/[svn]/linuxsampler/trunk/src/voice.h
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Contents of /linuxsampler/trunk/src/voice.h

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Revision 26 - (show annotations) (download) (as text)
Fri Dec 26 16:39:58 2003 UTC (20 years, 3 months ago) by schoenebeck
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File size: 8606 byte(s)
* implemented looping; RAM only loops (that is loops that end within the
  cached part of the sample) are handled in src/voice.cpp whereas
  disk stream looping is handled in src/stream.cpp and is mostly covered
  there by the new ReadAndLoop() method in class 'Sample' from src/gig.cpp

1 /***************************************************************************
2 * *
3 * LinuxSampler - modular, streaming capable sampler *
4 * *
5 * Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck *
6 * *
7 * This program is free software; you can redistribute it and/or modify *
8 * it under the terms of the GNU General Public License as published by *
9 * the Free Software Foundation; either version 2 of the License, or *
10 * (at your option) any later version. *
11 * *
12 * This program is distributed in the hope that it will be useful, *
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15 * GNU General Public License for more details. *
16 * *
17 * You should have received a copy of the GNU General Public License *
18 * along with this program; if not, write to the Free Software *
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20 * MA 02111-1307 USA *
21 ***************************************************************************/
22
23 #ifndef __VOICE_H__
24 #define __VOICE_H__
25
26 #include "global.h"
27 #include "diskthread.h"
28 #include "ringbuffer.h"
29 #include "stream.h"
30 #include "gig.h"
31
32 #define MAX_PITCH 4 //FIXME: at the moment in octaves, should be changed into semitones
33 #define USE_LINEAR_INTERPOLATION 1 ///< set to 0 if you prefer cubic interpolation (slower, better quality)
34
35 class Voice {
36 public:
37 // Attributes
38 int MIDIKey; ///< MIDI key number of the key that triggered the voice
39 Voice** pSelfPtr; ///< FIXME: hack to be able to remove the voice from the active voices list within the audio thread, ugly but fast
40 uint ReleaseVelocity; ///< Reflects the release velocity value if a note-off command arrived for the voice.
41
42 // Methods
43 Voice(DiskThread* pDiskThread);
44 ~Voice();
45 void Kill();
46 void RenderAudio();
47 int Trigger(int MIDIKey, uint8_t Velocity, gig::Instrument* Instrument);
48 inline bool IsActive() { return Active; }
49 inline void SetOutput(float* pOutput, uint OutputBufferSize) { this->pOutput = pOutput; this->OutputBufferSize = OutputBufferSize; }
50 private:
51 // Types
52 enum playback_state_t {
53 playback_state_ram,
54 playback_state_disk,
55 playback_state_end
56 };
57
58 // Attributes
59 float Volume; ///< Volume level of the voice
60 float* pOutput; ///< Audio output buffer
61 uint OutputBufferSize; ///< Fragment size of the audio output buffer
62 double Pos; ///< Current playback position in sample
63 double CurrentPitch; ///< Current pitch depth (number of sample points to move on with each render step)
64 gig::Sample* pSample; ///< Pointer to the sample to be played back
65 gig::Region* pRegion; ///< Pointer to the articulation information of the respective keyboard region of this voice
66 bool Active; ///< If this voice object is currently in usage
67 playback_state_t PlaybackState; ///< When a sample will be triggered, it will be first played from RAM cache and after a couple of sample points it will switch to disk streaming and at the end of a disk stream we have to add null samples, so the interpolator can do it's work correctly
