229 lines
7.6 KiB
Plaintext
229 lines
7.6 KiB
Plaintext
'\" e
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'\"! eqn | mmdoc
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'\"macro stdmacro
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.ds Vn Version 1.2
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.ds Dt 6 March 1997
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.ds Re Release 1.2.0
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.ds Dp May 02 11:53
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.ds Dm 37 build1dmi
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.ds Xs 40806 9 build1dmipmaps.gl
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.TH GLUBUILD1DMIPMAPS 3G
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.SH NAME
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.B "gluBuild1DMipmaps
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\- builds a one-dimensional mipmap
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.SH C SPECIFICATION
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GLint \f3gluBuild1DMipmaps\fP(
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GLenum \fItarget\fP,
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.nf
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.ta \w'\f3GLint \fPgluBuild1DMipmaps( 'u
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GLint \fIinternalFormat\fP,
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GLsizei \fIwidth\fP,
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GLenum \fIformat\fP,
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GLenum \fItype\fP,
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const void \fI*data\fP )
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.fi
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.EQ
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delim $$
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.EN
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.SH PARAMETERS
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.TP \w'\fIinternalFormat\fP\ \ 'u
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\f2target\fP
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Specifies the target texture. Must be \%\f3GL_TEXTURE_1D\fP.
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.TP
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\f2internalFormat\fP
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Requests the internal storage of the texture image. The most
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current version of the SGI implementation of GLU does not check this
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value for validity before passing it on to the underlying OpenGL
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implementation. A value that is not accepted by the OpenGL
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implementation will lead to an OpenGL error. The benefit of not
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checking this value at the GLU level is that OpenGL extensions can add
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new internal texture formats without requiring a revision of the GLU
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implementation. Older implementations of GLU check this value and
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raise a GLU error if it is not 1, 2, 3, or 4 or one of the following
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symbolic constants:
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\%\f3GL_ALPHA\fP,
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\%\f3GL_ALPHA4\fP,
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\%\f3GL_ALPHA8\fP,
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\%\f3GL_ALPHA12\fP,
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\%\f3GL_ALPHA16\fP,
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\%\f3GL_LUMINANCE\fP,
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\%\f3GL_LUMINANCE4\fP,
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\%\f3GL_LUMINANCE8\fP,
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\%\f3GL_LUMINANCE12\fP,
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\%\f3GL_LUMINANCE16\fP,
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\%\f3GL_LUMINANCE_ALPHA\fP,
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\%\f3GL_LUMINANCE4_ALPHA4\fP,
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\%\f3GL_LUMINANCE6_ALPHA2\fP,
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\%\f3GL_LUMINANCE8_ALPHA8\fP,
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\%\f3GL_LUMINANCE12_ALPHA4\fP,
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\%\f3GL_LUMINANCE12_ALPHA12\fP,
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\%\f3GL_LUMINANCE16_ALPHA16\fP,
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\%\f3GL_INTENSITY\fP,
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\%\f3GL_INTENSITY4\fP,
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\%\f3GL_INTENSITY8\fP,
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\%\f3GL_INTENSITY12\fP,
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\%\f3GL_INTENSITY16\fP,
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\%\f3GL_RGB\fP,
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\%\f3GL_R3_G3_B2\fP,
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\%\f3GL_RGB4\fP,
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\%\f3GL_RGB5\fP,
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\%\f3GL_RGB8\fP,
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\%\f3GL_RGB10\fP,
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\%\f3GL_RGB12\fP,
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\%\f3GL_RGB16\fP,
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\%\f3GL_RGBA\fP,
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\%\f3GL_RGBA2\fP,
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\%\f3GL_RGBA4\fP,
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\%\f3GL_RGB5_A1\fP,
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\%\f3GL_RGBA8\fP,
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\%\f3GL_RGB10_A2\fP,
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\%\f3GL_RGBA12\fP, or
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\%\f3GL_RGBA16\fP.
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.TP
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\f2width\fP
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Specifies the width, in pixels, of the texture image.
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.TP
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\f2format\fP
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Specifies the of the pixel data.
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Must be one of
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\%\f3GL_COLOR_INDEX\fP,
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\%\f3GL_DEPTH_COMPONENT\fP,
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\%\f3GL_RED\fP,
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\%\f3GL_GREEN\fP,
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\%\f3GL_BLUE\fP,
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\%\f3GL_ALPHA\fP,
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\%\f3GL_RGB\fP,
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\%\f3GL_RGBA\fP,
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\%\f3GL_BGR\fP,
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\%\f3GL_BGRA\fP,
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\%\f3GL_LUMINANCE\fP,
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\%\f3GL_LUMINANCE_ALPHA\fP.
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.TP
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\f2type\fP
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Specifies the data type for \f2data\fP.
