1 files changed, 247 insertions, 0 deletions
diff --git a/Alc/effects/compressor.cpp b/Alc/effects/compressor.cpp
new file mode 100644
index 00000000..0a307a5f
--- /dev/null
+++ b/Alc/effects/compressor.cpp
@@ -0,0 +1,247 @@
+/**
+ * OpenAL cross platform audio library
+ * Copyright (C) 2013 by Anis A. Hireche
+ * 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.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * Or go to http://www.gnu.org/copyleft/lgpl.html
+ */
+
+#include <stdlib.h>
+
+#include "config.h"
+#include "alError.h"
+#include "alMain.h"
+#include "alAuxEffectSlot.h"
+#include "alu.h"
+
+
+#define AMP_ENVELOPE_MIN  0.5f
+#define AMP_ENVELOPE_MAX  2.0f
+
+#define ATTACK_TIME  0.1f /* 100ms to rise from min to max */
+#define RELEASE_TIME 0.2f /* 200ms to drop from max to min */
+
+
+struct ALcompressorState final : public ALeffectState {
+    /* Effect gains for each channel */
+    ALfloat Gain[MAX_EFFECT_CHANNELS][MAX_OUTPUT_CHANNELS];
+
+    /* Effect parameters */
+    ALboolean Enabled;
+    ALfloat AttackMult;
+    ALfloat ReleaseMult;
+    ALfloat EnvFollower;
+};
+
+static ALvoid ALcompressorState_Destruct(ALcompressorState *state);
+static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device);
+static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);
+static ALvoid ALcompressorState_process(ALcompressorState *state, ALsizei SamplesToDo, const ALfloat (*RESTRICT SamplesIn)[BUFFERSIZE], ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE], ALsizei NumChannels);
+DECLARE_DEFAULT_ALLOCATORS(ALcompressorState)
+
+DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
+
+
+static void ALcompressorState_Construct(ALcompressorState *state)
+{
+    new (state) ALcompressorState{};
+    ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
+    SET_VTABLE2(ALcompressorState, ALeffectState, state);
+
+    state->Enabled = AL_TRUE;
+    state->AttackMult = 1.0f;
+    state->ReleaseMult = 1.0f;
+    state->EnvFollower = 1.0f;
+}
+
+static ALvoid ALcompressorState_Destruct(ALcompressorState *state)
+{
+    ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
+    state->~ALcompressorState();
+}
+
+static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
+{
+    /* Number of samples to do a full attack and release (non-integer sample
+     * counts are okay).
+     */
+    const ALfloat attackCount  = (ALfloat)device->Frequency * ATTACK_TIME;
+    const ALfloat releaseCount = (ALfloat)device->Frequency * RELEASE_TIME;
+
+    /* Calculate per-sample multipliers to attack and release at the desired
+     * rates.
+     */
+    state->AttackMult  = powf(AMP_ENVELOPE_MAX/AMP_ENVELOPE_MIN, 1.0f/attackCount);
+    state->ReleaseMult = powf(AMP_ENVELOPE_MIN/AMP_ENVELOPE_MAX, 1.0f/releaseCount);
+
+    return AL_TRUE;
+}
+
+static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
+{
+    const ALCdevice *device = context->Device;
+    ALuint i;
+
+    state->Enabled = props->Compressor.OnOff;
+
+    STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
+    STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
+    for(i = 0;i < 4;i++)
+        ComputePanGains(&device->FOAOut, IdentityMatrixf.m[i], slot->Params.Gain, state->Gain[i]);
+}
+
+static ALvoid ALcompressorState_process(ALcompressorState *state, ALsizei SamplesToDo, const ALfloat (*RESTRICT SamplesIn)[BUFFERSIZE], ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
+{
+    ALsizei i, j, k;
+    ALsizei base;
+
+    for(base = 0;base < SamplesToDo;)
+    {
+        ALfloat gains[256];
+        ALsizei td = mini(256, SamplesToDo-base);
+        ALfloat env = state->EnvFollower;
+
+        /* Generate the per-sample gains from the signal envelope. */
+        if(state->Enabled)
+        {
+            for(i = 0;i < td;++i)
+            {
+                /* Clamp the absolute amplitude to the defined envelope limits,
+                 * then attack or release the envelope to reach it.
