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diff --git a/README.OPL b/README.OPL new file mode 100644 index 00000000..2b837c4c --- /dev/null +++ b/README.OPL @@ -0,0 +1,100 @@ +== Chocolate Doom hardware OPL support notes == + +Chocolate Doom is able to play MIDI music as it sounds in Vanilla Doom +with an OPL chip (as found in the Yamaha Adlib card, the Sound Blaster +and its clones). Most modern computers do not include an OPL chip any +more, as CPUs are fast enough to do decent software MIDI synthesis. +For this reason, a software OPL emulator is included as a substitute. + +However, no software emulator sounds exactly like a real (hardware) +OPL chip, so if you do have a sound card with hardware OPL, here's how +to configure Chocolate Doom to use it. + +=== Sound cards with OPL chips === + +If you have an ISA sound card, it almost certainly includes an OPL +chip. Modern computers don't have slots for ISA cards though, so you +must be running a pretty old machine. + +If you have a PCI sound card, you probably don't have an OPL chip. +However, there are some exceptions to this. The following cards are +known to include "legacy" OPL support: + + * C-Media CMI8738 (*) + * Forte Media FM801 + * Cards based on the Yamaha YMF724 (*) + +Other cards that apparently have OPL support but have not been tested: + + * S3 SonicVibes + * AZTech PCI 168 (AZT 3328 chipset) + * ESS Solo-1 sound cards (ES1938, ES1946, ES1969 chipset) + * Conexant Riptide Audio/Modem combo cards + * Cards based on the Crystal Semiconductors CS4281 + * Cards based on the Avance Logic ALS300 + * Cards based on the Avance Logic ALS4000 + +If you desperately want hardware OPL music, you may be able to find +one of these cards for sale cheap on eBay. + +For the cards listed above with (*) next to them, OPL support is +disabled by default and must be explictly enabled in software. + +If your machine is not a PC, you don't have an OPL chip, and you will +have to use the software OPL. + +=== Operating System support === + +If you're certain that you have a sound card with hardware OPL, you +may need to take extra steps to configure your operating system to +allow access to it. To do hardware OPL, Chocolate Doom must access +the chip directly, which is usually not possible in modern operating +systems unless you are running as the superuser (root/Administrator). + +=== Windows 9x === + +If you're running Windows 95, 98 or Me, there is no need to configure +anything. Windows allows direct access to the OPL chip. You can +confirm that hardware OPL is working by checking for this message in +stdout.txt: + + OPL_Init: Using driver 'Win9x'. + +=== Windows NT (including 2000, XP and later) === + +If you're running an NT-based system, it is not possible to directly +access the OPL chip, even when running as Administrator. Fortunately, +it is possible to use the third-party "PortTalk" driver: + + http://www.beyondlogic.org/porttalk/porttalk.htm + +TODO - the NT driver hasn't actually been written yet.. + +=== Linux === + +If you are using a system based on the Linux kernel, you can access +the OPL chip directly, but you must be running as root. You can +confirm that hardware OPL is working, by checking for this message on +startup: + + OPL_Init: Using driver 'Linux'. + +If you are using one of the PCI cards in the list above with a (*) +next to it, you may need to manually enable FM legacy support. Add +the following to your /etc/modprobe.conf file to do this: + + options snd-ymfpci fm_port=0x388 + options snd-cmipci fm_port=0x388 + +=== OpenBSD/NetBSD === + +You must be running as root to access the hardware OPL directly. You +can confirm that hadware OPL is working by checking for this message +on startup: + + OPL_Init: Using driver 'OpenBSD'. + +=== FreeBSD === + +There is no native OPL backend for FreeBSD yet. Sorry! + |