[clinton/guile-figl.git] / upstream-doc / man3 / glGetTransformFeedbackVarying.xml

<?xml version="1.0" encoding="UTF-8"?>\r
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"\r
              "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">\r
<refentry id="glGetTransformFeedbackVarying">\r
    <refmeta>\r
        <refmetainfo>\r
            <copyright>\r
                <year>2010</year>\r
                <holder>Khronos Group</holder>\r
            </copyright>\r
        </refmetainfo>\r
        <refentrytitle>glGetTransformFeedbackVarying</refentrytitle>\r
        <manvolnum>3G</manvolnum>\r
    </refmeta>\r
    <refnamediv>\r
        <refname>glGetTransformFeedbackVarying</refname>\r
        <refpurpose>retrieve information about varying variables selected for transform feedback</refpurpose>\r
    </refnamediv>\r
    <refsynopsisdiv><title>C Specification</title>\r
        <funcsynopsis>\r
            <funcprototype>\r
                <funcdef>void <function>glGetTransformFeedbackVarying</function></funcdef>\r
                <paramdef>GLuint<parameter>program</parameter></paramdef>\r
                <paramdef>GLuint<parameter>index</parameter></paramdef>\r
                <paramdef>GLsizei<parameter>bufSize</parameter></paramdef>\r
                <paramdef>GLsizei *<parameter>length</parameter></paramdef>\r
                <paramdef>GLsizei<parameter>size</parameter></paramdef>\r
                <paramdef>GLenum *<parameter>type</parameter></paramdef>\r
                <paramdef>char *<parameter>name</parameter></paramdef>\r
            </funcprototype>\r
        </funcsynopsis>\r
    </refsynopsisdiv>\r
    <refsect1 id="parameters"><title>Parameters</title>\r
        <variablelist>\r
        <varlistentry>\r
            <term><parameter>program</parameter></term>\r
            <listitem>\r
                <para>\r
                    The name of the target program object.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>index</parameter></term>\r
            <listitem>\r
                <para>\r
                    The index of the varying variable whose information to retrieve.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>bufSize</parameter></term>\r
            <listitem>\r
                <para>\r
                    The maximum number of characters, including the null terminator, that may be written into <parameter>name</parameter>.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>length</parameter></term>\r
            <listitem>\r
                <para>\r
                    The address of a variable which will receive the number of characters written into <parameter>name</parameter>,\r
                    excluding the null-terminator. If <parameter>length</parameter> is <constant>NULL</constant> no length is returned.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>size</parameter></term>\r
            <listitem>\r
                <para>\r
                    The address of a variable that will receive the size of the varying.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>type</parameter></term>\r
            <listitem>\r
                <para>\r
                    The address of a variable that will recieve the type of the varying.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>name</parameter></term>\r
            <listitem>\r
                <para>\r
                    The address of a buffer into which will be written the name of the varying.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        </variablelist>\r
    </refsect1>\r
    <refsect1 id="description"><title>Description</title>\r
        <para>\r
            Information about the set of varying variables in a linked program that will be captured\r
            during transform feedback may be retrieved by calling <function>glGetTransformFeedbackVarying</function>.\r
            <function>glGetTransformFeedbackVarying</function> provides information about the varying\r
            variable selected by <parameter>index</parameter>. An <parameter>index</parameter> of 0 selects\r
            the first varying variable specified in the <parameter>varyings</parameter> array passed\r
            to <citerefentry><refentrytitle>glTransformFeedbackVaryings</refentrytitle></citerefentry>, and\r
            an <parameter>index</parameter> of <constant>GL_TRANSFORM_FEEDBACK_VARYINGS-1</constant> selects\r
            the last such variable.\r
        </para>\r
        <para>\r
            The name of the selected varying is returned as a null-terminated string in\r
            <parameter>name</parameter>. The actual number of characters written into <parameter>name</parameter>,\r
            excluding the null terminator, is returned in <parameter>length</parameter>. If <parameter>length</parameter>\r
            is NULL, no length is returned. The maximum number of characters that may be written into <parameter>name</parameter>,\r
            including the null terminator, is specified by <parameter>bufSize</parameter>.\r
        </para>\r
        <para>\r
            The length of the longest varying name in program is given by <constant>GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</constant>,\r
            which can be queried with <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry>.\r
