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diff --git a/plugins/dumb/dumb-kode54/docs/dumb.txt b/plugins/dumb/dumb-kode54/docs/dumb.txt new file mode 100644 index 00000000..4f6cc69b --- /dev/null +++ b/plugins/dumb/dumb-kode54/docs/dumb.txt @@ -0,0 +1,1699 @@ +/* _______ ____ __ ___ ___
+ * \ _ \ \ / \ / \ \ / / ' ' '
+ * | | \ \ | | || | \/ | . .
+ * | | | | | | || ||\ /| |
+ * | | | | | | || || \/ | | ' ' '
+ * | | | | | | || || | | . .
+ * | |_/ / \ \__// || | |
+ * /_______/ynamic \____/niversal /__\ /____\usic /| . . ibliotheque
+ * / \
+ * / . \
+ * dumb.txt - DUMB library reference. / / \ \
+ * | < / \_
+ * See readme.txt for general information on | \/ /\ /
+ * DUMB and how to set it up. \_ / > /
+ * | \ / /
+ * If you are new to DUMB, see howto.txt. | ' /
+ * \__/
+ */
+
+
+***********************************
+*** Include Files and Libraries ***
+***********************************
+
+
+dumb.h
+
+ Include this if you only want the core DUMB library functions. You will
+ be able to load music files and render them into memory buffers at your
+ own pace. The core library is completely portable, and as such does not
+ access hardware; you must relay the sound data to the sound card yourself.
+ A stdio file input module is available, but you must actively register it
+ if you wish to use it (see dumb_register_stdfiles()); if you do not
+ register it, it will not be linked into your executable. You must register
+ it, or a DUMBFILE module of your own, in order to load stand-alone music
+ files.
+
+ Optimised: -ldumb or /link dumb.lib
+ Debugging: -ldumbd or /link dumbd.lib
+
+
+aldumb.h
+
+ Include this if you wish to use DUMB with Allegro. This will provide you
+ with functions to play DUHs back through Allegro's audio streams and embed
+ music files in Allegro datafiles. A file input module using Allegro's
+ packfiles is provided; you have a choice between this and the stdio
+ module (or provide one of your own). You will be able to load datafiles
+ containing music files no matter which file input module you register, or
+ even if you register no file input module. However, you must register a
+ file input module in order to load stand-alone files.
+
+ Optimised: -laldmb -ldumb -lalleg or /link aldmb.lib alleg.lib dumb.lib
+ Debugging: -laldmd -ldumbd -lalld or /link aldmd.lib alld.lib dumbd.lib
+
+ aldmb or aldmd must be linked in first, so the symbols can be resolved
+ when linking in the other two libraries.
+
+
+***************************
+*** Version Information ***
+***************************
+
+
+#define DUMB_MAJOR_VERSION
+#define DUMB_MINOR_VERSION
+#define DUMB_REVISION_VERSION
+
+ Numeric constants representing this version of DUMB. If this were version
+ 1.0, DUMB_MAJOR_VERSION would be 1 and DUMB_MINOR_VERSION would be 0.
+ DUMB_REVISION_VERSION will be 0 on any significant releases, and will be
+ incremented as releases with bugfixes and minor features are made.
+
+ Typical usage:
+
+ #if DUMB_MAJOR_VERSION < 1
+ #error This add-on requires DUMB v1.0 or higher. Please upgrade.
+ #endif
+
+
+#define DUMB_VERSION
+
+ A numeric constant which appears in the format MMmmrr when displayed in
+ decimal (M for major, m for minor, r for revision). This is most useful
+ for comparing version numbers; it has little other practical use.
+
+ Typical usage:
+
+ #if DUMB_VERSION < 801
+ #error This game requires DUMB v0.8.1 or higher. Please upgrade.
+ #endif
+
+ #if DUMB_VERSION < 10002
+ #error This game requires DUMB v1.0.2 or higher. Please upgrade.
+ #endif
+
+
+#define DUMB_VERSION_STR
+
+ String constant representing this version of DUMB. If this were Version
+ 1.0, DUMB_VERSION_STR would be "1.0". DUMB_REVISION_VERSION will only
+ appear on the end if it is nonzero; then DUMB_VERSION_STR might be
+ "1.0.1".
+
+
+#define DUMB_NAME
+
+ A string identifying DUMB and its version. If this were Version 1.0,
+ DUMB_NAME might be "DUMB v1.0". This constant is suitable for use in your
+ Credits screen if you wish to acknowledge the use of DUMB there.
+
+
+#define DUMB_YEAR
+#define DUMB_MONTH
+#define DUMB_DAY
+
+ Numeric constants representing the year, month and day of this release of
+ DUMB. All four digits are included in the year. Please note that
+ DUMB_MONTH and DUMB_DAY were inadvertently swapped in the v0.8 release.
+
+
+#define DUMB_YEAR_STR4
+#define DUMB_YEAR_STR2
+#define DUMB_MONTH_STR2
+#define DUMB_MONTH_STR1
+#define DUMB_DAY_STR2
+#define DUMB_DAY_STR1
+
+ String constants representing the year, month and day of this release of
+ DUMB. DUMB_MONTH_STR2 and DUMB_DAY_STR2 include a leading zero if the
+ month or day respectively are less than ten; the STR1 variations do not.
+ DUMB_YEAR_STR2 contains only the two rightmost digits of the year, while
+ DUMB_YEAR_STR4 contains all four. I recommend using DUMB_YEAR_STR4,
+ especially so soon after the turn of the century (indeed the millennium).
+ However, it is a matter of personal preference which you use.
+
+ Please note that the month and day were inadvertently swapped in the v0.8
+ release.
+
+
+#define DUMB_DATE
+
+ A numeric constant that appears in the form yyyymmdd when displayed in
+ decimal. This is most useful for comparing release dates; it has little
+ other practical use.
+
+ WARNING: The month and day were inadvertently swapped in the v0.8 release.
+ Please do not compare this constant against any date in 2002. In
+ any case, DUMB_VERSION is probably more useful for this purpose.
+
+
+#define DUMB_DATE_STR
+
+ The date as a string. The format is "d.m.yyyy", with dots used as
+ separators, the day written first, four digits for the year, and no
+ leading zeros on the day or month. This is my preferred format. If you
+ don't like it, you can construct your own format using the other
+ constants. For example, "mm/dd/yy" could be constructed as follows:
+
+ DUMB_MONTH_STR2 "/" DUMB_DAY_STR2 "/" DUMB_YEAR_STR2
+
+ Please note that the month and day were inadvertently swapped in the v0.8
+ release.
+
+
+*************************
+*** Basic Sample Type ***
+*************************
+
+
+typedef int sample_t;
+
+ DUMB works internally with 32-bit integer samples, with a 'normal range'
+ from -0x800000 to 0x7FFFFF (as of DUMB v0.9.2; previously they ranged from
+ -0x8000 to 0x7FFF). Any samples that exceed this range will eventually be
+ clipped, and could cause integer overflow in extreme cases.
+
+
+***********************************
+*** Library Clean-up Management ***
+***********************************
+
+
+int dumb_atexit(void (*proc)(void));
+
+ Registers a function to be called at the end of your program. You can
+ register multiple functions to be called, and the one you register last
+ will be called first. If you try to register the same function twice, the
+ second attempt will have no effect.
+
+ See fnptr.txt for help with function pointers.
+
+ You must call dumb_exit() before exiting your program for this to work
+ properly. The library itself registers functions with dumb_atexit(), so it
+ is important to call dumb_exit() even if you do not use dumb_atexit()
+ yourself.
+
+ This function will return zero on success. It will return zero when
+ trying to install the same function twice. If it fails through lack of
+ memory, it will return nonzero. Generally you can ignore the return code;
+ in the worst case some memory will not be freed at the end. If it is
+ crucial that your function be called (e.g. to shut down some hardware or
+ save critical data), then you should call your function manually at the
+ end of the program instead of registering it here - or use the stdlib
+ function atexit(), guaranteed under ANSI C to succeed for at least 32
+ functions.
+
+
+void dumb_exit(void);
+
+ You should call this before exiting your program if you have used any part
+ of DUMB in the program. Some parts of DUMB will allocate memory, and this
+ function will free it all up.
+
+ More specifically, this function will call any functions that have been
+ registered with dumb_atexit(). If a part of DUMB needs shutting down, the
+ shutdown procedure will have been registered in this way.
+
+ dumb_exit() will, of course, also call any functions you registered with
+ dumb_atexit() yourself.
+
+ After a call to dumb_exit(), the list of functions is erased. If you are
+ not ready to exit your program, you can start using DUMB anew as if your
+ program had just started. (Note that not everything will be reset in
+ practice - dumb_resampling_quality will retain whatever you set it to, for
+ example, though you should not assume it will.)
