Apply an oblique projection transformation to this matrix with the given values for <code>a</code> and
<code>b</code>.
<p>
If <code>M</code> is <code>this</code> matrix and <code>O</code> the oblique transformation matrix,
then the new matrix will be <code>M * O</code>. So when transforming a
vector <code>v</code> with the new matrix by using <code>M * O * v</code>, the
oblique transformation will be applied first!
<p>
The oblique transformation is defined as:
<pre>
x' = x + a*z
y' = y + a*z
z' = z
</pre>
or in matrix form:
<pre>
1 0 a
0 1 b
0 0 1
</pre>
@param a
the value for the z factor that applies to x
@param b
the value for the z factor that applies to y
@return this
Apply an oblique projection transformation to this matrix with the given values for <code>a</code> and <code>b</code>. <p> If <code>M</code> is <code>this</code> matrix and <code>O</code> the oblique transformation matrix, then the new matrix will be <code>M * O</code>. So when transforming a vector <code>v</code> with the new matrix by using <code>M * O * v</code>, the oblique transformation will be applied first! <p> The oblique transformation is defined as: <pre> x' = x + a*z y' = y + a*z z' = z </pre> or in matrix form: <pre> 1 0 a 0 1 b 0 0 1 </pre>
@param a the value for the z factor that applies to x @param b the value for the z factor that applies to y @return this