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Optimise usage of pow using fast equivalent and exp2 (#7548)

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* replace std::pow with better performing equivalents

* revert one instance where I swapped to fastPow10f

* Negative slope instead of multiplying -1

Co-authored-by: saker <sakertooth@gmail.com>

---------

Co-authored-by: saker <sakertooth@gmail.com>
This commit is contained in:
Rossmaxx
2024-11-21 14:29:51 +05:30
committed by GitHub
parent 7e65a87ba8
commit 26d5241dd7
6 changed files with 18 additions and 17 deletions
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21
src/core/DrumSynth.cpp
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@@ -30,6 +30,8 @@
#include <cstring>
#include <sstream>
#include "lmms_math.h"
#ifdef _MSC_VER
// not #if LMMS_BUILD_WIN32 because we have strncasecmp in mingw
#define strcasecmp _stricmp
@@ -403,13 +405,13 @@ int DrumSynth::GetDSFileSamples(QString dsfile, int16_t*& wave, int channels, sa
timestretch *= Fs / 44100.f;
DGain = 1.0f; // leave this here!
DGain = static_cast<float>(std::pow(10.0, 0.05 * GetPrivateProfileFloat(sec, "Level", 0, dsfile)));
DGain = fastPow10f(0.05 * GetPrivateProfileFloat(sec, "Level", 0, dsfile));
MasterTune = GetPrivateProfileFloat(sec, "Tuning", 0.0, dsfile);
MasterTune = static_cast<float>(std::pow(1.0594631f, MasterTune + mem_tune));
MasterTune = std::pow(1.0594631f, MasterTune + mem_tune);
MainFilter = 2 * GetPrivateProfileInt(sec, "Filter", 0, dsfile);
MFres = 0.0101f * GetPrivateProfileFloat(sec, "Resonance", 0.0, dsfile);
MFres = static_cast<float>(std::pow(MFres, 0.5f));
MFres = std::sqrt(MFres);
HighPass = GetPrivateProfileInt(sec, "HighPass", 0, dsfile);
GetEnv(7, sec, "FilterEnv", dsfile);
@@ -455,7 +457,7 @@ int DrumSynth::GetDSFileSamples(QString dsfile, int16_t*& wave, int channels, sa
TDroopRate = GetPrivateProfileFloat(sec, "Droop", 0.f, dsfile);
if (TDroopRate > 0.f)
{
TDroopRate = static_cast<float>(std::pow(10.0f, (TDroopRate - 20.0f) / 30.0f));
TDroopRate = fastPow10f((TDroopRate - 20.0f) / 30.0f);
TDroopRate = TDroopRate * -4.f / envData[1][MAX];
TDroop = 1;
F2 = F1 + ((F2 - F1) / (1.f - static_cast<float>(exp(TDroopRate * envData[1][MAX]))));
@@ -482,7 +484,7 @@ int DrumSynth::GetDSFileSamples(QString dsfile, int16_t*& wave, int channels, sa
OW1 = GetPrivateProfileInt(sec, "Wave1", 0, dsfile);
OW2 = GetPrivateProfileInt(sec, "Wave2", 0, dsfile);
OBal2 = static_cast<float>(GetPrivateProfileInt(sec, "Param", 50, dsfile));
ODrive = static_cast<float>(std::pow(OBal2, 3.0f)) / std::pow(50.0f, 3.0f);
ODrive = (OBal2 * OBal2 * OBal2) / 125000.0f;
OBal2 *= 0.01f;
OBal1 = 1.f - OBal2;
Ophi1 = Tphi;
@@ -556,9 +558,8 @@ int DrumSynth::GetDSFileSamples(QString dsfile, int16_t*& wave, int channels, sa
{
DAtten = DGain * static_cast<short>(LoudestEnv());
clippoint = DAtten > 32700 ? 32700 : static_cast<short>(DAtten);
DAtten = static_cast<float>(std::pow(2.0, 2.0 * GetPrivateProfileInt(sec, "Bits", 0, dsfile)));
DGain = DAtten * DGain
* static_cast<float>(std::pow(10.0, 0.05 * GetPrivateProfileInt(sec, "Clipping", 0, dsfile)));
DAtten = std::exp2(2.0 * GetPrivateProfileInt(sec, "Bits", 0, dsfile));
DGain = DAtten * DGain * fastPow10f(0.05 * GetPrivateProfileInt(sec, "Clipping", 0, dsfile));
}
// prepare envelopes
@@ -856,7 +857,7 @@ int DrumSynth::GetDSFileSamples(QString dsfile, int16_t*& wave, int channels, sa
MFtmp = envData[7][ENV];
if (MFtmp > 0.2f)
{
MFfb = 1.001f - static_cast<float>(std::pow(10.0f, MFtmp - 1));
MFfb = 1.001f - fastPow10f(MFtmp - 1);
}
else
{
@@ -883,7 +884,7 @@ int DrumSynth::GetDSFileSamples(QString dsfile, int16_t*& wave, int channels, sa
MFtmp = envData[7][ENV];
if (MFtmp > 0.2f)
{
MFfb = 1.001f - static_cast<float>(std::pow(10.0f, MFtmp - 1));
MFfb = 1.001f - fastPow10f(MFtmp - 1);
}
else
{