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Diffstat (limited to 'doc/gl-docs/GLU/build2dmipmaps.3gl')
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diff --git a/doc/gl-docs/GLU/build2dmipmaps.3gl b/doc/gl-docs/GLU/build2dmipmaps.3gl new file mode 100644 index 000000000..e7d970c64 --- /dev/null +++ b/doc/gl-docs/GLU/build2dmipmaps.3gl @@ -0,0 +1,236 @@ +'\" e +'\"! eqn | mmdoc +'\"macro stdmacro +.ds Vn Version 1.2 +.ds Dt 6 March 1997 +.ds Re Release 1.2.0 +.ds Dp May 02 11:53 +.ds Dm 37 build2dmi +.ds Xs 21901 10 build2dmipmaps.gl +.TH GLUBUILD2DMIPMAPS 3G +.SH NAME +.B "gluBuild2DMipmaps +\- builds a two-dimensional mipmap + +.SH C SPECIFICATION +GLint \f3gluBuild2DMipmaps\fP( +GLenum \fItarget\fP, +.nf +.ta \w'\f3GLint \fPgluBuild2DMipmaps( 'u + GLint \fIinternalFormat\fP, + GLsizei \fIwidth\fP, + GLsizei \fIheight\fP, + GLenum \fIformat\fP, + GLenum \fItype\fP, + const void \fI*data\fP ) +.fi + +.EQ +delim $$ +.EN +.SH PARAMETERS +.TP \w'\fIinternalFormat\fP\ \ 'u +\f2target\fP +Specifies the target texture. Must be \%\f3GL_TEXTURE_2D\fP. +.TP +\f2internalFormat\fP +Requests the internal storage 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: +\%\f3GL_ALPHA\fP, +\%\f3GL_ALPHA4\fP, +\%\f3GL_ALPHA8\fP, +\%\f3GL_ALPHA12\fP, +\%\f3GL_ALPHA16\fP, +\%\f3GL_LUMINANCE\fP, +\%\f3GL_LUMINANCE4\fP, +\%\f3GL_LUMINANCE8\fP, +\%\f3GL_LUMINANCE12\fP, +\%\f3GL_LUMINANCE16\fP, +\%\f3GL_LUMINANCE_ALPHA\fP, +\%\f3GL_LUMINANCE4_ALPHA4\fP, +\%\f3GL_LUMINANCE6_ALPHA2\fP, +\%\f3GL_LUMINANCE8_ALPHA8\fP, +\%\f3GL_LUMINANCE12_ALPHA4\fP, +\%\f3GL_LUMINANCE12_ALPHA12\fP, +\%\f3GL_LUMINANCE16_ALPHA16\fP, +\%\f3GL_INTENSITY\fP, +\%\f3GL_INTENSITY4\fP, +\%\f3GL_INTENSITY8\fP, +\%\f3GL_INTENSITY12\fP, +\%\f3GL_INTENSITY16\fP, +\%\f3GL_RGB\fP, +\%\f3GL_R3_G3_B2\fP, +\%\f3GL_RGB4\fP, +\%\f3GL_RGB5\fP, +\%\f3GL_RGB8\fP, +\%\f3GL_RGB10\fP, +\%\f3GL_RGB12\fP, +\%\f3GL_RGB16\fP, +\%\f3GL_RGBA\fP, +\%\f3GL_RGBA2\fP, +\%\f3GL_RGBA4\fP, +\%\f3GL_RGB5_A1\fP, +\%\f3GL_RGBA8\fP, +\%\f3GL_RGB10_A2\fP, +\%\f3GL_RGBA12\fP or +\%\f3GL_RGBA16\fP. +.TP +\f2width\fP, \f2height\fP +Specifies in pixels the width and height, respectively, of the texture image. +.TP +\f2format\fP +Specifies the of the pixel data. +Must be one of +\%\f3GL_COLOR_INDEX\fP, +\%\f3GL_DEPTH_COMPONENT\fP, +\%\f3GL_RED\fP, +\%\f3GL_GREEN\fP, +\%\f3GL_BLUE\fP, +\%\f3GL_ALPHA\fP, +\%\f3GL_RGB\fP, +\%\f3GL_RGBA\fP, +\%\f3GL_BGR\fP, +\%\f3GL_BGRA\fP, +\%\f3GL_LUMINANCE\fP, or +\%\f3GL_LUMINANCE_ALPHA\fP. +.TP +\f2type\fP +Specifies the data type for \f2data\fP. +Must be one of +\%\f3GL_UNSIGNED_BYTE\fP, +\%\f3GL_BYTE\fP, +\%\f3GL_BITMAP\fP, +\%\f3GL_UNSIGNED_SHORT\fP, +\%\f3GL_SHORT\fP, +\%\f3GL_UNSIGNED_INT\fP, +\%\f3GL_INT\fP, +\%\f3GL_FLOAT\fP, +\%\f3GL_UNSIGNED_BYTE_3_3_2\fP, +\%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP, +\%\f3GL_UNSIGNED_SHORT_5_6_5\fP, +\%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP, +\%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP, +\%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP, +\%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP, +\%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP, +\%\f3GL_UNSIGNED_INT_8_8_8_8\fP, +\%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP, +\%\f3GL_UNSIGNED_INT_10_10_10_2\fP, or +\%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP. +.TP +\f2data\fP +Specifies a pointer to the image data in memory. + + +.SH DESCRIPTION +\%\f3gluBuild2DMipmaps\fP builds a series of prefiltered two-dimensional texture maps of decreasing +resolutions called a mipmap. This is used for the antialiasing of +texture-mapped primitives. +.P +A return value of zero indicates success, otherwise a GLU error code is +returned (see \%\f3gluErrorString\fP). +.P +Initially, the \f2width\fP and \f2height\fP of \f2data\fP are checked to see if they +are a power of 2. If not, a copy of \f2data\fP (not \f2data\fP), is scaled up +or down to the nearest power of 2. This copy will be used for subsequent +mipmapping operations described below. (If \f2width\fP or \f2height\fP is exactly +between powers of 2, then the copy of \f2data\fP will scale upwards.) For +example, if \f2width\fP is 57 and \f2height\fP is 23 then a copy of \f2data\fP will +scale up to 64 in \f2width\fP and down to 