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glTexImage2D(3G)
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glTexImage2D - specify a two-dimensional texture image
void glTexImage2D(
GLenum target,
GLint level,
GLint internalformat,
GLsizei width,
GLsizei height,
GLint border,
GLenum format,
GLenum type,
const GLvoid *pixels );
Specifies the target texture. Must be GL_TEXTURE_2D or
GL_PROXY_TEXTURE_2D. Specifies the level-of-detail number.
Level 0 is the base image level. Level n is the nth
mipmap reduction image. 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. Specifies
the width of the texture image. Must be 2^n + 2 ( border )
for some integer n. All implementations support texture
images that are at least 64 texels wide. Specifies the
height of the texture image. Must be 2^m + 2 ( border )
for some integer m. All implementations support texture
images that are at least 64 texels high. Specifies the
width of the border. Must be either 0 or 1. Specifies the
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. Specifies the data type of the
pixel data. The following symbolic 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. Specifies a pointer to
the image data in memory.
Texturing maps a portion of a specified texture image onto
each graphical primitive for which texturing is enabled.
To enable and disable two-dimensional texturing, call
glEnable() and glDisable() with argument GL_TEXTURE_2D.
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; they are identical to the
pixel formats used for glDrawPixels().
If target is GL_PROXY_TEXTURE_2D, 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_2D, 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 lower left corner of
the texture image. Subsequent elements progress left-toright
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 pixels.
It can assume one of eleven symbolic values: 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]. 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] (see glPixelTransfer()).
Each element is a single green component.
The GL converts it to floating point and assembles it into
an RGBA element by attaching 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()).
Each element is a single blue component. The
GL converts it to floating point and assembles it into an
RGBA element by attaching 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 [0,1] (see glPixelTransfer()).
Each element is a single alpha component.
The GL converts it to floating point and assembles it into
an RGBA element by attaching 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()). 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] (see glPixelTransfer()).
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()). 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()). 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 acceptable values for the type parameter.
If an application wants to store the texture at a certain
resolution or in a certain , it can request the resolution
and 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_2D target to try out a resolution
and format. The implementation will update and recompute
its best match for the requested storage resolution and .
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 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.
If the GL_ARB_imaging extension is supported, RGBA elements
may also be processed by the imaging pipeline. The
following stages may be applied to an RGBA color before
color component clamping to the range [0, 1]:
GL_COLOR_TABLE, if enabled. See glColorTable(). glConvolutionFilter1D().
If a convolution filter changes the __width of the
texture (by processing with a GL_CONVOLUTION_BORDER_MODE
of GL_REDUCE, for example), the width must
2^n + 2 ( height ), for some integer n, and height
must be 2^m + ( border ), for some integer m,
after filtering. and added to GL_POST_CONVOLUTION_c_BIAS,
if enabled. See glPixelTransfer().
GL_POST_CONVOLUTION_COLOR_TABLE, if enabled. See
glColorTable(). and added to
GL_POST_COLOR_MATRIX_c_BIAS, if enabled. See
glPixelTransfer().
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 version 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, pixels 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.
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() specifies the two-dimensional texture for
the current texture unit, specified with glActiveTextureARB().
GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D
or GL_PROXY_TEXTURE_2D.
GL_INVALID_ENUM is generated if format is not an accepted
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 0.
GL_INVALID_VALUE may be generated if level is greater than
log sub 2max, 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 symbolic
constants.
GL_INVALID_VALUE is generated if width or height is less
than 0 or greater than 2 + GL_MAX_TEXTURE_SIZE, or if
either cannot be represented as 2^k + 2(border) for some
integer value of k.
GL_INVALID_VALUE is generated if border 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 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.
glGetTexImage()
glIsEnabled() with argument GL_TEXTURE_2D
glColorTable(3), glConvolutionFilter2D(3), glCopyPixels(3), glCopyTexImage1D(3), glCopyTexImage2D(3), glCopyTexSubImage1D(3), glCopyTexSubImage2D(3), glCopyTexSubImage3D(3), , glDrawPixels(3), glMatrixMode(3), glPixelStore(3), glPixelTransfer(3), glSeparableFilter2D(3),
glTexEnv(3), glTexGen(3), glTexImage1D(3), glTexSubImage1D(3), glTexImage3D(3), glTexSubImage2D(3), glTexSubImage3D(3), glTexParameter(3)
glTexImage2D(3G)
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