mirror of
https://github.com/Ryujinx/Opentk.git
synced 2024-12-27 02:25:44 +00:00
610 lines
32 KiB
XML
610 lines
32 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="glCopyPixels">
|
||
|
|
<refmeta>
|
||
|
|
<refmetainfo>
|
||
|
|
<copyright>
|
||
|
|
<year>1991-2006</year>
|
||
|
|
<holder>Silicon Graphics, Inc.</holder>
|
||
|
|
</copyright>
|
||
|
|
</refmetainfo>
|
||
|
|
<refentrytitle>glCopyPixels</refentrytitle>
|
||
|
|
<manvolnum>3G</manvolnum>
|
||
|
|
</refmeta>
|
||
|
|
<refnamediv>
|
||
|
|
<refname>glCopyPixels</refname>
|
||
|
|
<refpurpose>copy pixels in the frame buffer</refpurpose>
|
||
|
|
</refnamediv>
|
||
|
|
<refsynopsisdiv><title>C Specification</title>
|
||
|
|
<funcsynopsis>
|
||
|
|
<funcprototype>
|
||
|
|
<funcdef>void <function>glCopyPixels</function></funcdef>
|
||
|
|
<paramdef>GLint <parameter>x</parameter></paramdef>
|
||
|
|
<paramdef>GLint <parameter>y</parameter></paramdef>
|
||
|
|
<paramdef>GLsizei <parameter>width</parameter></paramdef>
|
||
|
|
<paramdef>GLsizei <parameter>height</parameter></paramdef>
|
||
|
|
<paramdef>GLenum <parameter>type</parameter></paramdef>
|
||
|
|
</funcprototype>
|
||
|
|
</funcsynopsis>
|
||
|
|
</refsynopsisdiv>
|
||
|
|
<!-- eqn: ignoring delim $$ -->
|
||
|
|
<refsect1 id="parameters"><title>Parameters</title>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>x</parameter></term>
|
||
|
|
<term><parameter>y</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specify the window coordinates of the lower left corner
|
||
|
|
of the rectangular region of pixels to be copied.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>width</parameter></term>
|
||
|
|
<term><parameter>height</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specify the dimensions of the rectangular region of pixels to be copied.
|
||
|
|
Both must be nonnegative.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>type</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies whether color values,
|
||
|
|
depth values,
|
||
|
|
or stencil values are to be copied.
|
||
|
|
Symbolic constants
|
||
|
|
<constant>GL_COLOR</constant>,
|
||
|
|
<constant>GL_DEPTH</constant>,
|
||
|
|
and <constant>GL_STENCIL</constant> are accepted.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="description"><title>Description</title>
|
||
|
|
<para>
|
||
|
|
<function>glCopyPixels</function> copies a screen-aligned rectangle of pixels
|
||
|
|
from the specified frame buffer location to a region relative to the
|
||
|
|
current raster position.
|
||
|
|
Its operation is well defined only if the entire pixel source region
|
||
|
|
is within the exposed portion of the window.
|
||
|
|
Results of copies from outside the window,
|
||
|
|
or from regions of the window that are not exposed,
|
||
|
|
are hardware dependent and undefined.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<parameter>x</parameter> and <parameter>y</parameter> specify the window coordinates of
|
||
|
|
the lower left corner of the rectangular region to be copied.
|
||
|
|
<parameter>width</parameter> and <parameter>height</parameter> specify the dimensions of the
|
||
|
|
rectangular region to be copied.
|
||
|
|
Both <parameter>width</parameter> and <parameter>height</parameter> must not be negative.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
Several parameters control the processing of the pixel data
|
||
|
|
while it is being copied.
|
||
|
|
These parameters are set with three commands:
|
||
|
|
<citerefentry><refentrytitle>glPixelTransfer</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPixelMap</refentrytitle></citerefentry>, and
|
||
|
|
<citerefentry><refentrytitle>glPixelZoom</refentrytitle></citerefentry>.
|
||
|
|
This reference page describes the effects on <function>glCopyPixels</function> of most,
|
||
|
|
but not all, of the parameters specified by these three commands.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<function>glCopyPixels</function> copies values from each pixel with the lower left-hand corner at
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x + i, y + j):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
for
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: 0 <= i < width:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>0</mml:mn>
|
||
|
|
<mml:mo><=</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
<mml:mo><</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">width</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
and
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: 0 <= j < height:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>0</mml:mn>
|
||
|
|
<mml:mo><=</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
<mml:mo><</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">height</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>.
|
||
|
|
This pixel is said to be the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>th
|
||
|
|
pixel in the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>th
|
||
|
|
row.
