glAreTexturesResident.3G man page
glAreTexturesResident — determine if textures are loaded in texture memory
GLboolean glAreTexturesResident(GLsizei n, const GLuint * textures, GLboolean * residences);
Specifies the number of textures to be queried.
Specifies an array containing the names of the textures to be queried.
Specifies an array in which the texture residence status is returned. The residence status of a texture named by an element of textures is returned in the corresponding element of residences.
GL 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.
glAreTexturesResident queries the texture residence status of the n textures named by the elements of textures. If all the named textures are resident, glAreTexturesResident returns GL_TRUE, and the contents of residences are undisturbed. If not all the named textures are resident, glAreTexturesResident returns GL_FALSE, and detailed status is returned in the n elements of residences. If an element of residences is GL_TRUE, then the texture named by the corresponding element of textures is resident.
The residence status of a single bound texture may also be queried by calling glGetTexParameter() with the target argument set to the target to which the texture is bound, and the pname argument set to GL_TEXTURE_RESIDENT. This is the only way that the residence status of a default texture can be queried.
glAreTexturesResident is available only if the GL version is 1.1 or greater.
glAreTexturesResident returns the residency status of the textures at the time of invocation. It does not guarantee that the textures will remain resident at any other time.
If textures reside in virtual memory (there is no texture memory), they are considered always resident.
Some implementations may not load a texture until the first use of that texture.
GL_INVALID_VALUE is generated if n is negative.
GL_INVALID_VALUE is generated if any element in textures is 0 or does not name a texture. In that case, the function returns GL_FALSE and the contents of residences is indeterminate.
GL_INVALID_OPERATION is generated if glAreTexturesResident is executed between the execution of glBegin() and the corresponding execution of glEnd().
glGetTexParameter() with parameter name GL_TEXTURE_RESIDENT retrieves the residence status of a currently bound texture.
glBindTexture(), glGetTexParameter(), glPrioritizeTextures(), glTexImage1D(), glTexImage2D(), glTexImage3D(), glTexParameter()
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