Implement a skeleton Ring Modulator effect

2 files changed, 97 insertions, 0 deletions

diff --git a/Alc/ALc.c b/Alc/ALc.c
index c2908c53..e7d3d343 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -349,6 +349,7 @@ static void alc_init(void)
             { "eaxreverb", EAXREVERB },
             { "reverb", REVERB },
             { "echo", ECHO },
+            { "modulator", MODULATOR },
             { NULL, 0 }
         };
         int n;
diff --git a/Alc/alcModulator.c b/Alc/alcModulator.c
new file mode 100644
index 00000000..558e861b
--- /dev/null
+++ b/Alc/alcModulator.c
@@ -0,0 +1,96 @@
+/**
+ * OpenAL cross platform audio library
+ * Copyright (C) 2009 by Chris Robinson.
+ * This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ *  License along with this library; if not, write to the
+ *  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ *  Boston, MA  02111-1307, USA.
+ * Or go to http://www.gnu.org/copyleft/lgpl.html
+ */
+
+#include "config.h"
+
+#include <math.h>
+#include <stdlib.h>
+
+#include "alMain.h"
+#include "alFilter.h"
+#include "alAuxEffectSlot.h"
+#include "alError.h"
+#include "alu.h"
+
+
+typedef struct ALmodulatorState {
+    // Must be first in all effects!
+    ALeffectState state;
+} ALmodulatorState;
+
+static ALvoid ModulatorDestroy(ALeffectState *effect)
+{
+    ALmodulatorState *state = (ALmodulatorState*)effect;
+    free(state);
+}
+
+static ALboolean ModulatorDeviceUpdate(ALeffectState *effect, ALCdevice *Device)
+{
+    return AL_TRUE;
+    (void)Device;
+    (void)effect;
+}
+
+static ALvoid ModulatorUpdate(ALeffectState *effect, ALCcontext *Context, const ALeffect *Effect)
+{
+    (void)effect;
+    (void)Context;
+    (void)Effect;
+}
+
+static ALvoid ModulatorProcess(ALeffectState *effect, const ALeffectslot *Slot, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[OUTPUTCHANNELS])
+{
+    ALmodulatorState *state = (ALmodulatorState*)effect;
+    const ALfloat gain = Slot->Gain;
+    ALfloat samp;
+    ALuint i;
+    (void)state;
+
+    for(i = 0;i < SamplesToDo;i++)
+    {
+        samp = SamplesIn[i];
+
+        // Apply slot gain
+        samp *= gain;
+
+        SamplesOut[i][FRONT_LEFT]  += samp;
+        SamplesOut[i][FRONT_RIGHT] += samp;
+        SamplesOut[i][SIDE_LEFT]   += samp;
+        SamplesOut[i][SIDE_RIGHT]  += samp;
+        SamplesOut[i][BACK_LEFT]   += samp;
+        SamplesOut[i][BACK_RIGHT]  += samp;
+    }
+}
+
+ALeffectState *ModulatorCreate(void)
+{
+    ALmodulatorState *state;
+
+    state = malloc(sizeof(*state));
+    if(!state)
+        return NULL;
+
+    state->state.Destroy = ModulatorDestroy;
+    state->state.DeviceUpdate = ModulatorDeviceUpdate;
+    state->state.Update = ModulatorUpdate;
+    state->state.Process = ModulatorProcess;
+
+    return &state->state;
+}