glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
NAME
glTexImage3DEXT - specify a three-dimensional texture image
C SPECIFICATION
void glTexImage3DEXT( GLenum target,
GLint level,
GLenum internalformat,
GLsizei width,
GLsizei height,
GLsizei depth,
GLint border,
GLenum format,
GLenum type,
const GLvoid *pixels )
PARAMETERS
target Specifies the target texture. Must be GLTEXTURE3DEXT
or GLPROXYTEXTURE3DEXT.
level Specifies the level-of-detail number. Level 0 is the
base image level. Level n is the nth mipmap reduction
image.
internalformat Specifies the internal storage format of the texture
image. it must be one of the following symbolic
constants: GLALPHA, GLALPHA4EXT, GLALPHA8EXT,
GLALPHA12EXT, GLALPHA16EXT, GLLUMINANCE,
GLLUMINANCE4EXT, GLLUMINANCE8EXT, GLLUMINANCE12EXT,
GLLUMINANCE16EXT, GLLUMINANCEALPHA,
GLLUMINANCE4ALPHA4EXT, GLLUMINANCE6ALPHA2EXT,
GLLUMINANCE8ALPHA8EXT, GLLUMINANCE12ALPHA4EXT,
GLLUMINANCE12ALPHA12EXT, GLLUMINANCE16ALPHA16EXT,
GLINTENSITYEXT, GLINTENSITY4EXT, GLINTENSITY8EXT,
GLINTENSITY12EXT, GLINTENSITY16EXT, GLRGB,
GLRGB2EXT, GLRGB4EXT, GLRGB5EXT, GLRGB8EXT,
GLRGB10EXT, GLRGB12EXT, GLRGB16EXT, GLRGBA,
GLRGBA2EXT, GLRGBA4EXT, GLRGB5A1EXT, GLRGBA8EXT,
GLRGB10A2EXT, GLRGBA12EXT, GLRGBA16EXT,
GLDUALALPHA4SGIS, GLDUALALPHA8SGIS,
GLDUALALPHA12SGIS, GLDUALALPHA16SGIS,
GLDUALLUMINANCE4SGIS, GLDUALLUMINANCE8SGIS,
GLDUALLUMINANCE12SGIS, GLDUALLUMINANCE16SGIS,
GLDUALINTENSITY4SGIS, GLDUALINTENSITY8SGIS,
GLDUALINTENSITY12SGIS, GLDUALINTENSITY16SGIS,
GLDUALLUMINANCEALPHA4SGIS,
GLDUALLUMINANCEALPHA8SGIS, GLQUADALPHA4SGIS,
GLQUADALPHA8SGIS, GLQUADLUMINANCE4SGIS,
GLQUADLUMINANCE8SGIS, GLQUADINTENSITY4SGIS, or
GLQUADINTENSITY8SGIS.
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
width Specifies the width of the texture image. Must be
2**n+2*border for some integer n.
height Specifies the height of the texture image. Must be
2**m+I*border for some integer m, where I is 2 when
GLINTERLACESGIX is disabled, and 1 otherwise.
depth Specifies the depth of the texture image. Must be
2**l+2*border for some integer l.
border Specifies the width of the border. Must be either 0 or
1.
format Specifies the format of the pixel data. The following
symbolic values are accepted: GLCOLORINDEX, GLRED,
GLGREEN, GLBLUE, GLALPHA, GLRGB, GLRGBA,
GLABGREXT, GLLUMINANCE, and GLLUMINANCEALPHA.
type Specifies the data type of the pixel data. The following
symbolic values are accepted: GLUNSIGNEDBYTE, GLBYTE,
GLUNSIGNEDSHORT, GLSHORT, GLUNSIGNEDINT, GLINT,
GLFLOAT, GLUNSIGNEDBYTE332EXT,
GLUNSIGNEDSHORT4444EXT,
GLUNSIGNEDSHORT5551EXT,
GLUNSIGNEDINT8888EXT, and
GLUNSIGNEDINT1010102EXT.
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. Three-dimensional texturing is
enabled and disabled using glEnable and glDisable with argument
GLTEXTURE3DEXT.
Texture images are defined with glTexImage3DEXT. The arguments describe
the parameters of the texture image, such as height, width, depth, 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 the way the image is represented in memory, and they
are identical to the pixel formats used for glDrawPixels.
If target is GLPROXYTEXTURE3DEXT 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
will set all of the texture image state to 0 (GLTEXTUREWIDTH,
GLTEXTUREHEIGHT, GLTEXTUREBORDER, GLTEXTURECOMPONENTS,
GLTEXTUREREDSIZEEXT, GLTEXTUREGREENSIZEEXT,
GLTEXTUREBLUESIZEEXT, GLTEXTUREALPHASIZEEXT,
GLTEXTURELUMINANCESIZEEXT, and GLTEXTUREINTENSITYSIZEEXT), but no
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
error will be generated.