16 in depth, before mipmapping takes +place. +.P +Then, proxy textures (see \f3glTexImage2D\fP) are used to determine if +the implementation can fit the requested texture. If not, both dimensions +are continually halved until it fits. (If the OpenGL version is \(<= 1.0, +both maximum texture dimensions are clamped to the value returned +by \f3glGetIntegerv\fP with the argument \%\f3GL_MAX_TEXTURE_SIZE\fP.) +.P +Next, a series of mipmap levels is built by decimating a copy of \f2data\fP +in half along both dimensions until size $1 ~times~ 1$ 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 $N ~times~ 1$ or +$1 ~times~ N$ configuration. Here, two texels are averaged instead.) +.P +\f3glTexImage2D\fP is called to load each of these mipmap levels. +Level 0 is a copy of \f2data\fP. The highest level is +${log sub 2} ( max ("width","height"))$. For example, +if \f2width\fP is 64 and \f2height\fP is 16 +and the implementation can store a texture of this size, the following +mipmap levels are built: $64 ~times~ 16$, $32 ~times~ 8$, $16 ~times~ 4$, +$8 ~times~ 2$, $4 ~times~ 1$, $2 ~times~ 1$ and $1 ~times~ 1$. These correspond to +levels 0 through 6, respectively. +.P +See the \f3glTexImage1D\fP reference page for a description of the +acceptable values for \f2format\fP parameter. See the \f3glDrawPixels\fP +reference page for a description of the acceptable values +for \f2type\fP parameter. +.SH NOTES + +Note that there is no direct way of querying the maximum level. This can +be derived indirectly via \f3glGetTexLevelParameter\fP. First, query +for the width and height actually used at level 0. (The width and +height may not be equal to \f2width\fP and \f2height\fP respectively since proxy +textures might have scaled them to fit the implementation.) Then the +maximum level can be derived from the formula +${log sub 2}( max (\f2width\fP,\f2height\fP))$. +.SH NOTES +Formats \%\f3GL_BGR\fP, and \%\f3GL_BGRA\fP, and types +\%\f3GL_UNSIGNED_BYTE_3_3_2\fP, +\%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP, +\%\f3GL_UNSIGNED_SHORT_5_6_5\fP, +\%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP, +\%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP, +\%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP, +\%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP, +\%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP, +\%\f3GL_UNSIGNED_INT_8_8_8_8\fP, +\%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP, +\%\f3GL_UNSIGNED_INT_10_10_10_2\fP, and +\%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP are only available if the GL version +is 1.2 or greater and if the GLU version is 1.3 or greater. +.SH ERRORS +\%\f3GLU_INVALID_VALUE\fP is returned if \f2width\fP, or \f2height\fP is < 1. +.P +\%\f3GLU_INVALID_ENUM\fP is returned if \f2internalFormat\fP, \f2format\fP, or \f2type\fP is not +legal. +.P +\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_BYTE_3_3_2\fP or \%\f3GL_UNSIGNED_BYTE_2_3_3_REV\fP +and \f2format\fP is not \%\f3GL_RGB\fP. +.P +\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_SHORT_5_6_5\fP or \%\f3GL_UNSIGNED_SHORT_5_6_5_REV\fP +and \f2format\fP is not \%\f3GL_RGB\fP. +.P +\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_SHORT_4_4_4_4\fP or \%\f3GL_UNSIGNED_SHORT_4_4_4_4_REV\fP +and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP. +.P +\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_SHORT_5_5_5_1\fP or \%\f3GL_UNSIGNED_SHORT_1_5_5_5_REV\fP +and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP. +.P +\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_INT_8_8_8_8\fP or \%\f3GL_UNSIGNED_INT_8_8_8_8_REV\fP +and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP. +.P +\%\f3GLU_INVALID_OPERATION\fP is returned if \f2type\fP is \%\f3GL_UNSIGNED_INT_10_10_10_2\fP or \%\f3GL_UNSIGNED_INT_2_10_10_10_REV\fP +and \f2format\fP is neither \%\f3GL_RGBA\fP nor \%\f3GL_BGRA\fP. +.SH SEE ALSO +\f3glDrawPixels(3G)\fP, +\f3glTexImage1D(3G)\fP, +\f3glTexImage2D(3G)\fP, +\f3glTexImage3D(3G)\fP, +\%\f3gluBuild1DMipmaps(3G)\fP, +\%\f3gluBuild3DMipmaps(3G)\fP, +\%\f3gluErrorString(3G)\fP, +\f3glGetTexImage(3G)\fP, +\f3glGetTexLevelParameter(3G)\fP, +\%\f3gluBuild1DMipmapLevels(3G)\fP, +\%\f3gluBuild2DMipmapLevels(3G)\fP, +\%\f3gluBuild3DMipmapLevels(3G)\fP |