Fix Birdy being drawn behind hogs and other gears (
bug #453)
(*
* 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 uRandom;
(*
* This unit supplies platform-independent functions for getting various
* pseudo-random values based on a shared seed.
*
* This is necessary for accomplishing pseudo-random behavior in the game
* without causing a desynchronisation of different clients when playing over
* a network.
*)
interface
uses uFloat;
procedure SetRandomSeed(Seed: shortstring; dropAdditionalPart: boolean); // Sets the seed that should be used for generating pseudo-random values.
function GetRandomf: hwFloat; // Returns a pseudo-random hwFloat.
function GetRandom(m: LongWord): LongWord; inline; // Returns a positive pseudo-random integer smaller than m.
procedure AddRandomness(r: LongWord); inline;
function rndSign(num: hwFloat): hwFloat; // Returns num with a random chance of having a inverted sign.
implementation
var cirbuf: array[0..63] of Longword;
n: byte;
procedure AddRandomness(r: LongWord); inline;
begin
n:= (n + 1) and $3F;
cirbuf[n]:= cirbuf[n] xor r;
end;
function GetNext: Longword; inline;
begin
n:= (n + 1) and $3F;
cirbuf[n]:=
(cirbuf[(n + 40) and $3F] + {n - 24 mod 64}
cirbuf[(n + 9) and $3F]) {n - 55 mod 64}
and $7FFFFFFF; {mod 2^31}
GetNext:= cirbuf[n];
end;
procedure SetRandomSeed(Seed: shortstring; dropAdditionalPart: boolean);
var i, t, l: Longword;
begin
n:= 54;
if Length(Seed) > 54 then
Seed:= copy(Seed, 1, 54); // not 55 to ensure we have odd numbers in cirbuf
t:= 0;
l:= Length(Seed);
while (t < l) and ((not dropAdditionalPart) or (Seed[t + 1] <> '|')) do
begin
cirbuf[t]:= byte(Seed[t + 1]);
inc(t)
end;
for i:= t to 54 do
cirbuf[i]:= $A98765 + 68; // odd number
for i:= 0 to 2047 do
GetNext;
end;
function GetRandomf: hwFloat;
begin
GetNext;
GetRandomf.isNegative:= false;
GetRandomf.QWordValue:= GetNext
end;
function GetRandom(m: LongWord): LongWord; inline;
begin
GetNext;
GetRandom:= GetNext mod m
end;
function rndSign(num: hwFloat): hwFloat;
begin
num.isNegative:= odd(GetNext);
rndSign:= num
end;
end.