OpenAL Operation
OpenAL Fundamentals
TBA.
Primitive Types
As OpenAL is meant to allow for seamless integration with OpenGL code if needed, the OpenAL primitive (scalar) data types mimic the OpenGL data types. Guaranteed minimum sizes are stated for OpenGL data types (see table 2.2 of the OpenGL 1.2 Specification), but the actual choice of C datatype is left to the implementation. All implementations on a given binary architecture, however, must use a common definition of these datatypes.
Note that this table uses explicit AL prefixes for clarity, while they might be omitted from the rest of the document for brevity. GCC equivalents are given for IA32, i.e. a portable and widely available compiler on the most common target architecture.
Table 1. OpenAL Primitive Data Types
| AL Type | Description | GL Type | GCC IA32 |
|---|---|---|---|
| ALboolean | 8-bit boolean | GLboolean | unsigned char |
| ALbyte | signed 8-bit 2's-complement integer | GLbyte | signed char |
| ALubyte | unsigned 8-bit integer | GLubyte | unsigned char |
| ALshort | signed 16-bit 2's-complement integer | GLshort | short |
| ALushort | unsigned 16-bit integer | GLushort | unsigned short |
| ALint | signed 32-bit 2's-complement integer | GLint | int |
| ALuint | unsigned 32-bit integer | GLuint | unsigned int |
| ALsizei | non-negative 32-bit binary integer size | GLsizei | int |
| ALenum | enumerated 32-bit value | GLenum | unsigned int |
| ALbitfield | 32 bit bitfield | GLbitfield | unsigned int |
| ALfloat | 32-bit IEEE754 floating-point | GLfloat | float |
| ALclampf | Same as ALfloat, but in range [0, 1] | GLclampf | float |
| ALdouble | 64-bit IEEE754 floating-point | GLdouble | double |
| ALclampd | Same as ALdouble, but in range [0, 1] | GLclampd | double |
 | Annotation on Type Sizes |
|---|---|
It would be desirable to guarantee the bit size of OpenAL data types, but this might affect the mapping to OpenGL types for which the OpenGL specification only guarantees a minimum size. |
| Annotation on 64bit integral |
|---|---|
It would be desirable to define ulong and long, but again we defer to OpenGL in this decision. |
| Annotation on Enumeration |
|---|---|
enum is not a C or C++ enumaration, but implemented as C preprocesor defines. This makes it easier to handle extensions to the OpenAL namespace, in particular in dealing with delays in distributing updated reference headers. |