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diff --git a/plugins/dumb/dumb-kode54/docs/deprec.txt b/plugins/dumb/dumb-kode54/docs/deprec.txt new file mode 100644 index 00000000..6ab7b60a --- /dev/null +++ b/plugins/dumb/dumb-kode54/docs/deprec.txt @@ -0,0 +1,281 @@ +/* _______ ____ __ ___ ___
+ * \ _ \ \ / \ / \ \ / / ' ' '
+ * | | \ \ | | || | \/ | . .
+ * | | | | | | || ||\ /| |
+ * | | | | | | || || \/ | | ' ' '
+ * | | | | | | || || | | . .
+ * | |_/ / \ \__// || | |
+ * /_______/ynamic \____/niversal /__\ /____\usic /| . . ibliotheque
+ * / \
+ * / . \
+ * deprec.txt - Deprecated functions, why they / / \ \
+ * were deprecated, and what to do | < / \_
+ * instead. | \/ /\ /
+ * \_ / > /
+ * | \ / /
+ * | ' /
+ * \__/
+ */
+
+
+**********************************************
+*** How the functions have been deprecated ***
+**********************************************
+
+
+ GCC 3.1 and later provide a very useful attribute. The following:
+
+ __attribute__((__deprecated__))
+
+ when written alongside a function prototype, variable declaration or type
+ definition, will result in a warning from GCC if any such part of the API
+ is used. The warning will even tell you where the declaration is, and I
+ have inserted comments by all the deprecated declarations, telling you
+ what to do.
+
+ Unfortunately, GCC 2.x and 3.0.x and MSVC do not have any means to
+ deprecate things. The approach I have taken with these compilers is to
+ avoid prototyping the deprecated parts of the API. This means you will get
+ warnings and errors, and they won't be very helpful. If your program
+ compiles, you may get strange crashes when you run it, since the compiler
+ needs the declarations in order to make sure function calls are carried
+ out correctly.
+
+ If you would like the deprecated parts of the API to be declared, you can
+ compile with the -DDUMB_DECLARE_DEPRECATED switch for GCC, or the
+ -D"DUMB_DECLARE_DEPRECATED" switch for MSVC. This will be accepted by
+ GCC 3.x but is unnecessary. Use this switch with other people's projects
+ if necessary, but please make the effort to update your own projects to
+ use the new API, as the deprecated parts may be removed in the future.
+
+ The rest of this file explains why some parts of the API were deprecated,
+ and how to adapt your code.
+
+
+**************************************
+*** What happened to DUH_RENDERER? ***
+**************************************
+
+
+ The DUH_RENDERER struct was designed for rendering audio to an end-user
+ format - 8-bit or 16-bit, signed or unsigned, with stereo samples
+ interleaved. In order for it to do this, it was built on top of the
+ hitherto undocumented DUH_SIGRENDERER struct, which rendered audio in
+ DUMB's internal 32-bit signed format with channels (left/right) stored
+ separately. The DUH_RENDERER struct contained a pointer to a
+ DUH_SIGRENDERER struct, along with some other data like the position and
+ number of channels.
+
+ There were then some developments in the API. The DUH_SIGRENDERER struct
+ also stored the position and the number of channels, so I decided to write
+ functions for returning these. Suddenly there was no need to store them in
+ the DUH_RENDERER struct. Before long, the DUH_RENDERER struct contained
+ nothing but a pointer to a DUH_SIGRENDERER.
+
+ I decided it would be a good idea to unify the structs. After all, there
+ really is no difference between the data stored in each, and it would be
+ easy to make duh_render(DUH_RENDERER *dr, ...) and
+ duh_render_signal(DUH_SIGRENDERER *sr, ...) work on the same type of
+ struct. (Note that duh_render_signal() is now deprecated too; see the next
+ section.) It took some deliberation, but I decided I didn't want functions
+ to be #defined (it prevents you from using these names for member
+ functions in C++ classes), and that meant they had to be defined
+ somewhere. Defining redundant functions is a source of bloat, inefficiency
+ and general inelegance. After weighing things up, I decided it was better
+ to deprecate the redundant functions and have people begin to use the more
+ efficient versions, and eventually the redundant functions will be able to
+ be removed.
