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Simplify LuaPseudoRandom::l_next and fix docs

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Also extends the allowed range on the C++ side. This has no side-effects.
This commit is contained in:
sfan5
2024-01-10 20:08:00 +01:00
parent d20f1182f2
commit e824e9023f
5 changed files with 22 additions and 20 deletions
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2
src/noise.h
View File

@@ -70,7 +70,7 @@ public:
PcgRandom, we cannot modify this RNG's range as it would change the
output of this RNG for reverse compatibility.
*/
if ((u32)(max - min) > (RANDOM_RANGE + 1) / 10)
if ((u32)(max - min) > (RANDOM_RANGE + 1) / 5)
throw PrngException("Range too large");
return (next() % (max - min + 1)) + min;

25
src/script/lua_api/l_noise.cpp
View File

@@ -405,25 +405,22 @@ int LuaPseudoRandom::l_next(lua_State *L)
NO_MAP_LOCK_REQUIRED;
LuaPseudoRandom *o = checkObject<LuaPseudoRandom>(L, 1);
int min = 0;
int max = 32767;
lua_settop(L, 3);
int min = 0, max = PseudoRandom::RANDOM_RANGE;
if (lua_isnumber(L, 2))
min = luaL_checkinteger(L, 2);
if (lua_isnumber(L, 3))
max = luaL_checkinteger(L, 3);
if (max < min) {
errorstream<<"PseudoRandom.next(): max="<<max<<" min="<<min<<std::endl;
throw LuaError("PseudoRandom.next(): max < min");
int val;
if (max - min == PseudoRandom::RANDOM_RANGE) {
val = o->m_pseudo.next() + min;
} else {
try {
val = o->m_pseudo.range(min, max);
} catch (PrngException &e) {
throw LuaError(e.what());
}
}
if(max - min != 32767 && max - min > 32767/5)
throw LuaError("PseudoRandom.next() max-min is not 32767"
" and is > 32768/5. This is disallowed due to"
" the bad random distribution the"
" implementation would otherwise make.");
PseudoRandom &pseudo = o->m_pseudo;
int val = pseudo.next();
val = (val % (max-min+1)) + min;
lua_pushinteger(L, val);
return 1;
}

2
src/unittest/test_random.cpp
View File

@@ -81,7 +81,7 @@ void TestRandom::testPseudoRandomRange()
{
PseudoRandom pr((int)time(NULL));
EXCEPTION_CHECK(PrngException, pr.range(2000, 6000));
EXCEPTION_CHECK(PrngException, pr.range(2000, 8600));
EXCEPTION_CHECK(PrngException, pr.range(5, 1));
for (u32 i = 0; i != 32768; i++) {