Opentk/Source/Bind/Specifications/Docs/ES31/glTexImage2D.xml
2014-03-28 20:06:55 +01:00

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<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>
<!-- Converted by db4-upgrade version 1.1 -->
<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glTexImage2D">
<info>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
<copyright>
<year>2010-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glTexImage2D</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glTexImage2D</refname>
<refpurpose>specify a two-dimensional texture image</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glTexImage2D</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLint <parameter>internalFormat</parameter></paramdef>
<paramdef>GLsizei <parameter>width</parameter></paramdef>
<paramdef>GLsizei <parameter>height</parameter></paramdef>
<paramdef>GLint <parameter>border</parameter></paramdef>
<paramdef>GLenum <parameter>format</parameter></paramdef>
<paramdef>GLenum <parameter>type</parameter></paramdef>
<paramdef>const GLvoid * <parameter>data</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>
Specifies the target texture.
Must be <constant>GL_TEXTURE_2D</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>, or
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>level</parameter></term>
<listitem>
<para>
Specifies the level-of-detail number.
Level 0 is the base image level.
Level <emphasis>n</emphasis> is the <emphasis>n</emphasis>th mipmap reduction image.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>internalFormat</parameter></term>
<listitem>
<para>
Specifies the number of color components in the texture.
Must be one of base internal formats given in Table 1, or
one of the sized internal formats given in Table 2, below.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>width</parameter></term>
<listitem>
<para>
Specifies the width of the texture image.
All implementations support texture images that are at least 2048 texels
wide.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>height</parameter></term>
<listitem>
<para>
Specifies the height of the texture image.
All implementations support texture images that are at least 2048 texels
high.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>border</parameter></term>
<listitem>
<para>
This value must be 0.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
Specifies the format of the pixel data.
The following symbolic values are accepted:
<constant>GL_RED</constant>,
<constant>GL_RED_INTEGER</constant>,
<constant>GL_RG</constant>,
<constant>GL_RG_INTEGER</constant>,
<constant>GL_RGB</constant>,
<constant>GL_RGB_INTEGER</constant>,
<constant>GL_RGBA</constant>,
<constant>GL_RGBA_INTEGER</constant>,
<constant>GL_DEPTH_COMPONENT</constant>,
<constant>GL_DEPTH_STENCIL</constant>,
<constant>GL_LUMINANCE_ALPHA</constant>,
<constant>GL_LUMINANCE</constant>, and
<constant>GL_ALPHA</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
Specifies the data type of the pixel data.
The following symbolic values are accepted:
<constant>GL_UNSIGNED_BYTE</constant>,
<constant>GL_BYTE</constant>,
<constant>GL_UNSIGNED_SHORT</constant>,
<constant>GL_SHORT</constant>,
<constant>GL_UNSIGNED_INT</constant>,
<constant>GL_INT</constant>,
<constant>GL_HALF_FLOAT</constant>,
<constant>GL_FLOAT</constant>,
<constant>GL_UNSIGNED_SHORT_5_6_5</constant>,
<constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>,
<constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>,
<constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>,
<constant>GL_UNSIGNED_INT_10F_11F_11F_REV</constant>,
<constant>GL_UNSIGNED_INT_5_9_9_9_REV</constant>,
<constant>GL_UNSIGNED_INT_24_8</constant>, and
<constant>GL_FLOAT_32_UNSIGNED_INT_24_8_REV</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>
Specifies a pointer to the image data in memory.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
Texturing allows elements of an image array to be read by shaders.
</para>
<para>
To define texture images, call <function>glTexImage2D</function>.
The arguments describe the parameters of the texture image,
such as height, width, width of the border, level-of-detail number
(see <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>),
and number of color components provided.
The last three arguments describe how the image is represented in memory.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_TEXTURE_2D</constant>
or one of the <constant>GL_TEXTURE_CUBE_MAP</constant>
targets, data is read from <parameter>data</parameter> as a sequence of signed or unsigned
bytes, shorts, or longs, or single-precision floating-point values,
depending on <parameter>type</parameter>. These values are grouped into sets of one, two,
three, or four values, depending on <parameter>format</parameter>, to form elements.
</para>
<para>
If a non-zero named buffer object is bound to the <constant>GL_PIXEL_UNPACK_BUFFER</constant> target
(see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a texture image is
specified, <parameter>data</parameter> is treated as a byte offset into the buffer object's data store.
</para>
<para>
The first element corresponds to the lower left corner of the texture image.
Subsequent elements progress left-to-right through the remaining texels
in the lowest row of the texture image, and then in successively higher
rows of the texture image.
The final element corresponds to the upper right corner of the texture
image.
</para>
<para>
<parameter>format</parameter> determines the composition of each element in <parameter>data</parameter>.
It can assume one of these symbolic values:
</para>
<variablelist>
<varlistentry>
<term><constant>GL_RED</constant></term>
<listitem>
<para>
Each element is a single red component.
For fixed point normalized components, the GL converts it to floating point, clamps to the range [0,1],
and assembles it into an RGBA element by attaching 0.0 for green and blue, and 1.0 for alpha.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RED_INTEGER</constant></term>
<listitem>
<para>
Each element is a single red component.
The GL performs assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RG</constant></term>
<listitem>
<para>
Each element is a red/green double.
For fixed point normalized components, the GL converts each component to floating point, clamps to the range [0,1],
and assembles them into an RGBA element by attaching 0.0 for blue, and 1.0 for alpha.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RG</constant></term>
<listitem>
<para>
Each element is a red/green double.
