C SPECIFICATION
GLint GLAPIENTRY 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 GL_TEXTURE_3D.
internalFormat Requests the internal storage format of the texture
image. Must be 1, 2, 3, 4, or one of the following
symbolic constants: GL_ALPHA, GL_ALPHA4, GL_ALPHA8,
GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4,
GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16,
GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4,
GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8,
GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12,
GL_LUMINANCE16_ALPHA16, GL_INTENSITY, GL_INTENSITY4,
GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16, GL_RGB,
GL_R3_G3_B2, GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10,
GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4,
GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2, GL_RGBA12, or
GL_RGBA16.
width, height, depth
Specifies in pixels the width, height and depth respec-
tively, in pixels of the texture image.
format Specifies the format of the pixel data. Must be one of
GL_COLOR_INDEX, GL_DEPTH_COMPONENT, GL_RED, GL_GREEN,
GL_BLUE, GL_ALPHA, GL_RGB, GL_RGBA, GL_BGR, GL_BGRA,
GL_LUMINANCE, or GL_LUMINANCE_ALPHA.
type Specifies the data type for data. Must be one of:
GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT,
GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2,
GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4,
GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1,
GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8,
GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, or
GL_UNSIGNED_INT_2_10_10_10_REV.
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 dimen-
sions 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 1x1x1 is reached. At each
level, each texel in the halved mipmap level is an average of the cor-
responding 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 log2(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: 64x16x32, 32x8x16, 16x4x8, 8x2x4, 4x1x2, 2x1x1 and
1x1x1. 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 for
the width, height and depth actually used at level 0. (The width,
height and depth may not be equal to width, height and depth respec-
tively since proxy textures might have scaled them to fit the implemen-
tation.) Then the maximum level can be derived from the formula
log2(max(width,height,depth)).
gluBuild3DMipmaps is only available if the GLU version is 1.3 or
greater.
Formats GL_BGR, and GL_BGRA, and types GL_UNSIGNED_BYTE_3_3_2,
GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4,
GL_UNSIGNED_SHORT_4_4_4_4_REV, GL_UNSIGNED_SHORT_5_5_5_1,
GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8,
GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2, and
GL_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
GL_BGRA.
GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_INT_8_8_8_8 or
GL_UNSIGNED_INT_8_8_8_8_REV and format is neither GL_RGBA nor GL_BGRA.
GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_INT_10_10_10_2
or GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA nor
GL_BGRA.
SEE ALSO
glDrawPixels, glTexImage1D, glTexImage2D, glTexImage3D,
gluBuild1DMipmaps, gluBuild3DMipmaps, gluErrorString, glGetTexImage,
glGetTexLevelParameter, gluBuild1DMipmapLevels, gluBuild2DMipmapLevels,
gluBuild3DMipmapLevels
GLUBUILD3DMIPMAPS(3G)
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