        </para>\r
        <para>\r
            For the selected varying variable, its type is returned into <parameter>type</parameter>. The size of\r
            the varying is returned into <parameter>size</parameter>. The value in <parameter>size</parameter> is\r
            in units of the type returned in <parameter>type</parameter>. The type returned can be any of the\r
            scalar, vector, or matrix attribute types returned by <citerefentry><refentrytitle>glGetActiveAttrib</refentrytitle></citerefentry>.\r
            If an error occurred, the return parameters <parameter>length</parameter>, <parameter>size</parameter>,\r
            <parameter>type</parameter> and <parameter>name</parameter> will be unmodified. This command will return as much\r
            information about the varying variables as possible. If no information is available, <parameter>length</parameter>\r
            will be set to zero and <parameter>name</parameter> will be an empty string. This situation could\r
            arise if <function>glGetTransformFeedbackVarying</function> is called after a failed link.\r
        </para>\r
    </refsect1>\r
    <refsect1 id="errors"><title>Errors</title>\r
        <para>\r
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>program</parameter> is not\r
            the name of a program object.\r
        </para>\r
        <para>\r
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>index</parameter> is greater or equal to\r
            the value of <constant>GL_TRANSFORM_FEEDBACK_VARYINGS</constant>.\r
        </para>\r
        <para>\r
            <constant>GL_INVALID_OPERATION</constant> is generated <parameter>program</parameter> has not been linked.\r
        </para>\r
    </refsect1>\r
    <refsect1 id="associatedgets"><title>Associated Gets</title>\r
        <para>\r
            <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry> with argument <constant>GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</constant>.\r
        </para>\r
    </refsect1>\r
    <refsect1 id="seealso"><title>See Also</title>\r
        <para>\r
            <citerefentry><refentrytitle>glBeginTransformFeedback</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>glEndTransformFeedback</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>glTransformFeedbackVaryings</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry>\r
        </para>\r
    </refsect1>    <refsect1 id="Copyright"><title>Copyright</title>\r
        <para>\r
            Copyright <trademark class="copyright"></trademark> 2010 Khronos Group. \r
            This material may be distributed subject to the terms and conditions set forth in \r
            the Open Publication License, v 1.0, 8 June 1999.\r
            <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.\r
        </para>\r
    </refsect1>\r
</refentry>\r
Commit	Line	Data
7faf1d71 AW	1	<?xml version="1.0" encoding="UTF-8"?>\r
	2	<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"\r
	3	"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">\r
	4	<refentry id="glGetTransformFeedbackVarying">\r
	5	<refmeta>\r
	6	<refmetainfo>\r
	7	<copyright>\r
	8	<year>2010</year>\r
	9	<holder>Khronos Group</holder>\r
	10	</copyright>\r
	11	</refmetainfo>\r
	12	<refentrytitle>glGetTransformFeedbackVarying</refentrytitle>\r
	13	<manvolnum>3G</manvolnum>\r
	14	</refmeta>\r
	15	<refnamediv>\r
	16	<refname>glGetTransformFeedbackVarying</refname>\r
	17	<refpurpose>retrieve information about varying variables selected for transform feedback</refpurpose>\r
	18	</refnamediv>\r
	19	<refsynopsisdiv><title>C Specification</title>\r
	20	<funcsynopsis>\r
	21	<funcprototype>\r
	22	<funcdef>void <function>glGetTransformFeedbackVarying</function></funcdef>\r
	23	<paramdef>GLuint<parameter>program</parameter></paramdef>\r
	24	<paramdef>GLuint<parameter>index</parameter></paramdef>\r
	25	<paramdef>GLsizei<parameter>bufSize</parameter></paramdef>\r
	26	<paramdef>GLsizei *<parameter>length</parameter></paramdef>\r
	27	<paramdef>GLsizei<parameter>size</parameter></paramdef>\r
	28	<paramdef>GLenum *<parameter>type</parameter></paramdef>\r
	29	<paramdef>char *<parameter>name</parameter></paramdef>\r
	30	</funcprototype>\r
	31	</funcsynopsis>\r
	32	</refsynopsisdiv>\r
	33	<refsect1 id="parameters"><title>Parameters</title>\r
	34	<variablelist>\r
	35	<varlistentry>\r
	36	<term><parameter>program</parameter></term>\r
	37	<listitem>\r
	38	<para>\r
	39	The name of the target program object.\r
	40	</para>\r
	41	</listitem>\r
	42	</varlistentry>\r
	43	<varlistentry>\r
	44	<term><parameter>index</parameter></term>\r
	45	<listitem>\r
	46	<para>\r
	47	The index of the varying variable whose information to retrieve.\r
	48	</para>\r
	49	</listitem>\r
	50	</varlistentry>\r
	51	<varlistentry>\r
	52	<term><parameter>bufSize</parameter></term>\r
	53	<listitem>\r
	54	<para>\r
	55	The maximum number of characters, including the null terminator, that may be written into <parameter>name</parameter>.\r
	56	</para>\r
	57	</listitem>\r
	58	</varlistentry>\r
	59	<varlistentry>\r
	60	<term><parameter>length</parameter></term>\r
	61	<listitem>\r
	62	<para>\r
	63	The address of a variable which will receive the number of characters written into <parameter>name</parameter>,\r