The GL assembles them into an RGBA element by attaching 0 for blue, and 1 for alpha.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RGB</constant></term>
<listitem>
<para>
Each element is an RGB triple.
For fixed point normalized components, the GL converts each component to floating point, clamps to the range [0,1],
and assembles them into an RGBA element by attaching 1.0 for alpha.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RGB_INTEGER</constant></term>
<listitem>
<para>
Each element is an RGB triple.
The GL assembles them into an RGBA element by attaching 1 for alpha.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RGBA</constant></term>
<listitem>
<para>
Each element contains all four components.
For fixed point normalized components, the GL converts each component to floating point and
clamps them to the range [0,1].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_RGBA_INTEGER</constant></term>
<listitem>
<para>
Each element contains all four components.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_DEPTH_COMPONENT</constant></term>
<listitem>
<para>
Each element is a single depth value.
The GL converts it to floating point, and clamps to the range [0,1].
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_DEPTH_STENCIL</constant></term>
<listitem>
<para>
Each element is a pair of depth and stencil values. The depth component of
the pair is interpreted as in <constant>GL_DEPTH_COMPONENT</constant>. The stencil
component is interpreted based on specified the depth + stencil internal format.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_LUMINANCE_ALPHA</constant></term>
<listitem>
<para>
Each element is an luminance/alpha double.
The GL converts each component to floating point, clamps to the range [0,1],
and assembles them into an RGBA element by placing the luminance value in the red, green and blue channels.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_LUMINANCE</constant></term>
<listitem>
<para>
Each element is a single luminance component.
The GL converts it to floating point, clamps to the range [0,1],
and assembles it into an RGBA element by placing the luminance value in the red, green and blue channels,
and attaching 1.0 to the alpha channel.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_ALPHA</constant></term>
<listitem>
<para>
Each element is a single alpha component.
The GL converts it to floating point, clamps to the range [0,1],
and assembles it into an RGBA element by placing attaching 0.0 to the red, green and blue channels.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
If an application wants to store the texture at a certain
resolution or in a certain format, it can request the resolution
and format with <parameter>internalFormat</parameter>. The GL will choose an internal
representation with least the internal component sizes, and exactly the component types shown for that
format, although it may not match exactly.
</para>
<para>
<parameter>internalFormat</parameter> may be one of the unsized (base) internal formats shown, together with valid
<parameter>format</parameter> and <parameter>type</parameter> combinations, in Table 1, below
</para>
<para>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="unsizedformattable.xml"/>
</para>
<para>
<parameter>internalFormat</parameter> may also be one of the sized internal formats shown, together with valid
<parameter>format</parameter> and <parameter>type</parameter> combinations, in Table 2, below
</para>
<para>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="internalformattable.xml"/>
</para>
<para>
If the <parameter>internalFormat</parameter> parameter is
<constant>GL_SRGB8</constant>, or
<constant>GL_SRGB8_ALPHA8</constant>, the texture is treated as if the red, green, or blue components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component
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<para>
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</para>
<para>
A one-component texture image uses only the red component of the RGBA
color extracted from <parameter>data</parameter>.
A two-component image uses the R and G values.
A three-component image uses the R, G, and B values.
A four-component image uses all of the RGBA components.
</para>
<para>
Image-based shadowing can be enabled by comparing texture r coordinates to
depth texture values to generate a boolean result.
See <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry> for details on texture comparison.
</para>
</refsect1>
<refsect1 xml:id="notes"><title>Notes</title>
<para>
The <citerefentry><refentrytitle>glPixelStorei</refentrytitle></citerefentry> mode affects texture images.
</para>
<para>
<parameter>data</parameter> may be a null pointer.
In this case, texture memory is
allocated to accommodate a texture of width <parameter>width</parameter> and height <parameter>height</parameter>.
You can then download subtextures to initialize this
texture memory.
The image is undefined if the user tries to apply
an uninitialized portion of the texture image to a primitive.
</para>
<para>
<function>glTexImage2D</function> specifies the two-dimensional texture for the texture object bound to the current texture unit,
specified with <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>.
</para>
</refsect1>
<refsect1 xml:id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not
<constant>GL_TEXTURE_2D</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>, or
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is one of the six cube map 2D image targets
and the width and height parameters are not equal.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>type</parameter> is not a type constant.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>width</parameter> is less than 0
or greater than <constant>GL_MAX_TEXTURE_SIZE</constant>.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>level</parameter> is less than 0.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> may be generated if <parameter>level</parameter> is greater than
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</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>internalFormat</parameter> is not one of the
accepted resolution and format symbolic constants.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>width</parameter> or <parameter>height</parameter> is less than 0
or greater than <constant>GL_MAX_TEXTURE_SIZE</constant>.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>border</parameter> is not 0.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if the combination of <parameter>internalFormat</parameter>,
<parameter>format</parameter> and <parameter>type</parameter> is not one of those in the tables above.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the buffer object's data store is currently mapped.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the data would be unpacked from the buffer
object such that the memory reads required would exceed the data store size.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and <parameter>data</parameter> is not evenly divisible
into the number of bytes needed to store in memory a datum indicated by <parameter>type</parameter>.
</para>
</refsect1>
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_UNPACK_BUFFER_BINDING</constant>
</para>
</refsect1>
<refsect1 xml:id="versions">
<title>API Version Support</title>
<informaltable>
<tgroup cols="4" align="left">
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry>glTexImage2D</entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es20']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelStorei</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexStorage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexStorage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 1991-2006 Silicon Graphics, Inc.
Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
This document is licensed under the SGI Free Software B License.
For details, see
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
</para>
</refsect1>
</refentry>