 then
if Land[y, x] > 0 then
begin
if ((Land[y, x] and Gear^.CollisionMask) and lfNotObjMask) <> 0 then
exit(Land[y, x] and Gear^.CollisionMask)
else // if Land[y, x] <> 0 then
pixel:= Land[y, x] and Gear^.CollisionMask;
end;
inc(x)
until (x > i);
end;
TestCollisionYKick:= pixel;
if pixel <> 0 then
begin
if hwAbs(Gear^.dY) < cHHKick then
exit;
if (Gear^.State and gstHHJumping <> 0) and (not Gear^.dY.isNegative) and (Gear^.dY < _0_4) then
exit;
mx:= hwRound(Gear^.X);
my:= hwRound(Gear^.Y);
myr:= my+Gear^.Radius;
for i:= 0 to Pred(Count) do
with cinfos[i] do
if (Gear <> cGear) and
((myr > y) xor (Dir > 0)) and
(Gear^.State and gstNotKickable = 0) and
(cGear^.Kind in [gtHedgehog, gtMine, gtKnife, gtExplosives]) and
(sqr(mx - x) + sqr(my - y) <= sqr(Radius + Gear^.Radius + 2)) then
begin
with cGear^ do
begin
if (Kind <> gtExplosives) or ((State and gsttmpflag) <> 0) then
dX:= Gear^.dX * _0_5;
dY:= Gear^.dY;
State:= State or gstMoving;
if Kind = gtKnife then State:= State and (not gstCollision);
Active:= true
end;
DeleteCI(cGear);
exit(0)
end
end
end;
function TestCollisionXwithXYShift(Gear: PGear; ShiftX: hwFloat; ShiftY: LongInt; Dir: LongInt): Word; inline;
begin
TestCollisionXwithXYShift:= TestCollisionXwithXYShift(Gear, ShiftX, ShiftY, Dir, true);
end;
function TestCollisionXwithXYShift(Gear: PGear; ShiftX: hwFloat; ShiftY: LongInt; Dir: LongInt; withGear: boolean): Word;
begin
Gear^.X:= Gear^.X + ShiftX;
Gear^.Y:= Gear^.Y + int2hwFloat(ShiftY);
if withGear then
TestCollisionXwithXYShift:= TestCollisionXwithGear(Gear, Dir)
else TestCollisionXwithXYShift:= TestCollisionX(Gear, Dir);
Gear^.X:= Gear^.X - ShiftX;
Gear^.Y:= Gear^.Y - int2hwFloat(ShiftY)
end;
function TestCollisionX(Gear: PGear; Dir: LongInt): Word;
var x, y, i: LongInt;
begin
x:= hwRound(Gear^.X);
if Dir < 0 then
x:= x - Gear^.Radius
else
x:= x + Gear^.Radius;
if (x and LAND_WIDTH_MASK) = 0 then
begin
y:= hwRound(Gear^.Y) - Gear^.Radius + 1;
i:= y + Gear^.Radius * 2 - 2;
repeat
if (y and LAND_HEIGHT_MASK) = 0 then
if ((Land[y, x] and Gear^.CollisionMask) and lfNotObjMask) <> 0 then
exit(Land[y, x] and Gear^.CollisionMask);
inc(y)
until (y > i);
end;
TestCollisionX:= 0
end;
function TestCollisionY(Gear: PGear; Dir: LongInt): Word;
var x, y, i: LongInt;
begin
y:= hwRound(Gear^.Y);
if Dir < 0 then
y:= y - Gear^.Radius
else
y:= y + Gear^.Radius;
if (y and LAND_HEIGHT_MASK) = 0 then
begin
x:= hwRound(Gear^.X) - Gear^.Radius + 1;
i:= x + Gear^.Radius * 2 - 2;
repeat
if (x and LAND_WIDTH_MASK) = 0 then
if ((Land[y, x] and Gear^.CollisionMask) and lfNotObjMask) <> 0 then
exit(Land[y, x] and Gear^.CollisionMask);
inc(x)
until (x > i);
end;
TestCollisionY:= 0
end;
function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt): Word; inline;
begin
TestCollisionYwithXYShift:= TestCollisionYwithXYShift(Gear, ShiftX, ShiftY, Dir, true);
end;
function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt; withGear: boolean): Word;
begin
Gear^.X:= Gear^.X + int2hwFloat(ShiftX);
Gear^.Y:= Gear^.Y + int2hwFloat(ShiftY);
if withGear then
TestCollisionYwithXYShift:= TestCollisionYwithGear(Gear, Dir)
else
