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Allow per-house town cargo generation to be truncated to 0

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This effectively applies the town cargo scaling setting more strictly
This commit is contained in:
Jonathan G Rennison
2021-11-30 23:11:25 +00:00
parent a8f879251b
commit 431d33f149
3 changed files with 13 additions and 8 deletions
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13
src/economy.cpp
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@@ -2453,16 +2453,16 @@ CommandCost CmdDeclineBuyCompany(TileIndex tile, DoCommandFlag flags, uint32 p1,
return CommandCost();
}
uint ScaleQuantity(uint amount, int scale_factor)
uint ScaleQuantity(uint amount, int scale_factor, bool allow_trunc)
{
scale_factor += 200; // ensure factor is positive
assert(scale_factor >= 0);
int cf = (scale_factor / 10) - 20;
int fine = scale_factor % 10;
return ScaleQuantity(amount, cf, fine);
return ScaleQuantity(amount, cf, fine, allow_trunc);
}
uint ScaleQuantity(uint amount, int cf, int fine)
uint ScaleQuantity(uint amount, int cf, int fine, bool allow_trunc)
{
if (fine != 0) {
// 2^0.1 << 16 to 2^0.9 << 16
@@ -2474,9 +2474,12 @@ uint ScaleQuantity(uint amount, int cf, int fine)
// apply scale factor
if (cf < 0) {
// approx (amount / 2^cf)
// adjust with a constant offset of {(2 ^ cf) - 1} (i.e. add cf * 1-bits) before dividing to ensure that it doesn't become zero
// when allow_trunc is false: adjust with a constant offset of {(2 ^ cf) - 1} (i.e. add cf * 1-bits) before dividing to ensure that it doesn't become zero
// this skews the curve a little so that isn't entirely exponential, but will still decrease
amount = (amount + ((1 << -cf) - 1)) >> -cf;
// when allow_trunc is true: adjust with a randomised offset
uint offset = ((1 << -cf) - 1);
if (allow_trunc) offset &= Random();
amount = (amount + offset) >> -cf;
} else if (cf > 0) {
// approx (amount * 2^cf)
amount = amount << cf;