1991-2006
Silicon Graphics, Inc.
glTexImage1D
3G
glTexImage1D
specify a one-dimensional texture image
C Specification
void glTexImage1D
GLenum target
GLint level
GLint internalFormat
GLsizei width
GLint border
GLenum format
GLenum type
const GLvoid * data
Parameters
target
Specifies the target texture.
Must be GL_TEXTURE_1D or GL_PROXY_TEXTURE_1D.
level
Specifies the level-of-detail number.
Level 0 is the base image level.
Level n is the nth mipmap reduction image.
internalFormat
Specifies the number of color components in the texture.
Must be one of the following symbolic constants:
GL_COMPRESSED_RED,
GL_COMPRESSED_RG,
GL_COMPRESSED_RGB,
GL_COMPRESSED_RGBA,
GL_COMPRESSED_SRGB,
GL_COMPRESSED_SRGB_ALPHA,
GL_DEPTH_COMPONENT,
GL_DEPTH_COMPONENT16,
GL_DEPTH_COMPONENT24,
GL_DEPTH_COMPONENT32,
GL_R3_G3_B2,
GL_RED,
GL_RG,
GL_RGB,
GL_RGB4,
GL_RGB5,
GL_RGB8,
GL_RGB10,
GL_RGB12,
GL_RGB16,
GL_RGBA,
GL_RGBA2,
GL_RGBA4,
GL_RGB5_A1,
GL_RGBA8,
GL_RGB10_A2,
GL_RGBA12,
GL_RGBA16,
GL_SRGB,
GL_SRGB8,
GL_SRGB_ALPHA, or
GL_SRGB8_ALPHA8.
width
Specifies the width of the texture image.
All implementations support texture images that are at least 1024 texels
wide. The height of the 1D texture image is 1.
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 maps a portion of a specified texture image
onto each graphical primitive for which texturing is enabled.
To enable and disable one-dimensional texturing, call glEnable
and glDisable with argument GL_TEXTURE_1D.
Texture images are defined with glTexImage1D.
The arguments describe the parameters of the texture image,
such as width,
width of the border,
level-of-detail number
(see glTexParameter),
and the internal resolution and format used to store the image.
The last three arguments describe how the image is represented in
memory.
If target is GL_PROXY_TEXTURE_1D, 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_1D,
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 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 left end of the texture array.
Subsequent elements progress left-to-right through the remaining texels
in the texture array.
The final element corresponds to the right end of the texture array.
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 single 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].
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_ALPHAor
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_1D 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 from data.
A two-component image uses the R and A 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
glPixelStore modes affect texture images.
data may be a null pointer. In this case texture memory is
allocated to accommodate a texture of width width.
You can then download subtextures to initialize the
texture memory. The image is undefined if the program tries to apply
an uninitialized portion of the texture image to a primitive.
glTexImage1D specifies the one-dimensional texture for the current texture unit,
specified with glActiveTexture.
Errors
GL_INVALID_ENUM is generated if target is not GL_TEXTURE_1D
or GL_PROXY_TEXTURE_1D.
GL_INVALID_ENUM is generated if format is not an accepted
format constant. Format constants other than GL_STENCIL_INDEX
are accepted.
GL_INVALID_ENUM is generated if type is not a type constant.
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 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 cannot be represented as
2
n
+
2
⁡
border
for some integer value of n.
GL_INVALID_VALUE is generated if border is not 0 or 1.
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, or
GL_UNSIGNED_SHORT_5_6_5_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, or
GL_UNSIGNED_INT_2_10_10_10_REV
and format is neither GL_RGBA nor GL_BGRA.
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_COMPONENT32.
GL_INVALID_OPERATION is generated if internalFormat is
GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16,
GL_DEPTH_COMPONENT24, or GL_DEPTH_COMPONENT32, 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.
Associated Gets
glGetTexImage
glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING
See Also
glActiveTexture,
glCompressedTexImage1D,
glCompressedTexSubImage1D,
glCopyTexImage1D,
glCopyTexSubImage1D,
glGetCompressedTexImage,
glPixelStore,
glTexImage2D,
glTexImage3D,
glTexSubImage1D,
glTexSubImage2D,
glTexSubImage3D,
glTexParameter
Copyright
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/.