Remove FindSDL2 find-module, use sdl2-config.cmake instead
This requires SDL >= 2.0.4.
Since <https://bugzilla.libsdl.org/show_bug.cgi?id=2464> was fixed in
SDL 2.0.4, SDL behaves as a CMake "config-file package", even if it was
not itself built using CMake: it installs a sdl2-config.cmake file to
${libdir}/cmake/SDL2, which tells CMake where to find SDL's headers and
library, analogous to a pkg-config .pc file.
As a result, we no longer need to copy/paste a "find-module package"
to be able to find a system copy of SDL >= 2.0.4 with find_package(SDL2).
Find-module packages are now discouraged by the CMake developers, in
favour of having upstream projects behave as config-file packages.
This results in a small API change: FindSDL2 used to set SDL2_INCLUDE_DIR
and SDL2_LIBRARY, but the standard behaviour for config-file packages is
to set <name>_INCLUDE_DIRS and <name>_LIBRARIES. Use the CONFIG keyword
to make sure we search in config-file package mode, and will not find a
FindSDL2.cmake in some other directory that implements the old interface.
In addition to deleting redundant code, this avoids some assumptions in
FindSDL2 about the layout of a SDL installation. The current libsdl2-dev
package in Debian breaks those assumptions; this is considered a bug
and will hopefully be fixed soon, but it illustrates how fragile these
assumptions can be. We can be more robust against different installation
layouts by relying on SDL's own CMake integration.
When linking to a copy of CMake in a non-standard location, users can
now set the SDL2_DIR or CMAKE_PREFIX_PATH environment variable to point
to it; previously, these users would have used the SDL2DIR environment
variable. This continues to be unnecessary if using matching system-wide
installations of CMake and SDL2, for example both from Debian.
(*
* 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.