2 orgux - a just-for-fun real time synth
3 Copyright (C) 2009 Evan Rinehart
5 This program is free software; you can redistribute it and/or
6 modify it under the terms of the GNU General Public License
7 as published by the Free Software Foundation; either version 2
8 of the License, or (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 /* precompute waveforms */
25 #include "constants.h"
27 extern float square_wave
[WAVEFORM_LENGTH
];
28 extern float saw_wave
[WAVEFORM_LENGTH
];
29 extern float triangle_wave
[WAVEFORM_LENGTH
];
31 extern const unsigned char instr_config
[128][16];
33 extern float waveform
[128][WAVEFORM_LENGTH
];
34 extern float samples
[SAMPLE_COUNT
][SAMPLE_LENGTH
];
35 extern float antipop
[ANTIPOP_LENGTH
];
37 float linterp(float x
, int k
, float wave
[]){
39 float Xw
= X
- WAVEFORM_LENGTH
*floor(X
/WAVEFORM_LENGTH
);
42 if(X1
== WAVEFORM_LENGTH
) X1
= 0;
46 float m
= (y1
-y0
)/(X1
-X0
);
51 void precompute(int sample_rate
){
53 float dt
= 1.0/sample_rate
;
55 printf("generating band limited bases... ");
58 for(int i
=0; i
<WAVEFORM_LENGTH
; i
++){
62 for(int j
=0; j
<7; j
++){
63 square_wave
[i
] += (4/PI
)*sin(i
*(2*j
+1)*PI2
/WAVEFORM_LENGTH
)/(2*j
+1);
64 triangle_wave
[i
] += (8/(PI
*PI
))*(j
&1?1:-1)*sin(i
*(2*j
+1)*PI2
/WAVEFORM_LENGTH
)/((2*j
+1)*(2*j
+1));
65 saw_wave
[i
] += (2/PI
)*sin(i
*(j
+1)*PI2
/WAVEFORM_LENGTH
)/(j
+1);
69 float maxf
[3] = {0,0,0};
70 for(int i
=0; i
<WAVEFORM_LENGTH
; i
++){
71 if(maxf
[0] < square_wave
[i
]) maxf
[0] = square_wave
[i
];
72 if(maxf
[1] < triangle_wave
[i
]) maxf
[1] = triangle_wave
[i
];
73 if(maxf
[2] < saw_wave
[i
]) maxf
[2] = saw_wave
[i
];
76 for(int i
=0; i
<WAVEFORM_LENGTH
; i
++){
77 square_wave
[i
] /= maxf
[0];
78 triangle_wave
[i
] /= maxf
[1];
79 saw_wave
[i
] /= maxf
[2];
82 //printf("\nsquare max = %f\n",maxf[0]);
83 //printf("triangle max = %f\n",maxf[1]);
84 //printf("saw max = %f\n\n",maxf[2]);
89 /* setup wave tables */
91 printf("generating instruments... ");
93 printf(" 0 1 2 3 4 5 6 7 | basis FM FM_freq LP HP\n");
94 for(int i
=0; i
<128; i
++){
99 printf("instrument[%d] = {",i
);
101 for(int j
=0; j
<HARMONIC_COUNT
; j
++){
102 printf("%d ",instr_config
[i
][j
]);
103 if(instr_config
[i
][j
] > max
){ max
= instr_config
[i
][j
]; }
108 for(int j
=0; j
<HARMONIC_COUNT
; j
++){
109 float M
= ((float)instr_config
[i
][j
])/max
;
113 switch(instr_config
[i
][BASE_CONFIG
]){
115 for(int k
=0; k
<WAVEFORM_LENGTH
; k
++){
116 waveform
[i
][k
]+=M
*sin(k
*(j
+1)*PI2
/WAVEFORM_LENGTH
);
120 for(int k
=0; k
<WAVEFORM_LENGTH
; k
++){
121 waveform
[i
][k
]+=M
*linterp(k
,j
+1,square_wave
);;
125 for(int k
=0; k
<WAVEFORM_LENGTH
; k
++){
126 waveform
[i
][k
]+=M
*linterp(k
,j