TestCollisionYwithXYShift:= TestCollisionY(Gear, Dir);
Gear^.X:= Gear^.X - int2hwFloat(ShiftX);
Gear^.Y:= Gear^.Y - int2hwFloat(ShiftY)
end;
function TestRectangleForObstacle(x1, y1, x2, y2: LongInt; landOnly: boolean): boolean;
var x, y: LongInt;
TestWord: LongWord;
begin
TestRectangleForObstacle:= true;
if landOnly then
TestWord:= 255
else
TestWord:= 0;
if x1 > x2 then
begin
x := x1;
x1 := x2;
x2 := x;
end;
if y1 > y2 then
begin
y := y1;
y1 := y2;
y2 := y;
end;
if (hasBorder and ((y1 < 0) or (x1 < 0) or (x2 > LAND_WIDTH))) then
exit;
for y := y1 to y2 do
for x := x1 to x2 do
if ((y and LAND_HEIGHT_MASK) = 0) and ((x and LAND_WIDTH_MASK) = 0) and (Land[y, x] > TestWord) then
exit;
TestRectangleForObstacle:= false
end;
function CalcSlopeTangent(Gear: PGear; collisionX, collisionY: LongInt; var outDeltaX, outDeltaY: LongInt; TestWord: LongWord): boolean;
var ldx, ldy, rdx, rdy: LongInt;
i, j, k, mx, my, li, ri, jfr, jto, tmpo : ShortInt;
tmpx, tmpy: LongWord;
dx, dy, s: hwFloat;
offset: array[0..7,0..1] of ShortInt;
isColl: Boolean;
begin
CalcSlopeTangent:= false;
dx:= Gear^.dX;
dy:= Gear^.dY;
// we start searching from the direction the gear came from
if (dx.QWordValue > _0_995.QWordValue )
or (dy.QWordValue > _0_995.QWordValue ) then
begin // scale
s := _0_995 / Distance(dx,dy);
dx := s * dx;
dy := s * dy;
end;
mx:= hwRound(Gear^.X-dx) - hwRound(Gear^.X);
my:= hwRound(Gear^.Y-dy) - hwRound(Gear^.Y);
li:= -1;
ri:= -1;
// go around collision pixel, checking for first/last collisions
// this will determinate what angles will be tried to crawl along
for i:= 0 to 7 do
begin
offset[i,0]:= mx;
offset[i,1]:= my;
// multiplicator k tries to skip small pixels/gaps when possible
for k:= 4 downto 1 do
begin
tmpx:= collisionX + k * mx;
tmpy:= collisionY + k * my;
if (((tmpy) and LAND_HEIGHT_MASK) = 0) and (((tmpx) and LAND_WIDTH_MASK) = 0) then
if (Land[tmpy,tmpx] > TestWord) then
begin
// remember the index belonging to the first and last collision (if in 1st half)
if (i <> 0) then
begin
if (ri = -1) then
ri:= i
else
li:= i;
end;
end;
end;
if i = 7 then
break;
// prepare offset for next check (clockwise)
if (mx = -1) and (my <> -1) then
my:= my - 1
else if (my = -1) and (mx <> 1) then
mx:= mx + 1
else if (mx = 1) and (my <> 1) then
my:= my + 1
else
mx:= mx - 1;
end;
ldx:= collisionX;
ldy:= collisionY;
rdx:= collisionX;
rdy:= collisionY;
// edge-crawl
for i:= 0 to 8 do
begin
// using mx,my as temporary value buffer here
jfr:= 8+li+1;
jto:= 8+li-1;
isColl:= false;
for j:= jfr downto jto do
begin
tmpo:= j mod 8;
// multiplicator k tries to skip small pixels/gaps when possible
for k:= 3 downto 1 do
begin
tmpx:= ldx + k * offset[tmpo,0];
tmpy:= ldy + k * offset[tmpo,1];
if (((tmpy) and LAND_HEIGHT_MASK) = 0) and (((tmpx) and LAND_WIDTH_MASK) = 0)
and (Land[tmpy,tmpx] > TestWord) then
begin
ldx:= tmpx;
ldy:= tmpy;
isColl:= true;
break;
end;
end;
if isColl then
break;
end;
jfr:= 8+ri-1;
jto:= 8+ri+1;
isColl:= false;
for j:= jfr to jto do
begin
tmpo:= j mod 8;
for k:= 3 downto 1 do
begin
tmpx:= rdx + k * offset[tmpo,0];
tmpy:= rdy + k * offset[tmpo,1];