+
+ If you only need to call dumb_exit() once at the end of the program, you
+ can use the following to register dumb_exit() with stdlib.h atexit():
+
+ #include <stdlib.h>
+
+ atexit(&dumb_exit);
+
+ Then dumb_exit() will be called for you when your program exits. This is
+ the recommended method, since it will ensure clean-up even if your program
+ aborts. You should only call dumb_exit() manually if you need to shut DUMB
+ down prematurely, or if atexit() is unavailable for one reason or another.
+
+
+*****************************
+*** Sequential File Input ***
+*****************************
+
+
+ DUMB provides a strictly sequential file input system which uses the
+ DUMBFILE struct. "Strictly sequential" means you cannot seek backwards.
+ However, the system will keep track of how many bytes you have read,
+ enabling you to seek forwards. DUMBFILEs provide a convenient error
+ detection system, so you do not have to check the return value from every
+ function call in the way you do with the ANSI C functions.
+
+ Note that DUMBFILEs cannot be used for output, nor can they be used
+ portably for text files.
+
+ If an error occurs when reading data from a DUMBFILE, the DUMBFILE will
+ become inoperative. All subsequent activities on the DUMBFILE will return
+ error codes without attempting to read from the file. The position in the
+ file will also be forgotten. You can find out if this has happened at any
+ stage with the dumbfile_error() function. You are still required to close
+ the DUMBFILE, and the return value from dumbfile_close() will tell you if
+ an error has occurred.
+
+ This system allows you to input large chunks of your file, neither
+ checking every return value nor wasting time accessing a file that has
+ already experienced an error. However, before you allocate an amount of
+ memory or read in a quantity of data depending on previous input from the
+ file, you should always check that such input was valid. In particular you
+ should avoid passing zero or negative numbers to malloc(), and avoid
+ passing negative numbers to dumbfile_skip() and dumbfile_getnc().
+
+ DUMBFILEs can be hooked. In other words, you can specify your own
+ functions to do the work of reading from a file. While DUMB contains two
+ modules for this purpose, it does not set them up for you automatically.
+ In most cases you must register one of these modules yourself, or provide
+ your own module. See register_dumbfile_system(), dumb_register_stdfiles()
+ and dumb_register_packfiles().
+
+
+void register_dumbfile_system(DUMBFILE_SYSTEM *dfs);
+
+ Use this function to register a set of functions for use by the DUMBFILEs
+ (a DUMBFILE system). The DUMBFILE_SYSTEM struct contains the following
+ fields:
+
+ void *(*open)(const char *filename);
+ int (*skip)(void *f, long n);
+ int (*getc)(void *f);
+ long (*getnc)(char *ptr, long n, void *f);
+ void (*close)(void *f);
+
+ See fnptr.txt for help with function pointers such as these.
+
+ Your 'open' function should open the file specified and return a pointer
+ to a struct representing the open file. This pointer will be passed to
+ your other functions as 'f'. Your 'close' function should close the file
+ and free all memory pointed to by 'f'. Note that the 'close' operation
+ should never be able to fail; if you are calling a function with a return
+ value, you can generally ignore it.
+
+ Your 'getc' function should read one byte from the file and return its
+ value in the range 0 to 255. If an error occurs, you should return -1. Do
+ not worry about remembering that an error has occurred; DUMB will do that
+ for you.
+
+ 'skip' is for skipping parts of the file, and should skip n bytes,
+ returning 0 on success or any other number on failure. 'getnc' should read
+ n bytes from the file, store them at 'ptr', and return the number of bytes
+ read (n on success, fewer on failure). However, these two functions are
+ optional, and you should only provide them if the operations can be done
+ more efficiently than with repeated calls to your 'getc' function. If this
+ is not the case, specify NULL for 'skip', 'getnc' or both, and DUMB will
+ use your 'getc' function to do the work.
+
+ Once you have written all your functions, you need to create a
+ DUMBFILE_SYSTEM struct to hold them, and pass its pointer to
+ register_dumbfile_system().
+
+ The DUMBFILE_SYSTEM struct must be permanent. In other words, it must be
+ either global or static, and you should not modify it later. DUMB will not
+ make its own copy.
+
+ You will most likely create your own struct to represent the open file,
+ but do not be tempted to specify that struct in the function prototypes
+ and pacify the compiler warnings by casting your function pointers. There
+ exist computer systems where a (void *) pointer and a (MY_STRUCT *)
+ pointer are represented differently in memory, and a cast of such a
+ pointer causes a tangible conversion to take place. If you cast the
+ function pointers, the computer cannot know when such a conversion is
+ necessary. Instead, use the following structure:
+
+ int myskip(void *f, long n)
+ {
+ FILE *file = f;
+ /* Do some stuff with 'file' */
+ return something;
+ }
+
+ If you need examples, have a look at the two existing DUMBFILE systems in
+ dumb/src/core/stdfile.c and dumb/src/allegro/packfile.c.
+
+
+DUMBFILE *dumbfile_open(const char *filename);
+
+ Open the specified file for input. You must pass the DUMBFILE pointer
+ whenever you wish to operate on this file. When you have finished with the
+ file, you must pass it to dumbfile_close().
+
+ Before you use this function, make sure you have registered a DUMBFILE
+ system. See register_dumbfile_system(), dumb_register_stdfiles() and
+ dumb_register_packfiles().
+
+ You must check the return value from this function. If it is NULL, the
+ file could not be opened, and you must not pass the DUMBFILE to any other
+ function. The debugging library will abort if you get this wrong; the
+ optimised library will act weird.
+
+
+DUMBFILE *dumbfile_open_ex(void *file, DUMBFILE_SYSTEM *dfs);
+
+ This function is provided for more specialised use. You should create a
+ DUMBFILE_SYSTEM specially for the purpose. Its 'open' field is irrelevant;
+ for neatness, set it to NULL, unless you are using this DUMBFILE_SYSTEM
+ with register_dumbfile_system() as well.
+
+ When you have called this function, the DUMBFILE struct it returned can be
+ used as normal. The specified DUMBFILE_SYSTEM will be used for all input,
+ with 'file' passed to your 'skip', 'getc' and 'getnc' functions as 'f'.
+ This can be used, for example, to read from an already open file.
+
+ Note that the position will always be initialised to 0 for this DUMBFILE.
+ This means for example that offsets in the file do not need adjusting when
+ embedding data in a larger file.
+
+ There are two ways to use this function. If you want 'file' to persist
+ after using a DUMBFILE returned by this function, you should make sure the
+ 'close' field in the DUMBFILE is set to NULL. When the DUMBFILE is closed,
+ 'file' will be left alone, and you can and should deal with it yourself
+ when the DUMBFILE has been closed.
+
+ Alternatively, you can provide a 'close' function to get rid of 'file' for
+ you when the DUMBFILE is closed. If you do this, you should not otherwise
+ use 'file' after a call to this function.
+
+ If dumbfile_open_ex() has to return NULL, owing to lack of memory, then
+ your 'close' function will be called if provided. In other words, if you
+ have provided a 'close' function, then you no longer need to worry about
+ 'file' whether this function succeeds or not.
+
+ See dumb/src/helpers/stdfile.c and dumb/src/allegro/packfile.c for
+ examples of how to use this function. Neither provides a 'close' function,
+ so I hope my explanation here will suffice. If not, please feel free to
+ contact me so I can make the explanation clearer and help you do what you
+ want to do. Contact details are at the end of this file.
+
+
+long dumbfile_pos(DUMBFILE *f);
+
+ Returns the number of bytes read from the DUMBFILE (or skipped) since it
+ was opened, or -1 if an error has occurred while reading.
+
+
+int dumbfile_skip(DUMBFILE *f, long n);
+
+ Skips n bytes of the specified DUMBFILE. Returns zero on success.
+
+
+int dumbfile_getc(DUMBFILE *f);
+
+ Reads one byte from the DUMBFILE and returns it in unsigned format (from 0
+ to 255). If an error occurs, or occurred before, this function returns -1.
+
+
+int dumbfile_igetw(DUMBFILE *f);
+
+ Reads two bytes from the DUMBFILE and combines them into a word ranging
+ from 0 to 65535. The first byte read is the least significant byte, as
+ with Intel processors. This function returns -1 on error.
+
+
+int dumbfile_mgetw(DUMBFILE *f);
+
+ Reads two bytes from the DUMBFILE and combines them into a word ranging
+ from 0 to 65535. The first byte read is the most significant byte, as
+ with the Apple Macintosh. This function returns -1 on error.
+
+
+long dumbfile_igetl(DUMBFILE *f);
+
+ Reads four bytes from the DUMBFILE and combines them into a long integer
+ ranging from -2147483648 to 2147483647. The first byte read is the least
+ significant byte, as with Intel processors. This function returns -1 on
+ error, but -1 is also a valid return value. After a call to this function,
+ you can use dumbfile_error() to find out if an error occurred.
