Commit | Line | Data |
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c6c2311a | 1 | /* |
1b261ae5 | 2 | * gus_vol.c - Compute volume for GUS. |
c6c2311a | 3 | * |
1b261ae5 JH |
4 | * Greg Lee 1993. |
5 | */ | |
6 | #include "sound_config.h" | |
7 | #ifndef EXCLUDE_GUS | |
c6c2311a | 8 | #include "gus_linearvol.h" |
1b261ae5 JH |
9 | |
10 | #define GUS_VOLUME gus_wave_volume | |
11 | ||
12 | ||
13 | extern int gus_wave_volume; | |
14 | ||
c6c2311a | 15 | /* |
1b261ae5 JH |
16 | * Calculate gus volume from note velocity, main volume, expression, and |
17 | * intrinsic patch volume given in patch library. Expression is multiplied | |
18 | * in, so it emphasizes differences in note velocity, while main volume is | |
19 | * added in -- I don't know whether this is right, but it seems reasonable to | |
20 | * me. (In the previous stage, main volume controller messages were changed | |
21 | * to expression controller messages, if they were found to be used for | |
22 | * dynamic volume adjustments, so here, main volume can be assumed to be | |
23 | * constant throughout a song.) | |
c6c2311a | 24 | * |
1b261ae5 JH |
25 | * Intrinsic patch volume is added in, but if over 64 is also multiplied in, so |
26 | * we can give a big boost to very weak voices like nylon guitar and the | |
27 | * basses. The normal value is 64. Strings are assigned lower values. | |
28 | */ | |
29 | unsigned short | |
30 | gus_adagio_vol (int vel, int mainv, int xpn, int voicev) | |
31 | { | |
32 | int i, m, n, x; | |
33 | ||
34 | ||
c6c2311a | 35 | /* |
1b261ae5 JH |
36 | * A voice volume of 64 is considered neutral, so adjust the main volume if |
37 | * something other than this neutral value was assigned in the patch | |
38 | * library. | |
39 | */ | |
40 | x = 256 + 6 * (voicev - 64); | |
41 | ||
c6c2311a AC |
42 | /* |
43 | * Boost expression by voice volume above neutral. | |
b33e3049 | 44 | */ |
1b261ae5 JH |
45 | if (voicev > 65) |
46 | xpn += voicev - 64; | |
47 | xpn += (voicev - 64) / 2; | |
48 | ||
c6c2311a AC |
49 | /* |
50 | * Combine multiplicative and level components. | |
b33e3049 | 51 | */ |
1b261ae5 JH |
52 | x = vel * xpn * 6 + (voicev / 4) * x; |
53 | ||
54 | #ifdef GUS_VOLUME | |
c6c2311a | 55 | /* |
1b261ae5 | 56 | * Further adjustment by installation-specific master volume control |
b33e3049 | 57 | * (default 60). |
1b261ae5 JH |
58 | */ |
59 | x = (x * GUS_VOLUME * GUS_VOLUME) / 10000; | |
60 | #endif | |
61 | ||
b33e3049 SW |
62 | #ifdef GUS_USE_CHN_MAIN_VOLUME |
63 | /* | |
64 | * Experimental support for the channel main volume | |
65 | */ | |
66 | ||
67 | mainv = (mainv / 2) + 64; /* Scale to 64 to 127 */ | |
68 | x = (x * mainv * mainv) / 16384; | |
69 | #endif | |
70 | ||
71 | if (x < 2) | |
72 | return (0); | |
1b261ae5 JH |
73 | else if (x >= 65535) |
74 | return ((15 << 8) | 255); | |
75 | ||
c6c2311a | 76 | /* |
1b261ae5 JH |
77 | * Convert to gus's logarithmic form with 4 bit exponent i and 8 bit |
78 | * mantissa m. | |
79 | */ | |
80 | n = x; | |
81 | i = 7; | |
82 | if (n < 128) | |
83 | { | |
84 | while (i > 0 && n < (1 << i)) | |
85 | i--; | |
86 | } | |
87 | else | |
88 | while (n > 255) | |
89 | { | |
90 | n >>= 1; | |
91 | i++; | |
92 | } | |
c6c2311a | 93 | /* |
1b261ae5 JH |
94 | * Mantissa is part of linear volume not expressed in exponent. (This is |
95 | * not quite like real logs -- I wonder if it's right.) | |
96 | */ | |
97 | m = x - (1 << i); | |
98 | ||
c6c2311a AC |
99 | /* |
100 | * Adjust mantissa to 8 bits. | |
b33e3049 | 101 | */ |
1b261ae5 JH |
102 | if (m > 0) |
103 | { | |
104 | if (i > 8) | |
105 | m >>= i - 8; | |
106 | else if (i < 8) | |
107 | m <<= 8 - i; | |
108 | } | |
109 | ||
1b261ae5 JH |
110 | return ((i << 8) + m); |
111 | } | |
112 | ||
c6c2311a AC |
113 | /* |
114 | * Volume-values are interpreted as linear values. Volume is based on the | |
115 | * value supplied with SEQ_START_NOTE(), channel main volume (if compiled in) | |
116 | * and the volume set by the mixer-device (default 60%). | |
117 | */ | |
118 | ||
119 | unsigned short | |
120 | gus_linear_vol (int vol, int mainvol) | |
121 | { | |
122 | int mixer_mainvol; | |
123 | ||
124 | if (vol <= 0) | |
125 | vol = 0; | |
126 | else if (vol >= 127) | |
127 | vol = 127; | |
128 | ||
129 | #ifdef GUS_VOLUME | |
130 | mixer_mainvol = GUS_VOLUME; | |
131 | #else | |
132 | mixer_mainvol = 100; | |
133 | #endif | |
134 | ||
135 | #ifdef GUS_USE_CHN_MAIN_VOLUME | |
136 | if (mainvol <= 0) | |
137 | mainvol = 0; | |
138 | else if (mainvol >= 127) | |
139 | mainvol = 127; | |
140 | #else | |
141 | mainvol = 128; | |
142 | #endif | |
143 | ||
144 | return gus_linearvol[(((vol * mainvol) / 128) * mixer_mainvol) / 100]; | |
145 | } | |
146 | ||
1b261ae5 | 147 | #endif |