gluBuild1DMipmaps — builds a one-dimensional mipmap
GLint gluBuild1DMipmaps( | GLenum | target, |
| GLint | internalFormat, | |
| GLsizei | width, | |
| GLenum | format, | |
| GLenum | type, | |
| const void * | data); |
target
Specifies the target texture. Must be GLU_TEXTURE_1D.
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.
widthSpecifies the width, 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.
dataSpecifies a pointer to the image data in memory.
gluBuild1DMipmaps builds a series of prefiltered one-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 of data is checked to see if it is
a power of 2. If not, a copy of data is scaled up or down to the
nearest power of 2. (If width 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, then a copy of data
will scale up to 64 before mipmapping
takes place.
Then, proxy textures (see glTexImage1D) are used to determine if
the implementation can fit the requested texture. If not, width is
continually halved until it fits.
Next, a series of mipmap levels is built by decimating a copy of
data in half
until size
glTexImage1D is called to load each of these mipmap levels.
Level 0 is a copy of data.
The highest level is
width is 64 and the implementation can store a texture of
this size, the following mipmap levels are
built:
See the glTexImage1D reference page for a description of the
acceptable values for the type parameter. See the glDrawPixels
reference page for a description of the acceptable values
for the data parameter.
Note that there is no direct way of querying the maximum level. This can
be derived indirectly via glGetTexLevelParameter. First, query
for the
width actually used at level 0.
(The width may not be equal to width since
proxy textures might have scaled it to fit the implementation.)
Then the maximum
level can be derived from the formula
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, and if the GLU version is 1.3 or greater.
GLU_INVALID_VALUE is returned if width is < 1.
GLU_INVALID_ENUM is returned if format or type are 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.
gluBuild1DMipmapLevels, gluBuild2DMipmapLevels, gluBuild2DMipmaps, gluBuild3DMipmapLevels, gluBuild3DMipmaps, gluErrorString, glDrawPixels, glGetTexImage, glGetTexLevelParameter, glTexImage1D, glTexImage2D, glTexImage3D
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/.