accela: guard against negative value overflow properly

Accela attempted to guard against both negative and positive value
overstepping the last value due to gain, but the check for negative
values was incorrect.

Issue: #231
Reported-by: @nanospork, @alterscape, @SgtGrumbles

1 files changed, 1 insertions, 1 deletions

diff --git a/ftnoir_filter_accela/ftnoir_filter_accela.cpp b/ftnoir_filter_accela/ftnoir_filter_accela.cpp
index b246a925..7f1d9d0a 100644
--- a/ftnoir_filter_accela/ftnoir_filter_accela.cpp
+++ b/ftnoir_filter_accela/ftnoir_filter_accela.cpp
@@ -97,7 +97,7 @@ void FTNoIR_Filter::filter(const double* input, double *output)
         const double thres = i >= 3 ? rot_t : trans_t;
         const double val = m.getValue(vec_ / thres);
         const double result = last_output[i] + (vec < 0 ? -1 : 1) * dt * val;
-        const bool negp = vec < 0.;
+        const bool negp = in < 0.;
         const bool done = negp
             ? result <= in
             : result >= in;