Add API for restoring PseudoRandom and PcgRandom state (#14123)

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sfence 2024-01-16 23:20:52 +01:00 committed by GitHub
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commit ceaa7e2fb0
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9 changed files with 155 additions and 29 deletions

@ -30,6 +30,7 @@ core.features = {
sound_params_start_time = true, sound_params_start_time = true,
physics_overrides_v2 = true, physics_overrides_v2 = true,
hud_def_type_field = true, hud_def_type_field = true,
random_state_restore = true,
} }
function core.has_feature(arg) function core.has_feature(arg)

@ -5284,6 +5284,10 @@ Utilities
physics_overrides_v2 = true, physics_overrides_v2 = true,
-- In HUD definitions the field `type` is used and `hud_elem_type` is deprecated (5.9.0) -- In HUD definitions the field `type` is used and `hud_elem_type` is deprecated (5.9.0)
hud_def_type_field = true, hud_def_type_field = true,
-- PseudoRandom and PcgRandom state is restorable
-- PseudoRandom has get_state method
-- PcgRandom has get_state and set_state methods (5.9.0)
random_state_restore = true,
} }
``` ```
@ -8056,7 +8060,7 @@ child will follow movement and rotation of that bone.
* `get_lighting()`: returns the current state of lighting for the player. * `get_lighting()`: returns the current state of lighting for the player.
* Result is a table with the same fields as `light_definition` in `set_lighting`. * Result is a table with the same fields as `light_definition` in `set_lighting`.
* `respawn()`: Respawns the player using the same mechanism as the death screen, * `respawn()`: Respawns the player using the same mechanism as the death screen,
including calling on_respawnplayer callbacks. including calling `on_respawnplayer` callbacks.
`PcgRandom` `PcgRandom`
----------- -----------
@ -8079,6 +8083,8 @@ offering very strong randomness.
* `mean = (max - min) / 2`, and * `mean = (max - min) / 2`, and
* `variance = (((max - min + 1) ^ 2) - 1) / (12 * num_trials)` * `variance = (((max - min + 1) ^ 2) - 1) / (12 * num_trials)`
* Increasing `num_trials` improves accuracy of the approximation * Increasing `num_trials` improves accuracy of the approximation
* `get_state()`: return generator state encoded in string
* `set_state(state_string)`: restore generator state from encoded string
`PerlinNoise` `PerlinNoise`
------------- -------------
@ -8171,6 +8177,8 @@ Uses a well-known LCG algorithm introduced by K&R.
* `next(min, max)`: return next integer random number [`min`...`max`] * `next(min, max)`: return next integer random number [`min`...`max`]
* Either `max - min == 32767` or `max - min <= 6553` must be true * Either `max - min == 32767` or `max - min <= 6553` must be true
due to the simple implementation making a bad distribution otherwise. due to the simple implementation making a bad distribution otherwise.
* `get_state()`: return state of pseudorandom generator as number
* use returned number as seed in PseudoRandom constructor to restore
`Raycast` `Raycast`
--------- ---------

@ -27,6 +27,7 @@ read_globals = {
"Settings", "Settings",
"check", "check",
"PseudoRandom", "PseudoRandom",
"PcgRandom",
string = {fields = {"split", "trim"}}, string = {fields = {"split", "trim"}},
table = {fields = {"copy", "getn", "indexof", "insert_all"}}, table = {fields = {"copy", "getn", "indexof", "insert_all"}},

@ -1,15 +1,37 @@
local function test_random() local function test_pseudo_random()
-- We have comprehensive unit tests in C++, this is just to make sure the API code isn't messing up -- We have comprehensive unit tests in C++, this is just to make sure the API code isn't messing up
local pr = PseudoRandom(13) local gen1 = PseudoRandom(13)
assert(pr:next() == 22290) assert(gen1:next() == 22290)
assert(pr:next() == 13854) assert(gen1:next() == 13854)
local pr2 = PseudoRandom(-101) local gen2 = PseudoRandom(gen1:get_state())
assert(pr2:next(0, 100) == 35) for n = 0, 16 do
assert(gen1:next() == gen2:next())
end
local pr3 = PseudoRandom(-101)
assert(pr3:next(0, 100) == 35)
-- unusual case that is normally disallowed: -- unusual case that is normally disallowed:
