Add a config option to boost reverb output

Alc/ALc.c

@@ -564,6 +564,9 @@ static void alc_initconfig(void)
     if(DefaultResampler >= RESAMPLER_MAX || DefaultResampler <= RESAMPLER_MIN)
         DefaultResampler = RESAMPLER_DEFAULT;
 
+    ReverbBoost *= aluPow(10.0f, GetConfigValueFloat("reverb", "boost", 0.0f) /
+                                 20.0f);
+
     devs = GetConfigValue(NULL, "drivers", "");
     if(devs[0])
     {

Alc/alcReverb.c

@@ -135,6 +135,11 @@ typedef struct ALverbState {
     ALfloat *Gain;
 } ALverbState;
 
+/* This is a user config option for modifying the overall output of the reverb
+ * effect.
+ */
+ALfloat ReverbBoost = 1.0f;
+
 /* This coefficient is used to define the maximum frequency range controlled
  * by the modulation depth.  The current value of 0.1 will allow it to swing
  * from 0.9x to 1.1x.  This value must be below 1.  At 1 it will cause the
@@ -602,6 +607,8 @@ static ALvoid Update3DPanning(const ALCdevice *Device, const ALfloat *Reflection
     ALuint index;
     ALint pos;
 
+    Gain *= ReverbBoost;
+
     // Attenuate non-directional reverb according to the number of channels
     ambientGain = aluSqrt(2.0f/Device->NumChan);
 
@@ -1106,7 +1113,8 @@ static ALvoid VerbUpdate(ALeffectState *effect, ALCcontext *Context, const ALeff
 
     // Update channel gains
     gain = Slot->Gain;
-    gain *= aluSqrt(2.0/Device->NumChan);
+    gain *= aluSqrt(2.0f/Device->NumChan);
+    gain *= ReverbBoost;
     for(index = 0;index < MAXCHANNELS;index++)
          State->Gain[index] = 0.0f;
     for(index = 0;index < Device->NumChan;index++)

OpenAL32/Include/alEffect.h

@@ -18,6 +18,8 @@ enum {
 };
 extern ALboolean DisabledEffects[MAX_EFFECTS];
 
+extern ALfloat ReverbBoost;
+
 typedef struct ALeffect
 {
     // Effect type (AL_EFFECT_NULL, ...)

alsoftrc.sample

@@ -150,6 +150,18 @@
 #layout_61CHN  = fl=-30, fr=30, fc=0, sl=-90, sr=90, bc=180
 #layout_71CHN  = fl=-30, fr=30, fc=0, sl=-90, sr=90, bl=-150, br=150
 
+##
+## Reverb effect stuff (includes EAX reverb)
+##
+[reverb]
+
+## boost:
+#  A global amplification for reverb output, expressed in decibels. The value
+#  is logarithmic, so +6 will be a scale of (approximately) 2x, +12 will be a
+#  scale of 4x, etc. Similarly, -6 will be about half, and -12 about 1/4th. A
+#  value of 0 means no change.
+#boost = 0
+
 ##
 ## ALSA backend stuff
 ##