← Back to branch summary

~ubuntu-branches/ubuntu/hoary/kdemultimedia/hoary

« back to all changes in this revision

Viewing changes to arts/modules/synth_envelope_adsr_impl.cc

  • Committer: Bazaar Package Importer
  • Author(s): Martin Schulze
  • Date: 2003-01-22 15:00:51 UTC
  • Revision ID: james.westby@ubuntu.com-20030122150051-uihwkdoxf15mi1tn
Tags: upstream-2.2.2
Import upstream version 2.2.2

Show diffs side-by-side

added added

removed removed

Lines of Context:
arts/modules/synth_envelope_adsr_impl.cc
 
1
    /*
 
2
 
 
3
    Copyright (C) 2000 Stefan Westerfeld
 
4
                       stefan@space.twc.de
 
5
 
 
6
    This library is free software; you can redistribute it and/or
 
7
    modify it under the terms of the GNU Library General Public
 
8
    License as published by the Free Software Foundation; either
 
9
    version 2 of the License, or (at your option) any later version.
 
10
  
 
11
    This library is distributed in the hope that it will be useful,
 
12
    but WITHOUT ANY WARRANTY; without even the implied warranty of
 
13
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 
14
    Library General Public License for more details.
 
15
   
 
16
    You should have received a copy of the GNU Library General Public License
 
17
    along with this library; see the file COPYING.LIB.  If not, write to
 
18
    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 
19
    Boston, MA 02111-1307, USA.
 
20
 
 
21
    */
 
22
 
 
23
#include "artsmodules.h"
 
24
#include "debug.h"
 
25
#include "stdsynthmodule.h"
 
26
 
 
27
using namespace Arts;
 
28
 
 
29
class Synth_ENVELOPE_ADSR_impl : virtual public Synth_ENVELOPE_ADSR_skel,
 
30
                                                        virtual public StdSynthModule
 
31
{
 
32
protected:
 
33
        enum { NOOUT, ATTACK, SUSTAIN, DECAY, RELEASE } currentphase;
 
34
        float level,increment,decrement;
 
35
public:
 
36
        void streamInit()
 
37
        {
 
38
                currentphase = NOOUT;
 
39
                level = 0;
 
40
        }
 
41
        void calculateBlock(unsigned long samples);
 
42
};
 
43
 
 
44
void Synth_ENVELOPE_ADSR_impl::calculateBlock(unsigned long samples)
 
45
{
 
46
        /* FIXME:
 
47
     * should be rewritten as generic envelope, would certainly
 
48
         * be faster & more flexible
 
49
         */
 
50
        unsigned long i;
 
51
 
 
52
        for(i=0;i<samples;i++)
 
53
        {
 
54
                done[i] = 0;
 
55
                if(active[i] < 0.5)
 
56
                {
 
57
                        if(currentphase == NOOUT)
 
58
                        {
 
59
                                level = 0;
 
60
                                done[i] = 1;
 
61
                        }
 
62
                        else
 
63
                        {
 
64
                                if(currentphase != RELEASE) {
 
65
                                        artsdebug("ADSR: entering release phase\n");
 
66
                                        currentphase = RELEASE;
 
67
                                        decrement = level / (release[i] * samplingRateFloat);
 
68
                                }
 
69
                                level -= decrement;
 
70
                                if(level <= 0)
 
71
                                {
 
72
                                        level = 0;
 
73
                                        currentphase = NOOUT;
 
74
                                }
 
75
                        }
 
76
                }
 
77
                else
 
78
                {
 
79
                        switch(currentphase)
 
80
                        {
 
81
                                //quickly kill the note that is still there (channel busy ;)
 
82
                                case RELEASE:
 
83
                                                level -= 1/200;
 
84
                                                if(level <= 0) {
 
85
                                                        currentphase = NOOUT;
 
86
                                                        level = 0;
 
87
                                                }
 
88
                                        break;
 
89
                                case NOOUT:
 
90
                                                artsdebug("ADSR: entering attack\n");
 
91
                                                increment = 1 / (attack[i] * samplingRateFloat);
 
92
                                                currentphase = ATTACK;
 
93
                                        break;
 
94
                                case ATTACK:
 
95
                                                level += increment;
 
96
                                                if (level >= 1)
 
97
                                                {
 
98
                                                        level = 1;
 
99
                                                        currentphase = DECAY;
 
100
                                                        decrement = (1-sustain[i]) /
 
101
                                                                                (decay[i] * samplingRateFloat);
 
102
                                                }
 
103
                                        break;
 
104
                                case DECAY:
 
105
                                                level -= decrement;
 
106
                                                if (level <= sustain[i])
 
107
                                                {
 
108
                                                        level = sustain[i];
 
109
                                                        currentphase = SUSTAIN;
 
110
                                                }
 
111
                                        break;
 
112
                                case SUSTAIN:
 
113
                                                level = sustain[i];
 
114
                                        break;
 
115
                        }
 
116
                }
 
117
                outvalue[i] = invalue[i] * level;
 
118
        }
 
119
}
 
120
 
 
121
REGISTER_IMPLEMENTATION(Synth_ENVELOPE_ADSR_impl);