mirror of
https://github.com/Ryujinx/Opentk.git
synced 2024-12-27 08:35:32 +00:00
208 lines
10 KiB
XML
208 lines
10 KiB
XML
<!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="glMultiDrawElementsIndirect">
|
|
<info>
|
|
<copyright>
|
|
<year>2013</year>
|
|
<holder>Khronos Group.</holder>
|
|
</copyright>
|
|
</info>
|
|
<refmeta>
|
|
<refentrytitle>glMultiDrawElementsIndirect</refentrytitle>
|
|
<manvolnum>3G</manvolnum>
|
|
</refmeta>
|
|
<refnamediv>
|
|
<refname>glMultiDrawElementsIndirect</refname>
|
|
<refpurpose>render indexed primitives from array data, taking parameters from memory</refpurpose>
|
|
</refnamediv>
|
|
<refsynopsisdiv><title>C Specification</title>
|
|
<funcsynopsis>
|
|
<funcprototype>
|
|
<funcdef>void <function>glMultiDrawElementsIndirect</function></funcdef>
|
|
<paramdef>GLenum <parameter>mode</parameter></paramdef>
|
|
<paramdef>GLenum <parameter>type</parameter></paramdef>
|
|
<paramdef>const void *<parameter>indirect</parameter></paramdef>
|
|
<paramdef>GLsizei <parameter>drawcount</parameter></paramdef>
|
|
<paramdef>GLsizei <parameter>stride</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>type</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies the type of data in the buffer bound to the <constant>GL_ELEMENT_ARRAY_BUFFER</constant> binding.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>indirect</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies the address of a structure containing an array of draw parameters.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>drawcount</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies the number of elements in the array addressed by <parameter>indirect</parameter>.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>stride</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies the distance in basic machine units between elements of the draw parameter array.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
<refsect1 xml:id="description"><title>Description</title>
|
|
<para>
|
|
<function>glMultiDrawElementsIndirect</function> specifies multiple indexed geometric primitives
|
|
with very few subroutine calls. <function>glMultiDrawElementsIndirect</function> behaves
|
|
similarly to a multitude of calls to <citerefentry><refentrytitle>glDrawElementsInstancedBaseVertexBaseInstance</refentrytitle></citerefentry>,
|
|
execpt that the parameters to <citerefentry><refentrytitle>glDrawElementsInstancedBaseVertexBaseInstance</refentrytitle></citerefentry>
|
|
are stored in an array in memory at the address given by <parameter>indirect</parameter>, separated
|
|
by the stride, in basic machine units, specified by <parameter>stride</parameter>. If <parameter>stride</parameter>
|
|
is zero, then the array is assumed to be tightly packed in memory.
|
|
</para>
|
|
<para>
|
|
The parameters addressed by <parameter>indirect</parameter> are packed into a structure
|
|
that takes the form (in C):
|
|
<programlisting> typedef struct {
|
|
uint count;
|
|
uint instanceCount;
|
|
uint firstIndex;
|
|
uint baseVertex;
|
|
uint baseInstance;
|
|
} DrawElementsIndirectCommand;</programlisting>
|
|
</para>
|
|
<para>
|
|
A single call to <function>glMultiDrawElementsIndirect</function> is equivalent, assuming no errors
|
|
are generated to:
|
|
<programlisting> GLsizei n;
|
|
for (n = 0; n < drawcount; n++) {
|
|
const DrawElementsIndirectCommand *cmd;
|
|
if (stride != 0) {
|
|
cmd = (const DrawElementsIndirectCommand *)((uintptr)indirect + n * stride);
|
|
} else {
|
|
cmd = (const DrawElementsIndirectCommand *)indirect + n;
|
|
}
|
|
|
|
glDrawElementsInstancedBaseVertexBaseInstance(mode,
|
|
cmd->count,
|
|
type,
|
|
cmd->firstIndex + size-of-type,
|
|
cmd->instanceCount,
|
|
cmd->baseVertex,
|
|
cmd->baseInstance);
|
|
}</programlisting>
|
|
</para>
|
|
<para>
|
|
If a buffer is bound to the <constant>GL_DRAW_INDIRECT_BUFFER</constant> binding at the time
|
|
of a call to <function>glDrawElementsIndirect</function>, <parameter>indirect</parameter>
|
|
is interpreted as an offset, in basic machine units, into that buffer and the parameter
|
|
data is read from the buffer rather than from client memory.
|
|
</para>
|
|
<para>
|
|
Note that indices stored in client memory are not supported. If no buffer is bound to the
|
|
<constant>GL_ELEMENT_ARRAY_BUFFER</constant> binding, an error will be generated.
|
|
</para>
|
|
<para>
|
|
The results of the operation are undefined if the <code>reservedMustBeZero</code> member
|
|
of the parameter structure is non-zero. However, no error is generated in this case.
|
|
</para>
|
|
<para>
|
|
Vertex attributes that are modified by <function>glDrawElementsIndirect</function> have an
|
|
unspecified value after <function>glDrawElementsIndirect</function> returns. Attributes that aren't
|
|
modified remain well defined.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="notes"><title>Notes</title>
|
|
<para>
|
|
The <parameter>baseInstance</parameter> member of the <parameter>DrawElementsIndirectCommand</parameter>
|
|
structure is defined only if the GL version is 4.2 or greater. For versions of the GL less than 4.2,
|
|
this parameter is present but is reserved and should be set to zero. On earlier versions of the GL,
|
|
behavior is undefined if it is non-zero.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="errors"><title>Errors</title>
|
|
<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>stride</parameter> is not a multiple
|
|
of four.
|
|
</para>
|
|
<para>
|
|
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>drawcount</parameter> is negative.
|
|
</para>
|
|
<para>
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if no buffer is bound to the <constant>GL_ELEMENT_ARRAY_BUFFER</constant>
|
|
binding, or if such a buffer'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 an
|
|
enabled array or to the <constant>GL_DRAW_INDIRECT_BUFFER</constant> binding and the buffer object's data store is currently mapped.
|
|
</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 <parameter>mode</parameter> is <constant>GL_PATCHES</constant>
|
|
and no tessellation control shader is active.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="seealso"><title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glDrawArraysInstanced</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glDrawArraysIndirect</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glDrawElementsIndirect</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glMultiDrawArraysIndirect</refentrytitle></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="Copyright"><title>Copyright</title>
|
|
<para>
|
|
Copyright <trademark class="copyright"/> 2010-2013 Khronos Group.
|
|
This material may be distributed subject to the terms and conditions set forth in
|
|
the Open Publication License, v 1.0, 8 June 1999.
|
|
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://opencontent.org/openpub/">http://opencontent.org/openpub/</link>.
|
|
</para>
|
|
</refsect1>
|
|
</refentry>
|