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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="glDrawRangeElements">
<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>glDrawRangeElements</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glDrawRangeElements</refname>
<refpurpose>render primitives from array data</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glDrawRangeElements</function></funcdef>
<paramdef>GLenum <parameter>mode</parameter></paramdef>
<paramdef>GLuint <parameter>start</parameter></paramdef>
<paramdef>GLuint <parameter>end</parameter></paramdef>
<paramdef>GLsizei <parameter>count</parameter></paramdef>
<paramdef>GLenum <parameter>type</parameter></paramdef>
<paramdef>const GLvoid * <parameter>indices</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>mode</parameter></term>
<listitem>
<para>
Specifies what kind of primitives to render.
Symbolic constants
<constant>GL_POINTS</constant>,
<constant>GL_LINE_STRIP</constant>,
<constant>GL_LINE_LOOP</constant>,
<constant>GL_LINES</constant>,
<constant>GL_LINE_STRIP_ADJACENCY</constant>,
<constant>GL_LINES_ADJACENCY</constant>,
<constant>GL_TRIANGLE_STRIP</constant>,
<constant>GL_TRIANGLE_FAN</constant>,
<constant>GL_TRIANGLES</constant>,
<constant>GL_TRIANGLE_STRIP_ADJACENCY</constant>,
<constant>GL_TRIANGLES_ADJACENCY</constant> and <constant>GL_PATCHES</constant>
are accepted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>start</parameter></term>
<listitem>
<para>
Specifies the minimum array index contained in <parameter>indices</parameter>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>end</parameter></term>
<listitem>
<para>
Specifies the maximum array index contained in <parameter>indices</parameter>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
Specifies the number of elements to be rendered.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
Specifies the type of the values in <parameter>indices</parameter>. Must be one of
<constant>GL_UNSIGNED_BYTE</constant>, <constant>GL_UNSIGNED_SHORT</constant>, or
<constant>GL_UNSIGNED_INT</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>indices</parameter></term>
<listitem>
<para>
Specifies a pointer to the location where the indices are stored.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
<function>glDrawRangeElements</function> is a restricted form of <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>. <parameter>mode</parameter>, <parameter>start</parameter>, <parameter>end</parameter>,
and <parameter>count</parameter> match the corresponding arguments to <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>, with
the additional constraint that all values in the arrays <parameter>count</parameter> must lie
between <parameter>start</parameter> and <parameter>end</parameter>, inclusive.
</para>
<para>
Implementations denote recommended maximum amounts of vertex and
index data,
which may be queried by calling <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument
<constant>GL_MAX_ELEMENTS_VERTICES</constant> and <constant>GL_MAX_ELEMENTS_INDICES</constant>.
If
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: end - start + 1: -->
<mml:mrow>
<mml:mi mathvariant="italic">end</mml:mi>
<mml:mo>-</mml:mo>
<mml:mi mathvariant="italic">start</mml:mi>
<mml:mo>+</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:math></inlineequation>
is greater than the value of
<constant>GL_MAX_ELEMENTS_VERTICES</constant>, or if <parameter>count</parameter> is greater than the value of
<constant>GL_MAX_ELEMENTS_INDICES</constant>, then the call may operate at reduced
performance. There is no requirement that all vertices in the range
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: [start, end]: -->
<mml:mfenced open="[" close="]">
<mml:mi mathvariant="italic">start</mml:mi>
<mml:mi mathvariant="italic">end</mml:mi>
</mml:mfenced>
</mml:math></inlineequation>
be referenced. However, the implementation may
partially process unused vertices, reducing performance from what could
be achieved with an optimal index set.
</para>
<para>
When <function>glDrawRangeElements</function> is called, it uses <parameter>count</parameter> sequential elements from an
enabled array, starting at <parameter>start</parameter> to construct a sequence of
geometric primitives. <parameter>mode</parameter> specifies what kind of primitives are
constructed, and how the array elements construct these primitives. If
more than one array is enabled, each is used.
</para>
<para>
Vertex attributes that are modified by <function>glDrawRangeElements</function> have an
unspecified value after <function>glDrawRangeElements</function> returns. Attributes that aren't
modified maintain their previous values.
</para>
</refsect1>
<refsect1 xml:id="notes"><title>Notes</title>
<para>
<constant>GL_LINE_STRIP_ADJACENCY</constant>,
<constant>GL_LINES_ADJACENCY</constant>,
<constant>GL_TRIANGLE_STRIP_ADJACENCY</constant> and
<constant>GL_TRIANGLES_ADJACENCY</constant>
are available only if the GL version is 3.2 or greater.
</para>
</refsect1>
<refsect1 xml:id="errors"><title>Errors</title>
<para>
It is an error for indices to lie outside the range
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: [start, end]: -->
<mml:mfenced open="[" close="]">
<mml:mi mathvariant="italic">start</mml:mi>
<mml:mi mathvariant="italic">end</mml:mi>
</mml:mfenced>
</mml:math></inlineequation>,
but implementations may not check for this situation. Such indices
cause implementation-dependent behavior.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>mode</parameter> is not an accepted value.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>count</parameter> is negative.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: end < start: -->
<mml:mrow>
<mml:mi mathvariant="italic">end</mml:mi>
<mml:mo><</mml:mo>
<mml:mi mathvariant="italic">start</mml:mi>
</mml:mrow>
</mml:math></inlineequation>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a geometry shader is active and <parameter>mode</parameter>
is incompatible with the input primitive type of the geometry shader in the currently installed program object.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to an
enabled array or the element array and the buffer object's data store is currently mapped.
</para>
</refsect1>
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAX_ELEMENTS_VERTICES</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAX_ELEMENTS_INDICES</constant>
</para>
</refsect1>
<refsect1 xml:id="versions"><title>Version Support</title>
<informaltable>
<tgroup cols="13" align="left">
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry><function>glDrawRangeElements</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glDrawElementsBaseVertex</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>
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