Style: Partially apply clang-tidy's `cppcoreguidelines-pro-type-member-init`

Didn't commit all the changes where it wants to initialize a struct
with `{}`. Should be reviewed in a separate PR.

Option `IgnoreArrays` enabled for now to be conservative, can be
disabled to see if it proposes more useful changes.

Also fixed manually a handful of other missing initializations / moved
some from constructors.

8 files changed, 40 insertions, 53 deletions

diff --git a/servers/audio/audio_filter_sw.cpp b/servers/audio/audio_filter_sw.cpp
index 082931647a..003275f302 100644
--- a/servers/audio/audio_filter_sw.cpp
+++ b/servers/audio/audio_filter_sw.cpp
@@ -211,15 +211,6 @@ float AudioFilterSW::get_response(float p_freq, Coeffs *p_coeffs) {
 	return H;
 }
 
-AudioFilterSW::AudioFilterSW() {
-	sampling_rate = 44100;
-	resonance = 0.5;
-	cutoff = 5000;
-	gain = 1.0;
-	mode = LOWPASS;
-	stages = 1;
-}
-
 AudioFilterSW::Processor::Processor() {
 	set_filter(nullptr);
 }
diff --git a/servers/audio/audio_filter_sw.h b/servers/audio/audio_filter_sw.h
index 1ec1abd4d5..e3f8188997 100644
--- a/servers/audio/audio_filter_sw.h
+++ b/servers/audio/audio_filter_sw.h
@@ -36,11 +36,11 @@
 class AudioFilterSW {
 public:
 	struct Coeffs {
-		float a1, a2;
-		float b0, b1, b2;
-
-		//bool operator==(const Coeffs &p_rv) { return (FLOATS_EQ(a1,p_rv.a1) && FLOATS_EQ(a2,p_rv.a2) && FLOATS_EQ(b1,p_rv.b1) && FLOATS_EQ(b2,p_rv.b2) && FLOATS_EQ(b0,p_rv.b0) ); }
-		Coeffs() { a1 = a2 = b0 = b1 = b2 = 0.0; }
+		float a1 = 0.0f;
+		float a2 = 0.0f;
+		float b0 = 0.0f;
+		float b1 = 0.0f;
+		float b2 = 0.0f;
 	};
 
 	enum Mode {
@@ -52,14 +52,16 @@ public:
 		BANDLIMIT,
 		LOWSHELF,
 		HIGHSHELF
-
 	};
 
-	class Processor { // simple filter processor
-
+	class Processor { // Simple filter processor.
 		AudioFilterSW *filter = nullptr;
 		Coeffs coeffs;
-		float ha1, ha2, hb1, hb2; //history
+		// History.
+		float ha1 = 0.0f;
+		float ha2 = 0.0f;
+		float hb1 = 0.0f;
+		float hb2 = 0.0f;
 		Coeffs incr_coeffs;
 
 	public:
@@ -73,12 +75,12 @@ public:
 	};
 
 private:
-	float cutoff;
-	float resonance;
-	float gain;
-	float sampling_rate;
-	int stages;
-	Mode mode;
+	float cutoff = 5000.0f;
+	float resonance = 0.5f;
+	float gain = 1.0f;
+	float sampling_rate = 44100.0f;
+	int stages = 1;
+	Mode mode = LOWPASS;
 
 public:
 	float get_response(float p_freq, Coeffs *p_coeffs);
@@ -92,7 +94,7 @@ public:
 
 	void prepare_coefficients(Coeffs *p_coeffs);
 
-	AudioFilterSW();
+	AudioFilterSW() {}
 };
 
 /* inline methods */
diff --git a/servers/audio/audio_stream.cpp b/servers/audio/audio_stream.cpp
index 1ebd57fa7f..9a9b9815ae 100644
--- a/servers/audio/audio_stream.cpp
+++ b/servers/audio/audio_stream.cpp
@@ -709,10 +709,7 @@ void AudioStreamRandomizer::_bind_methods() {
 	BIND_ENUM_CONSTANT(PLAYBACK_SEQUENTIAL);
 }
 
-AudioStreamRandomizer::AudioStreamRandomizer() {
-	random_pitch_scale = 1.1;
-	random_volume_offset_db = 5;
-}
+AudioStreamRandomizer::AudioStreamRandomizer() {}
 
 void AudioStreamPlaybackRandomizer::start(float p_from_pos) {
 	playing = playback;
diff --git a/servers/audio/audio_stream.h b/servers/audio/audio_stream.h
index 55031dec2c..9800707849 100644
--- a/servers/audio/audio_stream.h
+++ b/servers/audio/audio_stream.h
@@ -78,7 +78,7 @@ class AudioStreamPlaybackResampled : public AudioStreamPlayback {
 
 	AudioFrame internal_buffer[INTERNAL_BUFFER_LEN + CUBIC_INTERP_HISTORY];
 	unsigned int internal_buffer_end = -1;
-	uint64_t mix_offset;
+	uint64_t mix_offset = 0;
 
 protected:
 	void begin_resample();
@@ -145,8 +145,8 @@ class AudioStreamPlaybackMicrophone : public AudioStreamPlaybackResampled {
 	GDCLASS(AudioStreamPlaybackMicrophone, AudioStreamPlaybackResampled);
 	friend class AudioStreamMicrophone;
 
