initHEADmain

1 files changed, 342 insertions, 0 deletions

diff --git a/mod/playback.c b/mod/playback.c
new file mode 100644
index 0000000..f9d22ca
--- /dev/null
+++ b/mod/playback.c
@@ -0,0 +1,342 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+#include "sample.h"
+
+#define PLAYBACK_TYPENAME "playback"
+
+struct playback
+{
+	ml_node       *node;
+	struct sample *smp;
+	double         speed;
+	double         phase;
+	bool           active;
+	bool           loop;
+	int            fn;
+	int            arg;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct playback *pb = args->userp;
+
+	if (pb->smp == NULL)
+	{
+		memset(args->out[0],0,sizeof(*args->out[0])*args->nframes);
+		return;
+	}
+
+	unsigned long sr = ml_sample_rate();
+	double phase = pb->phase;
+	float *dst = args->out[0];
+	size_t len = pb->smp->len;
+	float *data = pb->smp->data;
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		if (!pb->active)
+		{
+			memset(&dst[i],0,(args->nframes - i)*sizeof(*dst));
+			return;
+		}
+
+		float t = phase*len;
+
+		size_t i0 = (size_t) t;
+		size_t i1 = i0 + 1;
+		float ip = t - i0;
+
+		i0 %= len;
+		i1 %= len;
+
+		float s0 = data[i0];
+		float s1 = data[i1];
+
+		dst[i] = s0 + ip*(s1 - s0);
+
+		phase += pb->speed/len;
+
+		while (phase > 1)
+		{
+			phase -= 1;
+
+			if (pb->fn != LUA_NOREF)
+			{
+				ml_schedule_event(0,pb->fn,pb->arg);
+
+			}
+
+			if (!pb->loop)
+			{
+				pb->active = false;
+				pb->phase = 0;
+			}
+		}
+
+		while (phase < 0)
+		{
+			phase += 1;
+
+			if (pb->fn != LUA_NOREF)
+			{
+				ml_schedule_event(0,pb->fn,pb->arg);
+
+			}
+
+			if (!pb->loop)
+			{
+				pb->active = false;
+				pb->phase = 0;
+			}
+		}
+	}
+
+	pb->phase = phase;
+}
+
+static int l_init(lua_State *s)
+{
+	struct sample *smp = NULL;
+
+	if (!lua_isnoneornil(s,1))
+	{
+		smp = *(void**) luaL_checkudata(s,1,SAMPLE_TYPENAME);
+	}
+
+	struct playback *pb = calloc(1,sizeof(*pb));
+
+	pb->smp = smp;
+	pb->speed = 1;
+	pb->fn = LUA_NOREF;
+	pb->arg = LUA_NOREF;
+	pb->node = ml_create_node(proc,pb);
+	ml_label_node(pb->node,"playback (%s)",smp ? smp->path : "NULL");
+
+	ml_add_output(pb->node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = pb;
+	luaL_setmetatable(s,PLAYBACK_TYPENAME);
+
+	return 1;
+}
+
+static int l_set_sample(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	struct sample *smp = *(void**) luaL_checkudata(s,2,SAMPLE_TYPENAME);
+	pb->smp = smp;
+	return 0;
+}
+
+static int l_play(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->active = true;
+	return 0;
+}
+
+static int l_pause(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->active = false;
+	return 0;
+}
+
+static int l_reset(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->phase = 0;
+	return 0;
+}
+
+static int l_stop(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->phase = 0;
+	pb->active = false;
+	return 0;
+}
+
+static int l_speed(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+
+	if (!lua_isnil(s,2))
+	{
+		pb->speed = luaL_checknumber(s,2);
+	}
+
+	lua_pushnumber(s,pb->speed);
+	return 1;
+}
+
+static int l_loop(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+
+	if (!lua_isnil(s,2))
+	{
+		luaL_checktype(s,2,LUA_TBOOLEAN);
+		pb->loop = lua_toboolean(s,2);
+	}
+
+	lua_pushboolean(s,pb->loop);
+	return 1;
+}
+
+static int l_phase(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+
+	if (!lua_isnil(s,2))
+	{
+		double phase = luaL_checknumber(s,2);
+
+		if (phase > 1)
+		{
+			phase = 1;
+		}
+
+		if (phase < 0)
+		{
+			phase = 0;
+		}
+
+		pb->phase = phase;
+	}
+
+	lua_pushnumber(s,pb->phase);
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(pb->node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_playback(lua_State *s)
+{
+/*** Audio sample playback.
+
+	local msample = require 'melisma.sample'
+	local mplayback = require 'melisma.playback'
+
+	local sample = msample.load('sample.wav')
+	local playb = mplayback.init(sample)
+
+	playb:loop(true)
+	playb:spped(2)
+	playb:play()
+
+@classmod playback
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Intialize a playback unit.
+@static
+@function init
+@tparam sample|nil smp
+@treturn playback
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Set playback sample.
+@function set_sample
+@tparam sample smp
+*/
+	lua_pushcfunction(s,l_set_sample);
+	lua_setfield(s,tbl,"set_sample");
+
+/*** Start playback.
+@function play
+*/
+	lua_pushcfunction(s,l_play);
+	lua_setfield(s,tbl,"play");
+
+/*** Pause playback.
+@function pause
+*/
+	lua_pushcfunction(s,l_pause);
+	lua_setfield(s,tbl,"pause");
+
+/*** Stop playback.
+
+Equivalent to @{playback.pause}; @{playback.reset}.
+
+@function stop
+*/
+	lua_pushcfunction(s,l_stop);
+	lua_setfield(s,tbl,"stop");
+
+
+/*** Reset playback.
+
+Equivalent to @{playback.phase}(0).
+
+@function reset
+*/
+	lua_pushcfunction(s,l_reset);
+	lua_setfield(s,tbl,"reset");
+
+/*** Set playback speed.
+
+A negative speed will play the sample in reverse.
+
+@function reset
+*/
+	lua_pushcfunction(s,l_speed);
+	lua_setfield(s,tbl,"speed");
+
+/*** Enable/disable automatic looping.
+@function loop
+@tparam bool b
+*/
+	lua_pushcfunction(s,l_loop);
+	lua_setfield(s,tbl,"loop");
+
+/*** Set playback phase.
+@function phase
+@tparam number x Phase ranging from 0 to 1.
+*/
+	lua_pushcfunction(s,l_phase);
+	lua_setfield(s,tbl,"phase");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,PLAYBACK_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}