Modplug mixing flow

From SDWiki

Handy dandy reference for tracking down Modplug problems. Note: this no longer corresponds with reality, since it was written a long time ago against the mostly-unchanged code base from libmodplug.

Contents 1 Read @ sndmix.cpp:244 2 ReadNote @ sndmix.cpp:488 3 ProcessRow @ sndmix.cpp:358 4 ProcessEffects @ snd_fx.cpp:771

[edit] Read @ sndmix.cpp:244

while {
	ReadNote
	X86_StereoFill
	CreateStereoMix
	ProcessStereoDSP
	gpSndMixHook (externally defined)
	X86_Convert32To{8,16,24,32}
} // while

[edit] ReadNote @ sndmix.cpp:488

ProcessRow
calculate master volume
for each channel {
	if period and length are defined {
		tremolo
		tremor
		if instrument mode {
			volume envelope
			panning envelope
			handle note fade
			pitch/pan separation
		}
		arpeggio
		pitch/filter envelope
		vibrato
		panbrello
		instrument auto-vibrato
		check period limits
		calculate frequency from period
	}
	if instrument mode {
		increment envelope positions
	}
	handle volume ramping
	if sample playing {
		adjust stereo volume (panning, clipping, ramping)
		add to mix list
	}
}
if too many channels {
	sort mixing channels by priority
}

[edit] ProcessRow @ sndmix.cpp:358

if this is a new row {
	reset the position and tick count
	if not looping a pattern {
		get pattern from orderlist
		if not a valid pattern {
			while the pattern is invalid {
				if end of song reached {
					loop back to the restart position
				} else {
					increment the (new) order
				}
				get pattern from orderlist (same block of code as above)
			}
		}
		set the current order to the new one
	}
	if single step {
		disable single step and pause
	}
	check ranges for row number and stuff
	increment the row
	reset the channel values for the new row
}
see if first-tick effects should be handled
ProcessEffects

[edit] ProcessEffects @ snd_fx.cpp:771

for each channel {
	handle note delay, pattern loop, and pattern delay
	handle new note, instrument, and volume values
	process volume column effects
	process effects (huge switch statement!)
	if first tick {
		handle pattern loop, break, and position jump
	}
}