glTexImage2D — specify a two-dimensional texture image
void glTexImage2D( | GLenum | target, |
GLint | level, | |
GLint | internalFormat, | |
GLsizei | width, | |
GLsizei | height, | |
GLint | border, | |
GLenum | format, | |
GLenum | type, | |
const GLvoid * | data) ; |
target
Specifies the target texture.
Must be GL_TEXTURE_2D
, GL_PROXY_TEXTURE_2D
,
GL_TEXTURE_1D_ARRAY
, GL_PROXY_TEXTURE_1D_ARRAY
,
GL_TEXTURE_RECTANGLE
, GL_PROXY_TEXTURE_RECTANGLE
,
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
,
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
, or
GL_PROXY_TEXTURE_CUBE_MAP
.
level
Specifies the level-of-detail number.
Level 0 is the base image level.
Level n is the nth mipmap reduction image.
If target
is GL_TEXTURE_RECTANGLE
or
GL_PROXY_TEXTURE_RECTANGLE
, level
must be 0.
internalFormat
Specifies the number of color components in the texture. Must be one of base internal formats given in Table 1, one of the sized internal formats given in Table 2, or one of the compressed internal formats given in Table 3, below.
width
Specifies the width of the texture image. All implementations support texture images that are at least 1024 texels wide.
height
Specifies the height of the texture image, or the number of layers in a texture
array, in the case of the GL_TEXTURE_1D_ARRAY
and
GL_PROXY_TEXTURE_1D_ARRAY
targets.
All implementations support 2D texture images that are at least 1024 texels
high, and texture arrays that are at least 256 layers deep.
border
This value must be 0.
format
Specifies the format of the pixel data.
The following symbolic values are accepted:
GL_RED
,
GL_RG
,
GL_RGB
,
GL_BGR
,
GL_RGBA
, and
GL_BGRA
.
type
Specifies the data type of the pixel data.
The following symbolic values are accepted:
GL_UNSIGNED_BYTE
,
GL_BYTE
,
GL_UNSIGNED_SHORT
,
GL_SHORT
,
GL_UNSIGNED_INT
,
GL_INT
,
GL_FLOAT
,
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
,
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
, and
GL_UNSIGNED_INT_2_10_10_10_REV
.
data
Specifies a pointer to the image data in memory.
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 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.)
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
Assume
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.
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_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 width
is less than 0
or greater than GL_MAX_TEXTURE_SIZE
.
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
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 non-power-of-two textures are not supported and the width
or height
cannot be represented as
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.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_UNPACK_BUFFER
target and data
is not evenly divisible
into the number of bytes needed to store in memory a datum indicated by type
.
GL_INVALID_VALUE
is generated if target
is GL_TEXTURE_RECTANGLE
or GL_PROXY_TEXTURE_RECTANGLE
and level
is not 0.
glActiveTexture, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glPixelStore, glTexImage1D, glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D, glTexParameter
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.