If target is GLTEXTURE3DEXT, 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. (Note that if type is set to GLUNSIGNEDBYTE332EXT,
GLUNSIGNEDSHORT4444EXT, GLUNSIGNEDSHORT5551EXT,
GLUNSIGNEDINT8888EXT, or GLUNSIGNEDINT1010102EXT then it is
a special case in which all the elements of each group are packed into a
single unsigned byte, unsigned short, or unsigned int. This is described
in glDrawPixels.)
The first element corresponds to the lower-left-rear corner of the
texture volume. Subsequent elements progress left-to-right through the
remaining texels in the lowest-rear row of the texture volume, then in
successively higher rows of the rear 2D slice of the texture volume, then
in successively closer 2D slices of the texture volume. The final
element corresponds to the upper-right-front corner of the texture
volume.
When GLINTERLACESGIX is enabled, only rows (0,2,4,...) of each S-T
slice (where the border is considered part of the slice) are defined.
Rows (1,3,5,...) are left undefined and can only be defined using
glTexSubImage3DEXT or glCopyTexSubImage3DEXT. Note, that when
GLINTERLACESGIX is enabled the total height (i.e., the height of
interior texture image plus twice the border) of the defined texture is
2*height.
Each element of pixels is converted to an RGBA element according to
format, as detailed below. Except for GLCOLORINDEX, after the
conversion to RGBA, each component is multiplied by the signed scale
factor GLcSCALE, added to the signed bias GLcBIAS, and clamped to the
range [0,1], where c is RED, GREEN, BLUE, or ALPHA, respectively (see
glPixelTransfer).
According to format, the conversion to RGBA is as follows:
GLCOLORINDEX
Each element is a single value, a color index. It is converted
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 GLINDEXSHIFT, and added to
GLINDEXOFFSET (see glPixelTransfer). The resulting index is
converted to a set of color components using the
GLPIXELMAPITOR, GLPIXELMAPITOG, GLPIXELMAPITOB,
and GLPIXELMAPITOA tables, and clamped to the range [0,1].
GLRED Each element is a single red component. It is converted to
floating point and assembled into an RGBA element by attaching
0.0 for green and blue, and 1.0 for alpha.
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
GLGREEN Each element is a single green component. It is converted to
floating point and assembled into an RGBA element by attaching
0.0 for red and blue, and 1.0 for alpha.
GLBLUE Each element is a single blue component. It is converted to
floating point and assembled into an RGBA element by attaching
0.0 for red and green, and 1.0 for alpha.
GLALPHA Each element is a single alpha component. It is converted to
floating point and assembled into an RGBA element by attaching
0.0 for red, green, and blue.
GLRGB Each element is an RGB triple. It is converted to floating
point and assembled into an RGBA element by attaching 1.0 for
alpha. (see glPixelTransfer).
GLRGBA,
GLABGREXT
Each element contains all four components; for GLRGBA, the red
component is first, followed by green, then blue, and then
alpha; for GLABGREXT the order is alpha, blue, green, and
then red.
GLLUMINANCE
Each element is a single luminance value. It is converted to
floating point, then assembled into an RGBA element by
replicating the luminance value three times for red, green, and
blue and attaching 1.0 for alpha.
GLLUMINANCEALPHA
Each element is a luminance/alpha pair. It is converted to
floating point, then assembled into an RGBA element by
replicating the luminance value three times for red, green, and
blue.
Please refer to the glDrawPixels reference page for a description of the
acceptable values for the type parameter.
An application may desire that the texture be stored at a certain
resolution, or that it be stored in a certain format. This resolution and
format can be requested by internalformat, but the implementation may not
support that resolution (The formats of GLLUMINANCE, GLLUMINANCEALPHA,
GLRGB, and GLRGBA must be supported.) When a resolution and storage
format is specified, the implementation will update the texture state to
provide the best match to the requested resolution. The
GLPROXYTEXTURE3DEXT target can be used to try a resolution and
format. The implementation will compute its best match for the requested
storage resolution and format; this state can then be queried using
glGetTexLevelParameter.
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
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.
The mapping of components from the canonical RGBA to the internal storage
formats that begin with GLDUAL and GLQUAD needs to be clarified.
There are three cases. The first case is for the GLDUAL formats that
are groups of GLALPHA, GLLUMINANCE, and GLINTENSITY. The R value goes
to the first group while the A value goes to the second group. The
second case is for the GLDUAL formats that are groups of
GLLUMINANCEALPHA. The R and G values go to the first group while the B
and A values go to the second group. The third case is for the GLQUAD
formats. The R value goes to the first group, the G value to the second
group, the B value to the third group, and the A value to the fourth
group.
NOTES
Texturing has no effect in color index mode.
The texture image can be represented by the same data formats and types
as the pixels in a glDrawPixels command, except that formats
GLSTENCILINDEX and GLDEPTHCOMPONENT cannot be used, and type
GLBITMAP cannot be used. glPixelStore and glPixelTransfer modes affect
texture images in exactly the way they affect glDrawPixels.
A texture image with zero height, width, or depth indicates the null
texture. If the null texture is specified for level-of-detail 0, it is
as if texturing were disabled.
glTexImage3DEXT is part of the EXTtexture3d extension.
