mirror of https://github.com/ZDoom/gzdoom-gles.git
142 lines
6.4 KiB
Plaintext
142 lines
6.4 KiB
Plaintext
al_duh_get_volume()
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* [23:25:12] <Mahogny> I prefer an API datagram :)
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* Create a glossary of terms like 'render', 'sigrenderer', etc.?
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* Consider the order in which stuff appears in dumb.h, and dumb.txt?
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PROPOSED CHANGE OF TERMINOLOGY:
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Current situation:
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A DUH comprises a number of "signals". A signal is an entity capable of
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producing a stream of audio. When a signal is called upon to generate
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sound, it may in turn call upon any other signals in the DUH and use the
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sound from those in generating its own.
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There are a number of "sigtypes", including 'SAMP' (a sample) and 'SEQU'
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(a sequence). Every signal in a DUH must be of one of these known types.
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Every sigtype is characterised by a four-byte identifier and the
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following function prototypes:
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typedef void signal_t;
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typedef void sampinfo_t;
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signal_t *load_signal(DUH *duh, DUMBFILE *file);
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sampinfo_t *start_samples(DUH *duh, signal_t *signal, int n_channels, long pos);
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void set_parameter(sampinfo_t *sampinfo, unsigned char id, long value);
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long render_samples(sampinfo_t *sampinfo, float volume, float delta, long size, sample_t **samples);
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void end_samples(sampinfo_t *sampinfo);
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void unload_signal(signal_t *signal);
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When a signal in a DUH needs to be loaded, DUMB's core first checks the
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identifier. If it is unknown, load_duh() fails. Each known sigtype will
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have pointers to the above functions, so DUMB's core will then call the
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load_signal() function. This loads the "signal", which could consist of
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sample data, or sequence data (like the patterns in a music module).
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(There's ambiguity here; we use the word "signal" for the whole entity
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and also for the specific data that distinguish it from other signals of
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the same sigtype.)
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Once a signal is in memory, it can be used to generate sound. Its
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start_samples() function is called for that, and a "sampinfo" block is
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returned; this will contain the current position and any necessary state
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information. render_samples() generates sound, and end_samples() destroys
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the sampinfo block.
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DUMB's support for existing file formats is implemented as follows. First
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a signal_t is constructed manually by reading the file. Then the special
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make_duh() function is called. This creates a DUH struct with just one
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signal in it, the one we just created. We provide all the above
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functions, except load_signal(), since that has been bypassed. DUMB's
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core now has our start_samples() etc. function for generating the sound,
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and it has our unload_signal() function for getting the file out of
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memory when we're done.
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It is possible with some sigtypes to adjust their sound using
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"parameters". set_parameter() is called for this. An example would be
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changing the cut-off frequency for a signal that acts as a filter. I plan
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to add a second version of this function that takes a pointer. This would
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be used when manipulating DUHs in code; an example is when installing a
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callback function for a music module file. It couldn't be used by a file
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on disk.
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This terminology is far from intuitive. Here are some proposals:
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- The things DUHs are made of can still be called "signals".
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- The types of signal can still be called "sigtypes" ("signal types").
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- The signal-specific data can be called the "sigdata" ("signal data").
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- The sampinfo block can be renamed to a "sigrenderer" ("signal renderer").
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- The parameters can be called "sigparams" ("signal parameters").
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This way we have some consistency between different parts of the library;
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the API for rendering a DUH as a whole uses the term "renderer". We also
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have a full name and an abbreviation for each term.
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Any advances on this?
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---
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Todo/Wishlist:
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* MOD/XM loading - change the effect memory system; it isn't robust when it
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comes to remembering stuff from one pattern to the next.
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* --- IMPORTANT --- Put link to IT in docs: http://www.noisemusic.org/it/
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* --- IMPORTANT --- Twist the sample decompression algorithm around, since
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it was derived from a GPL'd algorithm. We don't want
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to have to put it under GPL! :) ... or, find out that it
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wasn't originally written under the GPL and then credit
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the bloke who wrote it :)
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* MMX resamplers and downsamplers
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* Ability to load *.it, *.xm directly into DUH structs (IT done)
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* Ability to embed IT compressed samples... no, it's copyrighted. Let's do
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our own :)
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* Ability to embed ITs themselves (? not sure how useful that is)
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* Remove cit.c
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* Check all return values. I think the Winamp plug-in needs looking at...
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* resample.c - it seems x*y is safe if 0<=x<=65535 and -32768<=y<=32768 or
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vice versa. Check this is true on all compilers. If so, make
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use of it to gain more accuracy.
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* DUMB_IDs should always be long or always be int...
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* Decide whether the load_signal function really needs the DUH parameter...
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* Allow for DUH modularity; different pieces share samples etc.
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* Fix makefile so it can manage without alld - or put note in the FAQ that
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ppl must build alld
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* Arrange to detect file types by extension (probably not by content though)
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* Change aldmbd to aldmd in makefiles to maintain 8.3 compatibility
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* Put dumb_resampling_quality and dumb_it_max_to_mix in howto.txt
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* More info in howto.txt, in particular that install_sound() is needed...
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* Add a sanity check for restart_position?
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* Note in docs to let entheh know if you release a game using DUMB
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STUFF TO FIX FOR THE FIRST RELEASE
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==================================
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General
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-------
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* Naming is a bit confusing sometimes...
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* What to do about ASSERT() and TRACE() - they were hacked in when
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the lib was split from Allegro, and they need replacing.
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* Add some constants to dumb.h (DUMB_VERSION_STR etc.)
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entheh
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------
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* Update docs, write more docs (a lot to do here!)
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* Go through, eliminate warnings, resolve some "/** WARNING" comments
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(they used to be #warning but Bob complained :)
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* Program it to calculate the length of IT and S3M files (currently
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always set to 10 minutes IIRC)
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Bob
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---
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* dumb_resample() now has a volume parameter, so there are some extra
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floating-point multiply ops that could possibly be optimised.
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tjaden
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------
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* Test on Linux when it's all ready plz :)
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