GLint leve )
PARAMETERS
target Specifies the target texture. Must be GL_TEXTURE_2D or
GL_PROXY_TEXTURE_2D.
leve Specifies the level-of-detail number. Level 0 is the base image
level. Level n is the nth mipmap reduction image.
_param3 Specifies the number of color components in the texture. Must
be 1, 2, 3, or 4, or one of the following symbolic constants:
GL_ALPHA, GL_ALPHA4, GL_ALPHA8, GL_ALPHA12, GL_ALPHA16,
GL_LUMINANCE, GL_LUMINANCE4, GL_LUMINANCE8, GL_LUMINANCE12,
GL_LUMINANCE16, GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4,
GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8,
GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12,
GL_LUMINANCE16_ALPHA16, GL_INTENSITY, GL_INTENSITY4,
GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16, GL_R3_G3_B2,
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, or GL_RGBA16.
_param4 Specifies the width of the texture image. Must be 2n+2(_eqn‐
param6) for some integer n. All implementations support texture
images that are at least 64 texels wide.
_param5 Specifies the height of the texture image. Must be 2m+2(_eqn‐
param6) for some integer m. All implementations support texture
images that are at least 64 texels high.
_param6 Specifies the width of the border. Must be either 0 or 1.
_param7 Specifies the format of the pixel data. The following symbolic
values are accepted: GL_COLOR_INDEX, GL_RED, GL_GREEN, GL_BLUE,
GL_ALPHA, GL_RGB, GL_BGR GL_RGBA, GL_BGRA, GL_LUMINANCE, and
GL_LUMINANCE_ALPHA.
_param8 Specifies the data type of the pixel data. The following sym‐
bolic values are accepted: GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
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.
_param9 Specifies a pointer to the image data in memory.
DESCRIPTION
Texturing maps a portion of a specified texture image onto each graphi‐
cal primitive for which texturing is enabled. To enable and disable
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, data is read from _param9 as a sequence of
signed or unsigned bytes, shorts, or longs, or single-precision float‐
ing-point values, depending on _param8. These values are grouped into
sets of one, two, three, or four values, depending on _param7, to form
elements. If _param8 is GL_BITMAP, the data is considered as a string
of unsigned bytes (and _param7 must be GL_COLOR_INDEX).
Each data byte is treated as eight 1-bit elements, with bit ordering de‐
termined by GL_UNPACK_LSB_FIRST (see glPixelStore).
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.
_param7 determines the composition of each element in _param9. It can
assume one of eleven symbolic values:
GL_COLOR_INDEX
Each element is a single value, a color index. The GL con‐
verts 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 at‐
taching 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] (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 at‐
taching 0 for red 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] (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 at‐
taching 0 for red and green, 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
factor GL_c_SCALE, added to the signed bias GL_c_BIAS, and
clamped to the range [0,1] (see
glPixelTransfer).
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] (see
glPixelTransfer).
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 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).
Refer to the glDrawPixels reference page for a description of the ac‐
ceptable values for the _param8 parameter.
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
_param3. The GL will choose an internal representation that closely ap‐
proximates that requested by _param3, 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_2D target to try out a resolution and format.
The implementation will update and recompute its best match for the re‐
quested 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 _param9. 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.
NOTES
the _param4 must 2n+2(_eqnparam5), for some integer n, and _param5
must be 2m+(_eqnparam6), for some integer m, after filtering.
3. RGBA components may be multiplied by GL_POST_CONVOLUTION_c_SCALE,
and added to GL_POST_CONVOLUTION_c_BIAS, if enabled. See
glPixelTransfer.
4. Color component replacement by the color table specified for
GL_POST_CONVOLUTION_COLOR_TABLE, if enabled. See glColorTable.
5. Transformation by the color matrix. See glMatrixMode.
6. RGBA components may be multiplied by GL_POST_COLOR_MATRIX_c_SCALE,
and added to GL_POST_COLOR_MATRIX_c_BIAS, if enabled. See
glPixelTransfer.
7. Color component replacement by the color table specified for
GL_POST_COLOR_MATRIX_COLOR_TABLE, if enabled. See glColorTable.
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. glPixelStore and glPixelTransfer
modes affect texture images in exactly the way they affect glDrawPixels.
glTexImage2D and GL_PROXY_TEXTURE_2D are available only if the GL ver‐
sion is 1.1 or greater.
Internal formats other than 1, 2, 3, or 4 may be used only if the GL
version is 1.1 or greater.
In GL version 1.1 or greater, _param9 may be a null pointer. In this
case texture memory is allocated to accommodate a texture of width
_param4 and height _param5. You can then download subtextures to ini‐
tialize this texture memory. The image is undefined if the user tries
to apply an uninitialized portion of the texture image to a primitive.
Formats GL_BGR, and GL_BGRA and types 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 are available only if the GL version is
1.2 or greater.
When the GL_ARB_multitexture extension is supported, glTexImage2D speci‐
fies the two-dimensional texture for the current texture unit, specified
with glActiveTextureARB.
ERRORS
GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D or
GL_PROXY_TEXTURE_2D.
GL_INVALID_VALUE is generated if _param3 is not 1, 2, 3, 4, or one of
the accepted resolution and format symbolic constants.
GL_INVALID_VALUE is generated if _param4 or _param5 is less than 0 or
greater than 2 + GL_MAX_TEXTURE_SIZE, or if either cannot be represented
as 2k+2(_eqnparam6) for some integer value of k.
GL_INVALID_VALUE is generated if _param6 is not 0 or 1.
GL_INVALID_OPERATION is generated if glTexImage2D is executed between
the execution of glBegin and the corresponding execution of glEnd.
GL_INVALID_OPERATION is generated if _param8 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 _param7 is
not GL_RGB.
GL_INVALID_OPERATION is generated if _param8 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
_param7 is neither GL_RGBA nor GL_BGRA.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GL_TEXTURE_2D
SEE ALSO
glColorTable, glConvolutionFilter2D, glCopyPixels, glCopyTexImage1D,
glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D,
glCopyTexSubImage3D, glDrawPixels, glMatrixMode, glPixelStore,
glPixelTransfer, glSeparableFilter2D, glTexEnv, glTexGen, glTexImage1D,
glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D,
glTexParameter
GLTEXIMAGE2D(3G)
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