+
+
+long dumbfile_mgetl(DUMBFILE *f);
+
+ Reads four bytes from the DUMBFILE and combines them into a long integer
+ ranging from -2147483648 to 2147483647. The first byte read is the most
+ significant byte, as with the Apple Macintosh. This function returns -1 on
+ error, but -1 is also a valid return value. After a call to this function,
+ you can use dumbfile_error() to find out if an error occurred.
+
+
+unsigned long dumbfile_cgetul(DUMBFILE *f);
+
+ Reads an unsigned (nonnegative) integer from the DUMBFILE. The integer is
+ stored in a condensed format where smaller numbers use less space:
+
+ 0 to 127 1 byte
+ 128 to 16383 2 bytes
+ 16384 to 2097151 3 bytes
+ 2097152 to 268435455 4 bytes
+ 268435456 to 4294967295 5 bytes
+
+ This format is the same as that used for the times between notes in MIDI
+ files.
+
+ If an error occurs, this function returns (unsigned long)(-1), but that
+ may be a valid return value. After a call to this function, you can use
+ dumbfile_error() to find out if an error occurred.
+
+
+signed long dumbfile_cgetsl(DUMBFILE *f);
+
+ Reads a signed integer from the DUMBFILE. The integer is stored in a
+ condensed format where numbers closer to zero use less space:
+
+ -64 to 63 1 byte
+ -8192 to 8191 2 bytes
+ -1048576 to 1048575 3 bytes
+ -134217728 to 134217727 4 bytes
+ -2147483648 to 2147483647 5 bytes
+
+ If an error occurs, this function returns -1, but -1 is also a valid
+ return value. After a call to this function, you can use dumbfile_error()
+ to find out if an error occurred.
+
+
+long dumbfile_getnc(char *ptr, long n, DUMBFILE *f);
+
+ Reads n bytes from the DUMBFILE and stores them at 'ptr'. Note that the
+ pointer is to a series of chars. You may also use this function to read in
+ a series of signed chars or unsigned chars (which are both officially
+ distinct types from char), but do not use this to read ints, structs or
+ any other data type from the file. Integers must be read one at a time
+ using dumbfile_igetl(), dumbfile_cgetul(), etc. To load a struct in, you
+ must read each field separately using an appropriate function for each
+ one. For complicated data types, you can simplify this process by writing
+ a function for each struct.
+
+ dumbfile_getnc() returns the number of bytes successfully read, which will
+ be less than n if an error occurs, and may be as low as zero. If
+ dumbfile_getnc() returns -1, that means an error occurred on this DUMBFILE
+ earlier, before this function was called.
+
+
+int dumbfile_error(DUMBFILE *f);
+
+ This function returns -1 if an error has occurred with the specified
+ DUMBFILE, or 0 if all is well.
+
+
+int dumbfile_close(DUMBFILE *f);
+
+ This function closes the DUMBFILE, after which the pointer will be
+ invalid. dumbfile_close() returns the value that dumbfile_error() would
+ have returned, which is -1 if an error occurred while reading or 0
+ otherwise. Regardless of the return value, the file will always be closed
+ properly.
+
+
+*******************************
+*** stdio File Input Module ***
+*******************************
+
+
+void dumb_register_stdfiles(void);
+
+ This function registers the stdio file input module for use by DUMBFILEs.
+ FILE structs and their corresponding functions, as defined by the ANSI C
+ header stdio.h, will be used internally for all DUMBFILE input (unless
+ opened with dumbfile_open_ex()).
+
+ This must be called before dumbfile_open() is used, or else an alternative
+ system must be registered (see register_dumbfile_system() and
+ dumb_register_packfiles()).
+
+
+DUMBFILE *dumbfile_open_stdfile(FILE *p);
+
+ If you have a stdio FILE struct representing an open file, you can call
+ this if you wish to read from it using a DUMBFILE. This is useful when you
+ need to pass a DUMBFILE struct to a library function, to read an embedded
+ music file for example. When you close the DUMBFILE, you can continue
+ using the FILE struct to read what follows the embedded data.
+
+
+********************************
+*** Memory File Input Module ***
+********************************
+
+
+DUMBFILE *dumbfile_open_memory(const char *data, long size);
+
+ This function is useful if you have an image of a music file in memory.
+ You might have such an image if you use dat2s to encode a datafile
+ directly into the executable. Pass a pointer to the start of the memory,
+ and the size of the image to make sure DUMB doesn't overrun the buffer.
+ The resulting DUMBFILE will feed the contents of the image to you.
+
+ Note that the pointer is of type 'char *'. Files are series of chars, and
+ interpreting them directly as anything else isn't portable.
+
+
+**********************
+*** DUH Management ***
+**********************
+
+
+void unload_duh(DUH *duh);
+
+ Removes a DUH from memory. You must call this for all DUHs you load,
+ making sure they're not playing at the time.
+
+
+long duh_get_length(DUH *duh);
+
+ Returns the length of a DUH; 65536 represents one second. This value is
+ calculated when the DUH is created, and this function simply lifts it from
+ the struct. It may not truly correspond to the time for which the DUH will
+ generate sound. For module files, it will represent the point at which the
+ module first loops (or, in the case of some XM and MOD files, freezes).
+ Any add-ons to DUMB will provide their own code for calculating this.
+
+ The algorithm for calculating the length of a module file can be fooled,
+ but only by very deliberate methods. In the early days, when modules could
+ only be played by their editors and had to be exported to .wav or similar
+ in order to be used elsewhere, musicians would sometimes make the player
+ think it was looping when it wasn't in order to prevent their music from
+ being exported properly. If the length of a module seems a lot less than
+ it should be, the module is probably protected in this way.
+
+ Getting around this protection reliably would be extremely difficult, but
+ after considering it for a while I decided it would be better not to. The
+ musician has a right to protect his or her music in this way, and I have
+ no interest in actively breaking that protection.
+
+ (On the other hand, some musicians were just showing off!)
+
+
+***********************************
+*** IT, XM, S3M and MOD Support ***
+***********************************
+
+
+int dumb_it_max_to_mix;
+
+ Specifies the maximum number of samples DUMB will mix at any one time. The
+ default number is 64. Regardless of this value, all samples will continue
+ to be processed up to an internal maximum of 256 (roughly speaking; in
+ fact it will process one sample for each channel plus up to 192 extra
+ samples that are continuing to play owing to Impulse Tracker's New Note
+ Actions), and samples that have been cut will sound again as soon as the
+ congestion clears. Samples are given priority according to their final
+ volume after all factors affecting the volume of a sample have been
+ considered.
+
+ If you play two or more modules at once, this value represents the
+ maximum number of samples for each one. You will have to reduce it further
+ if your computer cannot keep up.
+
+ Despite the name, this variable controls XM, S3M and MOD files as well as
+ IT files.
+
+
+DUMB_IT_SIGDATA *duh_get_it_sigdata(DUH *duh);
+
+ This function attempts to retrieve the DUMB_IT_SIGDATA struct from a DUH.
+ This struct will exist for any IT, XM, S3M or MOD file, and you can use it
+ to obtain or override module-specific information. If 'duh' is NULL, or if
+ the DUH you pass contains something other than a music module, then this
+ function will return NULL (which can safely be passed to any other
+ function).
+
+
+DUMB_IT_SIGRENDERER *duh_get_it_sigrenderer(DUH_SIGRENDERER *sigrenderer);
+
+ This function attempts to retrieve the DUMB_IT_SIGRENDERER struct from a
+ DUH_SIGRENDERER. This struct will exist for any currently playing IT, XM,
+ S3M or MOD file, and you can use it to obtain or override information
+ specific to module playback. If 'sigrenderer' is NULL, or if the
+ DUH_SIGRENDERER you pass is rendering something other than a music module,
+ then this function will return NULL (which can safely be passed to any
+ other function).
+
+
+DUH_SIGRENDERER *dumb_it_start_at_order
+ (DUH *duh, int n_channels, int startorder);
+
+ This function, given a DUH containing an IT, XM, S3M or MOD file, will
+ start playing it at the specified order. If the DUH does not contain a
+ module, this function will fail and return NULL.
+
+ Note that starting at an arbitrary order may result in missing notes or
+ other playback oddities. It should be used primarily for modules that
+ contain multiple songs that start on different orders. If you wish just to
+ start some music in the middle, consider using duh_start_sigrenderer() or
+ al_start_duh() with the pos parameter set appropriately.
+
+
+void dumb_it_set_loop_callback(DUMB_IT_SIGRENDERER *sigrenderer,
+ int (*callback)(void *data), void *data);
+
+ Installs a callback which will be called every time the module loops. You
+ can pass any data pointer you like, and it will be passed to the callback
+ for you. DUMB considers a file to loop when it reaches the end, or when a
+ 'Jump to order' effect (Bxx in both IT/S3M and XM/MOD) jumps to the same
+ order or a preceding order. This can result in the loop callback being
+ called when the module isn't really looping, but this only happens if the
+ module has a very deliberate design. See duh_get_length() for further
+ musings on this subject.
