mirror of
https://github.com/Ryujinx/Opentk.git
synced 2024-12-26 20:55:38 +00:00
327 lines
18 KiB
XML
327 lines
18 KiB
XML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
|
||
|
|
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
|
||
|
|
<refentry id="glGetTexImage">
|
||
|
|
<refmeta>
|
||
|
|
<refmetainfo>
|
||
|
|
<copyright>
|
||
|
|
<year>1991-2006</year>
|
||
|
|
<holder>Silicon Graphics, Inc.</holder>
|
||
|
|
</copyright>
|
||
|
|
</refmetainfo>
|
||
|
|
<refentrytitle>glGetTexImage</refentrytitle>
|
||
|
|
<manvolnum>3G</manvolnum>
|
||
|
|
</refmeta>
|
||
|
|
<refnamediv>
|
||
|
|
<refname>glGetTexImage</refname>
|
||
|
|
<refpurpose>return a texture image</refpurpose>
|
||
|
|
</refnamediv>
|
||
|
|
<refsynopsisdiv><title>C Specification</title>
|
||
|
|
<funcsynopsis>
|
||
|
|
<funcprototype>
|
||
|
|
<funcdef>void <function>glGetTexImage</function></funcdef>
|
||
|
|
<paramdef>GLenum <parameter>target</parameter></paramdef>
|
||
|
|
<paramdef>GLint <parameter>level</parameter></paramdef>
|
||
|
|
<paramdef>GLenum <parameter>format</parameter></paramdef>
|
||
|
|
<paramdef>GLenum <parameter>type</parameter></paramdef>
|
||
|
|
<paramdef>GLvoid * <parameter>img</parameter></paramdef>
|
||
|
|
</funcprototype>
|
||
|
|
</funcsynopsis>
|
||
|
|
</refsynopsisdiv>
|
||
|
|
<!-- eqn: ignoring delim $$ -->
|
||
|
|
<refsect1 id="parameters"><title>Parameters</title>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>target</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies which texture is to be obtained.
|
||
|
|
<constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</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>, and
|
||
|
|
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>
|
||
|
|
are accepted.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>level</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies the level-of-detail number of the desired image.
|
||
|
|
Level 0 is the base image level.
|
||
|
|
Level
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
|
||
|
|
is the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>th
|
||
|
|
mipmap reduction image.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>format</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies a pixel format for the returned data.
|
||
|
|
The supported formats are
|
||
|
|
<constant>GL_RED</constant>,
|
||
|
|
<constant>GL_GREEN</constant>,
|
||
|
|
<constant>GL_BLUE</constant>,
|
||
|
|
<constant>GL_ALPHA</constant>,
|
||
|
|
<constant>GL_RGB</constant>,
|
||
|
|
<constant>GL_BGR</constant>,
|
||
|
|
<constant>GL_RGBA</constant>,
|
||
|
|
<constant>GL_BGRA</constant>,
|
||
|
|
<constant>GL_LUMINANCE</constant>, and
|
||
|
|
<constant>GL_LUMINANCE_ALPHA</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>type</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies a pixel type for the returned data.
|
||
|
|
The supported types are
|
||
|
|
<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_FLOAT</constant>,
|
||
|
|
<constant>GL_UNSIGNED_BYTE_3_3_2</constant>,
|
||
|
|
<constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_6_5</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_8_8_8_8</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_10_10_10_2</constant>, and
|
||
|
|
<constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>img</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Returns the texture image.
|
||
|
|
Should be a pointer to an array of the type specified by <parameter>type</parameter>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="description"><title>Description</title>
|
||
|
|
<para>
|
||
|
|
<function>glGetTexImage</function> returns a texture image into <parameter>img</parameter>.
|
||
|
|
<parameter>target</parameter> specifies whether the desired texture image is one specified by
|
||
|
|
<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry> (<constant>GL_TEXTURE_1D</constant>),
|
||
|
|
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry> (<constant>GL_TEXTURE_2D</constant> or any of
|
||
|
|
<constant>GL_TEXTURE_CUBE_MAP_*</constant>),
|
||
|
|
or
|
||
|
|
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> (<constant>GL_TEXTURE_3D</constant>).
|
||
|
|
<parameter>level</parameter> specifies the level-of-detail number of the desired image.
|
||
|
|
<parameter>format</parameter> and <parameter>type</parameter> specify the format and type of the desired image array.
|
||
|
|
See the reference pages <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>
|
||
|
|
for a description of the acceptable values for the <parameter>format</parameter> and <parameter>type</parameter>
|
||
|
|
parameters, respectively.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
If a non-zero named buffer object is bound to the <constant>GL_PIXEL_PACK_BUFFER</constant> target
|
||
|
|
(see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a texture image is
|
||
|
|
requested, <parameter>img</parameter> is treated as a byte offset into the buffer object's data store.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
To understand the operation of <function>glGetTexImage</function>, consider the selected internal
|
||
|
|
four-component texture image to be an RGBA color buffer the size of the image.
