X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Fardour%2FdB.h;h=1a4ed983abd3e5e1014ea6a0f6e5794b6a313657;hb=ae71e57e2422466716c0ec68ac841d778cf26e94;hp=e5865aabd8550a53458006938c21c5527637561f;hpb=01e006e46e6d4dd0ab25e08bd44d13dd1e195886;p=ardour.git

diff --git a/libs/ardour/ardour/dB.h b/libs/ardour/ardour/dB.h
index e5865aabd8..1a4ed983ab 100644
--- a/libs/ardour/ardour/dB.h
+++ b/libs/ardour/ardour/dB.h
@@ -20,8 +20,13 @@
 #ifndef __ardour_dB_h__
 #define __ardour_dB_h__
 
+#include <limits>
 #include "pbd/fastlog.h"
 
+#define GAIN_COEFF_ZERO 0.f
+#define GAIN_COEFF_SMALL 0.0000001f  //-140dB
+#define GAIN_COEFF_UNITY 1.f
+
 static inline float dB_to_coefficient (float dB) {
 	return dB > -318.8f ? pow (10.0f, dB * 0.05f) : 0.0f;
 }
@@ -31,9 +36,15 @@ static inline float fast_coefficient_to_dB (float coeff) {
 }
 
 static inline float accurate_coefficient_to_dB (float coeff) {
-	return 20.0f * log10 (coeff);
+	if (coeff < 1e-15) return  -std::numeric_limits<float>::infinity();
+	return 20.0f * log10f (coeff);
+}
+
+static inline double dB_coeff_step(double max_coeff) {
+	const double max_db = lrint(accurate_coefficient_to_dB(max_coeff));
+	return 0.1 * (max_coeff / max_db);
 }
 
-static const double zero_db_as_fraction = 0.781787;
+extern double zero_db_as_fraction;
 
 #endif /* __ardour_dB_h__ */