Commit | Line | Data |
---|---|---|
7faf1d71 AW |
1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> | |
3 | <!-- saved from url=(0013)about:internet --> | |
4 | <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glDrawElementsInstancedBaseVertexBaseInstance - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glDrawElementsInstancedBaseVertexBaseInstance"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glDrawElementsInstancedBaseVertexBaseInstance — render multiple instances of a set of primitives from array data with a per-element offset</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glDrawElementsInstancedBaseVertexBaseInstance</b>(</code></td><td>GLenum </td><td><var class="pdparam">mode</var>, </td></tr><tr><td> </td><td>GLsizei </td><td><var class="pdparam">count</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">type</var>, </td></tr><tr><td> </td><td>GLvoid * </td><td><var class="pdparam">indices</var>, </td></tr><tr><td> </td><td>GLsizei </td><td><var class="pdparam">primcount</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">basevertex</var>, </td></tr><tr><td> </td><td>GLuint </td><td><var class="pdparam">baseinstance</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>mode</code></em></span></dt><dd><p> | |
5 | Specifies what kind of primitives to render. | |
6 | Symbolic constants | |
7 | <code class="constant">GL_POINTS</code>, <code class="constant">GL_LINE_STRIP</code>, <code class="constant">GL_LINE_LOOP</code>, | |
8 | <code class="constant">GL_LINES</code>, <code class="constant">GL_TRIANGLE_STRIP</code>, <code class="constant">GL_TRIANGLE_FAN</code>, | |
9 | <code class="constant">GL_TRIANGLES</code>, <code class="constant">GL_LINES_ADJACENCY</code>, <code class="constant">GL_LINE_STRIP_ADJACENCY</code>, | |
10 | <code class="constant">GL_TRIANGLES_ADJACENCY</code>, <code class="constant">GL_TRIANGLE_STRIP_ADJACENCY</code> and <code class="constant">GL_PATCHES</code> are accepted. | |
11 | </p></dd><dt><span class="term"><em class="parameter"><code>count</code></em></span></dt><dd><p> | |
12 | Specifies the number of elements to be rendered. | |
13 | </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p> | |
14 | Specifies the type of the values in indices. Must be one of <code class="constant">GL_UNSIGNED_BYTE</code>, | |
15 | <code class="constant">GL_UNSIGNED_SHORT</code>, or <code class="constant">GL_UNSIGNED_INT</code>. | |
16 | </p></dd><dt><span class="term"><em class="parameter"><code>indices</code></em></span></dt><dd><p> | |
17 | Specifies a pointer to the location where the indices are stored. | |
18 | </p></dd><dt><span class="term"><em class="parameter"><code>primcount</code></em></span></dt><dd><p> | |
19 | Specifies the number of instances of the indexed geometry that should be drawn. | |
20 | </p></dd><dt><span class="term"><em class="parameter"><code>basevertex</code></em></span></dt><dd><p> | |
21 | Specifies a constant that should be added to each element of <em class="parameter"><code>indices</code></em> | |
22 | when chosing elements from the enabled vertex arrays. | |
23 | </p></dd><dt><span class="term"><em class="parameter"><code>baseinstance</code></em></span></dt><dd><p> | |
24 | Specifies the base instance for use in fetching instanced vertex attributes. | |
25 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
26 | <code class="function">glDrawElementsInstancedBaseVertexBaseInstance</code> behaves identically to | |
27 | <a href="glDrawElementsInstanced.xml"><span class="citerefentry"><span class="refentrytitle">glDrawElementsInstanced</span></span></a> except that the <span class="emphasis"><em>i</em></span>th element | |
28 | transferred by the corresponding draw call will be taken from element <em class="parameter"><code>indices</code></em>[i] + <em class="parameter"><code>basevertex</code></em> | |
29 | of each enabled array. If the resulting value is larger than the maximum value representable by <em class="parameter"><code>type</code></em>, | |
30 | it is as if the calculation were upconverted to 32-bit unsigned integers (with wrapping on overflow conditions). | |
31 | The operation is undefined if the sum would be negative. The <em class="parameter"><code>basevertex</code></em> has no effect on the | |
32 | shader-visible value of <code class="constant">gl_VertexID</code>. | |
33 | </p><p> | |
34 | Specific vertex attributes may be classified as <span class="emphasis"><em>instanced</em></span> through the use of | |
35 | <a href="glVertexAttribDivisor.xml"><span class="citerefentry"><span class="refentrytitle">glVertexAttribDivisor</span></span></a>. Instanced vertex attributes | |
36 | supply per-instance vertex data to the vertex shader. The index of the vertex fetched from the enabled instanced vertex | |
37 | attribute arrays is calculated as | |
38 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
39 | <mml:mrow> | |
40 | <mml:mfenced open="⌊" close="⌋"> | |
41 | <mml:mfrac> | |
42 | <mml:mrow> | |
43 | <mml:mi>gl</mml:mi> | |
44 | <mml:mo>_</mml:mo> | |
45 | <mml:mi>InstanceID</mml:mi> | |
46 | </mml:mrow> | |
47 | <mml:mi>divisor</mml:mi> | |
48 | </mml:mfrac> | |
49 | </mml:mfenced> | |
50 | <mml:mo lspace="2px" rspace="2px">+</mml:mo> | |
51 | <mml:mi>baseInstance</mml:mi> | |
52 | </mml:mrow> | |
53 | </mml:math>. Note that <em class="parameter"><code>baseinstance</code></em> does not affect the shader-visible value of <code class="constant">gl_InstanceID</code>. | |
54 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><code class="function">glDrawElementsInstancedBaseVertex</code> is only supported if the GL version is 3.2 or greater. | |
55 | </div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
56 | <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>mode</code></em> is not an accepted value. | |
57 | </p><p> | |
58 | <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>count</code></em> or <em class="parameter"><code>primcount</code></em> is negative. | |
59 | </p><p> | |
60 | <code class="constant">GL_INVALID_OPERATION</code> is generated if a geometry shader is active and <em class="parameter"><code>mode</code></em> | |
61 | is incompatible with the input primitive type of the geometry shader in the currently installed program object. | |
62 | </p><p> | |
63 | <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to an | |
64 | enabled array or the element array and the buffer object's data store is currently mapped. | |
65 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
66 | <a href="glDrawElements.xml"><span class="citerefentry"><span class="refentrytitle">glDrawElements</span></span></a>, | |
67 | <a href="glDrawRangeElements.xml"><span class="citerefentry"><span class="refentrytitle">glDrawRangeElements</span></span></a>, | |
68 | <a href="glDrawRangeElementsBaseVertex.xml"><span class="citerefentry"><span class="refentrytitle">glDrawRangeElementsBaseVertex</span></span></a>, | |
69 | <a href="glDrawElementsInstanced.xml"><span class="citerefentry"><span class="refentrytitle">glDrawElementsInstanced</span></span></a>, | |
70 | <a href="glDrawElementsInstancedBaseVertex.xml"><span class="citerefentry"><span class="refentrytitle">glDrawElementsInstancedBaseVertex</span></span></a> | |
71 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
72 | Copyright <span class="trademark"></span>© 2011 Khronos Group. | |
73 | This material may be distributed subject to the terms and conditions set forth in | |
74 | the Open Publication License, v 1.0, 8 June 1999. | |
75 | <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>. | |
76 | </p></div></div></body></html> |