+
+ So why did I choose to keep the more complicated name, DUH_SIGRENDERER?
+ The reason has to do with what DUMB will become in the future. Signals are
+ an inherent part of the DUH struct and how .duh files will be constructed.
+ It will be possible to have multiple signals in a single DUH struct, and
+ you will be able to choose which one you want to play (this is the 'sig'
+ parameter passed to duh_start_sigrenderer()). But don't hold your breath;
+ we still have a long way to go before .duh files will start to appear...
+
+
+typedef DUH_SIGRENDERER DUH_RENDERER;
+
+ Wherever you are using DUH_RENDERER in your program, simply replace it
+ with DUH_SIGRENDERER. An automated (case-sensitive!) search and replace
+ operation should get this done.
+
+
+DUH_RENDERER *duh_start_renderer(DUH *duh, int n_channels, long pos);
+
+ Use duh_start_sigrenderer() instead. It takes an extra parameter, 'sig',
+ which comes after 'duh' and before 'n_channels'; pass 0 for this. So an
+ example would be, replace:
+
+ sr = duh_start_renderer(duh, 2, 0);
+
+ with:
+
+ sr = duh_start_sigrenderer(duh, 0, 2, 0);
+
+
+int duh_renderer_get_n_channels(DUH_RENDERER *dr);
+long duh_renderer_get_position(DUH_RENDERER *dr);
+void duh_end_renderer(DUH_RENDERER *dr);
+
+ These are easy enough to fix; all you have to do is replace 'renderer'
+ with 'sigrenderer'. So the new functions are:
+
+ int duh_sigrenderer_get_n_channels(DUH_SIGRENDERER *sigrenderer);
+ long duh_sigrenderer_get_position(DUH_SIGRENDERER *sigrenderer);
+ void duh_end_sigrenderer(DUH_SIGRENDERER *sigrenderer);
+
+
+Note that duh_render() has NOT been deprecated. It now uses DUH_SIGRENDERER
+instead of DUH_RENDERER, but its functionality is unchanged. You do not have
+to change calls to this function in any way.
+
+
+DUH_RENDERER *duh_renderer_encapsulate_sigrenderer(DUH_SIGRENDERER *sr);
+DUH_SIGRENDERER *duh_renderer_get_sigrenderer(DUH_RENDERER *dr);
+DUH_SIGRENDERER *duh_renderer_decompose_to_sigrenderer(DUH_RENDERER *dr);
+
+ These functions did not exist in the last release of DUMB, so you are
+ probably not using them, but they are included here for completeness. All
+ you have to do here is unwrap the function, since the structs have been
+ unified. So, for instance, replace:
+
+ duh_renderer_encapsulate_sigrenderer(my_sigrenderer)
+
+ with:
+
+ my_sigrenderer
+
+ Simple!
+
+
+AL_DUH_PLAYER *al_duh_encapsulate_renderer(DUH_RENDERER *dr,
+ float volume, long bufsize, int freq);
+DUH_RENDERER *al_duh_get_renderer(AL_DUH_PLAYER *dp);
+DUH_RENDERER *al_duh_decompose_to_renderer(AL_DUH_PLAYER *dp);
+
+ Again, these functions were not in the last release, so you probably
+ aren't using them. Nevertheless, the fix is simple as always: simply
+ replace 'renderer' with 'sigrenderer'. So the new functions are:
+
+ AL_DUH_PLAYER *al_duh_encapsulate_sigrenderer(DUH_SIGRENDERER *sr,
+ float volume, long bufsize, int freq);
+ DUH_SIGRENDERER *al_duh_get_sigrenderer(AL_DUH_PLAYER *dp);
+ DUH_SIGRENDERER *al_duh_decompose_to_sigrenderer(AL_DUH_PLAYER *dp);
+
+
+*********************
+*** Miscellaneous ***
+*********************
+
+
+long duh_render_signal(DUH_SIGRENDERER *sigrenderer,
+ float volume, float delta,
+ long size, sample_t **samples);
+
+ This function used to return samples in DUMB's internal format. This
+ format consisted of 32-bit integers whose 'normal range' was -0x8000 to
+ 0x7FFF (any samples outside this range would have to be clipped when sent
+ to the sound card).
