glteximage3dext - Man Page
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 GL_TEXTURE_3D_EXT
or GL_PROXY_TEXTURE_3D_EXT.
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: GL_ALPHA, GL_ALPHA4_EXT, GL_ALPHA8_EXT,
GL_ALPHA12_EXT, GL_ALPHA16_EXT, GL_LUMINANCE,
GL_LUMINANCE4_EXT, GL_LUMINANCE8_EXT, GL_LUMINANCE12_EXT,
GL_LUMINANCE16_EXT, GL_LUMINANCE_ALPHA,
GL_LUMINANCE4_ALPHA4_EXT, GL_LUMINANCE6_ALPHA2_EXT,
GL_LUMINANCE8_ALPHA8_EXT, GL_LUMINANCE12_ALPHA4_EXT,
GL_LUMINANCE12_ALPHA12_EXT, GL_LUMINANCE16_ALPHA16_EXT,
GL_INTENSITY_EXT, GL_INTENSITY4_EXT, GL_INTENSITY8_EXT,
GL_INTENSITY12_EXT, GL_INTENSITY16_EXT, GL_RGB,
GL_RGB2_EXT, GL_RGB4_EXT, GL_RGB5_EXT, GL_RGB8_EXT,
GL_RGB10_EXT, GL_RGB12_EXT, GL_RGB16_EXT, GL_RGBA,
GL_RGBA2_EXT, GL_RGBA4_EXT, GL_RGB5_A1_EXT, GL_RGBA8_EXT,
GL_RGB10_A2_EXT, GL_RGBA12_EXT, GL_RGBA16_EXT,
GL_DUAL_ALPHA4_SGIS, GL_DUAL_ALPHA8_SGIS,
GL_DUAL_ALPHA12_SGIS, GL_DUAL_ALPHA16_SGIS,
GL_DUAL_LUMINANCE4_SGIS, GL_DUAL_LUMINANCE8_SGIS,
GL_DUAL_LUMINANCE12_SGIS, GL_DUAL_LUMINANCE16_SGIS,
GL_DUAL_INTENSITY4_SGIS, GL_DUAL_INTENSITY8_SGIS,
GL_DUAL_INTENSITY12_SGIS, GL_DUAL_INTENSITY16_SGIS,
GL_DUAL_LUMINANCE_ALPHA4_SGIS,
GL_DUAL_LUMINANCE_ALPHA8_SGIS, GL_QUAD_ALPHA4_SGIS,
GL_QUAD_ALPHA8_SGIS, GL_QUAD_LUMINANCE4_SGIS,
GL_QUAD_LUMINANCE8_SGIS, GL_QUAD_INTENSITY4_SGIS, or
GL_QUAD_INTENSITY8_SGIS.
Page 1
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
GL_INTERLACE_SGIX 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: 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_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. Three-dimensional texturing is
enabled and disabled using glEnable and glDisable with argument
GL_TEXTURE_3D_EXT.
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 GL_PROXY_TEXTURE_3D_EXT 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 (GL_TEXTURE_WIDTH,
GL_TEXTURE_HEIGHT, GL_TEXTURE_BORDER, GL_TEXTURE_COMPONENTS,
GL_TEXTURE_RED_SIZE_EXT, GL_TEXTURE_GREEN_SIZE_EXT,
GL_TEXTURE_BLUE_SIZE_EXT, GL_TEXTURE_ALPHA_SIZE_EXT,
GL_TEXTURE_LUMINANCE_SIZE_EXT, and GL_TEXTURE_INTENSITY_SIZE_EXT), but no
Page 2
glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
error will be generated.
If target is GL_TEXTURE_3D_EXT, 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 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 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 GL_INTERLACE_SGIX 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
GL_INTERLACE_SGIX 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 GL_COLOR_INDEX, after the
conversion to RGBA, 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], where c is RED, GREEN, BLUE, or ALPHA, respectively (see
glPixelTransfer).
According to format, the conversion to RGBA is as follows:
GL_COLOR_INDEX
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 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. 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.
Page 3
glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
GL_GREEN 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.
GL_BLUE 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.
GL_ALPHA 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.
GL_RGB 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).
GL_RGBA,
GL_ABGR_EXT
Each element contains all four components; for GL_RGBA, the red
component is first, followed by green, then blue, and then
alpha; for GL_ABGR_EXT the order is alpha, blue, green, and
then red.
GL_LUMINANCE
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.