+1,saw_wave
);;
130 for(int k
=0; k
<WAVEFORM_LENGTH
; k
++){
131 waveform
[i
][k
]+=M
*linterp(k
,j
+1,triangle_wave
);
139 for(int j
=0; j
<WAVEFORM_LENGTH
; j
++){
140 waveform
[i
][j
] /= N
*10;
145 for(int j=0; j<WAVEFORM_LENGTH; j++){
146 waveform[i][j] = 0.0f;
148 for(int k=0; k<HARMONIC_COUNT; k++){
149 float M = ((float)instr_config[i][k])/max;
154 switch(instr_config[i][BASE_CONFIG]){
155 case SINE_BASE: y = sin(j*(k+1)*PI2/WAVEFORM_LENGTH); break;
156 //case SQUARE_BASE: y = ((2*j*(1<<k)/WAVEFORM_LENGTH)&1)?1:-1; break;
157 case SQUARE_BASE: y = linterp(j,k+1,square_wave); break;
158 case TRIANGLE_BASE: y = linterp(j,k+1,triangle_wave); break;
159 case SAW_BASE: y = linterp(j,k+1,saw_wave); break;
160 //case NOISE_BASE: y = RANDF()*2 - 1; break;
161 case NOISE_BASE: y = 0; break;
162 default: y = 0;//use previously defined waveform
165 waveform[i][j] += M*y;
167 if(N>0){ waveform[i][j] /= N*10; }
177 //generate antipop cosine
178 for(int i
=0; i
<ANTIPOP_LENGTH
; i
++){
179 antipop
[i
] = -cos(i
*PI2
/(2.0*ANTIPOP_LENGTH
))/2.0+0.5;
185 float par
[16][8] = {/**/
186 {50, 500, 0.5, 10000, 0, 0, 0, 0},
187 {200, 200, 0.5, 10000, 0, 0, 0, 0},
188 {100, 500, 0.5, 10000, 0, 0, 0, 0},
189 {100, 1000, 0.5, 10000, 0, 0, 0, 0},
191 {100, 500, 0.5, 3000, 0, 0, 0, 0},
192 {200, 500, 0.5, 3000, 0, 0, 0, 0},
193 {300, 500, 0.5, 3000, 0, 0, 0, 0},
194 {400, 500, 0.5, 3000, 0, 0, 0, 0},
196 {400, 200, 0.5, 3000, 0, 0, 0, 0},
197 {400, 100, 0.5, 3000, 0, 0, 0, 0},
198 {400, 50, 0.5, 3000, 0, 0, 0, 0},
199 {400, 20, 0.5, 3000, 0, 0, 0, 0},
201 {100, 500, 0.5, 10000, 0, 0, 0, 0},
202 {100, 500, 0.5, 10000, 0, 0, 0, 0},
203 {100, 500, 0.5, 10000, 0, 0, 0, 0},
204 {100, 500, 0.5, 10000, 0, 0, 0, 0}
207 double K
= PI2
/ sample_rate
;
208 printf("generating samples... ");
209 for(int i
=0; i
<SAMPLE_LENGTH
; i
++){
210 for(int j
=0; j
<SAMPLE_COUNT
; j
++){
211 double F_i
= par
[j
][0];
212 double F_r
= par
[j
][1];
213 double A_i
= par
[j
][2];
214 double A_r
= par
[j
][3];
216 if(F_r
< 1){F_r
= 1;}
217 double f
= F_i
- i
/F_r
;
220 if(A_r
< 1){A_r
= 1;}
221 double A
= A_i
- i
/A_r
;
226 E
= -cos((i
/64.0) * PI2
/ 2)/2+0.5;
229 samples
[j
][i
] = E
*A
*sin(i
*f
*K
);
243 tau2 = 0.0001 / (1 + i/50.0)
244 alpha2 = tau2 / (tau2 + dt)
245 A = 0.2 - (i/10000.0)
253 for(int i
=0; i
<SAMPLE_LENGTH
; i
++){
255 float tau1
= (i
/200.0)*0.0001;
256 float alpha1
= dt
/(tau1
+dt
);
258 float tau2
= 0.0001 / (1 + i
/50.0);
259 float alpha2
= tau2
/(tau2
+dt
);
261 float y
= RAND_SIGNAL();
263 //y = y_l0 + alpha1*(y - y_l0);
267 y
= alpha2
*(y
- y_h0
+ y_h1
);
271 float A
= 0.2 - (i
/10000.0);
276 E
= -cos((i
/64.0) * PI2
/ 2)/2+0.5;
279 samples
[15][i
] = A
*E
*y
;
284 printf("precompute OK\n");