From 7454c4146395b32008a47c5fa0893a1bbe58c9c7 Mon Sep 17 00:00:00 2001
From: TheoryOfNekomata <allan.crisostomo@outlook.com>
Date: Sun, 29 May 2022 13:36:24 +0800
Subject: [PATCH] Add channel config

Allow MIDI input to be filtered through MIDI channels.
---
 docs/reference/files/config.ini   |  1 +
 src/packages/game/input/IZ_midi.c | 20 ++++++++++++++++++--
 src/packages/game/input/IZ_midi.h |  1 +
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/docs/reference/files/config.ini b/docs/reference/files/config.ini
index b7dff61..c583719 100644
--- a/docs/reference/files/config.ini
+++ b/docs/reference/files/config.ini
@@ -53,4 +53,5 @@ Action7=G4
 Action8="G#4"
 Action9=A4
 [MIDIInput.0]
+Channel=0
 DeviceID=0
diff --git a/src/packages/game/input/IZ_midi.c b/src/packages/game/input/IZ_midi.c
index 7845d42..e4f712a 100644
--- a/src/packages/game/input/IZ_midi.c
+++ b/src/packages/game/input/IZ_midi.c
@@ -63,12 +63,18 @@ uint8_t IZ_GetMIDINoteFromName(char* name) {
 void IZ_HandleMIDINoteOnOffEvents(PmEvent e, IZ_MIDIInputState* state, IZ_Action* action) {
 	uint32_t message = e.message;
 	uint8_t status = message & 0xF0u;
-	// uint8_t channel = message & 0x0Fu;
+	uint8_t channel = message & 0x0Fu;
 	uint8_t data1 = (message >> 8) & 0xFFu;
 	// uint8_t data2 = (message >> 16) & 0xFFu;
 
 	for (uint8_t i = 0; i < CONTROLS; i += 1) {
-		if (data1 == state->config.control_mapping[i]) {
+		if (
+			data1 == state->config.control_mapping[i]
+			&& (
+				(state->config.channel < 16 && channel == state->config.channel)
+				|| state->config.channel >= 16
+			)
+		) {
 			const uint16_t bitflag = (0x1 << i);
 			if (status == IZ_MIDI_NOTE_ON) {
 				*action |= bitflag;
@@ -108,6 +114,15 @@ IZ_ProcedureResult IZ_SaveMIDIInputConfig(const char* config_path, IZ_MIDIInputS
 		}
 
 		sprintf_s(main_section_name, 12, "MIDIInput.%d", player_index);
+		if (!ini_putl(
+			main_section_name,
+			"Channel",
+			state[player_index]->config.channel,
+			config_path
+		)) {
+			problem |= (1 << player_index);
+		}
+
 		if (!ini_putl(
 			main_section_name,
 			"DeviceID",
@@ -142,6 +157,7 @@ void IZ_LoadMIDIInputConfig(const char* config_path, IZ_MIDIInputState(* state)[
 		}
 
 		sprintf_s(main_section_name, 12, "MIDIInput.%d", player_index);
+		state[player_index]->config.channel = ini_getl(main_section_name, "Channel", player_index, config_path);
 		state[player_index]->config.device_id = ini_getl(main_section_name, "DeviceID", player_index, config_path);
 	}
 }
diff --git a/src/packages/game/input/IZ_midi.h b/src/packages/game/input/IZ_midi.h
index 5face3e..63d1f3f 100644
--- a/src/packages/game/input/IZ_midi.h
+++ b/src/packages/game/input/IZ_midi.h
@@ -16,6 +16,7 @@ static const uint8_t IZ_MIDI_NOTE_OFF = 0x80u;
 
 typedef struct {
 	PmDeviceID device_id;
+	uint8_t channel;
 	IZ_MIDINote control_mapping[CONTROLS];
 } IZ_MIDIInputConfig;