GL_LUMINANCE_ALPHA
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 GL_LUMINANCE, GL_LUMINANCE_ALPHA,
GL_RGB, and GL_RGBA 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
GL_PROXY_TEXTURE_3D_EXT 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.
Page 4
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 GL_DUAL_ and GL_QUAD_ needs to be clarified.
There are three cases. The first case is for the GL_DUAL_ formats that
are groups of GL_ALPHA, GL_LUMINANCE, and GL_INTENSITY. The R value goes
to the first group while the A value goes to the second group. The
second case is for the GL_DUAL_ formats that are groups of
GL_LUMINANCE_ALPHA. 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 GL_QUAD_
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
GL_STENCIL_INDEX and GL_DEPTH_COMPONENT cannot be used, and type
GL_BITMAP 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 EXT_texture3d 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 an accepted value.
GL_INVALID_ENUM is generated when format is not an accepted value.
GL_INVALID_ENUM is generated when type is not an accepted value.
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_3D_TEXTURE_SIZE_EXT.
Page 5
glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
GL_INVALID_VALUE is generated if internalformat is not an accepted value.
GL_INVALID_VALUE is generated if width, height, or depth is less than
zero or greater than GL_MAX_3D_TEXTURE_SIZE_EXT, 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
GL_INTERLACE_SGIX is disabled and 1 otherwise.
GL_INVALID_VALUE is generated if border is not 0 or 1.
GL_INVALID_OPERATION is generated if glTexImage3DEXT is executed between
the execution of glBegin and the corresponding execution of glEnd.
GL_TEXTURE_TOO_LARGE_EXT is generated if the implementation cannot
accomodate a texture of the size requested.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GL_TEXTURE_3D_EXT
glGetTexLevelParameter with a first argument of GL_PROXY_TEXTURE_3D_EXT
and a third argument of GL_TEXTURE_RED_SIZE_EXT,
GL_TEXTURE_GREEN_SIZE_EXT, GL_TEXTURE_BLUE_SIZE_EXT,
GL_TEXTURE_ALPHA_SIZE_EXT, GL_TEXTURE_LUMINANCE_SIZE_EXT,
GL_TEXTURE_INTENSITY_SIZE_EXT, GL_TEXTURE_WIDTH, GL_TEXTURE_HEIGHT,
GL_TEXTURE_DEPTH_EXT, GL_TEXTURE_BORDER, or GL_TEXTURE_COMPONENTS.
MACHINE DEPENDENCIES
RealityEngine, RealityEngine2, and VTX systems do not support convolving
images as they are loaded into texture memory.
InfiniteReality systems have limited support for convolving images as
they are loaded into texture memory. The image resulting from
convolution must be a multiple of 8 in width.
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
and on RealityEngine, RealityEngine2, and VTX systems.
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.
High Impact and Maximum Impact systems do not support texture internal
formats of the type GL_INTENSITY or GL_ALPHA. Internally the number of
bits per component 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.
Page 6
glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
High Impact and Maximum Impact systems without the TRAM option card
support 4 bits per component for GL_RGB and GL_RGBA, 4/8 bits per
component for GL_LUMINANCE_ALPHA, and 4/8/12 bits per component for
GL_RGBA.
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 GL_NEAREST or GL_LINEAR (see glTexParameter).
6 3D texturing when rendering to pixmaps is not supported.
7. GL_INTERLACE_SGIX is not supported (see glEnable).
On InfiniteReality systems, defining 2D and 3D textures in arbitrary
order can cause incorrect results if texture memory is overcommitted.
Workarounds are to define all 3D textures before defining any 2D
textures, or to ensure that the application never defines more textures
than will fit in texture memory. This will be fixed in the next release.
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 GL_NEAREST or GL_LINEAR (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. Borders will be supported in future
releases. However, borders use texture memory very inefficiently; up to
four times the memory required by the base texture may be needed to
support borders properly. Whenever possible, applications should use the
texture wrap mode GL_CLAMP_TO_EDGE_SGIS and borderless textures. This
might be essential for large textures, which otherwise won't fit in
texture memory because of the border overhead.
Page 7
glTexImage3DEXT(3G) OpenGL Reference glTexImage3DEXT(3G)
The SGIS_texture_select extension is supported only on InfiniteReality
systems and on High Impact and Maximum Impact systems with the TRAM
option card.
SEE ALSO
glDrawPixels, glFog, glPixelStore, glPixelTransfer, glTexEnv, glTexGen,
glTexImage1D, glTexImage2D, glTexParameter,
Page 8