1991-2006
Silicon Graphics, Inc.
glTexImage2D
3G
glTexImage2D
specify a two-dimensional texture image
C Specification
void glTexImage2D
GLenum target
GLint level
GLint internalFormat
GLsizei width
GLsizei height
GLint border
GLenum format
GLenum type
const GLvoid * data
Parameters
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,
GL_BGRA,
GL_RED_INTEGER,
GL_RG_INTEGER,
GL_RGB_INTEGER,
GL_BGR_INTEGER,
GL_RGBA_INTEGER,
GL_BGRA_INTEGER,
GL_STENCIL_INDEX,
GL_DEPTH_COMPONENT,
GL_DEPTH_STENCIL.
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.
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
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
c
s
to a linear component
c
l
is:
c
l
=
{
c
s
12.92
if
c
s
≤
0.04045
(
c
s
+
0.055
1.055
)
2.4
if
c
s
>
0.04045
Assume
c
s
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 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
log
2
⁡
max
,
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.
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.
Associated Gets
glGetTexImage
glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING
See Also
glActiveTexture,
glCopyTexImage1D,
glCopyTexImage2D,
glCopyTexSubImage1D,
glCopyTexSubImage2D,
glCopyTexSubImage3D,
glPixelStore,
glTexImage1D,
glTexImage3D,
glTexSubImage1D,
glTexSubImage2D,
glTexSubImage3D,
glTexParameter
Copyright
Copyright 1991-2006 Silicon Graphics, Inc.
Copyright 2011-2013 Khronos Group.
This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.