gluBuild2DMipmapLevels man page on RedHat
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GLUBUILD2DMIPMAPLEVE(3G) OpenGL Manual GLUBUILD2DMIPMAPLEVE(3G)
NAME
gluBuild2DMipmapLevels - builds a subset of two-dimensional mipmap
levels
C SPECIFICATION
GLint gluBuild2DMipmapLevels(GLenum target, GLint internalFormat,
GLsizei width, GLsizei height,
GLenum format, GLenum type, GLint level,
GLint base, GLint max, const void * data);
PARAMETERS
target
Specifies the target texture. Must be GLU_TEXTURE_2D.
internalFormat
Requests the internal storage format of the texture image. The most
current version of the SGI implementation of GLU does not check
this value for validity before passing it on to the underlying
OpenGL implementation. A value that is not accepted by the OpenGL
implementation will lead to an OpenGL error. The benefit of not
checking this value at the GLU level is that OpenGL extensions can
add new internal texture formats without requiring a revision of
the GLU implementation. Older implementations of GLU check this
value and raise a GLU error if it is not 1, 2, 3, or 4 or one of
the following symbolic constants: GLU_ALPHA, GLU_ALPHA4,
GLU_ALPHA8, GLU_ALPHA12, GLU_ALPHA16, GLU_LUMINANCE,
GLU_LUMINANCE4, GLU_LUMINANCE8, GLU_LUMINANCE12, GLU_LUMINANCE16,
GLU_LUMINANCE_ALPHA, GLU_LUMINANCE4_ALPHA4, GLU_LUMINANCE6_ALPHA2,
GLU_LUMINANCE8_ALPHA8, GLU_LUMINANCE12_ALPHA4,
GLU_LUMINANCE12_ALPHA12, GLU_LUMINANCE16_ALPHA16, GLU_INTENSITY,
GLU_INTENSITY4, GLU_INTENSITY8, GLU_INTENSITY12, GLU_INTENSITY16,
GLU_RGB, GLU_R3_G3_B2, GLU_RGB4, GLU_RGB5, GLU_RGB8, GLU_RGB10,
GLU_RGB12, GLU_RGB16, GLU_RGBA, GLU_RGBA2, GLU_RGBA4, GLU_RGB5_A1,
GLU_RGBA8, GLU_RGB10_A2, GLU_RGBA12, or GLU_RGBA16.
width, height
Specifies the width and height, respectively, in pixels of the
texture image. These should be a power of 2.
format
Specifies the format of the pixel data. Must be one of
GLU_COLOR_INDEX, GLU_DEPTH_COMPONENT, GLU_RED, GLU_GREEN, GLU_BLUE,
GLU_ALPHA, GLU_RGB, GLU_RGBA, GLU_BGR, GLU_BGRA, GLU_LUMINANCE, or
GLU_LUMINANCE_ALPHA.
type
Specifies the data type for data. Must be one of GLU_UNSIGNED_BYTE,
GLU_BYTE, GLU_BITMAP, GLU_UNSIGNED_SHORT, GLU_SHORT,
GLU_UNSIGNED_INT, GLU_INT, GLU_FLOAT, GLU_UNSIGNED_BYTE_3_3_2,
GLU_UNSIGNED_BYTE_2_3_3_REV, GLU_UNSIGNED_SHORT_5_6_5,
GLU_UNSIGNED_SHORT_5_6_5_REV, GLU_UNSIGNED_SHORT_4_4_4_4,
GLU_UNSIGNED_SHORT_4_4_4_4_REV, GLU_UNSIGNED_SHORT_5_5_5_1,
GLU_UNSIGNED_SHORT_1_5_5_5_REV, GLU_UNSIGNED_INT_8_8_8_8,
GLU_UNSIGNED_INT_8_8_8_8_REV, GLU_UNSIGNED_INT_10_10_10_2, or
GLU_UNSIGNED_INT_2_10_10_10_REV.
level
Specifies the mipmap level of the image data.
base
Specifies the minimum mipmap level to pass to glTexImage2D().
max
Specifies the maximum mipmap level to pass to glTexImage2D().
data
Specifies a pointer to the image data in memory.
DESCRIPTION
gluBuild2DMipmapLevels builds a subset of prefiltered two-dimensional
texture maps of decreasing resolutions called a mipmap. This is used
for the antialiasing of texture mapped primitives.
A return value of zero indicates success, otherwise a GLU error code is
returned (see gluErrorString()).