+
+ If your callback returns nonzero, the music will stop abruptly. Samples
+ will be cut, and the main program will be notified that the
+ DUH_SIGRENDERER has ended.
+
+ Alternatively, if you pass the DUMB_IT_SIGRENDERER for 'data', or
+ otherwise arrange for it to be available to the callback, then you can
+ call:
+
+ dumb_it_sr_set_speed(sigrenderer, 0);
+
+ from inside the callback, and this will cause the music to freeze but
+ samples will be able to continue playing. The xm_speed_zero callback will
+ NOT be called in this case (see below for information on this callback).
+ Note also that setting the speed in this way will work equally for IT and
+ S3M files, even though a 'speed zero' effect can only exist in XM and MOD
+ files. Beware when using this method; samples might not fade at all!
+
+ A helper callback, dumb_it_callback_terminate(), is provided; installing
+ this will cause the music to terminate when it tries to loop for the first
+ time.
+
+ Pass NULL to remove the callback function; the module will then loop as
+ normal.
+
+
+void dumb_it_set_xm_speed_zero_callback(DUMB_IT_SIGRENDERER *sigrenderer,
+ int (*callback)(void *data), void *data);
+
+ Installs a callback which is in many ways similar to the loop callback
+ (see dumb_it_set_loop_callback()). This callback will be called whenever
+ an F00 effect is encountered in a MOD or XM file, setting the speed to
+ zero. If the callback returns nonzero, the music will terminate. If not,
+ any currently playing samples will continue to play. You can pass any data
+ pointer you like to this function, and it will be passed to your callback
+ for you.
+
+ The helper callback, dumb_it_callback_terminate(), will also work here;
+ installing it will cause the music to terminate as soon as an F00 effect
+ is encountered.
+
+ Pass NULL to remove the callback function.
+
+
+void dumb_it_set_midi_callback(DUMB_IT_SIGRENDERER *sigrenderer,
+ int (*callback)(void *data, int channel, unsigned char byte),
+ void *data);
+
+ Installs a callback function which will be called whenever MIDI data are
+ generated by an IT file. (No other module formats are capable of
+ generating MIDI data, so your callback will never be called.)
+
+ Zxx macros will generate MIDI data. These are most often used to set the
+ parameters for IT's low-pass resonant filters, and DUMB will handle these
+ messages by itself by default. See Impulse Tracker's documentation for
+ the MIDI messages that control filters. However, Zxx macros can be used
+ to send any kind of MIDI data.
+
+ If you wish to interpret MIDI messages yourself, you can use this
+ callback. Note that the only MIDI messages generated by DUMB at present
+ are from Zxx macros; there are no messages for note start, stop, or
+ anything else.
+
+ If you return 1 from this callback, DUMB will subsequently ignore the byte
+ of MIDI data. You can use this to prevent Zxx macros from controlling the
+ filters, useful if they were intended to do something else. Note that this
+ is NOT an effective way to disable filters, since instruments can have
+ filter envelopes and initial filter parameters. DUMB provides no means to
+ disable filters, as any IT file that uses them will sound wrong without
+ them. If you want lower processor consumption, use a different piece of
+ music.
+
+ A helper callback, dumb_it_callback_midi_block(), is provided for blocking
+ all MIDI messages and making Zxx macros do nothing.
+
+ Pass NULL to remove the callback.
+
+
+int dumb_it_callback_terminate(void *data);
+
+ This is a helper callback that can be installed with both
+ dumb_it_set_loop_callback() and dumb_it_set_xm_speed_zero_callback(). In
+ each case it will cause the music to terminate abruptly.
+
+
+int dumb_it_callback_midi_block(void *data, int channel, unsigned char byte);
+
+ This helper callback, for use with dumb_it_set_midi_callback(), will
+ absorb all MIDI messages, returning 1 to prevent DUMB from interpreting
+ them itself.
+
+
+DUH *dumb_load_it(const char *filename);
+
+ Loads the specified Impulse Tracker file, encapsulating it in a DUH
+ struct. Once the file is loaded, it can be treated exactly the same as any
+ other DUH in memory. If this fails it will return NULL, but you can safely
+ pass this NULL value to DUMB's other functions, so you do not need to
+ check the return value explicitly.
+
+
+DUH *dumb_read_it(DUMBFILE *f);
+
+ Reads an Impulse Tracker file from an already open DUMBFILE. This leaves
+ the DUMBFILE open, but the DUMBFILE may not be positioned at the end of
+ the IT data. If you are embedding an IT in another file, you are advised
+ to store the size of the IT file and make up for it at the end using
+ dumbfile_pos().
+
+ Otherwise, this function is identical to dumb_load_it().
+
+ WARNING: The behaviour of this function is undefined if you pass a
+ DUMBFILE from which data have already been read; it is likely not
+ to work. This oversight will be fixed in future releases.
+
+
+DUH *dumb_load_xm(const char *filename);
+
+ Loads the specified Fast Tracker II file, encapsulating it in a DUH
+ struct. Once the file is loaded, it can be treated exactly the same as any
+ other DUH in memory. If this fails it will return NULL, but you can safely
+ pass this NULL value to DUMB's other functions, so you do not need to
+ check the return value explicitly.
+
+
+DUH *dumb_read_xm(DUMBFILE *f);
+
+ Reads a Fast Tracker II file from an already open DUMBFILE. This leaves
+ the DUMBFILE open, but the DUMBFILE may not be positioned at the end of
+ the XM data. If you are embedding an XM in another file, you are advised
+ to store the size of the XM file and make up for it at the end using
+ dumbfile_pos().
+
+ Otherwise, this function is identical to dumb_load_xm().
+
+ WARNING: The behaviour of this function is undefined if you pass a
+ DUMBFILE from which data have already been read; it is likely not
+ to work. This oversight will be fixed in future releases.
+
+
+DUH *dumb_load_s3m(const char *filename);
+
+ Loads the specified Scream Tracker 3 file, encapsulating it in a DUH
+ struct. Once the file is loaded, it can be treated exactly the same as any
+ other DUH in memory. If this fails it will return NULL, but you can safely
+ pass this NULL value to DUMB's other functions, so you do not need to
+ check the return value explicitly.
+
+
+DUH *dumb_read_s3m(DUMBFILE *f);
+
+ Reads a Scream Tracker 3 file from an already open DUMBFILE. This leaves
+ the DUMBFILE open, but the DUMBFILE may not be positioned at the end of
+ the S3M data. If you are embedding an S3M in another file, you are advised
+ to store the size of the S3M file and make up for it at the end using
+ dumbfile_pos().
+
+ Otherwise, this function is identical to dumb_load_s3m().
+
+ WARNING: The behaviour of this function is undefined if you pass a
+ DUMBFILE from which data have already been read; it is likely not
+ to work. This oversight will be fixed in future releases.
+
+
+DUH *dumb_load_mod(const char *filename);
+
+ Loads the specified Amiga module file, encapsulating it in a DUH struct.
+ Once the file is loaded, it can be treated exactly the same as any other
+ DUH in memory. If this fails it will return NULL, but you can safely pass
+ this NULL value to DUMB's other functions, so you do not need to check the
+ return value explicitly.
+
+
+DUH *dumb_read_mod(DUMBFILE *f);
+
+ Reads an Amiga module file from an already open DUMBFILE. This leaves the
+ DUMBFILE open, but the DUMBFILE may not be positioned at the end of the
+ MOD data. If you are embedding a MOD in another file, you are advised to
+ store the size of the MOD file and make up for it at the end using
+ dumbfile_pos().
+
+ Otherwise, this function is identical to dumb_load_mod().
+
+ WARNING: The behaviour of this function is undefined if you pass a
+ DUMBFILE from which data have already been read; it is likely not
+ to work. This oversight will be fixed in future releases.
+
+
+int dumb_it_sd_get_n_orders(DUMB_IT_SIGDATA *sd);
+
+ This function returns the number of orders in the module.
+
+
+int dumb_it_sd_get_initial_global_volume(DUMB_IT_SIGDATA *sd);
+void dumb_it_sd_set_initial_global_volume(DUMB_IT_SIGDATA *sd, int gv);
+
+ These functions obtain and set the initial global volume for the module.
+ This value ranges from 0 to 128 inclusive. The module can set the global
+ volume itself during playback, so your change may not last throughout the
+ playback.
+
+
+int dumb_it_sd_get_mixing_volume(DUMB_IT_SIGDATA *sd);
+void dumb_it_sd_set_mixing_volume(DUMB_IT_SIGDATA *sd, int mv);
+
+ These functions obtain and set the mixing volume for the module. This
+ value ranges from 0 to 128 inclusive, and does not change during playback.
+ IT files have the mixing volume stored in them; for other formats it is
+ set to 48 on loading.
