Specifies a one-dimensional (1D) texture image.
OpenGL C bindings library: libGL.a
void glTexImage1D(GLenum target,
GLint level,
GLint internalformat,
GLsizei width,
GLint border,
GLenum format,
GLenum type,
const GLvoid *pixels)
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; they are identical to the pixel formats used for glDrawPixels.
If target is GL_PROXY_TEXTURE_1D no data is read from pixels, 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 pixels 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. If type is GL_BITMAP, the data is considered as a string of unsigned bytes (and format must be GL_COLOR_INDEX). Each data byte is treated as eight 1-bit elements, with bit ordering determined by GL_UNPACK_LSB_FIRST (See glPixelStore).
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.
The format parameter determines the composition of each element in pixels. It can assume one of nine symbolic values:
| GL_COLOR_INDEX | Each element is a single value, a color index. The GL converts it to fixed point (with an unspecified number of zero bits to the right of the binary point), shifted left or right depending on the value and sign of GL_INDEX_SHIFT, and added to GL_INDEX_OFFSET (See glPixelTransfer). The resulting index is converted to a set of color components using the GL_PIXEL_MAP_I_TO_R, GL_PIXEL_MAP_I_TO_G, GL_PIXEL_MAP_I_TO_B, and GL_PIXEL_MAP_I_TO_A tables, and clamped to the range [0,1]. |
| 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 0.0 for green and blue, and 1.0 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] (See glPixelTransfer). |
| GL_GREEN | Each element is a single green component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0.0 for red and blue, and 1.0 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] (See glPixelTransfer). |
| GL_BLUE | Each element is a single blue component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0.0 for red and green, and 1.0 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] (See glPixelTransfer). |
| GL_ALPHA | Each element is a single alpha component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0.0 for red, green, and blue. 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] (See glPixelTransfer). |
| GL_RGB | Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1.0 for alpha. Eachcomponent 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] (See glPixelTransfer). |
| GL_RGBA | Each element contains all four components. 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] (See glPixelTransfer). |
| GL_BGR | Each pixel is a three-component group, blue first, followed by green, followed by red. Each component is converted to the internal floating-point format in the same way as the blue, green, and red components of an BGRA pixel are. The color triple is converted to an BGRA pixel with alpha set to 1.0. After this conversion, the pixel is treated just as if it had been read as an BGRA pixel. |
| GL_BGRA | Each pixel is a four-component group, blue first, followed by green,
followed by red, followed by alpha. Floating-point values are converted directly
to an internal floating-point format with unspecified precision. Signed integer
values are mapped linearly to the internal floating-point format such that the
most positive representable integer value maps to 1.0, and the most negative
representable value maps to -1.0. Unsigned integer data are mapped similarly:
the largest integer value maps to 1.0, and 0 maps to 0.0. The resulting
floating-point color values are then multiplied by
GL_c_SCALE and added to GL_c_BIAS,
where c is BLUE, GREEN, RED, and ALPHA for
the respective color components. The results are clamped to the range [0,1].
If GL_MAP_COLOR is True, each color component is scaled by the size of the lookup table GL_PIXEL_MAP_c_TO_c, then replaced by the value that it references in that table. c is B, G, R, or A, respectively. The resulting BGRA colors are then converted to fragments by attaching the current raster position z coordinate and texture coordinates to each pixel, then assigning x and y window coordinates to the nth fragment such that xn = xr + n mod Width and yn = yr + [n/Width], where (xr, yr) is the current raster position. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer. |
| GL_ABGR_EXT | Each pixel is a four-component group: for GL_RGBA,
the red component is first, followed by green, followed by blue, followed by
alpha; for GL_BGRA, the blue component is first, followed by green,
followed by red, followed by alpha; for
GL_ABGR_EXT the order is alpha, blue, green,
and then red.
Floating-point values are converted directly to an internal floatingpoint format
with unspecified precision. Signed integer values are mapped linearly to the
internal floating-point format such that the most positive representable integer
value maps to 1.0, and the most negative representable value maps to -1.0.
Unsigned integer data is mapped similarly: the largest integer value maps to
1.0, and zero maps to 0.0.
The resulting floating-point color values are then multiplied by
GL_c_SCALE and added to
GL_c_BIAS, where c is RED,
GREEN, BLUE, and ALPHA for the respective color components.
The results are clamped to the range [0,1].
If GL_MAP_COLOR is true, each color component is scaled by the size of lookup table GL_PIXEL_MAP_c_TO _c, then replaced by the value that it references in that table. c is R, G, B, or A, respectively. The resulting RGBA colors are then converted to fragments by attaching the current raster position z coordinate and texture coordinates to each pixel, then assigning x and y window coordinates to the nth fragment such that xn = xr + n mod width yn = yr + | n bwidthc where (xr,yr) is the current raster position. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer. |
| GL_LUMINANCE | Each element is a single luminance value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue and attaching 1.0 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] (See glPixelTransfer). |
| GL_LUMINANCE_ALPHA | Each element is a luminance/alpha pair. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue. 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] (See glPixelTransfer). |
For applications that store the texture at a certain resolution or in a certain format, 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_LUMINANCE, GL_LUMINANCE_ALPHA, GL_RGB, and GL_RGBA must match exactly. The numeric values 1, 2, 3, and 4 may also be used to specify the above representations.)
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 query this state, call glGetTexLevelParameter. If the texture cannot be accomodated, texture state is set to 0.
A one-component texture image uses only the red component of the RGBA color extracted from pixels. 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.
Texturing has no effect in color index mode.
The texture image can be represented by the same data formats as the pixels in a glDrawPixels command, except that GL_STENCIL_INDEX and GL_DEPTH_COMPONENT cannot be used. The glPixelStore and glPixelTransfer modes affect texture images in exactly the way they affect glDrawPixels.
GL_PROXY_TEXTURE_1D can only be used if the GL version is 1.1 or greater.
Internal formats other than 1, 2, 3, or 4 can only be used if the GL version is 1.1 or greater.
In GL version 1.1 or greater, pixels may be a null pointer. In this case texture memory is allocated to accomodate a texture of width width. You can then download subtextures to initialize the texture memory. The image is undefined if the user tries to apply an uninitialized portion of the texture image to a primitive.
Format of GL_ABGR_EXT is part of the _extname (EXT_abgr) extension, not part of the core GL command set.
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 and GL_DEPTH_COMPONENT are accepted.
GL_INVALID_ENUM is generated if type is not a type constant.
GL_INVALID_ENUM is generated if type is GL_BITMAP and format is not GL_COLOR_INDEX.
GL_INVALID_VALUE is generated if level is less than zero.
GL_INVALID_VALUE may be generated if level is greater than log2max, where max is the returned value of GL_MAX_TEXTURE_SIZE.
GL_INVALID_VALUE is generated if internalformat is not 1, 2, 3, 4, or one of the accepted resolution and format symbolic constants.
GL_INVALID_VALUE is generated if width is less than zero or greater than 2 + GL_MAX_TEXTURE_SIZE, or if it cannot be represented as 2n + 2 x 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 glTexImage1D is executed between the execution of glBegin and the corresponding execution of glEnd.
glIsEnabled with argument GL_TEXTURE_1D.
The glCopyTexImage1D subroutine, glDrawPixels subroutine, glFog subroutine, glPixelStore subroutine, glPixelTransfer subroutine, glTexEnv subroutine, glTexGen subroutine, glTexImage2D subroutine, glTexParameter subroutine, glTexSubImage1D subroutine.