1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/*
* 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 <string.h>
#include <stdlib.h>
#include <math.h>
#include <lauxlib.h>
#include "melisma.h"
#include "mutil.h"
#define GAIN_TYPENAME "gain"
struct gain
{
ml_node *node;
float value;
int mapped;
int db;
};
static void proc(const ml_proc_args *args)
{
struct gain *gain = args->userp;
float *in = args->in[0];
float *out = args->out[0];
float *mapped = gain->mapped ? args->in[1] : NULL;
float v;
for (size_t i = 0; i < args->nframes; i++)
{
v = mapped ? mapped[i] : gain->value;
if (gain->db)
{
v = powf(10,v/20.f);
}
out[i] = v*in[i];
}
}
static int l_init(lua_State *s)
{
int db_i = lua_upvalueindex(1);
int db = lua_tointeger(s,db_i);
ml_channel *audio_src, *mapped_src = NULL;
ml_channel *audio_dst, *mapped_dst;
float value = 0;
if (lua_isuserdata(s,1))
{
mapped_src = mutil_get_channel(s,1);
}
else
{
value = luaL_checknumber(s,1);
}
audio_src = mutil_get_channel(s,2);
struct gain *gain = calloc(1,sizeof(*gain));
gain->value = value;
gain->mapped = mapped_src != NULL;
gain->db = db;
ml_node *node = ml_create_node(proc,gain);
ml_label_node(node,"gain");
gain->node = node;
ml_add_output(node);
audio_dst = ml_add_input(node);
ml_connect(audio_src,audio_dst);
if (mapped_src)
{
mapped_dst = ml_add_input(node);
ml_connect(mapped_src,mapped_dst);
}
*(void**) lua_newuserdata(s,sizeof(void*)) = gain;
luaL_setmetatable(s,GAIN_TYPENAME);
return 1;
}
static int l_out(lua_State *s)
{
struct gain *gain = *(void**) luaL_checkudata(s,1,GAIN_TYPENAME);
*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(gain->node,0);
luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
return 1;
}
int luaopen_melisma_gain(lua_State *s)
{
ml_check_version();
/*** Apply gain to signals.
local mgain = require 'melisma.gain'
-- Interprets `cntl` as decibels and applies it to `input`
local input = ...
local cntl = ...
local gain = mgain.db(input,cntl)
@classmod gain
*/
lua_newtable(s);
int tbl = lua_gettop(s);
/*** Creates a linear gain unit.
@static
@function linear
@tparam channel input Input signal.
@tparam number|channel gain Constant gain or a controlling signal.
@treturn gain The newly created gain unit.
*/
lua_pushinteger(s,0);
lua_pushcclosure(s,l_init,1);
lua_setfield(s,tbl,"linear");
/*** Creates a decibel gain unit.
@static
@function db
@tparam channel input Input signal.
@tparam number|channel gain Constant gain in decibels or a controlling signal.
@treturn gain The newly created gain unit.
*/
lua_pushinteger(s,1);
lua_pushcclosure(s,l_init,1);
lua_setfield(s,tbl,"db");
lua_pushcfunction(s,l_out);
lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
luaL_newmetatable(s,GAIN_TYPENAME);
int mt = lua_gettop(s);
lua_pushvalue(s,tbl);
lua_setfield(s,mt,"__index");
lua_settop(s,tbl);
return 1;
}
|