if (((tmpy) and LAND_HEIGHT_MASK) = 0) and (((tmpx) and LAND_WIDTH_MASK) = 0)
and (Land[tmpy,tmpx] > TestWord) then
begin
rdx:= tmpx;
rdy:= tmpy;
isColl:= true;
break;
end;
end;
if isColl then
break;
end;
end;
ldx:= rdx - ldx;
ldy:= rdy - ldy;
if ((ldx = 0) and (ldy = 0)) then
exit;
outDeltaX:= ldx;
outDeltaY:= ldy;
CalcSlopeTangent:= true;
end;
function CalcSlopeNearGear(Gear: PGear; dirX, dirY: LongInt): hwFloat;
var dx, dy: hwFloat;
collX, collY, i, y, x, gx, gy, sdx, sdy: LongInt;
isColl, bSucc: Boolean;
begin
if dirY <> 0 then
begin
y:= hwRound(Gear^.Y) + Gear^.Radius * dirY;
gx:= hwRound(Gear^.X);
collX := gx;
isColl:= false;
if (y and LAND_HEIGHT_MASK) = 0 then
begin
x:= hwRound(Gear^.X) - Gear^.Radius + 1;
i:= x + Gear^.Radius * 2 - 2;
repeat
if (x and LAND_WIDTH_MASK) = 0 then
if Land[y, x] <> 0 then
if (not isColl) or (abs(x-gx) < abs(collX-gx)) then
begin
isColl:= true;
collX := x;
end;
inc(x)
until (x > i);
end;
end
else
begin
x:= hwRound(Gear^.X) + Gear^.Radius * dirX;
gy:= hwRound(Gear^.Y);
collY := gy;
isColl:= false;
if (x and LAND_WIDTH_MASK) = 0 then
begin
y:= hwRound(Gear^.Y) - Gear^.Radius + 1;
i:= y + Gear^.Radius * 2 - 2;
repeat
if (y and LAND_HEIGHT_MASK) = 0 then
if Land[y, x] <> 0 then
if (not isColl) or (abs(y-gy) < abs(collY-gy)) then
begin
isColl:= true;
collY := y;
end;
inc(y)
until (y > i);
end;
end;
if isColl then
begin
// save original dx/dy
dx := Gear^.dX;
dy := Gear^.dY;
if dirY <> 0 then
begin
Gear^.dX.QWordValue:= 0;
Gear^.dX.isNegative:= (collX >= gx);
Gear^.dY:= _1*dirY
end
else
begin
Gear^.dY.QWordValue:= 0;
Gear^.dY.isNegative:= (collY >= gy);
Gear^.dX:= _1*dirX
end;
sdx:= 0;
sdy:= 0;
if dirY <> 0 then
bSucc := CalcSlopeTangent(Gear, collX, y, sdx, sdy, 0)
else bSucc := CalcSlopeTangent(Gear, x, collY, sdx, sdy, 0);
// restore original dx/dy
Gear^.dX := dx;
Gear^.dY := dy;
if bSucc and ((sdx <> 0) or (sdy <> 0)) then
begin
dx := int2hwFloat(sdy) / (abs(sdx) + abs(sdy));
dx.isNegative := (sdx * sdy) < 0;
exit (dx);
end
end;
CalcSlopeNearGear := _0;
end;
function CalcSlopeBelowGear(Gear: PGear): hwFloat;
var dx, dy: hwFloat;
collX, i, y, x, gx, sdx, sdy: LongInt;
isColl, bSucc: Boolean;
begin
y:= hwRound(Gear^.Y) + Gear^.Radius;
gx:= hwRound(Gear^.X);
collX := gx;
isColl:= false;
if (y and LAND_HEIGHT_MASK) = 0 then
begin
x:= hwRound(Gear^.X) - Gear^.Radius + 1;
i:= x + Gear^.Radius * 2 - 2;
repeat
if (x and LAND_WIDTH_MASK) = 0 then
if (Land[y, x] and lfNotObjMask) <> 0 then
if (not isColl) or (abs(x-gx) < abs(collX-gx)) then
begin
isColl:= true;
collX := x;
end;
inc(x)
until (x > i);
end;
if isColl then
begin
// save original dx/dy
dx := Gear^.dX;
dy := Gear^.dY;
Gear^.dX.QWordValue:= 0;
Gear^.dX.isNegative:= (collX >= gx);
Gear^.dY:= _1;
sdx:= 0;
sdy:= 0;
bSucc := CalcSlopeTangent(Gear, collX, y, sdx, sdy, 255);
// restore original dx/dy
Gear^.dX := dx;
Gear^.dY := dy;
if bSucc and (sdx <> 0) and (sdy <> 0) then
begin
dx := int2hwFloat(sdy) / (abs(sdx) + abs(sdy));
dx.isNegative := (sdx * sdy) < 0;
exit (dx);
end;
end;
CalcSlopeBelowGear := _0;
end;
procedure initModule;
begin
Count:= 0;
end;
procedure freeModule;
begin
end;
end.