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Fix pressure-sensitive particles breaking on load, again

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Repurposing the comment I added because I'm lazy: pavg[1] used to be saved as a u16, which PressureInTmp3 elements then treated as an i16. tmp3 is now saved as a u32, or as a u16 if it's small enough. PressureInTmp3 elements will never use the upper 16 bits, and should still treat the lower 16 bits as an i16, so they need sign extension.

The code that was originally responsible for this somehow got lost in the tmp3/tmp4 migration.
This commit is contained in:
Tamás Bálint Misius 2021-12-25 09:40:56 +01:00
parent 286d0d60b9
commit 95a9e93645
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GPG Key ID: 5B472A12F6ECA9F2
1 changed files with 18 additions and 2 deletions
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20
src/client/GameSave.cpp
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@ -1354,6 +1354,19 @@ void GameSave::readOPS(char * data, int dataLength)
}
}
}
if (PressureInTmp3(particles[newIndex].type))
{
// pavg[1] used to be saved as a u16, which PressureInTmp3 elements then treated as
// an i16. tmp3 is now saved as a u32, or as a u16 if it's small enough. PressureInTmp3
// elements will never use the upper 16 bits, and should still treat the lower 16 bits
// as an i16, so they need sign extension.
auto tmp3 = (unsigned int)(particles[newIndex].tmp3);
if (tmp3 & 0x8000U)
{
tmp3 |= 0xFFFF0000U;
particles[newIndex].tmp3 = int(tmp3);
}
}
//note: PSv was used in version 77.0 and every version before, add something in PSv too if the element is that old
newIndex++;
partsCount++;
@ -2262,10 +2275,14 @@ char * GameSave::serialiseOPS(unsigned int & dataLength)
if ((tmp3 || tmp4) && (!PressureInTmp3(particles[i].type) || hasPressure))
{
fieldDesc |= 1 << 13;
if ((tmp3 >> 16) || (tmp4 >> 16))
// The tmp3 of PressureInTmp3 elements is okay to truncate because the loading code
// sign extends it anyway, expecting the value to not be higher in magnitude than
// 256 (max pressure value) * 64 (tmp3 multiplicative bias).
if (((tmp3 >> 16) || (tmp4 >> 16)) && !PressureInTmp3(particles[i].type))
{
fieldDesc |= 1 << 15;
fieldDesc |= 1 << 16;
RESTRICTVERSION(97, 0);
}
}
@ -2294,7 +2311,6 @@ char * GameSave::serialiseOPS(unsigned int & dataLength)
if (fieldDesc & (1 << 15))
{
RESTRICTVERSION(97, 0);
fieldDesc3Loc = partsDataLen++;
}