This module corresponds to section 6.2 (Managing Rendering Contexts) of the
OpenAL Specification and Reference (version 1.1).
All operations of the AL core API affect a current AL context. Within the
scope of AL, the ALC is implied - it is not visible as a handle or function
parameter. Only one AL Context per process can be current at a time.
Applications maintaining multiple AL Contexts, whether threaded or not,
have to set the current context accordingly. Applications can have multiple
threads that share one more or contexts. In other words, AL and ALC are
|Frequency, specified in samples per second, i.e. units of Hertz [Hz].
Note that the underlying OpenAL API currently uses integral frequencies
only, but we want to mirror physical reality here more closely.
|The application can choose to specify certain attributes for a context at
context-creation time. Attributes not specified explicitly are set to
implementation dependent defaults.
|Frequency Frequency||Frequency for mixing output buffer, in units of
|Refresh Frequency||Refresh intervals, in units of Hz
|Sync Bool||Flag, indicating a synchronous context
|MonoSources Int||A hint indicating how many sources should be
capable of supporting mono data
|StereoSources Int||A hint indicating how many sources should be
capable of supporting stereo data
|The abstract context type.
|Create a context for a given device and given attributes. Context creation
will fail in the following cases: a) if the application requests attributes
that, by themselves, can not be provided b) if the combination of specified
attributes can not be provided c) if a specified attribute, or the
combination of attributes, does not match the default values for unspecified
attributes If context creation fails, Nothing will be returned, otherwise
Just the new context. Note that createContext does not set the current
context, this must be done separately via currentContext.
|Contains Just the current context with respect to OpenAL operation, or
Nothing if there is no current context. Setting it to the latter is useful
when shutting OpenAL down. The state variable applies to the device that the
context was created for. For each OS process (usually this means for each
application), only one context can be current at any given time. All AL
commands apply to the current context. Commands that affect objects shared
among contexts (e.g. buffers) have side effects on other contexts.
|The current context is the only context accessible to state changes by AL
commands (aside from state changes affecting shared objects). However,
multiple contexts can be processed at the same time. To indicate that a
context should be processed (i.e. that internal execution state like offset
increments are supposed to be performed), the application has to use
processContext. Repeated calls to processContext are legal, and do not
affect a context that is already marked as processing. The default state of a
context created by createContext is that it is processing.
|The application can suspend any context from processing (including the
current one). To indicate that a context should be suspended from processing
(i.e. that internal execution state like offset increments is not supposed to
be changed), the application has to use suspendContext. Repeated calls to
suspendContext are legal, and do not affect a context that is already
marked as suspended.
|Destroy the given context. Note that the the correct way to destroy a
context is to first release it by setting currentContext to
Nothing. Applications should not attempt to destroy a current context,
doing so will not work and will result in an ALCInvalidOperation error.
|Contains Just the device of the given context or Nothing if the context
|Contains the attribute list for the current context of the specified
|Produced by Haddock version 0.8|