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NAME
glGetInternalformativ - retrieve information about implementation-dependent support for
internal formats
C SPECIFICATION
void glGetInternalformativ(GLenum target, GLenum internalformat, GLenum pname,
GLsizei bufSize, GLint *params);
void glGetInternalformati64v(GLenum target, GLenum internalformat, GLenum pname,
GLsizei bufSize, GLint64 *params);
PARAMETERS
target
Indicates the usage of the internal format. target must be GL_TEXTURE_1D,
GL_TEXTURE_1D_ARRAY, GL_TEXTURE_2D, GL_TEXTURE_2D_ARRAY, GL_TEXTURE_3D,
GL_TEXTURE_CUBE_MAP, GL_TEXTURE_CUBE_MAP_ARRAY, GL_TEXTURE_RECTANGLE,
GL_TEXTURE_BUFFER, GL_RENDERBUFFER, GL_TEXTURE_2D_MULTISAMPLE or
GL_TEXTURE_2D_MULTISAMPLE_ARRAY.
internalformat
Specifies the internal format about which to retrieve information.
pname
Specifies the type of information to query.
bufSize
Specifies the maximum number of basic machine units that may be written to params by
the function.
params
Specifies the address of a variable into which to write the retrieved information.
DESCRIPTION
glGetInternalformativ and glGetInternalformati64v retrieve information about
implementation-dependent support for internal formats. target indicates the target with
which the internal format will be used and must be one of GL_RENDERBUFFER,
GL_TEXTURE_2D_MULTISAMPLE, or GL_TEXTURE_2D_MULTISAMPLE_ARRAY, corresponding to usage as a
renderbuffer, two-dimensional multisample texture or two-dimensional multisample array
texture, respectively.
internalformat specifies the internal format about which to retrieve information and must
be a color-renderable, depth-renderable or stencil-renderable format.
The information retrieved will be written to memory addressed by the pointer specified in
params. No more than bufSize basic machine units will be written to this memory.
If pname is GL_NUM_SAMPLE_COUNTS, the number of sample counts that would be returned by
querying GL_SAMPLES will be returned in params.
If pname is GL_SAMPLES, the sample counts supported for internalformat and target are
written into params in descending numeric order. Only positive values are returned.
Querying GL_SAMPLES with bufSize of one will return just the maximum supported number of
samples for this format. The maximum value in GL_SAMPLES is guaranteed to be at least the
lowest of the following:
• The value of GL_MAX_INTEGER_SAMPLES if internalformat is a signed or unsigned integer
format..RE
• The value of GL_MAX_DEPTH_TEXTURE_SAMPLES if internalformat is a depth- or
stencil-renderable format and
target is GL_TEXTURE_2D_MULTISAMPLE,
GL_TEXTURE_2D_MULTISAMPLE_ARRAY..RE
• The value of GL_MAX_COLOR_TEXTURE_SAMPLES if internalformat is a
color-renderable format and
target is GL_TEXTURE_2D_MULTISAMPLE or
GL_TEXTURE_2D_MULTISAMPLE_ARRAY..RE
• The value of GL_MAX_SAMPLES..RE
If pname is GL_INTERNALFORMAT_SUPPORTED, params is set to GL_TRUE if
internalFormat is a supported internal format for target and to GL_FALSE
otherwise.
If pname is GL_INTERNALFORMAT_PREFERRED, params is set to GL_TRUE if
internalFormat is an format for target that is preferred by the
implementation and to GL_FALSE otherwise.
If pname is GL_INTERNALFORMAT_RED_SIZE, GL_INTERNALFORMAT_GREEN_SIZE,
GL_INTERNALFORMAT_BLUE_SIZE, GL_INTERNALFORMAT_ALPHA_SIZE,
GL_INTERNALFORMAT_DEPTH_SIZE, GL_INTERNALFORMAT_STENCIL_SIZE, or
GL_INTERNALFORMAT_SHARED_SIZE then params is set to the actual resolutions
that would be used for storing image array components for the resource for
the red, green, blue, alpha, depth, stencil and shared channels
respectively. If internalFormat is a compressed internal format, then
params is set to the component resolution of an uncompressed internal
format that produces an image of roughly the same quality as the
compressed algorithm. If the internal format is unsupported, or if a
particular component is not present in the format, 0 is written to params.
