From 5f2a413b4d7aff2f8e3c4a831c17f4de16cede6c Mon Sep 17 00:00:00 2001
From: Stefano D'Angelo <s@dangelo.audio>
Date: Wed, 13 Mar 2024 12:28:35 +0100
Subject: [PATCH] add gate param to bw_bd_reduce and examples + fix
 fxpp_bitcrush

---
 examples/fx_bitcrush/src/cmd.json       |  2 +-
 examples/fx_bitcrush/src/lv2.json       |  2 +-
 examples/fx_bitcrush/src/plugin.h       |  3 +
 examples/fx_bitcrush/src/product.json   | 10 +++
 examples/fxpp_bitcrush/src/cmd.json     |  2 +-
 examples/fxpp_bitcrush/src/impl.cpp     |  5 +-
 examples/fxpp_bitcrush/src/lv2.json     |  2 +-
 examples/fxpp_bitcrush/src/product.json | 10 +++
 include/bw_bd_reduce.h                  | 88 ++++++++++++++++++++++++-
 9 files changed, 117 insertions(+), 7 deletions(-)

diff --git a/examples/fx_bitcrush/src/cmd.json b/examples/fx_bitcrush/src/cmd.json
index 437bda7..3e0d454 100644
--- a/examples/fx_bitcrush/src/cmd.json
+++ b/examples/fx_bitcrush/src/cmd.json
@@ -1,6 +1,6 @@
 {
 	"cmd": {
 		"busIds": [ "input", "output" ],
-		"parameterIds": [ "sr_ratio", "bit_depth" ]
+		"parameterIds": [ "sr_ratio", "bit_depth", "gate" ]
 	}
 }
diff --git a/examples/fx_bitcrush/src/lv2.json b/examples/fx_bitcrush/src/lv2.json
index a587bb6..dc91929 100644
--- a/examples/fx_bitcrush/src/lv2.json
+++ b/examples/fx_bitcrush/src/lv2.json
@@ -7,6 +7,6 @@
 		"types": [ "@lv2:DistortionPlugin" ],
 		"version": "0.0",
 		"busSymbols": [ "input", "output" ],
-		"parameterSymbols": [ "sr_ratio", "bit_depth" ]
+		"parameterSymbols": [ "sr_ratio", "bit_depth", "gate" ]
 	}
 }
diff --git a/examples/fx_bitcrush/src/plugin.h b/examples/fx_bitcrush/src/plugin.h
index 68c06af..f5b29b6 100644
--- a/examples/fx_bitcrush/src/plugin.h
+++ b/examples/fx_bitcrush/src/plugin.h
@@ -67,6 +67,9 @@ static void plugin_set_parameter(plugin *instance, size_t index, float value) {
 	case 1:
 		bw_bd_reduce_set_bit_depth(&instance->bd_reduce_coeffs, (char)value);
 		break;
+	case 2:
+		bw_bd_reduce_set_gate_lin(&instance->bd_reduce_coeffs, value);
+		break;
 	}
 }
 
diff --git a/examples/fx_bitcrush/src/product.json b/examples/fx_bitcrush/src/product.json
index f9955a2..eca7438 100644
--- a/examples/fx_bitcrush/src/product.json
+++ b/examples/fx_bitcrush/src/product.json
@@ -40,6 +40,16 @@
 				"maximum": 16.0,
 				"integer": true,
 				"map": "linear"
+			},
+			{
+				"name": "Gate",
+				"shortName": "Gate",
+				"direction": "input",
+				"defaultValue": 0.0,
+				"minimum": 0.0,
+				"maximum": 1.0,
+				"optional": true,
+				"map": "linear"
 			}
 		]
 	}
diff --git a/examples/fxpp_bitcrush/src/cmd.json b/examples/fxpp_bitcrush/src/cmd.json
index 437bda7..3e0d454 100644
--- a/examples/fxpp_bitcrush/src/cmd.json
+++ b/examples/fxpp_bitcrush/src/cmd.json
@@ -1,6 +1,6 @@
 {
 	"cmd": {
 		"busIds": [ "input", "output" ],
-		"parameterIds": [ "sr_ratio", "bit_depth" ]
+		"parameterIds": [ "sr_ratio", "bit_depth", "gate" ]
 	}
 }
diff --git a/examples/fxpp_bitcrush/src/impl.cpp b/examples/fxpp_bitcrush/src/impl.cpp
index bb9e648..00814e5 100644
--- a/examples/fxpp_bitcrush/src/impl.cpp
+++ b/examples/fxpp_bitcrush/src/impl.cpp
@@ -66,6 +66,9 @@ void impl_set_parameter(impl handle, size_t index, float value) {
 	case 1:
 		instance->bd.setBitDepth((char)value);
 		break;
+	case 2:
+		instance->bd.setGateLin(value);
+		break;
 	}
 }
 