+
+ DUMB's internal format has changed. DUMB still uses 32-bit integers, but
+ now the normal range is -0x800000 to 0x7FFFFF. The lowest eight bits are
+ discarded at the final stage by duh_render() when you ask for 16-bit
+ output. A new function, duh_sigrenderer_get_samples(), will return samples
+ in DUMB's new internal format. It takes exactly the same parameters, so
+ all you have to do to the call itself is change the name; however, you
+ will most likely have to change your code to account for the new
+ normalised range.
+
+ duh_render_signal() will still be able to give you the samples in DUMB's
+ old internal format, but it is inefficient. You should change your code as
+ soon as possible.
+
+
+typedef void (*DUH_SIGRENDERER_CALLBACK)(void *data, sample_t **samples,
+ int n_channels, long length);
+
+void duh_sigrenderer_set_callback(DUH_SIGRENDERER *sigrenderer,
+ DUH_SIGRENDERER_CALLBACK callback, void *data);
+
+ This callback was intended to allow you to analyse the output. It was by
+ no means intended to let you modify the output. For this reason, the names
+ have been changed to DUH_SIGRENDERER_ANALYSER_CALLBACK and
+ duh_sigrenderer_set_analyser_callback, and the 'samples' parameter to your
+ callback should now be specified as follows:
+
+ const sample_t *const *samples
+
+ The first 'const' indicates that you must not modify the samples. The
+ second indicates that you must not modify the pointers to each channel.
+
+ There is a second reason why this change was necessary, and it is the one
+ described further up for duh_render_signal()'s entry: the format in which
+ the samples themselves are stored has changed. They are 256 times as
+ large, with a normal range from -0x800000 to 0x7FFFFF. You will most
+ likely need to change your code to account for this.
+
+ If you try to call the old function, it will print a message to stderr
+ directing you to this file, and it will not install the callback. You
+ shouldn't be able to get this far without a compiler warning (or, if you
+ don't have GCC 3.1 or later, some compiler errors).
+
+ If you wanted to use this callback to apply a DSP effect, don't worry;
+ there is a better way of doing this. It is undocumented, so contact me
+ and I shall try to help. Contact details are at the bottom of this file.
+
+ For reference, here are the new definitions:
+
+ typedef void (*DUH_SIGRENDERER_ANALYSER_CALLBACK)(void *data,
+ const sample_t *const *samples, int n_channels, long length);
+
+ void duh_sigrenderer_set_analyser_callback(DUH_SIGRENDERER *sigrenderer,
+ DUH_SIGRENDERER_ANALYSER_CALLBACK callback, void *data);
+
+
+int dumb_resampling_quality;
+
+ This variable has changed meaning. It used to hold a value from 0 to 4,
+ whose meaning was as follows:
+
+ 0 - aliasing
+ 1,2 - linear interpolation
+ 3 - quadratic interpolation
+ 4 - cubic interpolation
+
+ 0,1 - always use a straightforward interpolation algorithm
+ 2,3,4 - when decimating (increasing the pitch), use a linear average
+ algorithm designed to reduce frequencies that would otherwise
+ reflect off the Nyquist
+
+ Now the variable only holds values from 0 to 2, and these values have
+ preprocessor constants associated with them. The somewhat inappropriate
+ quadratic interpolation has been removed. The linear average algorithm has
+ also been removed, and may or may not come back; there are probably more
+ efficient ways of achieving the same effect, which I shall be
+ investigating in the future.
+
+ This change will have hardly any noticeable effect on existing programs.
+ Levels 2, 3 and 4 used considerably more processor time because of the
+ linear average algorithm. Likewise, Level 2 in the new scheme (cubic) uses
+ considerably more processor time than Levels 1 and 0, and Levels 3 and 4
+ will behave identically to Level 2.
+
+
+******************
+*** Conclusion ***
+******************
+
+
+"I conclude that... DUMB is the bestest music player in the world because...
+Complete this sentence in fifteen words or fewer... D'OH!"
+
+The preceding conclusion formerly appeared in dumb.txt, and is deprecated
+because it's lame.
+
+
+Ben Davis
+entheh@users.sf.net
+IRC EFnet #dumb
+See readme.txt for details on using IRC.
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