Signature
Parameters
Description
Texturing allows elements of an image array to be read by shaders.
To define texture images, call
glTexImage2D
.
The arguments describe the parameters of the texture image,
such as height, width, width of the border, level-of-detail number
(see
glTexParameter
),
and number of color components provided.
The last three arguments describe how the image is represented in memory.
If
target
is
GL_PROXY_TEXTURE_2D
,
GL_PROXY_TEXTURE_1D_ARRAY
,
GL_PROXY_TEXTURE_CUBE_MAP
, or
GL_PROXY_TEXTURE_RECTANGLE
,
no data is read from
data
, but
all of the texture image state is recalculated, checked for
consistency, and checked
against the implementation's capabilities. If the implementation cannot
handle a texture of the requested texture size, it sets
all of the image state to 0,
but does not generate an error (see
glGetError
). To query for an
entire mipmap array, use an image array level greater than or equal to 1.
If
target
is
GL_TEXTURE_2D
,
GL_TEXTURE_RECTANGLE
or one of the
GL_TEXTURE_CUBE_MAP
targets, data is read from
data
as a sequence of signed or unsigned
bytes, shorts, or longs, or single-precision floating-point values,
depending on
type
. These values are grouped into sets of one, two,
three, or four values, depending on
format
, to form elements.
Each data byte is treated as eight 1-bit elements,
with bit ordering determined by
GL_UNPACK_LSB_FIRST
(see
glPixelStore
).
If
target
is
GL_TEXTURE_1D_ARRAY
, data is interpreted
as an array of one-dimensional images.
If a non-zero named buffer object is bound to the
GL_PIXEL_UNPACK_BUFFER
target
(see
glBindBuffer
) while a texture image is
specified,
data
is treated as a byte offset into the buffer object's data store.
The first element corresponds to the lower left corner of the texture image.
Subsequent elements progress left-to-right through the remaining texels
in the lowest row of the texture image, and then in successively higher
rows of the texture image.
The final element corresponds to the upper right corner of the texture
image.
format
determines the composition of each element in
data
.
It can assume one of these symbolic values:
- GL_RED
-
Each element is a single red component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha. Each component is clamped to the range [0,1].
- GL_RG
-
Each element is a red/green double. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for blue, and 1 for alpha. Each component is clamped to the range [0,1].
- GL_RGB
- GL_BGR
-
Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1 for alpha. Each component is clamped to the range [0,1].
- GL_RGBA
- GL_BGRA
-
Each element contains all four components. Each component is clamped to the range [0,1].
- GL_DEPTH_COMPONENT
-
Each element is a single depth value. The GL converts it to floating point and clamps to the range [0,1].
- GL_DEPTH_STENCIL
-
Each element is a pair of depth and stencil values. The depth component of the pair is interpreted as in GL_DEPTH_COMPONENT . The stencil component is interpreted based on specified the depth + stencil internal format.
If an application wants to store the texture at a certain
resolution or in a certain format, it can request the resolution
and format with
internalformat
. The GL will choose an internal
representation that closely approximates that requested by
internalformat
, but
it may not match exactly.
(The representations specified by
GL_RED
,
GL_RG
,
GL_RGB
,
and
GL_RGBA
must match exactly.)
internalformat
may be one of the base internal formats shown in
Table 1, below
internalformat
may also be one of the sized internal formats
shown in Table 2, below
Finally,
internalformat
may also be one of the generic or compressed
texture formats shown in Table 3 below
If the
internalformat
parameter is one of the generic compressed formats,
GL_COMPRESSED_RED
,
GL_COMPRESSED_RG
,
GL_COMPRESSED_RGB
, or
GL_COMPRESSED_RGBA
, the GL will replace the internal format with the symbolic constant for a specific internal format and compress the texture before storage. If no corresponding internal format is available, or the GL can not compress that image for any reason, the internal format is instead replaced with a corresponding base internal format.
If the
internalformat
parameter is
GL_SRGB
,
GL_SRGB8
,
GL_SRGB_ALPHA
, or
GL_SRGB8_ALPHA8
, the texture is treated as if the red, green, or blue components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component
to a linear component
is:
Assume
is the sRGB component in the range [0,1].