+
+
+int dumb_it_sd_get_initial_speed(DUMB_IT_SIGDATA *sd);
+void dumb_it_sd_set_initial_speed(DUMB_IT_SIGDATA *sd, int speed);
+int dumb_it_sd_get_initial_tempo(DUMB_IT_SIGDATA *sd);
+void dumb_it_sd_set_initial_tempo(DUMB_IT_SIGDATA *sd, int tempo);
+
+ These functions obtain and set the initial speed and tempo for the module.
+ During module playback, everything happens on a tick. If a beat is 24
+ ticks, then the tempo is measured in beats per second. The speed is then
+ the number of ticks per row. With a speed of 6, a beat is then four rows.
+
+ Modules can set these values during playback, so your change may not last
+ throughout the playback. MOD files have to set the speed and tempo on the
+ first row if they want anything other than the default 6/125, so your
+ change may not be noticed at all!
+
+
+int dumb_it_sd_get_initial_channel_volume(DUMB_IT_SIGDATA *sd, int channel);
+void dumb_it_sd_set_initial_channel_volume(DUMB_IT_SIGDATA *sd, int channel,
+ int volume);
+
+ These functions obtain and set the initial volume for the specified
+ channel. The channel parameter is 0-based (contrary to the display in most
+ trackers so be careful), and can range from 0 to DUMB_IT_N_CHANNELS - 1,
+ i.e. from 0 to 63.
+
+ Modules can set their channel volumes during playback, so your changes may
+ not last throughout the playback.
+
+
+int dumb_it_sr_get_current_order(DUMB_IT_SIGRENDERER *sr);
+int dumb_it_sr_get_current_row(DUMB_IT_SIGRENDERER *sr);
+
+ These functions return the current order and row of playback. Both are
+ 0-based. If the DUMB_IT_SIGRENDERER is invalid, or has been terminated
+ by a callback (see dumb_it_set_loop_callback() and
+ dumb_it_set_xm_speed_zero_callback()), these functions will both return
+ -1.
+
+
+int dumb_it_sr_get_global_volume(DUMB_IT_SIGRENDERER *sr);
+void dumb_it_sr_set_global_volume(DUMB_IT_SIGRENDERER *sr, int gv);
+
+ These functions obtain and set the current global volume for the module.
+ This value ranges from 0 to 128 inclusive. The module can set the global
+ volume itself during playback, so your change may not last.
+
+
+int dumb_it_sr_get_tempo(DUMB_IT_SIGRENDERER *sr);
+void dumb_it_sr_set_tempo(DUMB_IT_SIGRENDERER *sr, int tempo);
+int dumb_it_sr_get_speed(DUMB_IT_SIGRENDERER *sr);
+void dumb_it_sr_set_speed(DUMB_IT_SIGRENDERER *sr, int speed);
+
+ These functions obtain and set the current speed and tempo of the module.
+ See the dumb_it_sd_*() equivalents of these functions for details on what
+ the speed and tempo mean.
+
+ Modules can set these values during playback, so your change may not last.
+
+
+int dumb_it_sr_get_channel_volume(DUMB_IT_SIGRENDERER *sr, int channel);
+void dumb_it_sr_set_channel_volume(DUMB_IT_SIGRENDERER *sr, int channel,
+ int volume);
+
+ These functions obtain and set the current volume for the specified
+ channel. The channel parameter is 0-based (contrary to the display in most
+ trackers so be careful), and can range from 0 to DUMB_IT_N_CHANNELS - 1,
+ i.e. from 0 to 63.
+
+ Modules can set their channel volumes during playback, so your changes may
+ not last.
+
+
+void dumb_it_sr_get_channel_state(DUMB_IT_SIGRENDERER *sr, int channel,
+ DUMB_IT_CHANNEL_STATE *state);
+
+ Returns the current playback state of the given channel. If you pass a
+ channel in the range 0 to DUMB_IT_N_CHANNELS-1 (0 to 63), you will get the
+ state of the most recently played note on that physical channel, if it is
+ still playing. For MOD, S3M and XM files, that's all there is to it.
+
+ IT files can have more than one note playing on a single channel, courtesy
+ of New Note Actions. This function also lets you query all the notes that
+ have been forced into the background and are still playing. For this, set
+ 'channel' to a value from DUMB_IT_N_CHANNELS to DUMB_IT_TOTAL_CHANNELS-1.
+ DUMB_IT_TOTAL_CHANNELS is defined as follows:
+
+ #define DUMB_IT_TOTAL_CHANNELS \
+ (DUMB_IT_N_CHANNELS + DUMB_IT_N_NNA_CHANNELS)
+
+ Querying these background channels for MOD, S3M and XM files will not do
+ any harm; the function will report that these channels are inactive. For
+ all files, be sure not to query any channel numbers greater than or equal
+ to DUMB_IT_TOTAL_CHANNELS.
+
+ You must provide a pointer to a preallocated DUMB_IT_CHANNEL_STATE struct.
+ The easiest way to do this is as follows:
+
+ DUMB_IT_CHANNEL_STATE state;
+ dumb_it_sr_get_channel_state(sr, channel, &state);
+
+ or:
+
+ DUMB_IT_CHANNEL_STATE state[IT_TOTAL_CHANNELS];
+ dumb_it_sr_get_channel_state(sr, channel, &state[channel]);
+
+ This struct contains the following fields:
+
+ int channel;
+ int sample;
+ int freq;
+ float volume;
+ unsigned char pan;
+ signed char subpan;
+ unsigned char filter_cutoff;
+ unsigned char filter_subcutoff;
+ unsigned char filter_resonance;
+
+ The first field to check is 'sample'; if this is 0, then the channel is
+ inactive and the other fields are undefined. Otherwise, it is the index of
+ the currently playing sample, and is 1-based.
+
+ The channel number is returned, 0-based. This will be the same as the
+ channel number you passed, unless you are querying a background channel in
+ which case it will represent the channel the note originated on.
+
+ The freq field is the current playback frequency, taking into account all
+ phenomena such as slides, vibrato and arpeggio.
+
+ The volume field ranges from 0.0f to 1.0f. In practical terms, it will
+ rarely reach 1.0f; if it does, the module is probably clipping a lot. This
+ takes mixing volume into account, along with all the other volume
+ phenomena in the IT file. The only one it doesn't take into account is the
+ one you pass to duh_render() or duh_sigrenderer_get_samples(), or the one
+ you passed to al_start_duh() (these are in fact the same thing).
+
+ The pan field ranges from 0 to 64 for a normally panned sample, but will
+ be 100 if the sample is playing using IT's surround mode where the right-
+ hand channel is inverted. If you want a more accurate pan reading, use one
+ of the following to get one:
+
+ int scaled_pan = ((int)state.pan << 8) + state.subpan;
+ float float_pan = state.pan + state.subpan / 256.0f;
+
+ The first will give a scaled value ranging (strictly) from 0 to 64*256.
+ The second will give a floating-point value whose scale corresponds to
+ that of the pan field. These results will only be valid if surround mode
+ is off, so you should check that pan <= 64 before using the above
+ expressions. At the time of writing, pitch-pan separation and panning
+ envelopes take advantage of the extra accuracy offered by subpan.
+
+ Note that subpan is signed. This means applications that only look at the
+ pan field will get an unbiased reading.
+
+ The filter cut-off and resonance both range from 0 to 127. If the cut-off
+ is 127 and the resonance is 0, then no filters are applied. These
+ parameters only ever change from the default values for IT files.
+
+ While IT allows you to set 127 different filter cut-off levels in the
+ patterns and as a default value per instrument, it also allows you to
+ create a filter envelope, which will result in an actual cut-off somewhere
+ between 0 and the first-mentioned value. By the time this has been
+ calculated, the actual cut-off may lie in between two levels on the
+ original scale. If this is the case, filter_subcutoff will be nonzero and
+ you can combine it with filter_cutoff. Typically you will want to use one
+ of the following:
+
+ int scaled_cutoff = ((int)state.filter_cutoff << 8) +
+ state.filter_subcutoff;
+
+ float float_cutoff = state.filter_cutoff +
+ state.filter_subcutoff / 256.0f;
+
+ The first will give you a scaled value whose maximum is 127*256. The
+ second will give you a floating-point value whose scale corresponds to the
+ scale used by filter_cutoff. These match the expressions given further up
+ for pan and subpan, but in this case, filter_subcutoff is unsigned.
+
+ Note that filter_subcutoff will always be zero if filter_cutoff is 127, so
+ you need not check it if you simply wish to determine whether filters are
+ being applied.
+
+
+*******************************
+*** DUH Rendering Functions ***
+*******************************
+
+
+ Use these functions to generate samples from a DUH. First you call
+ duh_start_sigrenderer() with the DUH, the number of channels you want and
+ the position at which you want to start. Then you use duh_render() or
+ duh_sigrenderer_get_samples() to generate the samples. You can call these
+ functions as many times as you like, and they will generate as many or as
+ few samples as you require. When you have finished, call
+ duh_end_sigrenderer().
