glPrioritizeTextures
[New
- Windows 95, OEM Service Release 2]
The glPrioritizeTextures
function sets the residence priority of textures.
void glPrioritizeTextures(
GLsizei n, |
|
GLuint * textures, |
|
GLclampf * priorities
|
|
); |
|
Parameters
n
The number of
textures to be prioritized.
textures
A pointer to
the first element of an array containing the names of the textures to be
prioritized.
priorities
A pointer to
the first element of an array containing the texture priorities. A priority
given in an element of the priorities parameter applies to the texture
named by the corresponding element of the textures parameter.
Remarks
The glPrioritizeTextures
function assigns the n texture priorities specified in the priorities
parameter to the n textures named in the textures parameter. On
machines with a limited amount of texture memory, OpenGL establishes a
``working set'' of textures that are resident in texture memory. These textures
can be bound to a texture target much more efficiently than textures that are
not resident.
By specifying
a priority for each texture, the glPrioritizeTextures function enables
you to determine which textures should be resident.
The texture
priorities elements in priorities are clamped to the range [0.0, 1.0]
before being assigned. Zero indicates the lowest priority; thus textures with
priority zero are least likely to be resident. The value 1.0 indicates the
highest priority; thus textures with priority 1.0 are most likely to be
resident. However, textures are not guaranteed to be resident until they are
bound.
The glPrioritizeTextures
function ignores attempts to prioritize textures with a priorities value
of zero or any texture name that does not correspond to an existing texture.
None of the functions named by the textures parameter need to be bound
to a texture target.
If a texture
is currently bound, you can also use the glTexParameter function to set
its priority. This is the only way to set the priority of a default texture.
You can
include glPrioritizeTextures in display lists.
Note The glPrioritizeTextures
function is only available in OpenGL version 1.1 or later.
The following
function retrieves the priority of a currently-bound texture related to glPrioritizeTextures:
glGetTexParameter with parameter name GL_TEXTURE_PRIORITY.
Error Codes
The following
are the error codes generated and their conditions.
Error
Code |
Condition |
GL_INVALID_VALUE
|
n was a negative value. |
GL_INVALID_OPERATION
|
glPrioritizeTextures was called between a call to glBegin and the
corresponding call to glEnd. |
See Also