glTexImage2D man page on RedHat
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GLTEXIMAGE2D(3G) OpenGL Manual GLTEXIMAGE2D(3G)
NAME
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, 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.
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 then
multiplied by the signed scale factor GL_c_SCALE, added to the
signed bias GL_c_BIAS, and 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 then multiplied by the
signed scale factor GL_c_SCALE, added to the signed bias GL_c_BIAS,
and 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 then multiplied by the signed scale factor
GL_c_SCALE, added to the signed bias GL_c_BIAS, and clamped to the
range [0,1].
GL_RGBA
GL_BGRA
Each element contains all four components. Each component is
multiplied by the signed scale factor GL_c_SCALE, added to the
signed bias GL_c_BIAS, and clamped to the range [0,1].
GL_DEPTH_COMPONENT
Each element is a single depth value. The GL converts it to
floating point, multiplies by the signed scale factor
GL_DEPTH_SCALE, adds the signed bias GL_DEPTH_BIAS, 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
<xi:include></xi:include>
internalFormat may also be one of the sized internal formats shown in
Table 2, below
<xi:include></xi:include>
Finally, internalFormat may also be one of the generic or compressed
compressed texture formats shown in Table 3 below
<xi:include></xi:include>
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().
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 non-power-of-two textures are not
supported and the width or height cannot be represented as 2 k + 2
border for some integer value of k.
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 Khronos
Group. This document is licensed under the SGI Free Software B License.
For details, see http://oss.sgi.com/projects/FreeB/.
AUTHORS
opengl.org
opengl.org 03/16/2013 GLTEXIMAGE2D(3G)
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