+
+
+DUH_SIGRENDERER *duh_start_sigrenderer
+ (DUH *duh, int sig, int n_channels, long pos);
+
+ Starts a DUH_SIGRENDERER off. This is the struct you can use to get
+ samples from a DUH. This function does not generate any samples; you must
+ pass the struct to duh_render() or duh_sigrenderer_get_samples() for that.
+ When you have finished with it, you must pass it to duh_end_sigrenderer().
+ You can use as many DUH_SIGRENDERER structs as you like at the same time.
+
+ Set sig to 0 for now. Currently, n_channels can only be 1 or 2, for
+ monaural and stereo sound respectively. The debugging library will cause
+ your program to abort if you pass anything else. Future versions will be
+ enhanced to support more channels as soon as someone needs them.
+
+ When specifying the position, 0 represents the start of the DUH, and 65536
+ represents one second. Unlike most other music systems, DUMB will always
+ make sure every note is there right from the start (assuming you aren't
+ using any broken add-ons). In other words, you can start a DUH at a point
+ halfway through a long note, and you will still hear the long note.
+
+
+void duh_sigrenderer_set_analyser_callback(DUH_SIGRENDERER *sigrenderer,
+ DUH_SIGRENDERER_ANALYSER_CALLBACK callback, void *data);
+
+ Installs a callback function which will be called every time the given
+ sigrenderer is used to generate some samples. This can be used to create
+ an oscilloscope or spectrum analyser. DUH_SIGRENDERER_ANALYSER_CALLBACK is
+ defined as follows:
+
+ typedef void (*DUH_SIGRENDERER_ANALYSER_CALLBACK)(void *data,
+ const sample_t *const *samples, int n_channels, long length);
+
+ If the above confuses you, see fnptr.txt. As for the 'samples' parameter,
+ the first 'const' says that the samples are read-only; the second says
+ that each channel's sample pointer is also read-only. If you don't
+ understand this, don't worry about it.
+
+ Beware: your callback function may occasionally be called with
+ samples == NULL. This means the main program has decided to skip through
+ the music without generating any data (see duh_sigrenderer_get_samples()).
+ You should handle this case elegantly, typically by returning immediately,
+ but you may wish to make a note of the fact that the music is being
+ skipped, for whatever reason.
+
+ Beware again: if the main program ever calls duh_sigrenderer_get_samples()
+ on a buffer that isn't all silence, this callback function will be passed
+ the existing buffer after mixing, and thus it will include the original
+ data. This will not be an issue if you stick to duh_render(), which always
+ starts with a buffer filled with silence.
+
+ The samples array is two-dimensional. Refer to it as follows:
+
+ samples[channel_number][sample_position]
+
+ where 0 <= channel_number < n_channels,
+ and 0 <= sample_position < length.
+
+ In addition you can pass any 'data' pointer you like to
+ duh_sigrenderer_set_analyser_callback(), and this pointer will be relayed
+ to your callback function each time.
+
+ To remove the callback function, pass NULL to
+ duh_sigrenderer_set_analyser_callback().
+
+
+int duh_sigrenderer_get_n_channels(DUH_SIGRENDERER *sigrenderer);
+
+ Tells you how many channels a DUH_SIGRENDERER is set up to generate, or 0
+ if it is invalid (perhaps owing to lack of memory). This will be 1 for
+ monaural sound or 2 for stereo, in this release.
+
+
+long duh_sigrenderer_get_position(DUH_SIGRENDERER *sigrenderer);
+
+ Tells you what position a DUH_SIGRENDERER is up to, or -1 if it is invalid
+ (perhaps owing to lack of memory). As usual, 65536 is one second.
+
+
+long duh_sigrenderer_get_samples(DUH_SIGRENDERER *sigrenderer,
+ float volume, float delta,
+ long size, sample_t **samples);
+
+ Generates some samples in DUMB's internal 32-bit format (see sample_t; see
+ also duh_render()). The samples buffer is a two-dimensional array, and can
+ be allocated with create_sample_buffer(); see
+ duh_sigrenderer_set_analyser_callback() for details.
+ duh_sigrenderer_get_samples() mixes sample data with what's already in the
+ buffer, so you have to call dumb_silence() first.
+
+ The volume is a float. 1.0f is the pseudo-maximum. If you pass 1.0f, any
+ properly designed DUH will play nice and loud, but will not clip. You can
+ pass a greater volume if you like, but be prepared for the possibility of
+ distortion due to integer overflow. Of course you can pass smaller values
+ to play the DUH more quietly, and this will also resolve clipping issues
+ in badly designed DUHs.
+
+ Use delta to control the speed of the output signal. If you pass 1.0f, the
+ resultant signal will be suitable for a 65536-Hz sampling rate (which
+ isn't a commonly used rate). The most common sampling rates are 11025 Hz,
+ 22050 Hz, 44100 Hz and 48000 Hz. You can work out the required delta value
+ as follows:
+
+ delta = 65536.0f / sampling_rate;
+
+ If you then increase this value, the DUH will speed up and increase in
+ pitch. If you decrease it, the DUH will slow down and decrease in pitch.
+
+ This function will attempt to render 'size' samples. In most cases it will
+ succeed. However, if the end of the DUH is reached, it may render fewer.
+ The number of samples rendered will be returned. Therefore, if the return
+ value is less than the value of 'size' passed, you know the DUH has
+ finished. It is safe to continue calling duh_sigrenderer_get_samples() if
+ you wish, and it will continually return 0.
+
+ If the DUH_SIGRENDERER is a null pointer, this function will generate
+ precisely 0 samples. If you pass NULL for 'samples', the function will
+ behave exactly the same as if you provided a sample buffer, except the
+ samples won't be stored anywhere and the function will execute very
+ quickly. This can be used to skip ahead in the audio.
+
+
+long duh_render(DUH_SIGRENDERER *sigrenderer,
+ int bits, int unsign,
+ float volume, float delta,
+ long size, void *sptr);
+
+ Generates some samples and converts them to an 8-bit or 16-bit format (see
+ also duh_sigrenderer_get_samples()). Pass the DUH_SIGRENDERER as returned
+ by duh_start_sigrenderer(). Pass the number of bits, which should be 8 or
+ 16. If unsign is nonzero, the samples will be unsigned (centred on 0x80 or
+ 0x8000 for 8 bits and 16 bits respectively). If unsign is zero, the
+ samples will be signed.
+
+ Allegro's audio streams always take unsigned samples. 8-bit .wav files
+ always take unsigned samples. 16-bit .wav files always take signed
+ samples.
+
+ The volume and delta parameters work the same as for
+ duh_sigrenderer_get_samples().
+
+ This function will attempt to render 'size' samples. In most cases it will
+ succeed. However, if the end of the DUH is reached, it may render fewer.
+ The number of samples rendered will be returned. Therefore, if the return
+ value is less than the value of 'size' passed, you know the DUH has
+ finished. It is safe to continue calling duh_render() if you wish, and it
+ will continually return 0. However, if you wish to do this, you will
+ probably have to fill the rest of the buffer with silence, which is 0 for
+ signed, 0x80 for 8-bit unsigned or 0x8000 for 16-bit unsigned.
+
+ The samples will be placed at sptr. Use an array of chars for 8 bits or an
+ array of shorts for 16 bits. Stereo samples will be interleaved, left
+ first. Your array should contain at least (size * n_channels) elements of
+ the appropriate bit resolution.
+
+ From an aesthetic standpoint if nothing else, it is wise to use the C
+ qualifiers 'signed' or 'unsigned' depending on whether the samples are
+ signed or unsigned. This is also convenient if you wish to process the
+ samples further yourself.
+
+ If the DUH_SIGRENDERER is a null pointer, this function will generate
+ precisely 0 samples. Unlike with duh_sigrenderer_get_samples(), you must
+ specify a sample buffer.
+
+
+void duh_end_sigrenderer(DUH_SIGRENDERER *dr);
+
+ Terminates a DUH_SIGRENDERER. Be sure to call this when you've finished
+ with one. You can safely pass a null pointer.
+
+
+********************************
+*** Allegro Packfile Support ***
+********************************
+
+
+void dumb_register_packfiles(void);
+
+ This function registers the Allegro PACKFILE input module for use by
+ DUMBFILEs. PACKFILE structs and their corresponding functions, as defined
+ by Allegro's header file allegro.h, will be used internally for all
+ DUMBFILE input (unless opened with dumbfile_open_ex()).
+
+ This must be called before dumbfile_open() is used, or else an alternative
+ system must be registered (see register_dumbfile_system() and
+ dumb_register_stdfiles()). Note that you don't have to call this function
+ in order to load datafiles that contain music.
