Merge pull request #567 from jmtd/pitch-shifting

Implementation of pitch shifting.

This appeared in early versions of Doom and (more importantly) in Heretic
and Hexen. Sound effects get pitched up and down to sound less repetitive.

src/doom/s_sound.c

@@ -59,7 +59,6 @@
 
 #define S_STEREO_SWING (96 * FRACUNIT)
 
-#define NORM_PITCH 128
 #define NORM_PRIORITY 64
 #define NORM_SEP 128
 
@@ -74,6 +73,8 @@ typedef struct
     // handle of the sound being played
     int handle;
 
+    int pitch;
+
 } channel_t;
 
 // The set of channels available
@@ -141,6 +142,12 @@ void S_Init(int sfxVolume, int musicVolume)
         S_sfx[i].lumpnum = S_sfx[i].usefulness = -1;
     }
 
+    // Doom defaults to pitch-shifting off.
+    if(snd_pitchshift == -1)
+    {
+        snd_pitchshift = 0;
+    }
+
     I_AtExit(S_Shutdown, true);
 }
 
@@ -390,12 +397,28 @@ static int S_AdjustSoundParams(mobj_t *listener, mobj_t *source,
     return (*vol > 0);
 }
 
+// clamp supplied integer to the range 0 <= x <= 255.
+
+static int Clamp(int x)
+{
+    if (x < 0)
+    {
+        return 0;
+    }
+    else if (x > 255)
+    {
+        return 255;
+    }
+    return x;
+}
+
 void S_StartSound(void *origin_p, int sfx_id)
 {
     sfxinfo_t *sfx;
     mobj_t *origin;
     int rc;
     int sep;
+    int pitch;
     int cnum;
     int volume;
 
@@ -411,9 +434,11 @@ void S_StartSound(void *origin_p, int sfx_id)
     sfx = &S_sfx[sfx_id];
 
     // Initialize sound parameters
+    pitch = NORM_PITCH;
     if (sfx->link)
     {
         volume += sfx->volume;
+        pitch = sfx->pitch;
 
         if (volume < 1)
         {
@@ -452,6 +477,17 @@ void S_StartSound(void *origin_p, int sfx_id)
         sep = NORM_SEP;
     }
 
+    // hacks to vary the sfx pitches
+    if (sfx_id >= sfx_sawup && sfx_id <= sfx_sawhit)
+    {
+        pitch += 8 - (M_Random()&15);
+    }
+    else if (sfx_id != sfx_itemup && sfx_id != sfx_tink)
+    {
+        pitch += 16 - (M_Random()&31);
+    }
+    pitch = Clamp(pitch);
+
     // kill old sound
     S_StopSound(origin);
 
@@ -474,7 +510,8 @@ void S_StartSound(void *origin_p, int sfx_id)
         sfx->lumpnum = I_GetSfxLumpNum(sfx);
     }
 
-    channels[cnum].handle = I_StartSound(sfx, cnum, volume, sep);
+    channels[cnum].pitch = pitch;
+    channels[cnum].handle = I_StartSound(sfx, cnum, volume, sep, channels[cnum].pitch);
 }
 
 //

src/heretic/s_sound.c

@@ -268,10 +268,8 @@ void S_StartSound(void *_origin, int sound_id)
             sep = 512 - sep;
     }
 
-    // TODO: Play pitch-shifted sounds as in Vanilla Heretic
-
-    channel[i].pitch = (byte) (127 + (M_Random() & 7) - (M_Random() & 7));
-    channel[i].handle = I_StartSound(&S_sfx[sound_id], i, vol, sep);
+    channel[i].pitch = (byte) (NORM_PITCH + (M_Random() & 7) - (M_Random() & 7));
+    channel[i].handle = I_StartSound(&S_sfx[sound_id], i, vol, sep, channel[i].pitch);
     channel[i].mo = origin;
     channel[i].sound_id = sound_id;
     channel[i].priority = priority;
@@ -327,9 +325,8 @@ void S_StartSoundAtVolume(void *_origin, int sound_id, int volume)
         S_sfx[sound_id].lumpnum = I_GetSfxLumpNum(&S_sfx[sound_id]);
     }
 
