diff options
| -rw-r--r-- | engines/sci/resource.cpp | 100 |
1 files changed, 48 insertions, 52 deletions
diff --git a/engines/sci/resource.cpp b/engines/sci/resource.cpp index 9afcba13e4..61c5ca92dd 100644 --- a/engines/sci/resource.cpp +++ b/engines/sci/resource.cpp @@ -2080,64 +2080,60 @@ SoundResource::Track *SoundResource::getDigitalTrack() { int SoundResource::getChannelFilterMask(int hardwareMask, bool wantsRhythm) { byte *data = _innerResource->data; int channelMask = 0; - int reverseHardwareMask = 0; - switch (_soundVersion) { - case SCI_VERSION_0_EARLY: - // TODO: MT32 driver uses no hardware mask at all and uses all channels - switch (hardwareMask) { - case 0x01: // AdLib needs an additional reverse check against bit 3 - reverseHardwareMask = 0x08; - break; - } - data++; // Skip over digital sample flag - // Now all 16 channels follow. Each one is specified by a single byte - // Upper 4 bits of the byte is a voices count - // Lower 4 bits -> bit 0 means use as AdLib driver - // bit 1 means use as PCjr driver - // bit 3 means is control channel (bit 0 needs to be unset) - for (int channelNr = 0; channelNr < 16; channelNr++) { - channelMask = channelMask >> 1; - if (*data & hardwareMask) { - if ((reverseHardwareMask == 0) || ((*data & reverseHardwareMask) == 0)) { - // This Channel is supposed to get played for hardware - channelMask |= 0x8000; - } - } - if ((*data & 0x08) && ((*data & 0x01) == 0)) { - // This channel is control channel, so don't filter it - channelMask |= 0x8000; - // TODO: We need to accept this channel in parseNextEvent() for events - } - data++; - } - break; + if (_soundVersion > SCI_VERSION_0_LATE) + return 0; - case SCI_VERSION_0_LATE: - data++; // Skip over digital sample flag - // Now all 16 channels follow. Each one is specified by 2 bytes - // 1st byte is voices count - // 2nd byte is play mask, which specifies if the channel is supposed to be played - // by the corresponding hardware - for (int channelNr = 0; channelNr < 16; channelNr++) { - data++; - channelMask = channelMask >> 1; - if (*data & hardwareMask) { - // This Channel is supposed to be played by the hardware - channelMask |= 0x8000; - } + data++; // Skip over digital sample flag + + for (int channelNr = 0; channelNr < 16; channelNr++) { + channelMask = channelMask >> 1; + + byte flags; + + if (_soundVersion == SCI_VERSION_0_EARLY) { + // Each channel is specified by a single byte + // Upper 4 bits of the byte is a voices count + // Lower 4 bits -> bit 0 set: use for AdLib + // bit 1 set: use for PCjr + // bit 2 set: use for PC speaker + // bit 3 set and bit 0 clear: control channel (15) + // bit 3 set and bit 0 set: rhythm channel (9) + flags = *data++; + + // Get device bits + flags &= 0x7; + } else { + // Each channel is specified by 2 bytes + // 1st byte is voices count + // 2nd byte is play mask, which specifies if the channel is supposed to be played + // by the corresponding hardware + + // Skip voice count data++; + + flags = *data++; } - // Play channel 15 at all times (control channel) - channelMask |= 0x8000; - channelMask &= ~(1 << 9); - if (wantsRhythm) - channelMask |= (1 << 9); + bool play; + switch (channelNr) { + case 15: + // Always play control channel + play = true; + break; + case 9: + // Play rhythm channel when requested + play = wantsRhythm; + break; + default: + // Otherwise check for flag + play = flags & hardwareMask; + } - break; - default: - break; + if (play) { + // This Channel is supposed to be played by the hardware + channelMask |= 0x8000; + } } return channelMask; |