+
+
+DUMBFILE *dumbfile_open_packfile(PACKFILE *p);
+
+ If you have an Allegro PACKFILE struct representing an open file, you can
+ call this if you wish to read from it using a DUMBFILE. This is useful
+ when you need to pass a DUMBFILE struct to a library function, to read an
+ embedded music file for example. When you close the DUMBFILE, you can
+ continue using the PACKFILE struct to read what follows the embedded data.
+
+
+DUMBFILE *dumbfile_from_packfile(PACKFILE *p);
+
+ This function is the same as dumbfile_open_packfile(), except it will
+ check if p is NULL, and arrange for pack_fclose() to be called on the
+ PACKFILE when you close the DUMBFILE. It can be seen as a function for
+ converting a PACKFILE to a DUMBFILE, but it will only work for a PACKFILE
+ you obtained with pack_fopen(), not pack_fopen_chunk(). If this function
+ fails, which may happen if memory is short, then the PACKFILE will be
+ closed immediately, so you need not worry about potential memory leaks or
+ files being left open when this happens.
+
+ The following is typical usage, and will open the compressed file foo.bin:
+
+ DUMBFILE *f = dumbfile_from_packfile(pack_fopen("foo.bin",
+ F_READ_PACKED));
+
+ This differs from calling dumb_register_packfiles() and dumbfile_open() in
+ that the latter will only read uncompressed files (and is thus a method
+ suitable for reading music modules).
+
+
+***********************************************
+*** Allegro Datafile Registration Functions ***
+***********************************************
+
+
+void dumb_register_dat_it(long type);
+
+ If you wish to embed an IT file in an Allegro datafile, it is recommended
+ that you use "IT " for the type. The grabber will have a box for the type
+ when you insert a new object. The grabber will treat the IT file as binary
+ data, which means the datafile will contain an exact copy of the IT file
+ on disk.
+
+ You must then call dumb_register_dat_it(DUMB_DAT_IT) in your program
+ before you load the datafile. Once you've done this, you'll be able to
+ access the DUH using the usual datafile[n].dat notation. You do not need
+ to call unload_duh() on this DUH; unload_datafile() will do that for you.
+
+ If you are using a different type for whatever reason, you can use
+ Allegro's DAT_ID() macro for encoding it and passing it to this function.
+ For example:
+
+ dumb_register_dat_it(DAT_ID('B','L','A','H'));
+
+ Assuming you used the recommended type, the following example iterates
+ through all the ITs in disan.dat:
+
+ DATAFILE *dat;
+ int n;
+
+ dumb_register_dat_it();
+ dat = load_datafile("disan.dat");
+
+ for (n = 0; dat[n].type != DAT_END; n++) {
+ if (dat[n].type == DUMB_DAT_IT) {
+ DUH *duh = dat[n].dat;
+ /* Insert code here to play 'duh' or whatever you want to do. */
+ }
+ }
+
+ unload_datafile(dat);
+
+
+void dumb_register_dat_xm(long type);
+
+ Inserting an XM file in an Allegro datafile is the same as inserting an IT
+ file, except that the recommended type is "XM ", the registration
+ function is dumb_register_dat_xm(), and the macro DUMB_DAT_XM is provided
+ for the type. The intuitive process of substituting XM for IT in the above
+ method will work.
+
+
+void dumb_register_dat_s3m(long type);
+
+ Inserting an S3M file in an Allegro datafile is the same as inserting an
+ IT file, except that the recommended type is "S3M ", the registration
+ function is dumb_register_dat_s3m(), and the macro DUMB_DAT_S3M is
+ provided for the type. The intuitive process of substituting S3M for IT in
+ the above method will work.
+
+
+void dumb_register_dat_mod(long type);
+
+ Inserting a MOD file in an Allegro datafile is the same as inserting an IT
+ file, except that the recommended type is "MOD ", the registration
+ function is dumb_register_dat_mod(), and the macro DUMB_DAT_MOD is
+ provided for the type. The intuitive process of substituting MOD for IT in
+ the above method will work.
+
+
+****************************************
+*** Sample Buffer Allocation Helpers ***
+****************************************
+
+
+ Many parts of DUMB require sample buffers allocated in a special way. A
+ pointer to one looks like this:
+
+ sample_t **samples;
+
+ and it can be indexed as follows:
+
+ samples[channel_number][sample_position]
+
+ where 0 <= channel_number < n_channels
+ and 0 <= sample_position < length.
+
+ The following helpers will allocate and deallocate such buffers for you.
+ They will not initialise them, and DUMB always writes into these buffers
+ by adding to what's already there, so you will generally have to call
+ dumb_silence() too.
+
+
+sample_t **create_sample_buffer(int n_channels, long length);
+
+ This will allocate a sample buffer to hold the specified number of samples
+ for the specified number of channels. Don't forget to check the return
+ value!
+
+ You will generally have to initialise the buffer by calling
+ dumb_silence(); the channels will be stored consecutively in memory, so
+ the following technique is officially supported:
+
+ dumb_silence(samples[0], n_channels * length);
+
+ See dumb_silence() for general information on what this function does.
+
+
+void destroy_sample_buffer(sample_t **samples);
+
+ This function does the obvious: it frees up a sample buffer when you've
+ finished with it. It is safe to pass a null pointer to this function.
+
+
+************************
+*** Silencing Helper ***
+************************
+
+
+void dumb_silence(sample_t *samples, long length);
+
+ This function simply stores 'length' samples' worth of silence in the
+ array. It is typically used straight after allocating a sample buffer with
+ create_sample_buffer().
+
+
+**************************
+*** Resampling Helpers ***
+**************************
+
+
+ Please forgive the odd section name; it has to do with DUMB's internal
+ structure and the fact that the resampling algorithm is there not just for
+ use in rendering module files but for use anywhere that a waveform needs
+ resampling. Unfortunately DUMB's resampling algorithm is not ready to be
+ documented and used yet. However, one thing can be documented, and that's
+ the global variable controlling the resampling quality.
+
+ (Ironically, even this variable has changed! See deprec.txt for
+ information on what it used to do.)
+
+
+int dumb_resampling_quality;
+
+ Allows you to control the quality of all resampling that takes place. This
+ may be set to any DUMB_RQ_* constant (except DUMB_RQ_N_LEVELS). Higher
+ values will sound better, but lower values will use up less processor
+ time. You may compare any two DUMB_RQ_* constants or values using the
+ integer inequalities <, <=, > and >=; higher numbers represent higher-
+ quality algorithms.
+
+ #define DUMB_RQ_ALIASING
+
+ | --___ 'Aliasing' has very noticeable and usually unwanted
+ |__--- __ overtones. It will occasionally produce acceptable
+ | ___-- results for noisy (impure) samples (or for cheap
+ speakers!), but usually you will want to pay for
+ the extra processor time, which isn't much, and go for linear
+ interpolation.
+
+ #define DUMB_RQ_LINEAR
+
+ | __ Linear interpolation is a pretty good algorithm in most
+ | / \ /\ cases. When resampling down a few octaves, however, you
+ |/ \/ \__ may begin to notice unwanted high frequencies. You can
+ reduce these by switching to cubic interpolation, but it
+ will cost you some processor time.
+
+ #define DUMB_RQ_CUBIC
+
+ Cubic interpolation looks like a smooth curve to the eye, and will
+ produce good results in most cases. At present this is the highest
+ quality offered by DUMB, and also the default. While this may seem
+ extravagant, GCC 3.x and an AthlonXP handle it quite well - and the
+ general trend is for processors to get better!
+
+ #define DUMB_RQ_N_LEVELS
+
+ This represents the number of resampling quality levels DUMB provides.
+ Values of dumb_resampling_quality from 0 to DUMB_RQ_N_LEVELS - 1 are
+ valid. You can use this constant if you wish to offer the resampling
+ quality as an option for the user.
+
+
+*************************************
+*** Allegro DUH Playing Functions ***
+*************************************
+
+
+ The functions in this section allow you to play back a DUH through
+ Allegro's sound system. You must call Allegro's install_sound() function
+ before you use them.
+
+
+AL_DUH_PLAYER *al_start_duh(DUH *duh, int n_channels, long pos,
+ float volume, long bufsize, int freq);
+
+ Starts playing the specified DUH.
+
+ An AL_DUH_PLAYER represents one instance of the DUH playing. If you wish,
+ you can have two or more AL_DUH_PLAYERs going at the same time, for the
+ same DUH or for different ones. Each uses one of Allegro's audio streams
+ and hence one voice. The voice will be given priority 255 initially, so a
+ build-up of sound effects will not cause your music streams to cut off (as
+ long as you don't give all your sound effects priority 255!). You can
+ change the priority of a stream with al_duh_set_priority(). See Allegro's
+ documentation for more information on how voice priorities work.