68 bool DiskVoice; ///< If the sample is very short it completely fits into the RAM cache and doesn't need to be streamed from disk, in that case this flag is set to false
69 Stream::reference_t DiskStreamRef; ///< Reference / link to the disk stream
70 unsigned long MaxRAMPos; ///< The upper allowed limit (not actually the end) in the RAM sample cache, after that point it's not safe to chase the interpolator another time over over the current cache position, instead we switch to disk then.
71 bool RAMLoop; ///< If this voice has a loop defined which completely fits into the cached RAM part of the sample, in this case we handle the looping within the voice class, else if the loop is located in the disk stream part, we let the disk stream handle the looping
72 int LoopCyclesLeft; ///< In case there is a RAMLoop and it's not an endless loop; reflects number of loop cycles left to be passed
73
74 // Static Attributes
75 static DiskThread* pDiskThread; ///< Pointer to the disk thread, to be able to order a disk stream and later to delete the stream again
76
77 // Methods
78 void Interpolate(sample_t* pSrc);
79 void InterpolateAndLoop(sample_t* pSrc);
80 inline void InterpolateOneStep_Stereo(sample_t* pSrc, int& i, float& effective_volume) {
81 int pos_int = double_to_int(this->Pos); // integer position
82 float pos_fract = this->Pos - pos_int; // fractional part of position
83 pos_int <<= 1;
84
85 #if USE_LINEAR_INTERPOLATION
86 // left channel
87 this->pOutput[i++] += effective_volume * (pSrc[pos_int] + pos_fract * (pSrc[pos_int+2] - pSrc[pos_int]));
88 // right channel
89 this->pOutput[i++] += effective_volume * (pSrc[pos_int+1] + pos_fract * (pSrc[pos_int+3] - pSrc[pos_int+1]));
90 #else // polynomial interpolation
91 // calculate left channel
92 float xm1 = pSrc[pos_int];
93 float x0 = pSrc[pos_int+2];
94 float x1 = pSrc[pos_int+4];
95 float x2 = pSrc[pos_int+6];
96 float a = (3 * (x0 - x1) - xm1 + x2) / 2;
97 float b = 2 * x1 + xm1 - (5 * x0 + x2) / 2;
98 float c = (x1 - xm1) / 2;
99 this->pOutput[i++] += effective_volume * ((((a * pos_fract) + b) * pos_fract + c) * pos_fract + x0);
100
101 //calculate right channel
102 xm1 = pSrc[pos_int+1];
103 x0 = pSrc[pos_int+3];
104 x1 = pSrc[pos_int+5];
105 x2 = pSrc[pos_int+7];
106 a = (3 * (x0 - x1) - xm1 + x2) / 2;
107 b = 2 * x1 + xm1 - (5 * x0 + x2) / 2;
108 c = (x1 - xm1) / 2;
109 this->pOutput[i++] += effective_volume * ((((a * pos_fract) + b) * pos_fract + c) * pos_fract + x0);
110 #endif // USE_LINEAR_INTERPOLATION
111
112 this->Pos += this->CurrentPitch;
113 }
114 inline void InterpolateOneStep_Mono(sample_t* pSrc, int& i, float& effective_volume) {
115 int pos_int = double_to_int(this->Pos); // integer position
116 float pos_fract = this->Pos - pos_int; // fractional part of position
117
118 #if USE_LINEAR_INTERPOLATION
119 float sample_point = effective_volume * (pSrc[pos_int] + pos_fract * (pSrc[pos_int+1] - pSrc[pos_int]));
120 #else // polynomial interpolation
121 float xm1 = pSrc[pos_int];
122 float x0 = pSrc[pos_int+1];
123 float x1 = pSrc[pos_int+2];
124 float x2 = pSrc[pos_int+3];
125 float a = (3 * (x0 - x1) - xm1 + x2) / 2;
126 float b = 2 * x1 + xm1 - (5 * x0 + x2) / 2;
127 float c = (x1 - xm1) / 2;
128 float sample_point = effective_volume * ((((a * pos_fract) + b) * pos_fract + c) * pos_fract + x0);
129 #endif // USE_LINEAR_INTERPOLATION
130
131 this->pOutput[i++] += sample_point;
132 this->pOutput[i++] += sample_point;
133
134 this->Pos += this->CurrentPitch;
135 }
136 inline int double_to_int(double f) {
137 #if ARCH_X86
138 int i;
139 __asm__ ("fistl %0" : "=m"(i) : "st"(f - 0.5) );
140 return i;
141 #else
142 return (int) f;
143 #endif // ARCH_X86
144 }
145 };
146
147 #endif // __VOICE_H__

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