|
||
|
|
The semantics of <function>glGetTexImage</function> are then identical to those of <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>,
|
||
|
|
with the exception that no pixel transfer operations are performed,
|
||
|
|
when called with the same <parameter>format</parameter> and <parameter>type</parameter>,
|
||
|
|
with <emphasis>x</emphasis> and <emphasis>y</emphasis> set to 0,
|
||
|
|
<emphasis>width</emphasis> set to the width of the texture image
|
||
|
|
(including border if one was specified),
|
||
|
|
and <emphasis>height</emphasis> set to 1 for 1D images,
|
||
|
|
or to the height of the texture image
|
||
|
|
(including border if one was specified)
|
||
|
|
for 2D images.
|
||
|
|
Because the internal texture image is an RGBA image,
|
||
|
|
pixel formats <constant>GL_COLOR_INDEX</constant>,
|
||
|
|
<constant>GL_STENCIL_INDEX</constant>,
|
||
|
|
and <constant>GL_DEPTH_COMPONENT</constant> are not accepted,
|
||
|
|
and pixel type <constant>GL_BITMAP</constant> is not accepted.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
If the selected texture image does not contain four components,
|
||
|
|
the following mappings are applied.
|
||
|
|
Single-component textures are treated as RGBA buffers with red set
|
||
|
|
to the single-component value,
|
||
|
|
green set to 0, blue set to 0, and alpha set to 1.
|
||
|
|
Two-component textures are treated as RGBA buffers with red set to
|
||
|
|
the value of component zero,
|
||
|
|
alpha set to the value of component one,
|
||
|
|
and green and blue set to 0.
|
||
|
|
Finally,
|
||
|
|
three-component textures are treated as RGBA buffers with red set to
|
||
|
|
component zero,
|
||
|
|
green set to component one,
|
||
|
|
blue set to component two,
|
||
|
|
and alpha set to 1.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
To determine the required size of <parameter>img</parameter>,
|
||
|
|
use <citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> to determine the dimensions of the
|
||
|
|
internal texture image,
|
||
|
|
then scale the required number of pixels by the storage required for
|
||
|
|
each pixel,
|
||
|
|
based on <parameter>format</parameter> and <parameter>type</parameter>.
|
||
|
|
Be sure to take the pixel storage parameters into account,
|
||
|
|
especially <constant>GL_PACK_ALIGNMENT</constant>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="notes"><title>Notes</title>
|
||
|
|
<para>
|
||
|
|
If an error is generated,
|
||
|
|
no change is made to the contents of <parameter>img</parameter>.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
The types <constant>GL_UNSIGNED_BYTE_3_3_2</constant>,
|
||
|
|
<constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_6_5</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_8_8_8_8</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_10_10_10_2</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>,
|
||
|
|
and the formats
|
||
|
|
<constant>GL_BGR</constant>, and <constant>GL_BGRA</constant> are available only if the GL version is
|
||
|
|
1.2 or greater.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
For OpenGL versions 1.3 and greater, or when the <code>ARB_multitexture</code> extension is supported, <function>glGetTexImage</function> returns
|
||
|
|
the texture image for the active texture unit.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="errors"><title>Errors</title>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter>, <parameter>format</parameter>, or <parameter>type</parameter> is not
|
||
|
|
an accepted value.
|
||
|
|
</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
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: log sub 2 (max):-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">log</mml:mi>
|
||
|
|
<mml:mn>2</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>⁡</mml:mo>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mi mathvariant="italic">max</mml:mi>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">max</mml:mi></mml:math></inlineequation>
|
||
|
|
is the returned value of <constant>GL_MAX_TEXTURE_SIZE</constant>.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is one of
|
||
|
|
<constant>GL_UNSIGNED_BYTE_3_3_2</constant>,
|
||
|
|
<constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_6_5</constant>, or
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant> and <parameter>format</parameter> is not <constant>GL_RGB</constant>.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is one of
|
||
|
|
<constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>,
|
||
|
|
<constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_8_8_8_8</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>,
|
||
|
|
<constant>GL_UNSIGNED_INT_10_10_10_2</constant>, or
|
||
|
|
<constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>, and <parameter>format</parameter> is neither <constant>GL_RGBA</constant>
|
||
|
|
or <constant>GL_BGRA</constant>.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
|
||
|
|
<constant>GL_PIXEL_PACK_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_PACK_BUFFER</constant> target and the data would be packed to the buffer
|
||
|
|
object such that the memory writes 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_PACK_BUFFER</constant> target and <parameter>img</parameter> is not evenly divisible
|
||
|
|
into the number of bytes needed to store in memory a datum indicated by <parameter>type</parameter>.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetTexImage</function>
|
||
|
|
is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
|
||
|
|
and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="associatedgets"><title>Associated Gets</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> with argument <constant>GL_TEXTURE_WIDTH</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> with argument <constant>GL_TEXTURE_HEIGHT</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> with argument <constant>GL_TEXTURE_BORDER</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> with argument <constant>GL_TEXTURE_INTERNAL_FORMAT</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with arguments <constant>GL_PACK_ALIGNMENT</constant> and others
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_PACK_BUFFER_BINDING</constant>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="seealso"><title>See Also</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexEnv</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="Copyright"><title>Copyright</title>
|
||
|
|
<para>
|
||
|
|
Copyright <trademark class="copyright"></trademark> 1991-2006
|
||
|
|
Silicon Graphics, Inc. This document is licensed under the SGI
|
||
|
|
Free Software B License. For details, see
|
||
|
|
<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
</refentry>
|