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Location: cpp/openttd-patchpack/source/src/mixer.cpp
r5625:52b2115bd185
2.6 KiB
text/x-c
(svn r8084) [Translations] Added nynorsk translation (pollux), renamed norwegian to norwegian bokmal, moved nynorsk to finished languages, and updated project files.
Strings pending to nynorsk will be preserved if they are differ from the current translation
Strings pending to nynorsk will be preserved if they are differ from the current translation
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 | /* $Id$ */
#include "stdafx.h"
#include "openttd.h"
#include "mixer.h"
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
uint volume_left;
uint volume_right;
uint flags;
};
static MixerChannel _channels[8];
static uint32 _play_rate;
static void mix_int8_to_int16(MixerChannel *sc, int16 *buffer, uint samples)
{
int8 *b;
uint32 frac_pos;
uint32 frac_speed;
uint volume_left;
uint 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] += *b * volume_left >> 8;
buffer[1] += *b * volume_right >> 8;
b++;
buffer += 2;
} while (--samples > 0);
} else {
do {
buffer[0] += *b * volume_left >> 8;
buffer[1] += *b * volume_right >> 8;
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(void)
{
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, uint 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 & 0xFFFF0000) {
size >>= 1;
rate = (rate >> 1) + 1;
}
mc->samples_left = 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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