-    // TODO: Pitch shifting.
-    channel[i].pitch = (byte) (127 - (M_Random() & 3) + (M_Random() & 3));
-    channel[i].handle = I_StartSound(&S_sfx[sound_id], i, volume, 128);
+    channel[i].pitch = (byte) (NORM_PITCH - (M_Random() & 3) + (M_Random() & 3));
+    channel[i].handle = I_StartSound(&S_sfx[sound_id], i, volume, 128, channel[i].pitch);
     channel[i].mo = origin;
     channel[i].sound_id = sound_id;
     channel[i].priority = 1;    //super low priority.
@@ -527,6 +524,12 @@ void S_Init(void)
 
     I_AtExit(S_ShutDown, true);
 
+    // Heretic defaults to pitch-shifting on
+    if(snd_pitchshift == -1)
+    {
+        snd_pitchshift = 1;
+    }
+
     I_PrecacheSounds(S_sfx, NUMSFX);
 }
 

src/hexen/s_sound.c

@@ -498,17 +498,16 @@ void S_StartSoundAtVolume(mobj_t * origin, int sound_id, int volume)
 //              vol = SoundCurve[dist];
     }
 
-#if 0
-// TODO
-    if (S_sfx[sound_id].changePitch)
+    // if the sfxinfo_t is marked as 'can be pitch shifted'
+    if (S_sfx[sound_id].pitch)
     {
-        Channel[i].pitch = (byte) (127 + (M_Random() & 7) - (M_Random() & 7));
+        Channel[i].pitch = (byte) (NORM_PITCH + (M_Random() & 7) - (M_Random() & 7));
     }
     else
     {
-        Channel[i].pitch = 127;
+        Channel[i].pitch = NORM_PITCH;
     }
-#endif
+
     if (S_sfx[sound_id].lumpnum == 0)
     {
         S_sfx[sound_id].lumpnum = I_GetSfxLumpNum(&S_sfx[sound_id]);
@@ -517,7 +516,8 @@ void S_StartSoundAtVolume(mobj_t * origin, int sound_id, int volume)
     Channel[i].handle = I_StartSound(&S_sfx[sound_id],
                                      i,
                                      vol,
-                                     sep /* , Channel[i].pitch] */);
+                                     sep,
+                                     Channel[i].pitch);
     Channel[i].sound_id = sound_id;
     Channel[i].priority = priority;
     Channel[i].volume = volume;
@@ -771,7 +771,7 @@ void S_UpdateSounds(mobj_t * listener)
                 if (sep > 192)
                     sep = 512 - sep;
             }
-            I_UpdateSoundParams(i, vol, sep /*, Channel[i].pitch */);
+            I_UpdateSoundParams(i, vol, sep);
             priority = S_sfx[Channel[i].sound_id].priority;
             priority *= PRIORITY_MAX_ADJUST - (dist / DIST_ADJUST);
             Channel[i].priority = priority;
@@ -799,6 +799,12 @@ void S_Init(void)
 
     I_AtExit(S_ShutDown, true);
 
+    // Hexen defaults to pitch-shifting on
+    if(snd_pitchshift == -1)
+    {
+        snd_pitchshift = 1;
+    }
+
     I_PrecacheSounds(S_sfx, NUMSFX);
 
     // Attempt to setup CD music

src/i_pcsound.c

@@ -174,7 +174,8 @@ static boolean IsDisabledSound(sfxinfo_t *sfxinfo)
 static int I_PCS_StartSound(sfxinfo_t *sfxinfo,
                             int channel,
                             int vol,
-                            int sep)
+                            int sep,
+                            int pitch)
 {
     int result;