diff options
author | Paul Davis <paul@linuxaudiosystems.com> | 2011-06-19 23:02:55 +0000 |
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committer | Paul Davis <paul@linuxaudiosystems.com> | 2011-06-19 23:02:55 +0000 |
commit | d5e09076ca69fda1402a12e383de7a7d9bc5f0ec (patch) | |
tree | 0d4df7147098ea57e58d96efb82f57dd5545023c /libs/ardour/ardour/utils.h | |
parent | 182b23e744d79b3387a779ea25010924daffe6af (diff) |
much ado about nothing when it comes to gain control
git-svn-id: svn://localhost/ardour2/branches/3.0@9748 d708f5d6-7413-0410-9779-e7cbd77b26cf
Diffstat (limited to 'libs/ardour/ardour/utils.h')
-rw-r--r-- | libs/ardour/ardour/utils.h | 59 |
1 files changed, 58 insertions, 1 deletions
diff --git a/libs/ardour/ardour/utils.h b/libs/ardour/ardour/utils.h index dac4086cba..17fa9070ff 100644 --- a/libs/ardour/ardour/utils.h +++ b/libs/ardour/ardour/utils.h @@ -36,6 +36,7 @@ bool string_is_affirmative (const std::string&); #include "ardour/ardour.h" #include "ardour/data_type.h" +#include "ardour/dB.h" class XMLNode; @@ -70,22 +71,78 @@ ARDOUR::SyncSource string_to_sync_source (std::string str); const char* edit_mode_to_string (ARDOUR::EditMode); ARDOUR::EditMode string_to_edit_mode (std::string); +#undef OLD_GAIN_MATH +#define OLD_GAIN_MATH static inline double gain_to_slider_position (ARDOUR::gain_t g) { if (g == 0) return 0; - return pow((6.0*log(g)/log(2.0)+192.0)/198.0, 8.0); +#ifndef OLD_GAIN_MATH + /* Power Law With Exponential Cutoff 2D, fit to data from TC Spectra + console (image of fader gradations + + y = C * x(-T) * exp(-x/K) + + C = 8.2857630370864188E-01 + T = -5.1526743785019269E-01 + K = 7.8990885960495589E+00 + + */ + + return 8.2857630370864188E-01 * pow(g,5.1526743785019269E-01) * exp (-g/7.8990885960495589E+00); +#else + return pow((6.0*log(g)/log(2.0)+192.0)/198.0, 8.0); +#endif } static inline ARDOUR::gain_t slider_position_to_gain (double pos) { + if (pos == 0.0) { + return 0.0; + } + +#ifndef OLD_GAIN_MATH + /* 5th order polynomial function fit to data from a TC Spectra console + fader (image of fader gradations). + + y = a + bx1 + cx2 + dx3 + fx4 + gx5 + + a = -1.1945480381045521E-02 + b = 1.5809476525537265E+00 + c = -1.5850710838966151E+01 + d = 6.1643128605961991E+01 + f = -8.5525246160607693E+01 + g = 4.1312725896188283E+01 + + */ + + double p = pos; + double g = -1.1945480381045521E-02; + + g += 1.5809476525537265E+00 * pos; + pos *= p; + g += -1.5850710838966151E+01 * pos; + pos *= p; + g += 6.1643128605961991E+01 * pos; + pos *= p; + g += -8.5525246160607693E+01 * pos; + pos *= p; + g += 4.1312725896188283E+01 * pos; + + return g; +#else /* XXX Marcus writes: this doesn't seem right to me. but i don't have a better answer ... */ if (pos == 0.0) return 0; return pow (2.0,(sqrt(sqrt(sqrt(pos)))*198.0-192.0)/6.0); +#endif } +#undef OLD_GAIN_MATH + +double gain_to_slider_position_with_max (double g, double max_gain = 2.0); +double slider_position_to_gain_with_max (double g, double max_gain = 2.0); /* I don't really like hard-coding these falloff rates here * Probably should use a map of some kind that could be configured |