If pname is GL_INTERNALFORMAT_RED_TYPE, GL_INTERNALFORMAT_GREEN_TYPE,
GL_INTERNALFORMAT_BLUE_TYPE, GL_INTERNALFORMAT_ALPHA_TYPE,
GL_INTERNALFORMAT_DEPTH_TYPE, or GL_INTERNALFORMAT_STENCIL_TYPE then
params is set to a token identifying the data type used to store the
respective component. If the internalFormat represents a compressed
internal format then the types returned specify how components are
interpreted after decompression.
If pname is GL_MAX_WIDTH, GL_MAX_HEIGHT, GL_MAX_DEPTH, or GL_MAX_LAYERS
then pname is filled with the maximum width, height, depth or layer count
for textures with internal format internalFormat, respectively. If pname
is GL_MAX_COMBINED_DIMENSIONS then pname is filled with the maximum
combined dimensions of a texture of the specified internal format.
If pname is GL_COLOR_COMPONENTS then params is set to the value GL_TRUE if
the internal format contains any color component (i.e., red, green, blue
or alpha) and to GL_FALSE otherwise. If pname is GL_DEPTH_COMPONENTS or
GL_STENCIL_COMPONENTS then params is set to GL_TRUE if the internal format
contains a depth or stencil component, respectively, and to GL_FALSE
otherwise.
If pname is GL_COLOR_RENDERABLE, GL_DEPTH_RENDERABLE or
GL_STENCIL_RENDERABLE then params is set to GL_TRUE if the specified
internal format is color, depth or stencil renderable, respectively, and
to GL_FALSE otherwise.
If pname is GL_FRAMEBUFFER_RENDERABLE or GL_FRAMEBUFFER_RENDERABLE_LAYERED
then params is set to one of GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT or GL_NONE
to indicate that framebuffer attachments (layered attachments in the case
of GL_FRAMEBUFFER_RENDERABLE_LAYERED) with that internal format are either
renderable with no restrictions, renderable with some restrictions or not
renderable at all.
If pname is GL_FRAMEBUFFER_BLEND, params is set to GL_TRUE to indicate
that the internal format is supported for blending operations when
attached to a framebuffer, and to GL_FALSE otherwise.
If pname is GL_READ_PIXELS then params is set to GL_FULL_SUPPORT,
GL_CAVEAT_SUPPORT or GL_NONE to that either full support, limited support
or no support at all is supplied for reading pixels from framebuffer
attachments in the specified internal format.
If pname is GL_READ_PIXELS_FORMAT or GL_READ_PIXELS_TYPE then params is
filled with the format or type, respectively, most recommended to obtain
the highest image quality and performance. For GL_READ_PIXELS_FORMAT, the
value returned in params is a token that is accepted for the format
argument to glReadPixels(). For GL_READ_PIXELS_TYPE, the value returned in
params is a token that is accepted for the type argument to
glReadPixels().
If pname is GL_TEXTURE_IMAGE_FORMAT or GL_TEXTURE_IMAGE_TYPE then params
is filled with the implementation-recommended format or type to be used in
calls to glTexImage2D() and other similar functions. For
GL_TEXTURE_IMAGE_FORMAT, params is filled with a token suitable for use as
the format argument to glTexImage2D(). For GL_TEXTURE_IMAGE_TYPE, params
is filled with a token suitable for use as the type argument to
glTexImage2D().
If pname is GL_GET_TEXTURE_IMAGE_FORMAT or GL_GET_TEXTURE_IMAGE_TYPE then
params is filled with the implementation-recommended format or type to be
used in calls to glGetTexImage2D() and other similar functions. For
GL_GET_TEXTURE_IMAGE_FORMAT, params is filled with a token suitable for
use as the format argument to glGetTexImage2D(). For
GL_GET_TEXTURE_IMAGE_TYPE, params is filled with a token suitable for use
as the type argument to glGetTexImage2D().
If pname is GL_MIPMAP then pname is set to GL_TRUE to indicate that the
specified internal format supports mipmaps and to GL_FALSE otherwise.
If pname is GL_GENERATE_MIPMAP or GL_AUTO_GENERATE_MIPMAP then params is
indicates the level of support for manual or automatic mipmap generation
for the specified internal format, respectively. Returned values may be
one of GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT and GL_NONE to indicate either
full support, limited support or no support at all.