	64	excluding the null-terminator. If <parameter>length</parameter> is <constant>NULL</constant> no length is returned.\r
65	</para>\r
66	</listitem>\r
67	</varlistentry>\r
68	<varlistentry>\r
69	<term><parameter>size</parameter></term>\r
70	<listitem>\r
71	<para>\r
72	The address of a variable that will receive the size of the varying.\r
73	</para>\r
74	</listitem>\r
75	</varlistentry>\r
76	<varlistentry>\r
77	<term><parameter>type</parameter></term>\r
78	<listitem>\r
79	<para>\r
80	The address of a variable that will recieve the type of the varying.\r
81	</para>\r
82	</listitem>\r
83	</varlistentry>\r
84	<varlistentry>\r
85	<term><parameter>name</parameter></term>\r
86	<listitem>\r
87	<para>\r
88	The address of a buffer into which will be written the name of the varying.\r
89	</para>\r
90	</listitem>\r
91	</varlistentry>\r
92	</variablelist>\r
93	</refsect1>\r
94	<refsect1 id="description"><title>Description</title>\r
95	<para>\r
96	Information about the set of varying variables in a linked program that will be captured\r
97	during transform feedback may be retrieved by calling <function>glGetTransformFeedbackVarying</function>.\r
98	<function>glGetTransformFeedbackVarying</function> provides information about the varying\r
99	variable selected by <parameter>index</parameter>. An <parameter>index</parameter> of 0 selects\r
100	the first varying variable specified in the <parameter>varyings</parameter> array passed\r
101	to <citerefentry><refentrytitle>glTransformFeedbackVaryings</refentrytitle></citerefentry>, and\r
102	an <parameter>index</parameter> of <constant>GL_TRANSFORM_FEEDBACK_VARYINGS-1</constant> selects\r
103	the last such variable.\r
104	</para>\r
105	<para>\r
106	The name of the selected varying is returned as a null-terminated string in\r
107	<parameter>name</parameter>. The actual number of characters written into <parameter>name</parameter>,\r
108	excluding the null terminator, is returned in <parameter>length</parameter>. If <parameter>length</parameter>\r
109	is NULL, no length is returned. The maximum number of characters that may be written into <parameter>name</parameter>,\r
110	including the null terminator, is specified by <parameter>bufSize</parameter>.\r
111	</para>\r
112	<para>\r
113	The length of the longest varying name in program is given by <constant>GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</constant>,\r
114	which can be queried with <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry>.\r
115	</para>\r
116	<para>\r
117	For the selected varying variable, its type is returned into <parameter>type</parameter>. The size of\r
118	the varying is returned into <parameter>size</parameter>. The value in <parameter>size</parameter> is\r
119	in units of the type returned in <parameter>type</parameter>. The type returned can be any of the\r
120	scalar, vector, or matrix attribute types returned by <citerefentry><refentrytitle>glGetActiveAttrib</refentrytitle></citerefentry>.\r
121	If an error occurred, the return parameters <parameter>length</parameter>, <parameter>size</parameter>,\r
122	<parameter>type</parameter> and <parameter>name</parameter> will be unmodified. This command will return as much\r
123	information about the varying variables as possible. If no information is available, <parameter>length</parameter>\r
124	will be set to zero and <parameter>name</parameter> will be an empty string. This situation could\r
125	arise if <function>glGetTransformFeedbackVarying</function> is called after a failed link.\r
126	</para>\r
127	</refsect1>\r
128	<refsect1 id="errors"><title>Errors</title>\r
129	<para>\r
130	<constant>GL_INVALID_VALUE</constant> is generated if <parameter>program</parameter> is not\r
131	the name of a program object.\r
132	</para>\r
133	<para>\r
134	<constant>GL_INVALID_VALUE</constant> is generated if <parameter>index</parameter> is greater or equal to\r
135	the value of <constant>GL_TRANSFORM_FEEDBACK_VARYINGS</constant>.\r
136	</para>\r
137	<para>\r
138	<constant>GL_INVALID_OPERATION</constant> is generated <parameter>program</parameter> has not been linked.\r
139	</para>\r
140	</refsect1>\r
141	<refsect1 id="associatedgets"><title>Associated Gets</title>\r
142	<para>\r
143	<citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry> with argument <constant>GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</constant>.\r
144	</para>\r
145	</refsect1>\r
146	<refsect1 id="seealso"><title>See Also</title>\r
147	<para>\r
148	<citerefentry><refentrytitle>glBeginTransformFeedback</refentrytitle></citerefentry>,\r
149	<citerefentry><refentrytitle>glEndTransformFeedback</refentrytitle></citerefentry>,\r
150	<citerefentry><refentrytitle>glTransformFeedbackVaryings</refentrytitle></citerefentry>,\r
151	<citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry>\r
152	</para>\r
153	</refsect1> <refsect1 id="Copyright"><title>Copyright</title>\r
154	<para>\r
155	Copyright <trademark class="copyright"></trademark> 2010 Khronos Group. \r
156	This material may be distributed subject to the terms and conditions set forth in \r
157	the Open Publication License, v 1.0, 8 June 1999.\r
158	<ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.\r
159	</para>\r
160	</refsect1>\r
161	</refentry>\r