|
||
|
|
Pixels are copied in row order from the lowest to the highest row,
|
||
|
|
left to right in each row.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<parameter>type</parameter> specifies whether color, depth, or stencil data is to be copied.
|
||
|
|
The details of the transfer for each data type are as follows:
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_COLOR</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Indices or RGBA colors are read from the buffer currently specified as the
|
||
|
|
read source buffer (see <citerefentry><refentrytitle>glReadBuffer</refentrytitle></citerefentry>).
|
||
|
|
If the GL is in color index mode,
|
||
|
|
each index that is read from this buffer is converted
|
||
|
|
to a fixed-point format with an unspecified
|
||
|
|
number of bits to the right of the binary point.
|
||
|
|
Each index is then shifted left by <constant>GL_INDEX_SHIFT</constant> bits,
|
||
|
|
and added to <constant>GL_INDEX_OFFSET</constant>.
|
||
|
|
If <constant>GL_INDEX_SHIFT</constant> is negative,
|
||
|
|
the shift is to the right.
|
||
|
|
In either case, zero bits fill otherwise unspecified bit locations in the
|
||
|
|
result.
|
||
|
|
If <constant>GL_MAP_COLOR</constant> is true,
|
||
|
|
the index is replaced with the value that it references in lookup table
|
||
|
|
<constant>GL_PIXEL_MAP_I_TO_I</constant>.
|
||
|
|
Whether the lookup replacement of the index is done or not,
|
||
|
|
the integer part of the index is then ANDed with
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: 2 sup b -1:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msup><mml:mn>2</mml:mn>
|
||
|
|
<mml:mi mathvariant="italic">b</mml:mi>
|
||
|
|
</mml:msup>
|
||
|
|
<mml:mo>-</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">b</mml:mi></mml:math></inlineequation>
|
||
|
|
is the number of bits in a color index buffer.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
If the GL is in RGBA mode,
|
||
|
|
the red, green, blue, and alpha components of each pixel that is read
|
||
|
|
are converted to an internal floating-point format with unspecified
|
||
|
|
precision.
|
||
|
|
The conversion maps the largest representable component value to 1.0,
|
||
|
|
and component value 0 to 0.0.
|
||
|
|
The resulting floating-point color values are then multiplied
|
||
|
|
by <constant>GL_c_SCALE</constant> and added to <constant>GL_c_BIAS</constant>,
|
||
|
|
where <emphasis>c</emphasis> is RED, GREEN, BLUE, and ALPHA
|
||
|
|
for the respective color components.
|
||
|
|
The results are clamped to the range [0,1].
|
||
|
|
If <constant>GL_MAP_COLOR</constant> is true,
|
||
|
|
each color component is scaled by the size of lookup table
|
||
|
|
<constant>GL_PIXEL_MAP_c_TO_c</constant>,
|
||
|
|
then replaced by the value that it references in that table.
|
||
|
|
<emphasis>c</emphasis> is R, G, B, or A.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
If the <code>ARB_imaging</code> extension is supported, the color values may
|
||
|
|
be
|
||
|
|
additionally processed by color-table lookups, color-matrix
|
||
|
|
transformations, and convolution filters.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
The GL then converts the resulting indices or RGBA colors to fragments
|
||
|
|
by attaching the current raster position <emphasis>z</emphasis> coordinate and
|
||
|
|
texture coordinates to each pixel,
|
||
|
|
then assigning window coordinates
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r + i , y sub r + j):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r , y sub r):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the current raster position,
|
||
|
|
and the pixel was the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>th
|
||
|
|
pixel in the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>th
|
||
|
|
row.
|
||
|
|
These pixel fragments are then treated just like the fragments generated by
|
||
|
|
rasterizing points, lines, or polygons.
|
||
|
|
Texture mapping,
|
||
|
|
fog,
|
||
|
|
and all the fragment operations are applied before the fragments are written
|
||
|
|
to the frame buffer.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_DEPTH</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Depth values are read from the depth buffer and
|
||
|
|
converted directly to an internal floating-point format
|
||
|
|
with unspecified precision.
|
||
|
|
The resulting floating-point depth value is then multiplied
|
||
|
|
by <constant>GL_DEPTH_SCALE</constant> and added to <constant>GL_DEPTH_BIAS</constant>.
|
||
|
|
The result is clamped to the range [0,1].