assert(pr2:next(10000, 42767) == 12485) assert(pr3:next(10000, 42767) == 12485)
end end
unittests.register("test_random", test_random) unittests.register("test_pseudo_random", test_pseudo_random)
local function test_pcg_random()
-- We have comprehensive unit tests in C++, this is just to make sure the API code isn't messing up
local gen1 = PcgRandom(55)
for n = 0, 16 do
gen1:next()
end
local gen2 = PcgRandom(26)
gen2:set_state(gen1:get_state())
for n = 16, 32 do
assert(gen1:next() == gen2:next())
end
end
unittests.register("test_pcg_random", test_pcg_random)
local function test_dynamic_media(cb, player) local function test_dynamic_media(cb, player)
if core.get_player_information(player:get_player_name()).protocol_version < 40 then if core.get_player_information(player:get_player_name()).protocol_version < 40 then

@ -152,6 +152,18 @@ s32 PcgRandom::randNormalDist(s32 min, s32 max, int num_trials)
return myround((float)accum / num_trials); return myround((float)accum / num_trials);
} }
void PcgRandom::getState(u64 state[2]) const
{
state[0] = m_state;
state[1] = m_inc;
}
void PcgRandom::setState(const u64 state[2])
{
m_state = state[0];
m_inc = state[1];
}
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
float noise2d(int x, int y, s32 seed) float noise2d(int x, int y, s32 seed)

@ -76,6 +76,11 @@ public:
return (next() % (max - min + 1)) + min; return (next() % (max - min + 1)) + min;
} }
// Allow save and restore of state
inline s32 getState() const
{
return m_next;
}
private: private:
s32 m_next; s32 m_next;
}; };
@ -94,6 +99,9 @@ public:
void bytes(void *out, size_t len); void bytes(void *out, size_t len);
s32 randNormalDist(s32 min, s32 max, int num_trials=6); s32 randNormalDist(s32 min, s32 max, int num_trials=6);
// Allow save and restore of state
void getState(u64 state[2]) const;
void setState(const u64 state[2]);
private: private:
u64 m_state; u64 m_state;
u64 m_inc; u64 m_inc;

@ -425,6 +425,17 @@ int LuaPseudoRandom::l_next(lua_State *L)
return 1; return 1;
} }
int LuaPseudoRandom::l_get_state(lua_State *L)
{
NO_MAP_LOCK_REQUIRED;
LuaPseudoRandom *o = checkObject<LuaPseudoRandom>(L, 1);
PseudoRandom &pseudo = o->m_pseudo;
int val = pseudo.getState();
lua_pushinteger(L, val);
return 1;
}
int LuaPseudoRandom::create_object(lua_State *L) int LuaPseudoRandom::create_object(lua_State *L)
{ {
@ -462,6 +473,7 @@ void LuaPseudoRandom::Register(lua_State *L)
const char LuaPseudoRandom::className[] = "PseudoRandom"; const char LuaPseudoRandom::className[] = "PseudoRandom";
const luaL_Reg LuaPseudoRandom::methods[] = { const luaL_Reg LuaPseudoRandom::methods[] = {
luamethod(LuaPseudoRandom, next), luamethod(LuaPseudoRandom, next),
luamethod(LuaPseudoRandom, get_state),
{0,0} {0,0}
}; };
@ -496,6 +508,45 @@ int LuaPcgRandom::l_rand_normal_dist(lua_State *L)
return 1; return 1;
} }
int LuaPcgRandom::l_get_state(lua_State *L)
{
NO_MAP_LOCK_REQUIRED;
LuaPcgRandom *o = checkObject<LuaPcgRandom>(L, 1);
u64 state[2];
o->m_rnd.getState(state);
std::ostringstream oss;
oss << std::hex << std::setw(16) << std::setfill('0')
<< state[0] << state[1];
lua_pushstring(L, oss.str().c_str());
return 1;
}
int LuaPcgRandom::l_set_state(lua_State *L)
{
NO_MAP_LOCK_REQUIRED;
LuaPcgRandom *o = checkObject<LuaPcgRandom>(L, 1);
std::string l_string = readParam<std::string>(L, 2);
if (l_string.size() != 32) {
throw LuaError("PcgRandom:set_state: Expected hex string of 32 characters");
}
std::istringstream s_state_0(l_string.substr(0, 16));
std::istringstream s_state_1(l_string.substr(16, 16));
u64 state[2];
s_state_0 >> std::hex >> state[0];
s_state_1 >> std::hex >> state[1];
o->m_rnd.setState(state);
return 0;
}
int LuaPcgRandom::create_object(lua_State *L) int LuaPcgRandom::create_object(lua_State *L)
{ {
@ -536,6 +587,8 @@ const char LuaPcgRandom::className[] = "PcgRandom";
const luaL_Reg LuaPcgRandom::methods[] = { const luaL_Reg LuaPcgRandom::methods[] = {
luamethod(LuaPcgRandom, next), luamethod(LuaPcgRandom, next),
luamethod(LuaPcgRandom, rand_normal_dist), luamethod(LuaPcgRandom, rand_normal_dist),
luamethod(LuaPcgRandom, get_state),
luamethod(LuaPcgRandom, set_state),
{0,0} {0,0}
}; };

@ -116,6 +116,8 @@ private:
// next(self, min=0, max=32767) -> get next value // next(self, min=0, max=32767) -> get next value
static int l_next(lua_State *L); static int l_next(lua_State *L);
// save state
static int l_get_state(lua_State *L);
public: public:
LuaPseudoRandom(s32 seed) : m_pseudo(seed) {} LuaPseudoRandom(s32 seed) : m_pseudo(seed) {}
@ -150,6 +152,9 @@ private:
// get next normally distributed random value // get next normally distributed random value
static int l_rand_normal_dist(lua_State *L); static int l_rand_normal_dist(lua_State *L);
// save and restore state
static int l_get_state(lua_State *L);
static int l_set_state(lua_State *L);
public: public:
LuaPcgRandom(u64 seed) : m_rnd(seed) {} LuaPcgRandom(u64 seed) : m_rnd(seed) {}
LuaPcgRandom(u64 seed, u64 seq) : m_rnd(seed, seq) {} LuaPcgRandom(u64 seed, u64 seq) : m_rnd(seed, seq) {}

@ -65,32 +65,39 @@ void TestRandom::testPseudoRandom()
for (u32 i = 0; i != 256; i++) for (u32 i = 0; i != 256; i++)
UASSERTEQ(s32, pr.next(), expected_pseudorandom_results[i]); UASSERTEQ(s32, pr.next(), expected_pseudorandom_results[i]);
PseudoRandom pr2(0); s32 state = pr.getState();
UASSERTEQ(int, pr2.next(), 0); PseudoRandom pr2(state);
UASSERTEQ(int, pr2.next(), 21469);
UASSERTEQ(int, pr2.next(), 9989);
PseudoRandom pr3(-101); for (u32 i = 0; i != 256; i++) {
UASSERTEQ(int, pr3.next(), 3267); UASSERTEQ(s32, pr.next(), pr2.next());
UASSERTEQ(int, pr3.next(), 2485); }
UASSERTEQ(int, pr3.next(), 30057);
PseudoRandom pr3(0);
UASSERTEQ(s32, pr3.next(), 0);
UASSERTEQ(s32, pr3.next(), 21469);
UASSERTEQ(s32, pr3.next(), 9989);
PseudoRandom pr4(-101);
UASSERTEQ(s32, pr4.next(), 3267);
UASSERTEQ(s32, pr4.next(), 2485);
UASSERTEQ(s32, pr4.next(), 30057);
} }
void TestRandom::testPseudoRandomRange() void TestRandom::testPseudoRandomRange()
{ {
PseudoRandom pr((int)time(NULL)); PseudoRandom pr((s32)time(NULL));
EXCEPTION_CHECK(PrngException, pr.range(2000, 8600)); EXCEPTION_CHECK(PrngException, pr.range(2000, 8600));
EXCEPTION_CHECK(PrngException, pr.range(5, 1)); EXCEPTION_CHECK(PrngException, pr.range(5, 1));
for (u32 i = 0; i != 32768; i++) { for (u32 i = 0; i != 32768; i++) {
int min = (pr.next() % 3000) - 500; s32 min = (pr.next() % 3000) - 500;
int max = (pr.next() % 3000) - 500; s32 max = (pr.next() % 3000) - 500;
if (min > max) if (min > max)
SWAP(int, min, max); SWAP(s32, min, max);
int randval = pr.range(min, max); s32 randval = pr.range(min, max);
UASSERT(randval >= min); UASSERT(randval >= min);
UASSERT(randval <= max); UASSERT(randval <= max);
} }
@ -103,12 +110,21 @@ void TestRandom::testPcgRandom()
for (u32 i = 0; i != 256; i++) for (u32 i = 0; i != 256; i++)
UASSERTEQ(u32, pr.next(), expected_pcgrandom_results[i]); UASSERTEQ(u32, pr.next(), expected_pcgrandom_results[i]);
PcgRandom pr2(0, 0);
u64 state[2];
pr.getState(state);
pr2.setState(state);
for (u32 i = 0; i != 256; i++) {
UASSERTEQ(u32, pr.next(), pr2.next());
}
} }
void TestRandom::testPcgRandomRange() void TestRandom::testPcgRandomRange()
{ {
PcgRandom pr((int)time(NULL)); PcgRandom pr((u64)time(NULL));
EXCEPTION_CHECK(PrngException, pr.range(5, 1)); EXCEPTION_CHECK(PrngException, pr.range(5, 1));
@ -116,12 +132,12 @@ void TestRandom::testPcgRandomRange()
pr.range(pr.RANDOM_MIN, pr.RANDOM_MAX); pr.range(pr.RANDOM_MIN, pr.RANDOM_MAX);
for (u32 i = 0; i != 32768; i++) { for (u32 i = 0; i != 32768; i++) {
int min = (pr.next() % 3000) - 500; s32 min = (pr.next() % 3000) - 500;
int max = (pr.next() % 3000) - 500; s32 max = (pr.next() % 3000) - 500;
if (min > max) if (min > max)
SWAP(int, min, max); SWAP(s32, min, max);
int randval = pr.range(min, max); s32 randval = pr.range(min, max);
UASSERT(randval >= min); UASSERT(randval >= min);
UASSERT(randval <= max); UASSERT(randval <= max);
} }
@ -147,8 +163,8 @@ void TestRandom::testPcgRandomBytes()
void TestRandom::testPcgRandomNormalDist() void TestRandom::testPcgRandomNormalDist()
{ {
static const int max = 120; static const s32 max = 120;
static const int min = -120; static const s32 min = -120;
static const int num_trials = 20; static const int num_trials = 20;
static const u32 num_samples = 61000; static const u32 num_samples = 61000;
s32 bins[max - min + 1]; s32 bins[max - min + 1];