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OpenGL ES 1.0 and EGL 1.0 reference manual and man pages (written by
Claude Knaus, based on OpenGL SI man pages).

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.2//EN" "DTD/docbook/docbookx.dtd">

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<refentry id="glMultMatrix">
  <refmeta>
    <refentrytitle>glMultMatrix</refentrytitle>
    <manvolnum>3G</manvolnum>
  </refmeta>

  <refnamediv>
    <refdescriptor>glMultMatrix</refdescriptor>
    <refname>glMultMatrixf</refname>
    <refname>glMultMatrixx</refname>
    <refpurpose>multiply the current matrix with the specified
    matrix</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <title>C Specification</title>

    <funcsynopsis>
      <funcprototype>
        <funcdef>void <function>glMultMatrixf</function></funcdef>
        <paramdef>const GLfloat * <parameter>m</parameter></paramdef>
      </funcprototype>
      <funcprototype>
        <funcdef>void <function>glMultMatrixx</function></funcdef>
        <paramdef>const GLfixed * <parameter>m</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Parameters</title>

    <variablelist>
      <varlistentry>
        <term>
          <parameter>m</parameter>
        </term>

        <listitem>
          <para>Points to 16 consecutive values that are used as
          the elements of a 
          <inlineequation><math>
            <mn>4</mn><mo>x</mo><mn>4</mn>
          </math></inlineequation>
          column-major matrix.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Description</title>

    <para><function>glMultMatrix</function>
    multiplies the current matrix with the one specified using 
    <parameter>m</parameter>,
    and replaces the current matrix with the product.</para>

    <para>The current matrix is determined by the current matrix mode (see 
    <citerefentry><refentrytitle>glMatrixMode</refentrytitle></citerefentry>).
    It is either the projection matrix, modelview matrix, or the
    texture matrix.</para>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <para>If the current matrix is <replaceable>C</replaceable>,
    and the coordinates to be transformed are, 
    <inlineequation><math>
      <mi>v</mi><mo>=</mo>
      <mfenced>
        <mrow><mi>v</mi><mo>[</mo><mn>0</mn><mo>]</mo></mrow>
        <mrow><mi>v</mi><mo>[</mo><mn>1</mn><mo>]</mo></mrow>
        <mrow><mi>v</mi><mo>[</mo><mn>2</mn><mo>]</mo></mrow>
        <mrow><mi>v</mi><mo>[</mo><mn>3</mn><mo>]</mo></mrow>
      </mfenced>
    </math></inlineequation>,
    then the current transformation is 
    <inlineequation><math>
      <mi>C</mi><mo>x</mo><mi>v</mi>
    </math></inlineequation>, or
    </para>

    <informalequation><math><mrow>
      <mo>(</mo>
      <mtable class="matrix">
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>0</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>4</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>8</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>12</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>1</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>5</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>9</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>13</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>2</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>6</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>10</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>14</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>3</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>7</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>11</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>15</mn><mo>]</mo></mtd>
        </mtr>
      </mtable>
      <mo>)</mo>
      <mo>x</mo>
      <mo>(</mo>
      <mtable class="vector">
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>0</mn><mo>]</mo></mtd></mtr>
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>1</mn><mo>]</mo></mtd></mtr>
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>2</mn><mo>]</mo></mtd></mtr>
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>3</mn><mo>]</mo></mtd></mtr>
      </mtable>
      <mo>)</mo>
    </mrow></math></informalequation>

    <para>Calling 
    <function>glMultMatrix</function>
    with an argument of 
    <inlineequation><math>
      <mrow>
        <mi>m</mi><mo>=</mo>
        <mi>m</mi><mo>[</mo><mn>0</mn><mo>]</mo>,
        <mi>m</mi><mo>[</mo><mn>1</mn><mo>]</mo>,
        <mo>...</mo>
        <mi>m</mi><mo>[</mo><mn>15</mn><mo>]</mo>
      </mrow>
    </math></inlineequation>
    replaces the current transformation with 
    <inlineequation><math>
      <mfenced><mrow><mi>C</mi><mo>x</mo><mi>M</mi></mrow></mfenced>
      <mo>x</mo><mi>v</mi>
    </math></inlineequation>, or</para>

    <informalequation><math><mrow>
      <mo>(</mo>
      <mtable class="matrix">
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>0</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>4</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>8</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>12</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>1</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>5</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>9</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>13</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>2</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>6</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>10</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>14</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>c</mi><mo>[</mo><mn>3</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>7</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>11</mn><mo>]</mo></mtd>
          <mtd><mi>c</mi><mo>[</mo><mn>15</mn><mo>]</mo></mtd>
        </mtr>
      </mtable>
      <mo>)</mo>
      <mo>x</mo>
      <mo>(</mo>
      <mtable class="matrix">
        <mtr>
          <mtd><mi>m</mi><mo>[</mo><mn>0</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>4</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>8</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>12</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>m</mi><mo>[</mo><mn>1</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>5</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>9</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>13</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>m</mi><mo>[</mo><mn>2</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>6</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>10</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>14</mn><mo>]</mo></mtd>
        </mtr>
        <mtr>
          <mtd><mi>m</mi><mo>[</mo><mn>3</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>7</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>11</mn><mo>]</mo></mtd>
          <mtd><mi>m</mi><mo>[</mo><mn>15</mn><mo>]</mo></mtd>
        </mtr>
      </mtable>
      <mo>)</mo>
      <mo>x</mo>
      <mo>(</mo>
      <mtable class="vector">
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>0</mn><mo>]</mo></mtd></mtr>
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>1</mn><mo>]</mo></mtd></mtr>
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>2</mn><mo>]</mo></mtd></mtr>
        <mtr><mtd><mi>v</mi><mo>[</mo><mn>3</mn><mo>]</mo></mtd></mtr>
      </mtable>
      <mo>)</mo>
    </mrow></math></informalequation>

   <para>Where
    ``<inlineequation><math><mo>x</mo></math></inlineequation>''
    denotes matrix multiplication, and
    <replaceable>v</replaceable>
    is represented as a 
    <inlineequation><math>
      <mn>4</mn><mo>x</mo><mn>1</mn>
    </math></inlineequation>
    matrix.</para>
  </refsect1>

  <refsect1>
    <title>Notes</title>

    <para>While the elements of the matrix may be specified with
    single or double precision, the GL may store or operate on
    these values in less than single precision.</para>

    <para>In many computer languages 
    <inlineequation><math>
      <mn>4</mn><mo>x</mo><mn>4</mn>
    </math></inlineequation>
    arrays are represented in row-major order. The transformations
    just described represent these matrices in column-major order.
    The order of the multiplication is important. For example, if
    the current transformation is a rotation, and 
    <function>glMultMatrix</function>
    is called with a translation matrix, the translation is done
    directly on the coordinates to be transformed, while the
    rotation is done on the results of that translation.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>

    <para>
    <citerefentry><refentrytitle>glLoadIdentity</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glLoadMatrix</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glMatrixMode</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glPushMatrix</refentrytitle></citerefentry>
    </para>
  </refsect1>
</refentry>