If pname is GL_COLOR_ENCODING then the color encoding for the resource is
returned in params. Possible values for color buffers are GL_LINEAR or
GL_SRGB, for linear or sRGB-encoded color components, respectively. For
non-color formats (such as depth or stencil), or for unsupported
resources, the value GL_NONE is returned.
If pname is GL_SRGB_READ, or GL_SRGB_WRITE then params indicates the level
of support for reading and writing to sRGB encoded images, respectively.
For GL_SRGB_READ, support for converting from sRGB colorspace on read
operations is returned in params and for GL_SRGB_WRITE, support for
converting to sRGB colorspace on write operations to the resource is
returned in params. params may be set to GL_FULL_SUPPORT,
GL_CAVEAT_SUPPORT, or GL_NONE to indicate full support, limited support or
no support at all, respecitively.
If pname is GL_FILTER the params is set to either GL_TRUE or GL_FALSE to
indicate support or lack thereof for filter modes other than GL_NEAREST or
GL_NEAREST_MIPMAP for the specified internal format.
If pname is GL_VERTEX_TEXTURE, GL_TESS_CONTROL_TEXTURE,
GL_TESS_EVALUATION_TEXTURE, GL_GEOMETRY_TEXTURE, GL_FRAGMENT_TEXTURE, or
GL_COMPUTE_TEXTURE, then the value written to params indicates support for
use of the resource as a source of texturing in the vertex, tessellation
control, tessellation evaluation, geometry, fragment and compute shader
stages, respectively. params may be set to GL_FULL_SUPPORT,
GL_CAVEAT_SUPPORT or GL_NONE to indicate full support, limited support or
no support at all, respectively.
If pname is GL_TEXTURE_SHADOW, GL_TEXTURE_GATHER or
GL_TEXTURE_GATHER_SHADOW then the value written to params indicates the
level of support for using the resource with a shadow sampler, in gather
operations or as a shadow sampler in gather operations, respectively.
Returned values may be GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT or GL_NONE to
indicate full support, limited support or no support at all, respectively.
If pname is GL_SHADER_IMAGE_LOAD, GL_SHADER_IMAGE_STORE or
GL_SHADER_IMAGE_ATOMIC then the value returned in params indicates the
level of support for image loads, stores and atomics for resources of the
specified internal format. Returned values may be GL_FULL_SUPPORT,
GL_CAVEAT_SUPPORT or GL_NONE to indicate full support, limited support or
no support at all, respectively.
If pname is GL_IMAGE_TEXEL_SIZE then the size of a texel when the resource
when used as an image texture is returned in params. If the resource is
not supported for image textures zero is returned.
If pname is GL_IMAGE_COMPATIBILITY_CLASS then the compatibility class of
the resource when used as an image texture is returned in params. The
possible values returned are GL_IMAGE_CLASS_4_X_32, GL_IMAGE_CLASS_2_X_32,
GL_IMAGE_CLASS_1_X_32, GL_IMAGE_CLASS_4_X_16, GL_IMAGE_CLASS_2_X_16,
GL_IMAGE_CLASS_1_X_16, GL_IMAGE_CLASS_4_X_8, GL_IMAGE_CLASS_2_X_8,
GL_IMAGE_CLASS_1_X_8, GL_IMAGE_CLASS_11_11_10, and
GL_IMAGE_CLASS_10_10_10_2, which correspond to the 4x32, 2x32, 1x32, 4x16,
2x16, 1x16, 4x8, 2x8, 1x8, the class (a) 11/11/10 packed floating-point
format, and the class (b) 10/10/10/2 packed formats, respectively. If the
resource is not supported for image textures, GL_NONE is returned.
If pname is GL_IMAGE_PIXEL_FORMAT or GL_IMAGE_PIXEL_TYPE then the pixel
format or type of the resource when used as an image texture is returned
in params, respectively. In either case, the resource is not supported for
image textures GL_NONE is returned.
If pname is GL_IMAGE_FORMAT_COMPATIBILITY_TYPE, the matching criteria use
for the resource when used as an image textures is returned in params.