@@ -78,7 +81,7 @@ float impl_get_parameter(impl handle, size_t index) {
 void impl_process(impl handle, const float **inputs, float **outputs, size_t n_samples) {
 	Engine *instance = reinterpret_cast<Engine *>(handle);
 	instance->sr.process(inputs, outputs, n_samples);
-	instance->bd.process(inputs, outputs, n_samples);
+	instance->bd.process(outputs, outputs, n_samples);
 }
 
 }
diff --git a/examples/fxpp_bitcrush/src/lv2.json b/examples/fxpp_bitcrush/src/lv2.json
index d6ddf3d..50fcc86 100644
--- a/examples/fxpp_bitcrush/src/lv2.json
+++ b/examples/fxpp_bitcrush/src/lv2.json
@@ -7,6 +7,6 @@
 		"types": [ "@lv2:DistortionPlugin" ],
 		"version": "0.0",
 		"busSymbols": [ "input", "output" ],
-		"parameterSymbols": [ "sr_ratio", "bit_depth" ]
+		"parameterSymbols": [ "sr_ratio", "bit_depth", "gate" ]
 	}
 }
diff --git a/examples/fxpp_bitcrush/src/product.json b/examples/fxpp_bitcrush/src/product.json
index 13d5786..ff1b073 100644
--- a/examples/fxpp_bitcrush/src/product.json
+++ b/examples/fxpp_bitcrush/src/product.json
@@ -40,6 +40,16 @@
 				"maximum": 16.0,
 				"integer": true,
 				"map": "linear"
+			},
+			{
+				"name": "Gate",
+				"shortName": "Gate",
+				"direction": "input",
+				"defaultValue": 0.0,
+				"minimum": 0.0,
+				"maximum": 1.0,
+				"optional": true,
+				"map": "linear"
 			}
 		]
 	}
diff --git a/include/bw_bd_reduce.h b/include/bw_bd_reduce.h
index 5dc1864..99c9828 100644
--- a/include/bw_bd_reduce.h
+++ b/include/bw_bd_reduce.h
@@ -20,17 +20,24 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 1.1.0 }}}
+ *  version {{{ 1.2.0 }}}
  *  requires {{{ bw_common bw_math }}}
  *  description {{{
- *    Bit depth reducer.
+ *    Bit depth reducer with input gate.
  *
  *    This is purely an audio effect, it doesn't actually produce an output
  *    signal with a different encoding. The algorithm is deliberately crude to
  *    obtain the characteristic noise due to lo-fi A/D quantization.
+ *
+ *    It 
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>1.2.0</strong>:
+ *        <ul>
+ *          <li>Added gate parameter.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>1.1.0</strong>:
  *        <ul>
  *          <li>Added silence_dc parameter.</li>
@@ -188,6 +195,30 @@ static inline void bw_bd_reduce_set_silence_dc(
  *
  *    Default value: non-`0` (non-null dc).
  *
+ *    #### bw_bd_reduce_set_gate_lin()
+ *  ```>>> */
+static inline void bw_bd_reduce_set_gate_lin(
+	bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
+	float                             value);
+/*! <<<```
+ *    Sets the input gate threshold `value` (linear) in `coeffs`.
+ *
+ *    Valid range: [`0.f`, `1.f`].
+ *
+ *    Default value: `0.f`.
+ *
+ *    #### bw_bd_reduce_set_gate_dBFS()
+ *  ```>>> */
+static inline void bw_bd_reduce_set_gate_dBFS(
+	bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
+	float                             value);
+/*! <<<```