A series of mipmap levels from base to max is built by decimating data
in half along both dimensions until size 1 × 1 is reached. At each
level, each texel in the halved mipmap level is an average of the
corresponding four texels in the larger mipmap level. (In the case of
rectangular images, the decimation will ultimately reach an N × 1 or 1
× N configuration. Here, two texels are averaged instead.)
glTexImage2D() is called to load these mipmap levels from base to max.
If max is larger than the highest mipmap level for the texture of the
specified size, then a GLU error code is returned (see
gluErrorString()) and nothing is loaded.
For example, if level is 2 and width is 16 and height is 8, the
following levels are possible: 16 × 8, 8 × 4, 4 × 2, 2 × 1, 1 × 1.
These correspond to levels 2 through 6 respectively. If base is 3 and
max is 5, then only mipmap levels 8 × 4, 4 × 2, and 2 × 1 are loaded.
However, if max is 7, then an error is returned and nothing is loaded
since max is larger than the highest mipmap level which is, in this
case, 6.
The highest mipmap level can be derived from the formula log 2 max
width height × 2 level.
See the glTexImage1D() reference page for a description of the
acceptable values for format parameter. See the glDrawPixels()
reference page for a description of the acceptable values for type
parameter.
NOTES
gluBuild2DMipmapLevels is only available if the GLU version is 1.3 or
greater.
Formats GLU_BGR, and GLU_BGRA, and types GLU_UNSIGNED_BYTE_3_3_2,
GLU_UNSIGNED_BYTE_2_3_3_REV, GLU_UNSIGNED_SHORT_5_6_5,
GLU_UNSIGNED_SHORT_5_6_5_REV, GLU_UNSIGNED_SHORT_4_4_4_4,
GLU_UNSIGNED_SHORT_4_4_4_4_REV, GLU_UNSIGNED_SHORT_5_5_5_1,
GLU_UNSIGNED_SHORT_1_5_5_5_REV, GLU_UNSIGNED_INT_8_8_8_8,
GLU_UNSIGNED_INT_8_8_8_8_REV, GLU_UNSIGNED_INT_10_10_10_2, and
GLU_UNSIGNED_INT_2_10_10_10_REV are only available if the GL version is
1.2 or greater.
ERRORS
GLU_INVALID_VALUE is returned if level > base, base < 0, max < base, or
max is > the highest mipmap level for data.
GLU_INVALID_VALUE is returned if width or height is < 1.
GLU_INVALID_ENUM is returned if internalFormat, format, or type is not
legal.
GLU_INVALID_OPERATION is returned if type is GLU_UNSIGNED_BYTE_3_3_2 or
GLU_UNSIGNED_BYTE_2_3_3_REV and format is not GLU_RGB.
GLU_INVALID_OPERATION is returned if type is GLU_UNSIGNED_SHORT_5_6_5
or GLU_UNSIGNED_SHORT_5_6_5_REV and format is not GLU_RGB.
GLU_INVALID_OPERATION is returned if type is GLU_UNSIGNED_SHORT_4_4_4_4
or GLU_UNSIGNED_SHORT_4_4_4_4_REV and format is neither GLU_RGBA nor
GLU_BGRA.
GLU_INVALID_OPERATION is returned if type is GLU_UNSIGNED_SHORT_5_5_5_1
or GLU_UNSIGNED_SHORT_1_5_5_5_REV and format is neither GLU_RGBA nor
GLU_BGRA.
GLU_INVALID_OPERATION is returned if type is GLU_UNSIGNED_INT_8_8_8_8
or GLU_UNSIGNED_INT_8_8_8_8_REV and format is neither GLU_RGBA nor
GLU_BGRA.
GLU_INVALID_OPERATION is returned if type is
GLU_UNSIGNED_INT_10_10_10_2 or GLU_UNSIGNED_INT_2_10_10_10_REV and
format is neither GLU_RGBA nor GLU_BGRA.
SEE ALSO
gluBuild1DMipmapLevels(), gluBuild1DMipmaps(), gluBuild2DMipmaps(),
gluBuild3DMipmapLevels(), gluBuild3DMipmaps(), gluErrorString(),
glDrawPixels(), glGetTexImage(), glGetTexLevelParameter(),
glTexImage1D(), glTexImage2D(), glTexImage3D()
COPYRIGHT
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.
AUTHORS
opengl.org
opengl.org 03/16/2013 GLUBUILD2DMIPMAPLEVE(3G)
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