+                 */
+                ALfloat amplitude = clampf(fabsf(SamplesIn[0][base+i]),
+                                           AMP_ENVELOPE_MIN, AMP_ENVELOPE_MAX);
+                if(amplitude > env)
+                    env = minf(env*state->AttackMult, amplitude);
+                else if(amplitude < env)
+                    env = maxf(env*state->ReleaseMult, amplitude);
+
+                /* Apply the reciprocal of the envelope to normalize the volume
+                 * (compress the dynamic range).
+                 */
+                gains[i] = 1.0f / env;
+            }
+        }
+        else
+        {
+            /* Same as above, except the amplitude is forced to 1. This helps
+             * ensure smooth gain changes when the compressor is turned on and
+             * off.
+             */
+            for(i = 0;i < td;++i)
+            {
+                ALfloat amplitude = 1.0f;
+                if(amplitude > env)
+                    env = minf(env*state->AttackMult, amplitude);
+                else if(amplitude < env)
+                    env = maxf(env*state->ReleaseMult, amplitude);
+
+                gains[i] = 1.0f / env;
+            }
+        }
+        state->EnvFollower = env;
+
+        /* Now compress the signal amplitude to output. */
+        for(j = 0;j < MAX_EFFECT_CHANNELS;j++)
+        {
+            for(k = 0;k < NumChannels;k++)
+            {
+                ALfloat gain = state->Gain[j][k];
+                if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
+                    continue;
+
+                for(i = 0;i < td;i++)
+                    SamplesOut[k][base+i] += SamplesIn[j][base+i] * gains[i] * gain;
+            }
+        }
+
+        base += td;
+    }
+}
+
+
+struct CompressorStateFactory final : public EffectStateFactory {
+    CompressorStateFactory() noexcept;
+};
+
+static ALeffectState *CompressorStateFactory_create(CompressorStateFactory *UNUSED(factory))
+{
+    ALcompressorState *state;
+
+    NEW_OBJ0(state, ALcompressorState)();
+    if(!state) return NULL;
+
+    return STATIC_CAST(ALeffectState, state);
+}
+
+DEFINE_EFFECTSTATEFACTORY_VTABLE(CompressorStateFactory);
+
+CompressorStateFactory::CompressorStateFactory() noexcept
+  : EffectStateFactory{GET_VTABLE2(CompressorStateFactory, EffectStateFactory)}
+{
+}
+
+EffectStateFactory *CompressorStateFactory_getFactory(void)
+{
+    static CompressorStateFactory CompressorFactory{};
+    return STATIC_CAST(EffectStateFactory, &CompressorFactory);
+}
+
+
+void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
+{
+    ALeffectProps *props = &effect->Props;
+    switch(param)
+    {
+        case AL_COMPRESSOR_ONOFF:
+            if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
+                SETERR_RETURN(context, AL_INVALID_VALUE,, "Compressor state out of range");
+            props->Compressor.OnOff = val;
+            break;
+
+        default:
+            alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
+                       param);
+    }
+}
+void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
+{ ALcompressor_setParami(effect, context, param, vals[0]); }
+void ALcompressor_setParamf(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALfloat UNUSED(val))
+{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
+void ALcompressor_setParamfv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALfloat *UNUSED(vals))
+{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
+
+void ALcompressor_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
+{ 
+    const ALeffectProps *props = &effect->Props;
+    switch(param)
+    {
+        case AL_COMPRESSOR_ONOFF:
+            *val = props->Compressor.OnOff;
+            break;
+
+        default:
+            alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
+                       param);
+    }
+}
+void ALcompressor_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
+{ ALcompressor_getParami(effect, context, param, vals); }
+void ALcompressor_getParamf(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALfloat *UNUSED(val))
+{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
+void ALcompressor_getParamfv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALfloat *UNUSED(vals))
+{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
+
+DEFINE_ALEFFECT_VTABLE(ALcompressor);