-	bool active;
-	unsigned int input_ofs;
+	bool active = false;
+	unsigned int input_ofs = 0;
 
 	Ref<AudioStreamMicrophone> microphone;
 
@@ -194,8 +194,8 @@ private:
 
 	Set<AudioStreamPlaybackRandomizer *> playbacks;
 	Vector<PoolEntry> audio_stream_pool;
-	float random_pitch_scale;
-	float random_volume_offset_db;
+	float random_pitch_scale = 1.1f;
+	float random_volume_offset_db = 5.0f;
 
 	Ref<AudioStreamPlayback> instance_playback_random();
 	Ref<AudioStreamPlayback> instance_playback_no_repeats();
diff --git a/servers/audio/effects/audio_effect_stereo_enhance.cpp b/servers/audio/effects/audio_effect_stereo_enhance.cpp
index c81efc55e2..7bb62bcbed 100644
--- a/servers/audio/effects/audio_effect_stereo_enhance.cpp
+++ b/servers/audio/effects/audio_effect_stereo_enhance.cpp
@@ -29,7 +29,9 @@
 /*************************************************************************/
 
 #include "audio_effect_stereo_enhance.h"
+
 #include "servers/audio_server.h"
+
 void AudioEffectStereoEnhanceInstance::process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) {
 	float intensity = base->pan_pullout;
 	bool surround_mode = base->surround > 0;
@@ -140,8 +142,4 @@ void AudioEffectStereoEnhance::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "surround", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_surround", "get_surround");
 }
 
-AudioEffectStereoEnhance::AudioEffectStereoEnhance() {
-	pan_pullout = 1;
-	time_pullout = 0;
-	surround = 0;
-}
+AudioEffectStereoEnhance::AudioEffectStereoEnhance() {}
diff --git a/servers/audio/effects/audio_effect_stereo_enhance.h b/servers/audio/effects/audio_effect_stereo_enhance.h
index 1f93d1cf9f..30ea11f625 100644
--- a/servers/audio/effects/audio_effect_stereo_enhance.h
+++ b/servers/audio/effects/audio_effect_stereo_enhance.h
@@ -28,8 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#ifndef AUDIOEFFECTSTEREOENHANCE_H
-#define AUDIOEFFECTSTEREOENHANCE_H
+#ifndef AUDIO_EFFECT_STEREO_ENHANCE_H
+#define AUDIO_EFFECT_STEREO_ENHANCE_H
 
 #include "servers/audio/audio_effect.h"
 
@@ -45,8 +45,8 @@ class AudioEffectStereoEnhanceInstance : public AudioEffectInstance {
 	};
 
 	float *delay_ringbuff = nullptr;
-	unsigned int ringbuff_pos;
-	unsigned int ringbuff_mask;
+	unsigned int ringbuff_pos = 0;
+	unsigned int ringbuff_mask = 0;
 
 public:
 	virtual void process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) override;
@@ -58,11 +58,11 @@ class AudioEffectStereoEnhance : public AudioEffect {
 	GDCLASS(AudioEffectStereoEnhance, AudioEffect);
 
 	friend class AudioEffectStereoEnhanceInstance;
-	float volume_db;
+	float volume_db = 0.0f;
 
-	float pan_pullout;
-	float time_pullout;
-	float surround;
+	float pan_pullout = 1.0f;
+	float time_pullout = 0.0f;
+	float surround = 0.0f;
 
 protected:
 	static void _bind_methods();
@@ -82,4 +82,4 @@ public:
 	AudioEffectStereoEnhance();
 };
 
-#endif // AUDIOEFFECTSTEREOENHANCE_H
+#endif // AUDIO_EFFECT_STEREO_ENHANCE_H
diff --git a/servers/audio/effects/reverb.cpp b/servers/audio/effects/reverb.cpp
index 4b5b9ab79f..adfd648514 100644
--- a/servers/audio/effects/reverb.cpp
+++ b/servers/audio/effects/reverb.cpp
@@ -28,8 +28,6 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-// Author: Juan Linietsky <reduzio@gmail.com>, (C) 2006
-
 #include "reverb.h"
 
 #include "core/math/math_funcs.h"
diff --git a/servers/audio/effects/reverb.h b/servers/audio/effects/reverb.h
index de25e8c52b..c9602c5b5a 100644
--- a/servers/audio/effects/reverb.h
+++ b/servers/audio/effects/reverb.h
@@ -77,10 +77,11 @@ private:
 	AllPass allpass[MAX_ALLPASS];
 	float *input_buffer = nullptr;
 	float *echo_buffer = nullptr;
-	int echo_buffer_size;
-	int echo_buffer_pos;
+	int echo_buffer_size = 0;
+	int echo_buffer_pos = 0;
 
-	float hpf_h1, hpf_h2 = 0;
+	float hpf_h1 = 0.0f;
+	float hpf_h2 = 0.0f;
 
 	struct Parameters {
 		float room_size;