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Location: cpp/openttd-patchpack/source/src/mixer.cpp
r11784:1f7706fe8337
3.1 KiB
text/x-c
(svn r16179) -Update: WebTranslator2 update to 2009-04-27 17:41:22
brazilian_portuguese - 24 fixed by tucalipe (24)
dutch - 10 fixed by habell (10)
estonian - 8 changed by kristjans (8)
hungarian - 10 fixed by IPG (10)
italian - 1 changed by lorenzodv (1)
malay - 22 fixed by Syed (22)
norwegian_bokmal - 1 fixed by khh (1)
polish - 336 fixed, 104 changed by konrad (440)
brazilian_portuguese - 24 fixed by tucalipe (24)
dutch - 10 fixed by habell (10)
estonian - 8 changed by kristjans (8)
hungarian - 10 fixed by IPG (10)
italian - 1 changed by lorenzodv (1)
malay - 22 fixed by Syed (22)
norwegian_bokmal - 1 fixed by khh (1)
polish - 336 fixed, 104 changed by konrad (440)
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 | /* $Id$ */
/** @file mixer.cpp Mixing of sound samples. */
#include "stdafx.h"
#include "mixer.h"
#include "core/math_func.hpp"
struct MixerChannel {
bool active;
/* pointer to allocated buffer memory */
int8 *memory;
/* current position in memory */
uint32 pos;
uint32 frac_pos;
uint32 frac_speed;
uint32 samples_left;
/* Mixing volume */
int volume_left;
int volume_right;
uint flags;
};
static MixerChannel _channels[8];
static uint32 _play_rate;
/**
* The theoretical maximum volume for a single sound sample. Multiple sound
* samples should not exceed this limit as it will sound too loud. It also
* stops overflowing when too many sounds are played at the same time, which
* causes an even worse sound quality.
*/
static const int MAX_VOLUME = 128 * 128;
static void mix_int8_to_int16(MixerChannel *sc, int16 *buffer, uint samples)
{
int8 *b;
uint32 frac_pos;
uint32 frac_speed;
int volume_left;
int volume_right;
if (samples > sc->samples_left) samples = sc->samples_left;
sc->samples_left -= samples;
assert(samples > 0);
b = sc->memory + sc->pos;
frac_pos = sc->frac_pos;
frac_speed = sc->frac_speed;
volume_left = sc->volume_left;
volume_right = sc->volume_right;
if (frac_speed == 0x10000) {
/* Special case when frac_speed is 0x10000 */
do {
buffer[0] = Clamp(buffer[0] + (*b * volume_left >> 8), -MAX_VOLUME, MAX_VOLUME);
buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 8), -MAX_VOLUME, MAX_VOLUME);
b++;
buffer += 2;
} while (--samples > 0);
} else {
do {
buffer[0] = Clamp(buffer[0] + (*b * volume_left >> 8), -MAX_VOLUME, MAX_VOLUME);
buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 8), -MAX_VOLUME, MAX_VOLUME);
buffer += 2;
frac_pos += frac_speed;
b += frac_pos >> 16;
frac_pos &= 0xffff;
} while (--samples > 0);
}
sc->frac_pos = frac_pos;
sc->pos = b - sc->memory;
}
static void MxCloseChannel(MixerChannel *mc)
{
if (mc->flags & MX_AUTOFREE) free(mc->memory);
mc->active = false;
mc->memory = NULL;
}
void MxMixSamples(void *buffer, uint samples)
{
MixerChannel *mc;
/* Clear the buffer */
memset(buffer, 0, sizeof(int16) * 2 * samples);
/* Mix each channel */
for (mc = _channels; mc != endof(_channels); mc++) {
if (mc->active) {
mix_int8_to_int16(mc, (int16*)buffer, samples);
if (mc->samples_left == 0) MxCloseChannel(mc);
}
}
}
MixerChannel *MxAllocateChannel()
{
MixerChannel *mc;
for (mc = _channels; mc != endof(_channels); mc++)
if (mc->memory == NULL) {
mc->active = false;
return mc;
}
return NULL;
}
void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate, uint flags)
{
mc->memory = mem;
mc->flags = flags;
mc->frac_pos = 0;
mc->pos = 0;
mc->frac_speed = (rate << 16) / _play_rate;
/* adjust the magnitude to prevent overflow */
while (size & ~0xFFFF) {
size >>= 1;
rate = (rate >> 1) + 1;
}
mc->samples_left = (uint)size * _play_rate / rate;
}
void MxSetChannelVolume(MixerChannel *mc, uint left, uint right)
{
mc->volume_left = left;
mc->volume_right = right;
}
void MxActivateChannel(MixerChannel *mc)
{
mc->active = true;
}
bool MxInitialize(uint rate)
{
_play_rate = rate;
return true;
}
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