glTexSubImage2D(3G) OpenGL Reference glTexSubImage2D(3G)NAMEglTexSubImage2D - specify a two-dimensional texture subimage
C SPECIFICATION
void glTexSubImage2D( GLenum target,
GLint level,
GLint xoffset,
GLint yoffset,
GLsizei width,
GLsizei height,
GLenum format,
GLenum type,
const GLvoid *pixels )
PARAMETERS
target Specifies the target texture. Must be GL_TEXTURE_2D.
level Specifies the level-of-detail number. Level 0 is the base image
level. Level n is the nth mipmap reduction image.
xoffset Specifies a texel offset in the x direction within the texture
array.
yoffset Specifies a texel offset in the y direction within the texture
array.
width Specifies the width of the texture subimage.
height Specifies the height of the texture subimage.
format 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_ABGR_EXT,
GL_LUMINANCE, and GL_LUMINANCE_ALPHA.
type 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.
pixels Specifies a pointer to the image data in memory.
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glTexSubImage2D(3G) OpenGL Reference glTexSubImage2D(3G)DESCRIPTION
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.
glTexSubImage2D redefines a contiguous subregion of an existing two-
dimensional texture image. The texels referenced by pixels replace the
portion of the existing texture array with x indices xoffset and
xoffset + width - 1, inclusive, and y indices yoffset and
yoffset + height - 1, inclusive. This region may not include any texels
outside the range of the texture array as it was originally specified.
It is not an error to specify a subtexture with zero width or height, but
such a specification has no effect.
Normally glTexSubImage2D is synchronous: OpenGL executes a
glTexSubImage2D command in the order it is issued in the OpenGL command
stream. Calling glEnable with parameter GL_ASYNC_TEX_IMAGE_SGIX causes
subsequent glTexSubImage2D commands to be asynchronous as defined by the
SGIX_async extension. An asynchronous glTexSubImage2D command samples
the OpenGL state vector at the point in the OpenGL command stream where
the command is issued, but the results of the command (e.g. availability
of texels for use in rasterization) do not happen until some unspecified
time in the future. In particular, the order of the asynchronous command
relative to other OpenGL commands issued later in the command stream is
undefined. An implementation may choose to execute asynchronous commands
in parallel with the normal command stream or at some convenient time in
the future.
Calling glDisable with parameter GL_ASYNC_TEX_IMAGE_SGIX restores the
default synchronous behavior for subsequent glTexSubImage2D commands. It
does not affect any pending asynchronous glTexImage commands, or wait for
their completion.
When an asynchronous glTexSubImage2D command is issued, it is associated
with the current value of GL_ASYNC_MARKER_SGIX as defined by the
SGIX_async extension. A program can determine if an asynchronous
glTexSubImage2D command has completed by using the glFinishAsyncSGIX or
glPollAsyncSGIX commands.
There is a maximum number of asynchronous glTexImage commands that can be
outstanding at any one time, defined by the implementation. This value
can be queried with glGetIntegerv with argument
GL_MAX_ASYNC_TEX_IMAGE_SGIX.
NOTESglTexSubImage2D is available only if the GL version is 1.1 or greater.
Texturing has no effect in color index mode.
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glTexSubImage2D(3G) OpenGL Reference glTexSubImage2D(3G)
glPixelStore and glPixelTransfer modes affect texture images in exactly
the way they affect glDrawPixels.
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.
GL_ABGR_EXT is valid only if the EXT_abgr extension is supported.
When the GL_ARB_imaging extension is supported, the RGBA components
specified in pixels may be processed by the imaging pipeline. See
glTexImage1D for specific details.
ERRORS
GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D.
GL_INVALID_OPERATION is generated if the texture array has not been
defined by a previous glTexImage2D operation.
GL_INVALID_VALUE is generated if level is less than 0.
GL_INVALID_VALUE may be generated if level is greater than log max, where
2
max is the returned value of GL_MAX_TEXTURE_SIZE.
GL_INVALID_VALUE is generated if xoffset < -b,
(xoffset + width) > (w - b), yoffset < -b, or
(yoffset + height) > (h - b), where w is the GL_TEXTURE_WIDTH, h is the
GL_TEXTURE_HEIGHT, and b is the border width of the texture image being
modified. Note that w and h include twice the border width.
GL_INVALID_VALUE is generated if width or height is less than 0.
GL_INVALID_ENUM is generated if format is not an accepted format
constant.
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_OPERATION is generated if glTexSubImage2D 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.
