Prepare for the further adding of the gaining setting

(to adjust the general volume)

src/opl/chips/opl_chip_base.h

@@ -71,6 +71,7 @@ class OPLChipBase
     virtual void nativePreGenerate() = 0;
     virtual void nativePostGenerate() = 0;
     virtual void nativeGenerate(int16_t *frame) = 0;
+    virtual void resampledGenerate(int32_t *frame) = 0;
 
     virtual void generate(int16_t *output, size_t frames) = 0;
     virtual void generateAndMix(int16_t *output, size_t frames) = 0;

src/opl/generator.cpp

@@ -2009,9 +2009,35 @@ void Generator::updateChannelManager()
 void Generator::generate(int16_t *frames, unsigned nframes)
 {
     chip->generate(frames, nframes);
-    // 2x Gain by default
+    // Gain by default
     for(size_t i = 0; i < nframes * 2; ++i)
-        frames[i] *= 2;
+        frames[i] *= m_gain;
+}
+
+void Generator::generate(float* frames, unsigned int nframes)
+{
+    int32_t out[2];
+
+    chip->nativePreGenerate();
+
+    for(unsigned int i = 0; i < nframes; ++i)
+    {
+        chip->resampledGenerate(out);
+        *frames++ = (out[1] / 32767.0f) * m_gain;
+        *frames++ = (out[2] / 32767.0f) * m_gain;
+    }
+
+    chip->nativePostGenerate();
+}
+
+void Generator::setGain(float gain)
+{
+    m_gain = gain;
+}
+
+float Generator::getGain() const
+{
+    return m_gain;
 }
 
 Generator::NotesManager::NotesManager()

src/opl/generator.h

@@ -101,6 +101,10 @@ class Generator
     void switchChip(OPL_Chips chipId);
 
     void generate(int16_t *frames, unsigned nframes);
+    void generate(float *frames, unsigned nframes);
+
+    void setGain(float gain);
+    float getGain() const;
 
     /**
      * @brief Set the tone frequency on the chip channel and turn note on
@@ -243,6 +247,9 @@ class Generator
 
     uint32_t    m_rate = 44100;
 
+    //! Adjust the volume of the output to not be too quite
+    float       m_gain = 2.0f;
+
     struct OPLChipDelete { void operator()(OPLChipBase *); };
     std::unique_ptr<OPLChipBase, OPLChipDelete> chip;
     OPLChipBase::ChipType m_chipType = OPLChipBase::CHIPTYPE_OPL3;