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
The GL then converts the resulting depth components to fragments
|
||
|
|
by attaching the current raster position color or color index and
|
||
|
|
texture coordinates to each pixel,
|
||
|
|
then assigning window coordinates
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r + i , y sub r + j):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r , y sub r):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the current raster position,
|
||
|
|
and the pixel was the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>th
|
||
|
|
pixel in the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>th
|
||
|
|
row.
|
||
|
|
These pixel fragments are then treated just like the fragments generated by
|
||
|
|
rasterizing points, lines, or polygons.
|
||
|
|
Texture mapping,
|
||
|
|
fog,
|
||
|
|
and all the fragment operations are applied before the fragments are written
|
||
|
|
to the frame buffer.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_STENCIL</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Stencil indices are read from the stencil buffer and
|
||
|
|
converted to an internal fixed-point format
|
||
|
|
with an unspecified number of bits to the right of the binary point.
|
||
|
|
Each fixed-point index is then shifted left by <constant>GL_INDEX_SHIFT</constant> bits,
|
||
|
|
and added to <constant>GL_INDEX_OFFSET</constant>.
|
||
|
|
If <constant>GL_INDEX_SHIFT</constant> is negative,
|
||
|
|
the shift is to the right.
|
||
|
|
In either case, zero bits fill otherwise unspecified bit locations in the
|
||
|
|
result.
|
||
|
|
If <constant>GL_MAP_STENCIL</constant> is true,
|
||
|
|
the index is replaced with the value that it references in lookup table
|
||
|
|
<constant>GL_PIXEL_MAP_S_TO_S</constant>.
|
||
|
|
Whether the lookup replacement of the index is done or not,
|
||
|
|
the integer part of the index is then ANDed with
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: 2 sup b -1:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msup><mml:mn>2</mml:mn>
|
||
|
|
<mml:mi mathvariant="italic">b</mml:mi>
|
||
|
|
</mml:msup>
|
||
|
|
<mml:mo>-</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">b</mml:mi></mml:math></inlineequation>
|
||
|
|
is the number of bits in the stencil buffer.
|
||
|
|
The resulting stencil indices are then written to the stencil buffer
|
||
|
|
such that the index read from the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>th
|
||
|
|
location of the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>th
|
||
|
|
row
|
||
|
|
is written to location
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r + i , y sub r + j):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r , y sub r):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the current raster position.
|
||
|
|
Only the pixel ownership test,
|
||
|
|
the scissor test,
|
||
|
|
and the stencil writemask affect these write operations.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
The rasterization described thus far assumes pixel zoom factors of 1.0.
|
||
|
|
If
|
||
|
|
<citerefentry><refentrytitle>glPixelZoom</refentrytitle></citerefentry> is used to change the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>
|
||
|
|
and
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>
|
||
|
|
pixel zoom factors,
|
||
|
|
pixels are converted to fragments as follows.
|
||
|
|
If
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r, y sub r):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the current raster position,
|
||
|
|
and a given pixel is in the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>th
|
||
|
|
location in the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>th
|
||
|
|
row of the source
|
||
|
|
pixel rectangle,
|
||
|
|
then fragments are generated for pixels whose centers are in the rectangle
|
||
|
|
with corners at
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r + {zoom sub x} i, y sub r + {zoom sub y} j):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">zoom</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mo>⁢</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">zoom</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mo>⁢</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
and
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: (x sub r + {zoom sub x} (i + 1), y sub r + {zoom sub y} ( j + 1 )):-->
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">zoom</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mo>⁡</mml:mo>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">zoom</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mo>⁡</mml:mo>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: zoom sub x:-->
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">zoom</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">x</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the value of <constant>GL_ZOOM_X</constant> and
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: zoom sub y:-->
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">zoom</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">y</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the value of <constant>GL_ZOOM_Y</constant>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="examples"><title>Examples</title>
|
||
|
|
<para>
|
||
|
|
To copy the color pixel in the lower left corner of the window to the current raster position,
|
||
|
|
use
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<programlisting>
|
||
|
|
glCopyPixels(0, 0, 1, 1, <constant>GL_COLOR</constant>);
|
||
|
|
</programlisting>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="notes"><title>Notes</title>
|
||
|
|
<para>
|
||
|
|
Modes specified by <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry> have no effect on the operation
|
||
|
|
of <function>glCopyPixels</function>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="errors"><title>Errors</title>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>type</parameter> is not an accepted value.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_VALUE</constant> is generated if either <parameter>width</parameter> or <parameter>height</parameter> is negative.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>type</parameter> is <constant>GL_DEPTH</constant>
|
||
|
|
and there is no depth buffer.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>type</parameter> is <constant>GL_STENCIL</constant>
|
||
|
|
and there is no stencil buffer.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glCopyPixels</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>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_POSITION</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_POSITION_VALID</constant>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="seealso"><title>See Also</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glColorTable</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glConvolutionFilter1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glConvolutionFilter2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glDepthFunc</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glDrawBuffer</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glMatrixMode</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPixelMap</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPixelTransfer</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPixelZoom</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glRasterPos</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glReadBuffer</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glSeparableFilter2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glStencilFunc</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glWindowPos</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>
|