1GLUBUILD1DMIPMAPS(3G) GLUBUILD1DMIPMAPS(3G)
2
6 gluBuild1DMipmaps - builds a one-dimensional mipmap
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10 GLint gluBuild1DMipmaps( GLenum target,
11 GLint internalFormat,
12 GLsizei width,
13 GLenum format,
14 GLenum type,
15 const void *data )
16
19 target Specifies the target texture. Must be GL_TEXTURE_1D.
20 internalFormat Requests the internal storage of the texture image.
22 The most current version of the SGI implementation of
23 GLU does not check this value for validity before pass‐
24 ing it on to the underlying OpenGL implementation. A
25 value that is not accepted by the OpenGL implementation
26 will lead to an OpenGL error. The benefit of not
27 checking this value at the GLU level is that OpenGL
28 extensions can add new internal texture formats without
29 requiring a revision of the GLU implementation. Older
30 implementations of GLU check this value and raise a GLU
31 error if it is not 1, 2, 3, or 4 or one of the follow‐
32 ing symbolic constants: GL_ALPHA, GL_ALPHA4, GL_ALPHA8,
33 GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4,
34 GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16,
35 GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4,
36 GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8,
37 GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12,
38 GL_LUMINANCE16_ALPHA16, GL_INTENSITY, GL_INTENSITY4,
39 GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16, GL_RGB,
40 GL_R3_G3_B2, GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10,
41 GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4,
42 GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2, GL_RGBA12, or
43 GL_RGBA16.
44 width Specifies the width, in pixels, of the texture image.
46 format Specifies the of the pixel data. Must be one of
48 GL_COLOR_INDEX, GL_DEPTH_COMPONENT, GL_RED, GL_GREEN,
49 GL_BLUE, GL_ALPHA, GL_RGB, GL_RGBA, GL_BGR, GL_BGRA,
50 GL_LUMINANCE, GL_LUMINANCE_ALPHA.
51 type Specifies the data type for data. Must be one of
53 GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
54 GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT,
55 GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2,
56 GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5,
57 GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4,
58 GL_UNSIGNED_SHORT_4_4_4_4_REV,
59 GL_UNSIGNED_SHORT_5_5_5_1,
60 GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8,
61 GL_UNSIGNED_INT_8_8_8_8_REV,
62 GL_UNSIGNED_INT_10_10_10_2, or
63 GL_UNSIGNED_INT_2_10_10_10_REV.
64 data Specifies a pointer to the image data in memory.
66
68 gluBuild1DMipmaps builds a series of prefiltered one-dimensional tex‐
69 ture maps of decreasing resolutions called a mipmap. This is used for
70 the antialiasing of texture mapped primitives.
71 A return value of zero indicates success, otherwise a GLU error code is
73 returned (see gluErrorString).
74 Initially, the width of data is checked to see if it is a power of 2.
76 If not, a copy of data is scaled up or down to the nearest power of 2.
77 (If width is exactly between powers of 2, then the copy of data will
78 scale upwards.) This copy will be used for subsequent mipmapping oper‐
79 ations described below. For example, if width is 57 then a copy of
80 data will scale up to 64 before mipmapping takes place.
81 Then, proxy textures (see glTexImage1D) are used to determine if the
83 implementation can fit the requested texture. If not, width is continu‐
84 ally halved until it fits.
85 Next, a series of mipmap levels is built by decimating a copy of data
87 in half until size 1×1 is reached. At each level, each texel in the
88 halved mipmap level is an average of the corresponding two texels in
89 the larger mipmap level.
90 glTexImage1D is called to load each of these mipmap levels. Level 0 is
92 a copy of data. The highest level is log2(width). For example, if
93 width is 64 and the implementation can store a texture of this size,
94 the following mipmap levels are built: 64×1, 32×1, 16×1, 8×1, 4×1, 2×1
95 and 1×1. These correspond to levels 0 through 6, respectively.
96 See the glTexImage1D reference page for a description of the acceptable
98 values for the type parameter. See the glDrawPixels reference page for
99 a description of the acceptable values for the data parameter.
100
102 Note that there is no direct way of querying the maximum level. This
103 can be derived indirectly via glGetTexLevelParameter. First, query for
104 the width actually used at level 0. (The width may not be equal to
105 width since proxy textures might have scaled it to fit the implementa‐
106 tion.) Then the maximum level can be derived from the formula
107 log2(width).
108 Formats GL_BGR, and GL_BGRA, and types GL_UNSIGNED_BYTE_3_3_2,
110 GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5,
111 GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4,
112 GL_UNSIGNED_SHORT_4_4_4_4_REV, GL_UNSIGNED_SHORT_5_5_5_1,
113 GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8,
114 GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2, and
115 GL_UNSIGNED_INT_2_10_10_10_REV are only available if the GL version is
116 1.2 or greater, and if the GLU version is 1.3 or greater.
117
119 GLU_INVALID_VALUE is returned if width is < 1.
120 GLU_INVALID_ENUM is returned if format or type are not legal.
122 GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_BYTE_3_3_2 or
124 GL_UNSIGNED_BYTE_2_3_3_REV and format is not GL_RGB.
125 GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_SHORT_5_6_5 or
127 GL_UNSIGNED_SHORT_5_6_5_REV and format is not GL_RGB.
128 GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_SHORT_4_4_4_4
130 or GL_UNSIGNED_SHORT_4_4_4_4_REV and format is neither GL_RGBA nor
131 GL_BGRA.
132 GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_SHORT_5_5_5_1
134 or GL_UNSIGNED_SHORT_1_5_5_5_REV and format is neither GL_RGBA nor
135 GL_BGRA.
136 GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_INT_8_8_8_8 or
138 GL_UNSIGNED_INT_8_8_8_8_REV and format is neither GL_RGBA nor GL_BGRA.
139 GLU_INVALID_OPERATION is returned if type is GL_UNSIGNED_INT_10_10_10_2
141 or GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA nor
142 GL_BGRA.
143
145 glDrawPixels(3G), glTexImage1D(3G), glTexImage2D(3G), glTexImage3D(3G),
146 gluBuild2DMipmaps(3G), gluBuild3DMipmaps(3G), gluErrorString(3G),
147 glGetTexImage(3G), glGetTexLevelParameter(3G),
148 gluBuild1DMipmapLevels(3G), gluBuild2DMipmapLevels(3G),
149 gluBuild3DMipmapLevels(3G)
150 GLUBUILD1DMIPMAPS(3G)