+ *    Sets the input gate threshold `value` (dBFS) in `coeffs`.
+ *
+ *    Valid range: [`-INFINITY`, `0.f`].
+ *
+ *    Default value: `-INFINITY`.
+ *
  *    #### bw_bd_reduce_coeffs_is_valid()
  *  ```>>> */
 static inline char bw_bd_reduce_coeffs_is_valid(
@@ -236,6 +267,7 @@ struct bw_bd_reduce_coeffs {
 	float				k;
 	float				ko;
 	float				max;
+	float				gate;
 	
 	// Parameters
 	char				bit_depth;
@@ -248,6 +280,7 @@ static inline void bw_bd_reduce_init(
 
 	coeffs->bit_depth = 16;
 	coeffs->ko = 0.5f;
+	coeffs->gate = 0.f;
 
 #ifdef BW_DEBUG_DEEP
 	coeffs->hash = bw_hash_sdbm("bw_bd_reduce_coeffs");
@@ -330,6 +363,7 @@ static inline float bw_bd_reduce_process1(
 	BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
 	BW_ASSERT(bw_is_finite(x));
 
+	x = bw_absf(x) < coeffs->gate ? 0.f : x;
 	const float y = coeffs->ki * (bw_floorf(coeffs->k * bw_clipf(x, -coeffs->max, coeffs->max)) + coeffs->ko);
 
 	BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
@@ -413,6 +447,36 @@ static inline void bw_bd_reduce_set_silence_dc(
 	BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
 }
 
+static inline void bw_bd_reduce_set_gate_lin(
+		bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
+		float                             value) {
+	BW_ASSERT(coeffs != BW_NULL);
+	BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
+	BW_ASSERT(bw_is_finite(value));
+	BW_ASSERT(value >= 0.f && value <= 1.f);
+
+	coeffs->gate = value;
+
+	BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
+}
+
+static inline void bw_bd_reduce_set_gate_dBFS(
+		bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
+		float                             value) {
+	BW_ASSERT(coeffs != BW_NULL);
+	BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
+	BW_ASSERT(bw_is_finite(value));
+	BW_ASSERT(value <= 0.f);
+
+	coeffs->gate = bw_dB2linf(value);
+
+	BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
+}
+
 static inline char bw_bd_reduce_coeffs_is_valid(
 		const bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
 	BW_ASSERT(coeffs != BW_NULL);
@@ -439,6 +503,8 @@ static inline char bw_bd_reduce_coeffs_is_valid(
 			return 0;
 		if (!bw_is_finite(coeffs->max) || coeffs->max < 0.5f || coeffs->max > 1.f)
 			return 0;
+		if (!bw_is_finite(coeffs->gate) || coeffs->gate < 0.f || coeffs->gate > 1.f)
+			return 0;
 	}
 #endif
 
@@ -486,6 +552,12 @@ public:
 
 	void setSilenceDc(
 		char value);
+
+	void setGateLin(
+		float value);
+
+	void setGateDBFS(
+		float value);
 /*! <<<...
  *  }
  *  ```
@@ -546,6 +618,18 @@ inline void BDReduce<N_CHANNELS>::setSilenceDc(
 	bw_bd_reduce_set_silence_dc(&coeffs, value);
 }
 
+template<size_t N_CHANNELS>
+inline void BDReduce<N_CHANNELS>::setGateLin(
+		float value) {
+	bw_bd_reduce_set_gate_lin(&coeffs, value);
+}
+
+template<size_t N_CHANNELS>
+inline void BDReduce<N_CHANNELS>::setGateDBFS(
+		float value) {
+	bw_bd_reduce_set_gate_dBFS(&coeffs, value);
+}
+
 }
 #endif