Fix crash due to undefined MIDI name variable

In ec445fe, the variable song_midi wasn't initialized properly when the greeting window was disabled, causing the program to crash. It's now defined both on startup and in the reset code.

What caused this whole business is the fact that MIDI import happens in two steps: open_midi (parses all the info in the file) and import_midi (converts the data into note blocks after you've picked instruments, etc.) Before the latter occurs, all the song data is reset, which also resets the MIDI filename that was stored on the first step. That made it necessary to remove it from the reset script and, instead, reset the name on unusual places, like in the greeting window and in the call for creating a new song.

Applied solution:
The first variable, midifile, stores the name on the first step. Every reset copies its value to a second variable, song_midi, used only for display. midifile is then set to "". With that, song_midi holds the song name for that session and displays it properly. When a song is created or loaded, a reset will occur and "" will be copied into song_midi, effectively clearing the display.

This also fixes an unintended side effect of how the name was being handled: if you loaded a MIDI but clicked 'Cancel' in the MIDI settings window, the name would still be displayed in song info. To prevent that from happening, the first variable (midifile) is reset when the user clicks 'Cancel', to prevent it from being copied over to the display variable (song_midi) on the next reset.

Author: Bentroen

scripts/control_create/control_create.gml

@@ -47,6 +47,7 @@ tonextbackup = 0
 filename = ""
 changed = 0
 midifile = ""
+song_midi = ""
 for (a = 0; a < 11; a += 1) {
     mididevice_instrument[a] = -1
     recent_song[a] = ""

scripts/draw_window_greeting/draw_window_greeting.gml

@@ -76,7 +76,7 @@ a += (a && (mouse_check_button(mb_left) || mouse_check_button_released(mb_left))
 draw_sprite(spr_frame2, a + 3 * theme, b, c)
 draw_sprite(spr_bigicons, 0, b + (a > 1), c + (a > 1))
 draw_text(b + 48 + (a > 1), c + 9 + (a > 1), "Create a new song")
-if (a = 2 && mouse_check_button_released(mb_left)) window = 0 song_midi = ""
+if (a = 2 && mouse_check_button_released(mb_left)) window = 0
 
 c += 44
 b = x1 + 300

scripts/draw_window_midi_import/draw_window_midi_import.gml

@@ -21,7 +21,7 @@ if (draw_checkbox(x1 + 300, y1 + 72, w_midi_octave, "Keep within octave range",
 if (draw_checkbox(x1 + 300, y1 + 92, w_midi_vel, "Read note velocity", "Whether to copy the volume data found\nin each MIDI note.") && wmenu = 0) w_midi_vel=!w_midi_vel
 if (draw_checkbox(x1 + 12, y1 + 374, w_midi_remember, "Remember changes", "Whether to use these settings the\nnext time you import a MIDI file.") && wmenu = 0) w_midi_remember=!w_midi_remember
 if (draw_button2(x1 + 520, y1 + 368, 72, "Import") && wmenu = 0) {w_midi_tab = 0 window = -1 import_midi()}
-if (draw_button2(x1 + 520 - 80, y1 + 368, 72, "Cancel") && wmenu = 0) {w_midi_tab = 0 window = 0}
+if (draw_button2(x1 + 520 - 80, y1 + 368, 72, "Cancel") && wmenu = 0) {midifile = "" w_midi_tab = 0 window = 0}
 if (draw_button2(x1 + 520 - 160, y1 + 368, 72, "Use default") && wmenu = 0) {
     if (question("Are you sure?", "Confirm")) { 
         midi_instruments()

scripts/load_song/load_song.gml

@@ -86,9 +86,7 @@ if (file_ext = ".nbs") {
     a = buffer_read_int()
     work_remove = max(0, a)
     // MIDI FILENAME
-    a = buffer_read_string_int()
-    if (filename_ext(a) = ".mid" || filename_ext(a) = ".midi") song_midi = a
-	else song_midi = ""
+    song_midi = buffer_read_string_int()
 	// LOOP
 	if (song_nbs_version >= 4) {
 		loop = buffer_read_byte()

scripts/new_song/new_song.gml

@@ -1,5 +1,4 @@
 // new_song()
-song_midi = ""
 if (confirm() > -1) {
 	reset()
 	backup_clear()

scripts/open_midi/open_midi.gml

@@ -25,7 +25,6 @@ if (r != 0 && r != 1 && r != 2) {message("Error loading MIDI file:\n\nFormat not
 
 midi_tracks = buffer_read_short_be()
 midifile = filename_name(fn)
-song_midi = string(midifile)
 midi_trackamount[midi_tracks] = 0
 reset_midi()
 midi_tempo = buffer_read_short_be()

scripts/reset/reset.gml

@@ -26,6 +26,7 @@ for (a = 0; a <= enda; a += 1) {
 // File
 filename = ""
 changed = 0
+song_midi = midifile
 midifile = ""
 
 // Playback