Possible values returned in params are
GL_IMAGE_FORMAT_COMPATIBILITY_BY_SIZE or
GL_IMAGE_FORMAT_COMPATIBILITY_BY_CLASS. If the resource is not supported
for image textures, GL_NONE is returned.
If pname is GL_SIMULTANEOUS_TEXTURE_AND_DEPTH_TEST or
GL_SIMULTANEOUS_TEXTURE_AND_STENCIL_TEST, support for using the resource
both as a source for texture sampling while it is bound as a buffer for
depth or stencil test, respectively, is written to params. Possible values
returned are GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT, or GL_NONE to indicate
full support, limited support or no support at all. If the resource or
operation is not supported, GL_NONE is returned.
If pname is GL_SIMULTANEOUS_TEXTURE_AND_DEPTH_WRITE or
GL_SIMULTANEOUS_TEXTURE_AND_STENCIL_WRITE, support for using the resource
both as a source for texture sampling while performing depth or stencil
writes to the resources, respectively, is written to params. Possible
values returned are GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT, or GL_NONE to
indicate full support, limited support or no support at all. If the
resource or operation is not supported, GL_NONE is returned.
If pname is GL_TEXTURE_COMPRESSED then GL_TRUE is returned in params if
internalformat is a compressed internal format. GL_FALSE is returned in
params otherwise.
If pname is GL_TEXTURE_COMPRESSED_BLOCK_WIDTH,
GL_TEXTURE_COMPRESSED_BLOCK_HEIGHT or GL_TEXTURE_COMPRESSED_BLOCK_SIZE
then the width, height or total size, respectively of a block (in basic
machine units) is returned in params. If the internal format is not
compressed, or the resource is not supported, 0 is returned.
If pname is GL_CLEAR_BUFFER, the level of support for using the resource
with glClearBufferData() and glClearBufferSubData() is returned in params.
Possible values returned are GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT, or
GL_NONE to indicate full support, limited support or no support at all,
respectively. If the resource or operation is not supported, GL_NONE is
returned.
If pname is GL_TEXTURE_VIEW, the level of support for using the resource
with the glTextureView() command is returned in params. Possible values
returned are GL_FULL_SUPPORT, GL_CAVEAT_SUPPORT, or GL_NONE to indicate
full support, limited support or no support at all, respectively. If the
resource or operation is not supported, GL_NONE is returned.
If pname is GL_VIEW_COMPATIBILITY_CLASS then the compatibility class of
the resource when used as a texture view is returned in params. The
possible values returned are GL_VIEW_CLASS_128_BITS,
GL_VIEW_CLASS_96_BITS, GL_VIEW_CLASS_64_BITS, GL_VIEW_CLASS_48_BITS,
GL_VIEW_CLASS_32_BITS, GL_VIEW_CLASS_24_BITS, GL_VIEW_CLASS_16_BITS,
GL_VIEW_CLASS_8_BITS, GL_VIEW_CLASS_S3TC_DXT1_RGB,
GL_VIEW_CLASS_S3TC_DXT1_RGBA, GL_VIEW_CLASS_S3TC_DXT3_RGBA,
GL_VIEW_CLASS_S3TC_DXT5_RGBA, GL_VIEW_CLASS_RGTC1_RED,
GL_VIEW_CLASS_RGTC2_RG, GL_VIEW_CLASS_BPTC_UNORM, and
GL_VIEW_CLASS_BPTC_FLOAT.
If pname is GL_CLEAR_TEXTURE then the presence of support for using the
glClearTexImage() and glClearTexSubImage() commands with the resource is
written to params. Possible values written are GL_FULL_SUPPORT,
GL_CAVEAT_SUPPORT, or GL_NONE to indicate full support, limited support or
no support at all, respectively. If the resource or operation is not
supported, GL_NONE is returned.
NOTES
glGetInternalformativ is available only if the GL version is 4.2 or higher.