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Must be one of
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\%\f3GL_UNSIGNED_BYTE\fP,
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\%\f3GL_BYTE\fP,
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\%\f3GL_BITMAP\fP,
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\%\f3GL_UNSIGNED_SHORT\fP,
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\%\f3GL_SHORT\fP,
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\%\f3GL_UNSIGNED_INT\fP,
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\%\f3GL_INT\fP,
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\%\f3GL_FLOAT\fP,
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\%\f3GL_UNSIGNED_BYTE_3_3_2\fP,
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\%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP,
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\%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP,
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\%\f3GL_UNSIGNED_INT_10_10_10_2\fP, or
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\%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP.
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.TP
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\f2data\fP
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Specifies a pointer to the image data in memory.
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.SH DESCRIPTION
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\%\f3gluBuild1DMipmaps\fP builds a series of prefiltered one-dimensional texture maps of decreasing
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resolutions called a mipmap. This is used for the antialiasing of
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texture mapped primitives.
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.P
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A return value of zero indicates success, otherwise a GLU error code is
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returned (see \%\f3gluErrorString\fP).
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.P
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Initially, the \f2width\fP of \f2data\fP is checked to see if it is
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a power of 2. If not, a copy of \f2data\fP is scaled up or down to the
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nearest power of 2. (If \f2width\fP is exactly between powers of 2, then
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the copy of \f2data\fP will scale upwards.) This copy will be used for
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subsequent mipmapping operations described below.
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For example, if \f2width\fP is 57 then a copy of \f2data\fP
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will scale up to 64 before mipmapping
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takes place.
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.P
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Then, proxy textures (see \f3glTexImage1D\fP) are used to determine if
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the implementation can fit the requested texture. If not, \f2width\fP is
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continually halved until it fits.
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.P
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Next, a series of mipmap levels is built by decimating a copy of
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\f2data\fP in half
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until size $1 ~times~ 1$ is reached. At each level, each texel in the
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halved mipmap level is an average of the corresponding two texels in the larger
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mipmap level.
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.P
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\f3glTexImage1D\fP is called to load each of these mipmap levels.
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Level 0 is a copy of \f2data\fP.
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The highest level is ${log sub 2}(\f2width\fP)$.
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For example, if \f2width\fP is 64 and the implementation can store a texture of
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this size, the following mipmap levels are
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built: $64 ~times~ 1$, $32 ~times~ 1$, $16 ~times~ 1$, $8 ~times~ 1$,
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$4 ~times~ 1$, $2 ~times~ 1$ and $1 ~times~ 1$. These correspond to
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levels 0 through 6, respectively.
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.P
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See the \f3glTexImage1D\fP reference page for a description of the
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acceptable values for the \f2type\fP parameter. See the \f3glDrawPixels\fP
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reference page for a description of the acceptable values
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for the \f2data\fP parameter.
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.SH NOTES
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Note that there is no direct way of querying the maximum level. This can
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be derived indirectly via \f3glGetTexLevelParameter\fP. First, query
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for the
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width actually used at level 0.
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(The width may not be equal to \f2width\fP since
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proxy textures might have scaled it to fit the implementation.)
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Then the maximum
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level can be derived from the formula ${log sub 2}(\f2width\fP)$.
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.P
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Formats \%\f3GL_BGR\fP, and \%\f3GL_BGRA\fP, and types
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\%\f3GL_UNSIGNED_BYTE_3_3_2\fP,
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\%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5\fP,
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\%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP,
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\%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP,
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\%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP,
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\%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8\fP,
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\%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP,
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\%\f3GL_UNSIGNED_INT_10_10_10_2\fP, and
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\%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP are only available if the GL version
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is 1.2 or greater, and if the GLU version is 1.3 or greater.
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.SH ERRORS
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\%\f3GLU_INVALID_VALUE\fP is returned if \f2width\fP is < 1.
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.P
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\%\f3GLU_INVALID_ENUM\fP is returned if \f2format\fP or \f2type\fP are not legal.
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.P
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\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_BYTE_3_3_2\fP or \%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP
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and \f2format\fP is not \%\f3GL_RGB\fP.
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.P
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\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_SHORT_5_6_5\fP or \%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP
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and \f2format\fP is not \%\f3GL_RGB\fP.
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.P
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\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP or \%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP
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and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP.
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.P
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\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP or \%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP
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and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP.
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.P
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\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_INT_8_8_8_8\fP or \%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP
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and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP.
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.P
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\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_INT_10_10_10_2\fP or \%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP
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and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP.
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.SH SEE ALSO
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\f3glDrawPixels(3G)\fP,
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\f3glTexImage1D(3G)\fP,
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\f3glTexImage2D(3G)\fP,
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\f3glTexImage3D(3G)\fP,
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\%\f3gluBuild2DMipmaps(3G)\fP,
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\%\f3gluBuild3DMipmaps(3G)\fP,
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\%\f3gluErrorString(3G)\fP,
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\f3glGetTexImage(3G)\fP,
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\f3glGetTexLevelParameter(3G)\fP,
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\%\f3gluBuild1DMipmapLevels(3G)\fP,
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\%\f3gluBuild2DMipmapLevels(3G)\fP,
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\%\f3gluBuild3DMipmapLevels(3G)\fP
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