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OpenGL 1.1 for AIX: Reference Manual

glPrioritizeTexturesEXT Subroutine

Purpose

Sets texture residence priority.

Library

OpenGL C bindings library: libGL.a

C Syntax

void glPrioritizeTexturesEXT(GLsizei n, 
                    const GLuint *textures, 
                    const GLclampf *priorities)

Parameters

n The number of textures to be prioritized.
textures An array containing the names of the textures to be prioritized.
priorities An array containing the texture priorities. A priority given in an element of priorities applies to the texture named by the corresponding element of textures.

Description

glPrioritizeTexturesEXT assigns the n texture priorities given in priorities to the n textures named in textures.

On machines with a limited amount of texture memory, OpenGL establishes a ``working set'' of textures that are resident in texture memory. These textures may be bound to a texture target much more efficiently than textures that are not resident. By specifying a priority for each texture, glPrioritizeTexturesEXT allows applications to guide the OpenGL implementation in determining which textures should be resident.

The priorities given in priorities are clamped to the range [0.0, 1.0] before being assigned. Zero indicates the lowest priority, and hence textures with priority zero are least likely to be resident. One indicates the highest priority, and hence textures with priority one are most likely to be resident. However, textures are not guaranteed to be resident until they are bound.

glPrioritizeTexturesEXT silently ignores attempts to prioritize texture zero, or any texture name that does not correspond to an existing texture.

glPrioritizeTexturesEXT does not require that any of the textures named by textures be bound to a texture target. glTexParameter may also be used to set a texture's priority, but only if the texture is currently bound. This is the only way to set the priority of a default texture.

glPrioritizeTexturesEXT is included in display lists.

Notes

glPrioritizeTexturesEXT is part of the EXT_texture_object extension, not part of the core GL command set. If GL_EXT_texture_object is included in the string returned by glGetString, when called with argument GL_EXTENSIONS, extension EXT_texture_object is supported by the connection.

Errors

GL_INVALID_VALUE is generated if n is negative.

GL_INVALID_OPERATION is generated if glPrioritizeTexturesEXT is executed between the execution of glBegin and the corresponding execution of glEnd.

Associated Gets

glGetTexParameter with parameter name GL_TEXTURE_PRIORITY_EXT retrieves the priority of a currently-bound texture.

File

/usr/include/GL/glext.h Contains extensions to C language constants, variable type definitions, and ANSI function prototypes for OpenGL.

Related Information

The glAreTexturesResidentEXT subroutine, glBindTextureEXT subroutine, glTexImage1D subroutine, glTexImage2D subroutine, glTexImage3DEXT subroutine, glTexParameter subroutine.


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