Use the
GL_PROXY_TEXTURE_2D
,
GL_PROXY_TEXTURE_1D_ARRAY
,
GL_PROXY_TEXTURE_RECTANGLE
, or
GL_PROXY_TEXTURE_CUBE_MAP
target to try out a resolution and
format. The implementation will
update and recompute its best match for the requested storage resolution
and format. To then query this state, call
glGetTexLevelParameter
.
If the texture cannot be accommodated, texture state is set to 0.
A one-component texture image uses only the red component of the RGBA
color extracted from
data
.
A two-component image uses the R and G values.
A three-component image uses the R, G, and B values.
A four-component image uses all of the RGBA components.
Image-based shadowing can be enabled by comparing texture r coordinates to
depth texture values to generate a boolean result.
See
glTexParameter
for details on texture comparison.
Notes
The
glPixelStore
mode affects texture images.
data
may be a null pointer.
In this case, texture memory is
allocated to accommodate a texture of width
width
and height
height
.
You can then download subtextures to initialize this
texture memory.
The image is undefined if the user tries to apply
an uninitialized portion of the texture image to a primitive.
glTexImage2D
specifies the two-dimensional texture for the current texture unit,
specified with
glActiveTexture
.
GL_STENCIL_INDEX
may be used for
format
only if the GL
version is 4.4 or higher.
Errors
GL_INVALID_ENUM
is generated if
target
is not
GL_TEXTURE_2D
,
GL_TEXTURE_1D_ARRAY
,
GL_TEXTURE_RECTANGLE
,
GL_PROXY_TEXTURE_2D
,
GL_PROXY_TEXTURE_1D_ARRAY
,
GL_PROXY_TEXTURE_RECTANGLE
,
GL_PROXY_TEXTURE_CUBE_MAP
,
GL_TEXTURE_CUBE_MAP_POSITIVE_X
,
GL_TEXTURE_CUBE_MAP_NEGATIVE_X
,
GL_TEXTURE_CUBE_MAP_POSITIVE_Y
,
GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
,
GL_TEXTURE_CUBE_MAP_POSITIVE_Z
, or
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
.
GL_INVALID_ENUM
is generated if
target
is one of the six cube map 2D image targets and the width and height parameters are not equal.
GL_INVALID_ENUM
is generated if
type
is not a type constant.
GL_INVALID_VALUE
is generated if
target
is not
GL_TEXTURE_1D_ARRAY
or
GL_PROXY_TEXTURE_1D_ARRAY
and
height
is less than 0 or greater than
GL_MAX_TEXTURE_SIZE
.
GL_INVALID_VALUE
is generated if
target
is
GL_TEXTURE_1D_ARRAY
or
GL_PROXY_TEXTURE_1D_ARRAY
and
height
is less than 0 or greater than
GL_MAX_ARRAY_TEXTURE_LAYERS
.
GL_INVALID_VALUE
is generated if
level
is less than 0.
GL_INVALID_VALUE
may be generated if
level
is greater than
,
where
max
is the returned value of
GL_MAX_TEXTURE_SIZE
.
GL_INVALID_VALUE
is generated if
internalformat
is not one of the
accepted resolution and format symbolic constants.
GL_INVALID_VALUE
is generated if
width
or
height
is less than 0
or greater than
GL_MAX_TEXTURE_SIZE
.
GL_INVALID_VALUE
is generated if
border
is not 0.
GL_INVALID_OPERATION
is generated if
type
is one of
GL_UNSIGNED_BYTE_3_3_2
,
GL_UNSIGNED_BYTE_2_3_3_REV
,
GL_UNSIGNED_SHORT_5_6_5
,
GL_UNSIGNED_SHORT_5_6_5_REV
, or
GL_UNSIGNED_INT_10F_11F_11F_REV
,
and
format
is not
GL_RGB
.
GL_INVALID_OPERATION
is generated if
type
is one of
GL_UNSIGNED_SHORT_4_4_4_4
,
GL_UNSIGNED_SHORT_4_4_4_4_REV
,
GL_UNSIGNED_SHORT_5_5_5_1
,
GL_UNSIGNED_SHORT_1_5_5_5_REV
,
GL_UNSIGNED_INT_8_8_8_8
,
GL_UNSIGNED_INT_8_8_8_8_REV
,
GL_UNSIGNED_INT_10_10_10_2
,
GL_UNSIGNED_INT_2_10_10_10_REV
, or
GL_UNSIGNED_INT_5_9_9_9_REV
,
and
format
is neither
GL_RGBA
nor
GL_BGRA
.
