gltexsubimage1dext
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glTexSubImage1DEXT(3G) OpenGL Reference glTexSubImage1DEXT(3G)
NAME
glTexSubImage1DEXT - specify a one-dimensional texture subimage
C SPECIFICATION
void glTexSubImage1DEXT( GLenum target,
GLint level,
GLint xoffset,
GLsizei width,
GLenum format,
GLenum type,
const GLvoid *pixels )
PARAMETERS
target Specifies the target texture. Must be GL_TEXTURE_1D.
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.
width Specifies the width 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_RGBA, 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_EXT,
GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT,
GL_UNSIGNED_INT_8_8_8_8_EXT, and GL_UNSIGNED_INT_10_10_10_2_EXT.
pixels 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. One-dimensional texturing is
enabled and disabled using glEnable and glDisable with argument
GL_TEXTURE_1D.
glTexSubImage1DEXT redefines a contiguous subregion of an existing one-
dimensional texture array. The texels referenced by pixels replace the
portion of the existing texture array with x indices xoffset and
xoffset+width-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, but such a
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glTexSubImage1DEXT(3G) OpenGL Reference glTexSubImage1DEXT(3G)
specification has no effect.
NOTES
Texturing has no effect in color index mode.
glPixelStore and glPixelTransfer modes affect texture images in exactly
the way they affect glDrawPixels.
glTexSubImage1DEXT is part of the EXT_subtexture extension.
If type is set to GL_UNSIGNED_BYTE_3_3_2_EXT,
GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT,
GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT and the
EXT_packed_pixels extension is not supported then a GL_INVALID_ENUM error
is generated.
See glIntro for more information on using extensions.
ERRORS
GL_INVALID_ENUM is generated when target is not GL_TEXTURE_1D.
GL_INVALID_OPERATION is generated when the texture image has not been
defined by a previous glTexImage1D operation.
GL_INVALID_VALUE is generated if level is less than zero or greater than
log2(max), where max is the returned value of GL_MAX_TEXTURE_SIZE.
GL_INVALID_VALUE is generated if xoffset<-TEXTURE_BORDER, or if
(xoffset+width)>(TEXTURE_WIDTH-TEXTURE_BORDER), where TEXTURE_WIDTH is
the width of the image being modified and TEXTURE_BORDER is the border
width of the image being modified. Note that TEXTURE_WIDTH includes
twice the border width.
GL_INVALID_ENUM is generated when 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 when 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 glTexSubImage1DEXT is executed
between the execution of glBegin and the corresponding execution of
glEnd.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GL_TEXTURE_1D
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glTexSubImage1DEXT(3G) OpenGL Reference glTexSubImage1DEXT(3G)
MACHINE DEPENDENCIES
On InfiniteReality systems, the width of the image to be transferred to
texture memory must be a multiple of 8. This constraint will be lifted
in a future release, though transfers that are a multiple of 8 in length
will have somewhat higher performance than other transfers.
Texture borders are not supported on InfiniteReality systems. They will
be supported in a future release, however, they will require large
amounts of texture memory. Whenever possible, applications should use
borderless textures and GL_CLAMP_TO_EDGE_SGIS wrap mode.
The EXT_packed_pixels extension is not supported on RealityEngine,
RealityEngine2, and VTX systems; it will be supported on High Impact and
Maximum Impact systems in a future release.
glTexSubImage1DEXT is not supported on RealityEngine, RealityEngine2, and
VTX systems.
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
glDrawPixels, glFog, glPixelStore, glPixelTransfer, glTexEnv, glTexGen,
glTexImage1D, glTexParameter.
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