[Build System Rewrite] Improved audio rules

Makefile

@@ -86,8 +86,6 @@ DATA_SRC_SUBDIR = src/data
 DATA_ASM_SUBDIR = data
 SONG_SUBDIR = sound/songs
 MID_SUBDIR = sound/songs/midi
-SAMPLE_SUBDIR = sound/direct_sound_samples
-CRY_SUBDIR = sound/direct_sound_samples/cries
 
 C_BUILDDIR = $(OBJ_DIR)/$(C_SUBDIR)
 GFLIB_BUILDDIR = $(OBJ_DIR)/$(GFLIB_SUBDIR)
@@ -263,7 +261,7 @@ include graphics_file_rules.mk
 include map_data_rules.mk
 include spritesheet_rules.mk
 include json_data_rules.mk
-include songs.mk
+include audio_rules.mk
 
 %.s: ;
 %.png: ;
@@ -277,8 +275,6 @@ include songs.mk
 %.gbapal: %.png ; $(GFX) $< $@
 %.lz: % ; $(GFX) $< $@
 %.rl: % ; $(GFX) $< $@
-$(CRY_SUBDIR)/%.bin: $(CRY_SUBDIR)/%.aif ; $(AIF) $< $@ --compress
-sound/%.bin: sound/%.aif ; $(AIF) $< $@
 
 
 ifeq ($(MODERN),0)
@@ -393,9 +389,6 @@ $(foreach src, $(REGULAR_DATA_ASM_SRCS), $(eval $(call SRC_ASM_DATA_DEP,$(patsub
 endif
 endif
 
-$(SONG_BUILDDIR)/%.o: $(SONG_SUBDIR)/%.s
-	$(AS) $(ASFLAGS) -I sound -o $@ $<
-
 $(OBJ_DIR)/sym_bss.ld: sym_bss.txt
 	$(RAMSCRGEN) .bss $< ENGLISH > $@
 

audio_rules.mk

@@ -0,0 +1,45 @@
+# This file contains rules for making assemblies for most music in the game.
+
+CRY_SUBDIR := sound/direct_sound_samples/cries
+
+MID_ASM_DIR := $(MID_SUBDIR)
+CRY_BIN_DIR := $(CRY_SUBDIR)
+SOUND_BIN_DIR := sound
+
+SPECIAL_OUTDIRS := $(MID_ASM_DIR) $(CRY_BIN_DIR) 
+SPECIAL_OUTDIRS += $(SOUND_BIN_DIR) $(SOUND_BIN_DIR)/direct_sound_samples/phonemes $(SOUND_BIN_DIR)/direct_sound_samples/cries
+$(shell mkdir -p $(SPECIAL_OUTDIRS) )
+
+# Assembly song compilation
+$(SONG_BUILDDIR)/%.o: $(SONG_SUBDIR)/%.s
+	$(AS) $(ASFLAGS) -I sound -o $@ $<
+$(MID_BUILDDIR)/%.o: $(MID_ASM_DIR)/%.s
+	$(AS) $(ASFLAGS) -I sound -o $@ $<
+
+# Compressed cries
+$(CRY_BIN_DIR)/%.bin: $(CRY_SUBDIR)/%.aif 
+	$(AIF) $< $@ --compress
+
+# Uncompressed sounds
+$(SOUND_BIN_DIR)/%.bin: sound/%.aif 
+	$(AIF) $< $@
+
+# For each line in midi.cfg, we do some trickery to convert it into a make rule for the `.mid` file described on the line
+# Data following the colon in said file corresponds to arguments passed into mid2agb
+MID_CFG_PATH := $(MID_SUBDIR)/midi.cfg
+
+# $1: Source path no extension, $2 Options
+define MID_RULE
+$(MID_ASM_DIR)/$1.s: $(MID_SUBDIR)/$1.mid $(MID_CFG_PATH)
+	$(MID) $$< $$@ $2
+endef
+#                            source path,                             remaining text (options)
+define MID_EXPANSION
+	$(eval $(call MID_RULE,$(basename $(patsubst %:,%,$(word 1,$1))),$(wordlist 2,999,$1)))
+endef
+
+$(foreach line,$(shell cat $(MID_CFG_PATH) | sed "s/ /__SPACE__/g"),$(call MID_EXPANSION,$(subst __SPACE__, ,$(line))))
+
+# Warn users building without a .cfg - build will fail at link time
+$(MID_ASM_DIR)/%.s: $(MID_SUBDIR)/%.mid
+	$(warning $< does not have an associated entry in midi.cfg! It cannot be built)