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glGetTexLevelParameter(3G)
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glGetTexLevelParameter, glGetTexLevelParameterfv, glGetTexLevelParameteriv
- return texture parameter values for
a specific level of detail
void glGetTexLevelParameterfv(
GLenum target,
GLint level,
GLenum pname,
GLfloat *params ); void glGetTexLevelParameteriv(
GLenum target,
GLint level,
GLenum pname,
GLint *params );
Specifies the symbolic name of the target texture, either
GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_PROXY_TEXTURE_1D,
GL_PROXY_TEXTURE_2D, or GL_PROXY_TEXTURE_3D.
Specifies the level-of-detail number of the desired image.
Level 0 is the base image level. Level n is the nth
mipmap reduction image. Specifies the symbolic name of a
texture parameter. GL_TEXTURE_WIDTH, GL_TEXTURE_HEIGHT,
GL_TEXTURE_DEPTH, GL_TEXTURE_INTERNAL_FORMAT, GL_TEXTURE_BORDER,
GL_TEXTURE_RED_SIZE, GL_TEXTURE_GREEN_SIZE,
GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_ALPHA_SIZE, GL_TEXTURE_LUMINANCE_SIZE,
and GL_TEXTURE_INTENSITY_SIZE are
accepted. Returns the requested data.
glGetTexLevelParameter() returns in params texture parameter
values for a specific level-of-detail value, specified
as level. target defines the target texture, either
GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_PROXY_TEXTURE_1D,
GL_PROXY_TEXTURE_2D, or GL_PROXY_TEXTURE_3D.
GL_MAX_TEXTURE_SIZE, and GL_MAX_3D_TEXTURE_SIZE are not
really descriptive enough. It has to report the largest
square texture image that can be accommodated with mipmaps
and borders, but a long skinny texture, or a texture without
mipmaps and borders, may easily fit in texture memory.
The proxy targets allow the user to more accurately query
whether the GL can accommodate a texture of a given configuration.
If the texture cannot be accommodated, the
texture state variables, which may be queried with glGetTexLevelParameter(),
are set to 0. If the texture can be
accommodated, the texture state values will be set as they
would be set for a non-proxy target.
pname specifies the texture parameter whose value or values
will be returned.
The accepted parameter names are as follows: params
returns a single value, the width of the texture image.
This value includes the border of the texture image. The
initial value is 0. params returns a single value, the
height of the texture image. This value includes the border
of the texture image. The initial value is 0. params
returns a single value, the depth of the texture image.
This value includes the border of the texture image. The
initial value is 0. params returns a single value, the
internal of the texture image. params returns a single
value, the width in pixels of the border of the texture
image. The initial value is 0.
GL_TEXTURE_RED_SIZE
GL_TEXTURE_GREEN_SIZE
GL_TEXTURE_BLUE_SIZE
GL_TEXTURE_ALPHA_SIZE
GL_TEXTURE_LUMINANCE_SIZE
The internal storage resolution of an individual component.
The resolution chosen by the GL will be a close
match for the resolution requested by the user with the
component argument of glTexImage1D(), glTexImage2D(),
glTexImage3D(), glCopyTexImage1D(), and glCopyTexImage2D().
The initial value is 0.
If an error is generated, no change is made to the contents
of params.
GL_TEXTURE_INTERNAL_FORMAT is available only if the GL
version is 1.1 or greater. In version 1.0, use GL_TEXTURE_COMPONENTS
instead.
GL_PROXY_TEXTURE_1D and GL_PROXY_TEXTURE_2D are available
only if the GL version is 1.1 or greater.
GL_TEXTURE_3D, GL_PROXY_TEXTURE_3D, and GL_TEXTURE_DEPTH
are available only if the GL version is 1.2 or greater.
When the GL_ARB_multitexture extension is supported,
glGetTexLevelParameter() returns the texture level parameters
for the active texture unit.
GL_INVALID_ENUM is generated if target or pname is not an
accepted value.
GL_INVALID_VALUE is generated if level is less than 0.
GL_INVALID_VALUE may be generated if level is greater than
log sub 2 max, where max is the returned value of
GL_MAX_TEXTURE_SIZE.
GL_INVALID_OPERATION is generated if glGetTexLevelParameter()
is executed between the execution of glBegin() and
the corresponding execution of glEnd().
glActiveTextureARB(3), glGetTexParameter(3), glCopyTexImage1D(3), glCopyTexImage2D(3), glCopyTexSubImage1D(3),
glCopyTexSubImage2D(3), glCopyTexSubImage3D(3), glTexEnv(3), glTexGen(3), glTexImage1D(3), glTexImage2D(3),
glTexImage3D(3), glTexSubImage1D(3), glTexSubImage2D(3),
glTexSubImage3D(3), glTexParameter(3)
glGetTexLevelParameter(3G)
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