The tokens GL_INTERNALFORMAT_SUPPORTED, GL_INTERNALFORMAT_PREFERRED,
GL_INTERNALFORMAT_RED_SIZE, GL_INTERNALFORMAT_GREEN_SIZE, GL_INTERNALFORMAT_BLUE_SIZE,
GL_INTERNALFORMAT_ALPHA_SIZE, GL_INTERNALFORMAT_DEPTH_SIZE,
GL_INTERNALFORMAT_STENCIL_SIZE, GL_INTERNALFORMAT_SHARED_SIZE, GL_INTERNALFORMAT_RED_TYPE,
GL_INTERNALFORMAT_GREEN_TYPE, GL_INTERNALFORMAT_BLUE_TYPE, GL_INTERNALFORMAT_ALPHA_TYPE,
GL_INTERNALFORMAT_DEPTH_TYPE, GL_INTERNALFORMAT_STENCIL_TYPE, GL_MAX_WIDTH, GL_MAX_HEIGHT,
GL_MAX_DEPTH, GL_MAX_LAYERS, GL_MAX_COMBINED_DIMENSIONS, GL_COLOR_COMPONENTS,
GL_DEPTH_COMPONENTS, GL_STENCIL_COMPONENTS, GL_COLOR_RENDERABLE, GL_DEPTH_RENDERABLE,
GL_STENCIL_RENDERABLE, GL_FRAMEBUFFER_RENDERABLE, GL_FRAMEBUFFER_RENDERABLE_LAYERED,
GL_FRAMEBUFFER_BLEND, GL_READ_PIXELS, GL_READ_PIXELS_FORMAT, GL_READ_PIXELS_TYPE,
GL_TEXTURE_IMAGE_FORMAT, GL_TEXTURE_IMAGE_TYPE, GL_GET_TEXTURE_IMAGE_FORMAT,
GL_GET_TEXTURE_IMAGE_TYPE, GL_MIPMAP, GL_GENERATE_MIPMAP, GL_AUTO_GENERATE_MIPMAP,
GL_COLOR_ENCODING, GL_SRGB_READ, GL_SRGB_WRITE, GL_SRGB_DECODE_ARB, GL_FILTER,
GL_VERTEX_TEXTURE, GL_TESS_CONTROL_TEXTURE, GL_TESS_EVALUATION_TEXTURE,
GL_GEOMETRY_TEXTURE, GL_FRAGMENT_TEXTURE, GL_COMPUTE_TEXTURE, GL_TEXTURE_SHADOW,
GL_TEXTURE_GATHER, GL_TEXTURE_GATHER_SHADOW, GL_SHADER_IMAGE_LOAD, GL_SHADER_IMAGE_STORE,
GL_SHADER_IMAGE_ATOMIC, GL_IMAGE_TEXEL_SIZE, GL_IMAGE_COMPATIBILITY_CLASS,
GL_IMAGE_PIXEL_FORMAT, GL_IMAGE_PIXEL_TYPE, GL_IMAGE_FORMAT_COMPATIBILITY_TYPE,
GL_SIMULTANEOUS_TEXTURE_AND_DEPTH_TEST, GL_SIMULTANEOUS_TEXTURE_AND_STENCIL_TEST,
GL_SIMULTANEOUS_TEXTURE_AND_DEPTH_WRITE, GL_SIMULTANEOUS_TEXTURE_AND_STENCIL_WRITE,
GL_TEXTURE_COMPRESSED, GL_TEXTURE_COMPRESSED_BLOCK_WIDTH,
GL_TEXTURE_COMPRESSED_BLOCK_HEIGHT, GL_TEXTURE_COMPRESSED_BLOCK_SIZE, GL_CLEAR_BUFFER,
GL_TEXTURE_VIEW, and GL_VIEW_COMPATIBILITY_CLASS are supported only if the GL version is
4.3 or higher.
The GL_CLEAR_TEXTURE token is accepted for pname only if the GL version is 4.4 or higher.
ERRORS
GL_INVALID_VALUE is generated if bufSize is negative.
GL_INVALID_ENUM is generated if pname is not GL_SAMPLES or GL_NUM_SAMPLE_COUNTS.
GL_INVALID_ENUM is generated if internalformat is not color-, depth-, or
stencil-renderable.
GL_INVALID_ENUM is generated if target is not one of GL_TEXTURE_2D_MULTISAMPLE,
GL_TEXTURE_2D_MULTISAMPLE_ARRAY or GL_RENDERBUFFER.
SEE ALSO
glGet()
COPYRIGHT
Copyright © 2011-2013 Khronos Group. This material may be distributed subject to the terms
and conditions set forth in the Open Publication License, v 1.0, 8 June 1999.
http://opencontent.org/openpub/.
AUTHORS
opengl.org