+
+ At present, n_channels can either be 1 or 2 for monaural or stereo
+ respectively. If you use the debugging library, your program will abort if
+ other values are passed; otherwise weird things will happen.
+
+ The DUH will start playing from position 'pos'. 0 represents the start of
+ the DUH, and 65536 represents one second. Unlike other music systems, DUMB
+ will always make sure every note is there right from the start. In other
+ words, you can start a DUH at a point halfway through a long note, and you
+ will still hear the long note.
+
+ The volume is a float. 1.0f is the pseudo-maximum. If you pass 1.0f, any
+ properly designed DUH file will play nice and loud, but will not clip. You
+ can pass a greater volume if you like, but be prepared for clipping to
+ occur. Of course you can pass smaller values to play the DUH more quietly,
+ and this will also resolve clipping issues in badly designed DUH files.
+
+ You will need to pass the AL_DUH_PLAYER to other functions when you need
+ to stop or pause the DUH, change its volume, or otherwise modify the way
+ it is playing. You will also need to pass it to al_poll_duh() at regular
+ intervals; if the sound is choppy, try calling al_poll_duh() more often.
+
+ 'bufsize' is the number of samples that will be rendered at once. 1024 is
+ a suitable value for most purposes. The greater this is, the less often
+ you will have to call al_poll_duh() - but when al_poll_duh() decides to
+ fill the buffer, it will take longer doing so. If your game exhibits
+ regular brief freezes, try reducing the buffer size. If the sound is
+ choppy, however, you may have to increase it.
+
+ 'freq' specifies the sampling frequency at which the DUH should be
+ rendered. At present there is no (official and portable) way of knowing
+ the frequency at which Allegro is mixing - but if you do know that
+ frequency, passing it here will give the highest quality sound. If you
+ reduce it, the DUH will sound less crisp but use less processor time.
+
+ When you have finished, you must pass the AL_DUH_PLAYER to al_stop_duh()
+ to free up memory. Do not destroy the DUH beforehand.
+
+ There is no real need to check the return value from this function. The
+ other functions can be called safely with null pointers, so if there is a
+ problem, your music will simply not play.
+
+
+void al_stop_duh(AL_DUH_PLAYER *dp);
+
+ This will stop an AL_DUH_PLAYER. You must call this when you have finished
+ with it, before destroying the DUH. The pointer will no longer be valid on
+ return from this function.
+
+
+void al_pause_duh(AL_DUH_PLAYER *dp);
+
+ This will pause an AL_DUH_PLAYER. Use al_resume_duh() when you want it to
+ continue. You can safely call al_poll_duh() while the music is paused, and
+ it will do nothing.
+
+
+void al_resume_duh(AL_DUH_PLAYER *dp);
+
+ Causes a paused AL_DUH_PLAYER to resume playing (see al_pause_duh()).
+
+
+void al_duh_set_priority(AL_DUH_PLAYER *dp, int priority);
+
+ This will set the priority of the audio stream underlying an
+ AL_DUH_PLAYER. The priority is an integer ranging from 0 to 255. When
+ too many samples play at the same time, those with lower priorities will
+ be cut. 128 is the usual default with Allegro, but DUMB overrides the
+ default for all AL_DUH_PLAYER structs: they will be set up initially with
+ priority 255, so your music won't be cut (unless you play too many other
+ streams or samples with priority 255). See Allegro's documentation for
+ more information on priorities.
+
+
+void al_duh_set_volume(AL_DUH_PLAYER *dp, float volume);
+
+ This will set the volume of an AL_DUH_PLAYER. See al_start_duh() for
+ details on the volume parameter.
+
+
+int al_poll_duh(AL_DUH_PLAYER *dp);
+
+ An AL_DUH_PLAYER is not interrupt-driven. That means it will not play by
+ itself. You must keep it alive from your main program. Call this function
+ at regular intervals. If the sound crackles, try calling it more often.
+ (There is nothing you can do if Windows decides to play with the hard
+ disk; that will make your sound crackle no matter what you do.)
+
+ Normally this function will return zero. However, if it returns nonzero,
+ that means the AL_DUH_PLAYER will not generate any more sound. Indeed the
+ underlying audio stream and DUH_SIGRENDERER have been destroyed. When this
+ happens, you can call al_stop_duh() whenever you wish - but you do not
+ have to. Note that this function will wait two buffers' worth of samples
+ before taking this action, allowing Allegro to mix the trailing sound
+ before the audio stream is destroyed. This is an attempt to make sure your
+ music does not get cut off prematurely, and it should work when using
+ Allegro's mixer (the only option on DOS, the default on Linux as far as I
+ know, but not the default on Windows). That said, if you immediately call
+ Allegro's remove_sound() or exit your program, the music may get cut off.
+ If you are using another mixer and experience problems, let me know (but I
+ don't guarantee to be able to come up with an elegant solution, i.e. it
+ might not get fixed).
+
+ In case you were wondering, it is not safe on all platforms to call
+ al_poll_duh() from an interrupt context (that means an Allegro timer
+ handler). Not only is no part of DUMB locked in memory, but many parts of
+ DUMB allocate and free their memory on a call-by-call basis! Remember that
+ any disk access that occurs in interrupt context is likely to crash the
+ machine; this is explained more fully in howto.txt. This limitation only
+ applies to DOS at present, and is due to the fact that the DOS file access
+ functions are not re-entrant.
+
+ Multitasking systems are generally safe. If you are sure you don't want to
+ target DOS, you can call al_poll_duh() from inside a timer handler, but I
+ recommend including a construction like the following!
+
+ #ifdef ALLEGRO_DOS
+ #error calling al_poll_duh() from a timer handler will not work in DOS!
+ #endif
+
+ Furthermore, if you call al_poll_duh() from inside a timer handler, you
+ must use a semaphore or other threading mechanism to make sure it is not
+ executing when you call al_stop_duh(). If you don't know what a semaphore
+ is, for Heaven's sake follow my advice and call al_poll_duh() from your
+ main loop!
+
+
+long al_duh_get_position(AL_DUH_PLAYER *dp);
+
+ Tells you what position an AL_DUH_PLAYER is up to, or -1 if it is invalid
+ (perhaps owing to lack of memory). As usual, 65536 is one second. Note
+ that this is a whole number, whereas a fractional part is stored
+ internally; the sample will not be continuous if you terminate the
+ AL_DUH_PLAYER and then reinitiate it with the same position. Furthermore,
+ note that Allegro will not have mixed in all the sound up to this point;
+ if you wait for this to reach a certain position and then terminate the
+ AL_DUH_PLAYER, the sound will cut off too early. Please contact me if you
+ need to get around this.
+
+
+AL_DUH_PLAYER *al_duh_encapsulate_sigrenderer
+ (DUH_SIGRENDERER *sigrenderer, float volume, long bufsize, int freq);
+
+ If you have a DUH_SIGRENDERER, and would like to start playing music from
+ it through an Allegro audio stream, use this function. Beware that it may
+ return NULL, in which case you will have to call duh_end_sigrenderer()
+ yourself instead of relying on the encapsulating AL_DUH_PLAYER to do it
+ for you.
+
+
+DUH_SIGRENDERER *al_duh_get_sigrenderer(AL_DUH_PLAYER *dp);
+
+ This returns the DUH_SIGRENDERER contained in an AL_DUH_PLAYER, useful for
+ controlling playback, installing callbacks, etc.
+
+
+DUH_SIGRENDERER *al_duh_decompose_to_sigrenderer(AL_DUH_PLAYER *dp);
+
+ This destroys an AL_DUH_PLAYER, but preserves the DUH_SIGRENDERER it
+ contains, and returns it to you. You can then continue rendering samples
+ from the DUH_SIGRENDERER and do whatever you like with them.
+
+
+*********************
+*** Thread Safety ***
+*********************
+
+
+The following points should pretty much sum up the essence of DUMB's thread
+safety. If I haven't covered the one thing you'd like to do, please don't
+hesitate to ask about it.
+
+DOs:
+
+- You may load and use multiple DUHs in separate threads.
+
+- You may change dumb_resampling_quality and dumb_it_max_to_mix while another
+ thread is generating samples.
+
+DON'Ts:
+
+- You may not generate samples from the same DUH in multiple threads, even if
+ you are using separate DUH_RENDERERs (separate AL_DUH_PLAYERS).
+
+
+******************
+*** Conclusion ***
+******************
+
+
+"DUMB is the bestest music player in the world because ..."
+
+Complete this sentence in fifteen words or fewer and receive a free copy of
+DUMB! (Your Internet Service Provider may issue charges for your connection,
+required for download of the Product. Your electricity supplier may issue
+charges for the electricity consumed in writing the Product to a Permanent
+Storage Device. You may have been charged for a Permanent Storage Device on
+which to store the Product.)
+
+
+Ben Davis
+entheh@users.sf.net
+IRC EFnet #dumb
+See readme.txt for details on using IRC.
|