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- do the 'inside' check with integers.

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Using floats and multiplications is not robust enough. This is a bit slower, but doesn't run the risk of underflows and other nasties.
Q: How many bits of fractional precision should we use? 16 seems fine
This commit is contained in:
Christoph Oelckers 2022-01-30 12:27:35 +01:00
parent 63f1a968d6
commit 651c25a7be
2 changed files with 15 additions and 10 deletions
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24
source/core/gamefuncs.cpp
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@ -439,21 +439,25 @@ int inside(double x, double y, const sectortype* sect)
{
if (sect)
{
double acc = 1;
int64_t acc = 1;
for (auto& wal : wallsofsector(sect))
{
double xs = (wal.pos.X - x);
double ys = (wal.pos.Y - y);
// Perform the checks here in 48.16 fixed point.
// Doing it directly with floats and multiplications does not work reliably.
// Unfortunately, due to the conversions, this is a bit slower. :(
int64_t xs = int64_t(0x10000 * (wal.pos.X - x));
int64_t ys = int64_t(0x10000 * (wal.pos.Y - y));
auto wal2 = wal.point2Wall();
double xe = (wal2->pos.X - x);
double ye = (wal2->pos.Y - y);
int64_t xe = int64_t(0x10000 * (wal2->pos.X - x));
int64_t ye = int64_t(0x10000 * (wal2->pos.Y - y));
if ((ys * ye) < 0)
if ((ys ^ ye) < 0)
{
double val;
if ((xs * xe) >= 0) val = xs;
else val = (xs * ye - xe * ys) * ye;
acc *= val;
int64_t val;
if ((xs ^ xe) >= 0) val = xs;
else val = ((xs * ye) - xe * ys) ^ ye;
acc ^= val;
}
}
return acc < 0;

1
source/core/rendering/hw_entrypoint.cpp
View file

@ -314,6 +314,7 @@ static void CheckTimer(FRenderState &state, uint64_t ShaderStartTime)
void animatecamsprite(double s);
void render_drawrooms(DCoreActor* playersprite, const vec3_t& position, int sectnum, binangle angle, fixedhoriz horizon, binangle rollang, double smoothratio)
{
checkRotatedWalls();