If type is set to GLUNSIGNEDBYTE332EXT,
GLUNSIGNEDSHORT4444EXT, GLUNSIGNEDSHORT5551EXT,
GLUNSIGNEDINT8888EXT, or GLUNSIGNEDINT1010102EXT and the
EXTpackedpixels extension is not supported then a GLINVALIDENUM error
is generated.
See glIntro for more information on using extensions.
ERRORS
GLINVALIDENUM is generated when target is not an accepted value.
GLINVALIDENUM is generated when format is not an accepted value.
GLINVALIDENUM is generated when type is not an accepted value.
GLINVALIDVALUE is generated if level is less than zero or greater than
log (max), where max is the returned value of GLMAX3DTEXTURESIZEEXT.
2
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
GLINVALIDVALUE is generated if internalformat is not an accepted value.
GLINVALIDVALUE is generated if width, height, or depth is less than
zero or greater than GLMAX3DTEXTURESIZEEXT, when width, or depth
cannot be represented as 2**k+2*border for some integer k, or when height
cannot be represented as 2**k+I*border, where I is 2 when
GLINTERLACESGIX is disabled and 1 otherwise.
GLINVALIDVALUE is generated if border is not 0 or 1.
GLINVALIDOPERATION is generated if glTexImage3DEXT is executed between
the execution of glBegin and the corresponding execution of glEnd.
GLINVALIDVALUE is generated if the implementation cannot accomodate a
texture of the size requested.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GLTEXTURE3DEXT
glGetTexLevelParameter with a first argument of GLPROXYTEXTURE3DEXT
and a third argument of GLTEXTUREREDSIZEEXT,
GLTEXTUREGREENSIZEEXT, GLTEXTUREBLUESIZEEXT,
GLTEXTUREALPHASIZEEXT, GLTEXTURELUMINANCESIZEEXT,
GLTEXTUREINTENSITYSIZEEXT, GLTEXTUREWIDTH, GLTEXTUREHEIGHT,
GLTEXTUREDEPTHEXT, GLTEXTUREBORDER, or GLTEXTURECOMPONENTS.
MACHINE DEPENDENCIES
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.
RealityEngine, RealityEngine2, and VTX systems do not support histogram
or minmax operations on images as they are being loaded into texture
memory.
The SGIXinterlace extension is supported only on InfiniteReality
systems, on RealityEngine, RealityEngine2, and VTX systems, and on O2
systems.
The EXTpackedpixels extension is not supported on RealityEngine,
RealityEngine2, and VTX systems.
On High Impact and Maximum Impact systems the number of bits per
component, represented internally, is the same for all components and
will be 4, 8, or 12 bits per component. All specified internal formats
will receive an equal or greater representation in this scheme, up to the
12-bit limit. High Impact and Maximum Impact on Indigo2 systems do not
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
support texture internal formats of the type GLINTENSITY or GLALPHA,
although High Impact and Maximum Impact on Octane systems do support
these types.
High Impact and Maximum Impact on Indigo2 systems without the TRAM option
card support 4 bits per component for GLRGB and GLRGBA, 4/8 bits per
component for GLLUMINANCEALPHA, and 4/8/12 bits per component for
GLLUMINANCE.
On RealityEngine, RealityEngine2, and VTX systems, the following
restrictions apply to 3D texturing:
1. The texture environment must be defined and texturing must be
enabled before loading a texture.
2. Texture formats composed only of alpha are not supported.
3. Borders are not supported; hence the border width must be 0.
4. Proxy textures are not supported.
5. 3D mipmaps are not supported. Hence, the minifying function must
be set to GLNEAREST or GLLINEAR (see glTexParameter).
6 3D texturing when rendering to pixmaps is not supported.
7. GLINTERLACESGIX is not supported (see glEnable).
On High Impact and Maximum Impact systems, the following restrictions
apply to 3D texturing:
1. Perspective views are not supported.
2. Borders are not supported; hence the border width must be 0.
3. 3D mipmaps are not supported. Hence, the minifying function must
be set to GLNEAREST or GLLINEAR (see glTexParameter), and the
level parameter must be 0.
4. Textures that have a width of 16 or less will not render
correctly at the wrap_s boundary.
Texture borders are not supported on InfiniteReality systems, so the
border width should always be zero. Applications should use the texture
wrap mode GLCLAMPTOEDGESGIS to obtain behavior similar to that of
borders.
The SGIStextureselect extension is supported only on InfiniteReality
systems, High Impact and Maximum Impact on Octane systems, and High
Impact and Maximum Impact on Indigo2 systems with the TRAM option card.
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glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
On InfiniteReality, RealityEngine, RealityEngine2, and VTX systems, and
High Impact and Maximum Impact systems, texture objects (see
glBindTextureEXT) are significantly faster than display-listed textures,
and therefore are recommended for managing texture memory.
SEE ALSO
glDrawPixels, glFog, glPixelStore, glPixelTransfer, glTexEnv, glTexGen,
glTexImage1D, glTexImage2D, glTexParameter,
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