GLUBUILD3DMIPMAPS(3G) OpenGL Manual GLUBUILD3DMIPMAPS(3G)
NAME
gluBuild3DMipmaps - builds a three-dimensional mipmap
C SPECIFICATION
GLint gluBuild3DMipmaps(GLenum target, GLint internalFormat, GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLenum type,
const void * data);
PARAMETERS
target
Specifies the target texture. Must be GLU_TEXTURE_3D.
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, depth
Specifies in pixels the width, height and depth respectively, in pixels of the texture image.
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.
data
Specifies a pointer to the image data in memory.
DESCRIPTION
gluBuild3DMipmaps builds a series of prefiltered three-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()).
Initially, the width, height and depth of data are checked to see if they are a power of 2. If not, a copy of data is made and scaled up or
down to the nearest power of 2. (If width, height, or depth is exactly between powers of 2, then the copy of data will scale upwards.) This
copy will be used for subsequent mipmapping operations described below. For example, if width is 57, height is 23, and depth is 24, then a
copy of data will scale up to 64 in width, down to 16 in height, and up to 32 in depth before mipmapping takes place.
Then, proxy textures (see glTexImage3D()) are used to determine if the implementation can fit the requested texture. If not, all three
dimensions are continually halved until it fits.
Next, a series of mipmap levels is built by decimating a copy of data in half along all three dimensions until size 1 x 1 x 1 is reached.
At each level, each texel in the halved mipmap level is an average of the corresponding eight texels in the larger mipmap level. (If
exactly one of the dimensions is 1, four texels are averaged. If exactly two of the dimensions are 1, two texels are averaged.)
glTexImage3D() is called to load each of these mipmap levels. Level 0 is a copy of data. The highest level is log 2 max width height
depth. For example, if width is 64, height is 16, and depth is 32, and the implementation can store a texture of this size, the following
mipmap levels are built: 64 x 16 x 32, 32 x 8 x 16, 16 x 4 x 8, 8 x 2 x 4, 4 x 1 x 2, 2 x 1 x 1, and 1 x 1 x 1. These correspond to levels
0 through 6, respectively.
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
Note that there is no direct way of querying the maximum level. This can be derived indirectly via glGetTexLevelParameter(). First, query
the width, height, and depth actually used at level 0. (The width, height, and depth may not be equal to width, height, and depth
respectively since proxy textures might have scaled them to fit the implementation.) Then the maximum level can be derived from the formula
log 2 max width height depth.
gluBuild3DMipmaps 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 width, height, or depth 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(), gluBuild2DMipmapLevels(), gluBuild3DMipmapLevels(), gluBuild3DMipmaps, gluErrorString(),
glDrawPixels(), glGetTexImage(), glGetTexLevelParameter(), glTexImage1D(), glTexImage2D(), glTexImage3D()
COPYRIGHT
Copyright (C) 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 06/10/2014 GLUBUILD3DMIPMAPS(3G)