GL_INVALID_OPERATION
is generated if
target
is not
GL_TEXTURE_2D
,
GL_PROXY_TEXTURE_2D
,
GL_TEXTURE_RECTANGLE
, or
GL_PROXY_TEXTURE_RECTANGLE
,
and
internalformat
is
GL_DEPTH_COMPONENT
,
GL_DEPTH_COMPONENT16
,
GL_DEPTH_COMPONENT24
, or
GL_DEPTH_COMPONENT32F
.
GL_INVALID_OPERATION
is generated if
format
is
GL_DEPTH_COMPONENT
and
internalformat
is not
GL_DEPTH_COMPONENT
,
GL_DEPTH_COMPONENT16
,
GL_DEPTH_COMPONENT24
, or
GL_DEPTH_COMPONENT32F
.
GL_INVALID_OPERATION
is generated if
internalformat
is
GL_DEPTH_COMPONENT
,
GL_DEPTH_COMPONENT16
,
GL_DEPTH_COMPONENT24
, or
GL_DEPTH_COMPONENT32F
, and
format
is
not
GL_DEPTH_COMPONENT
.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_UNPACK_BUFFER
target and the buffer object's data store is currently mapped.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_UNPACK_BUFFER
target and the data would be unpacked from the buffer
object such that the memory reads required would exceed the data store size.
Associated Gets
glGet
with argument
GL_PIXEL_UNPACK_BUFFER_BINDING
Version Support
glTexImage2D | |
GL_HALF_FLOAT |
See Also
Copyright
Copyright
1991-2006 Silicon Graphics, Inc.
Copyright
2011-2014 Khronos Group.
This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/
.
Sample Code References
The following code samples have been found which appear to reference the functions described here. Take care that the code may be old, broken or not even use PyOpenGL.
glTexImage2D
{LGPL or GPL or MPL} Kamaelia
Code/Python/Kamaelia/Kamaelia/Visualisation/PhysicsGraph3D/Particles3D.py
Lines: 415
{LGPL or GPL or MPL} Kamaelia
Sketches/CL/Topology3D/THF/Kamaelia/UI/OpenGL/OpenGLDisplay.py
Lines: 883
{LGPL or GPL or MPL} Kamaelia
Sketches/CL/Topology3D/THF/Sketches/playground/Display3D.py
Lines: 496
{LGPL or GPL or MPL} Kamaelia
Sketches/MPS/BugReports/FixTests/Kamaelia/Kamaelia/Visualisation/PhysicsGraph3D/Particles3D.py
Lines: 415
{LGPL or GPL or MPL} Kamaelia
Sketches/MPS/BugReports/FixTests/Kamaelia/Kamaelia/UI/OpenGL/OpenGLDisplay.py
Lines: 905
{LGPL or GPL or MPL} Kamaelia
Sketches/MPS/BugReports/FixTests/Kamaelia/Kamaelia/UI/OpenGL/Button.py
Lines: 259
{LGPL or GPL or MPL} Kamaelia
Sketches/MPS/BugReports/FixTests/Kamaelia/Kamaelia/UI/OpenGL/TexPlane.py
Lines: 139
{LGPL or GPL or MPL} Kamaelia
Sketches/MPS/BugReports/FixTests/Kamaelia/Kamaelia/UI/OpenGL/Label.py
Lines: 207
{LGPL or GPL or MPL} Kamaelia
Sketches/THF/Packages/Kamaelia/Community/THF/Kamaelia/UI/OpenGL/OpenGLDisplay.py
Lines: 882
{LGPL or GPL or MPL} Kamaelia
Sketches/THF/Packages/Kamaelia/Community/THF/Kamaelia/UI/OpenGL/Button.py
Lines: 259
{LGPL or GPL or MPL} Kamaelia
Sketches/THF/Packages/Kamaelia/Community/THF/Kamaelia/UI/OpenGL/TexPlane.py
Lines: 139
{LGPL or GPL or MPL} Kamaelia
Sketches/THF/Packages/Kamaelia/Community/THF/Kamaelia/UI/OpenGL/Label.py
Lines: 207