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@ r6888:f2ab5d0e6596
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Location: cpp/openttd-patchpack/source/src/mixer.cpp
r6888:f2ab5d0e6596
2.6 KiB
text/x-c
(svn r10131) -Fix [FS#810]: when removing a dock, a ship will always try to reach the old location of the dock even when it cannot anymore because it the old location of the dock is now land instead of water.
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/** @file mixer.cpp*/
#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()
{
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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