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glTexSubImage2D(3G) OpenGL Reference glTexSubImage2D(3G)
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 not GL_RGBA, GL_BGRA or GL_ABGR_EXT.
GL_INVALID_OPERATION is generated when the SGIX_subsample extension is
supported, and the pixel storage mode GL_UNPACK_SUBSAMPLE_RATE_SGIX is
not GL_PIXEL_SUBSAMPLE_4444_SGIX, and width is not a multiple of 2, or
format is not a 3 or 4 component format, or type is a packed pixels type.
GL_INVALID_OPERATION is generated if GL_ASYNC_TEX_IMAGE_SGIX is enabled
and the number of asynchronous glTexImage commands that have been issued
but not queried (using glFinishAsyncSGIX or glPollAsyncSGIX) exceeds
GL_MAX_ASYNC_TEX_IMAGE_SGIX.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GL_TEXTURE_2D
MACHINE DEPENDENCIES
The SGIX_async and SGIX_async_pixel extensions are implemented only on
Octane2 VPro systems.
RealityEngine, RealityEngine2, and VTX systems do not support color
matrix transformations on images as they are loaded to or read back from
texture memory.
RealityEngine, RealityEngine2, and VTX systems do not support convolving
images as they are loaded into texture memory.
On InfiniteReality systems, there is a performance benefit when the width
of the image to be transferred to texture memory is a multiple of 8.
Texture borders are not supported on InfiniteReality systems.
Applications should use borderless textures and GL_CLAMP_TO_EDGE_SGIS
wrap mode.
RealityEngine, RealityEngine2, and VTX systems do not support histogram
or minmax operations on images as they are being loaded into texture
memory.
The SGIX_interlace extension is supported only on InfiniteReality
systems, on RealityEngine, RealityEngine2, and VTX systems, on Octane2
VPro systems, and on O2 systems.
The EXT_packed_pixels extension is not supported on RealityEngine,
RealityEngine2, and VTX systems.
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glTexSubImage2D(3G) OpenGL Reference glTexSubImage2D(3G)
The SGIX_subsample and SGIX_resample extensions are supported only on
Octane2 VPro systems. Applying the GL_PIXEL_SUBSAMPLE_2424_SGIX
subsample rate is accelerated for direct immmediate mode transfers when
the format is GL_RGB or GL_RGBA, and the type is GL_UNSIGNED_BYTE or
GL_UNSIGNED_SHORT.
On RealityEngine, RealityEngine2, and VTX systems, glTexSubImage2D and
glTexSubImage2DEXT are supported with the following restrictions:
1. Performance is significantly better if the texture subimage X
offset, Y offset, width and height are multiples of 32.
2. glTexSubImage2D and glTexSubImage2DEXT may be used only with a
texture that was created using glTexImage2D with a NULL texture
image.
3. glTexSubImage2D and glTexSubImage2DEXT may not be used with a
mipmap texture. Only level 0 is supported.
4. Only the following texel format and type combinations are
supported: GL_LUMINANCE and GL_UNSIGNED_BYTE, GL_LUMINANCE and
GL_UNSIGNED_SHORT, GL_LUMINANCE_ALPHA and GL_UNSIGNED_BYTE,
GL_LUMINANCE_ALPHA and GL_UNSIGNED_SHORT, GL_RGB and
GL_UNSIGNED_BYTE and GL_RGBA and GL_UNSIGNED_BYTE. Any other
combination of format and type will result in a GL_INVALID_ENUM
error.
5. Using glTexSubImage2D or glTexSubImage2DEXT in conjunction with
pixel mapping results in a GL_INVALID_OPERATION error (see
glPixelTransfer and glPixelMap).
6. glTexSubImage2D and glTexSubImage2DEXT may not be used in
display lists or when rendering remotely.
7. GL_INTERLACE_SGIX is not supported (see glEnable).
On High Impact and Maximum Impact systems, if the right side of the image
to be transferred to texture memory is not the right side of the texture,
then its index must be a multiple of 32, where index = xoffset+width.
Otherwise it will generate a GL_INVALID_VALUE error.
SEE ALSO
glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D,
glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawPixels, glPixelStore,
glPixelTransfer, glTexEnv, glTexGen, glTexImage1D, glTexImage2D,
glTexImage3D, glTexSubImage1D, glTexSubImage3D, glTexParameter,
glAsyncMarkerSGIX, glDeleteAsyncMarkersSGIX, glFinishAsyncSGIX,
glGenAsyncMarkersSGIX, glIsAsyncMarkerSGIX, glPollAsyncSGIX
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