Node:Transform Operators, Next:, Previous:Transform Constructors, Up:Transform Reference



Operators

Transform operator= (const Transform& t) Assignment operator
Sets *this to t and returns t. Returning *this would, of course, have exactly the same effect.

real operator*= (real r) Operator
Multiplication with assignment by a scalar. This operator multiplies each element E of matrix by the scalar r. The return value is r. This makes it possible to chain invocations of this function: For a_x, b_x, c_x, ..., p_x in R , x in N
          Transform T0(a_0, b_0, c_0, d_0,
                       e_0, f_0, g_0, h_0,
                       i_0, j_0, k_0 l_0,
                       m_0, n_0, o_0, p_0);
          Transform T1(a_1, b_1, c_1, d_1,
                       e_1, f_1, g_1, h_1,
                       i_1, j_1, k_1 l_1,
                       m_1, n_1, o_1, p_1);
          Transform T2(a_2, b_2, c_2, d_2,
                       e_2, f_2, g_2, h_2,
                       i_2, j_2, k_2 l_2,
                       m_2, n_2, o_2, p_2);
          real r = 5;
          

Let M_0, M_1, and M_2 stand for T0.matrix, T1.matrix, and T2.matrix respectively:

          M_0 =
          a_0 b_0 c_0 d_0
          e_0 f_0 g_0 h_0
          i_0 j_0 k_0 l_0
          m_0 m_0 o_0 p_0
          
          M_1 =
          a_1 b_1 c_1 d_1
          e_1 f_1 g_1 h_1
          i_1 j_1 k_1 l_1
          m_1 m_1 o_1 p_1
          
          M_2 =
          a_2 b_2 c_2 d_2
          e_2 f_2 g_2 h_2
          i_2 j_2 k_2 l_2
          m_2 m_2 o_2 p_2
          
          T0 *= T1 *= T2 *= r;
          

Now,

          M_0 =
          5a_0 5b_0 5c_0 5d_0
          5e_0 5f_0 5g_0 5h_0
          5i_0 5j_0 5k_0 5l_0
          5m_0 5m_0 5o_0 5p_0
          
          M_1 =
          5a_1 5b_1 5c_1 5d_1
          5e_1 5f_1 5g_1 5h_1
          5i_1 5j_1 5k_1 5l_1
          5m_1 5m_1 5o_1 5p_1
          
          M_2 =
          5a_2 5b_2 5c_2 5d_2
          5e_2 5f_2 5g_2 5h_2
          5i_2 5j_2 5k_2 5l_2
          5m_2 5m_2 5o_2 5p_2
          

This function is not currently used anywhere, but it may turn out to be useful for something.

Transform operator* (const real r) const operator
Multiplication of a Transform by a scalar without assignment. The return value is a Transform A. If this.matrix has elements E_T, then A.matrix has elements E_A such that E_A = r * E_T

for all E.

Transform operator*= (const Transform& t) Operator
Performs matrix multiplication on matrix and t.matrix. The result is assigned to matrix. t is returned, not *this! This makes it possible to chain invocations of this function:
          Transform a;
          a.shift(1, 1, 1);
          Transform b;
          b.rotate(0, 90);
          Transform c;
          c.shear(5, 4);
          Transform d;
          d.scale(3, 4, 5);
          

Let a_m, b_m, and c_m stand for a.matrix, b.matrix, c.matrix, and d.matrix respectively:

          a_m =
          1        0        0        0
          0        1        0        0
          0        0        1        0
          1        1        1        1
          
          b_m =
           0.5      0.5        0.707      0
           0.146    0.854     -0.5        0
          -0.854    0.146      0.5        0
           0        0          0          1
          
          c_m =
           1       12       14        0
          10        1       15        0
          11       13        1        0
           0        0        0        1
          
          d_m =
          3        0        0        0
          0        4        0        0
          0        0        5        0
          0        0        0        1
          
a *= b *= c *= d;
a, b, and c are transformed by d, which remains unchanged.

Now,

          a_m =
          3        0        0        0
          0        4        0        0
          0        0        5        0
          3        4        5        1
          
          b_m =
           1.5     2       3.54  0
          -0.439   3.41   -2.5   0
          -2.56    0.586   2.5   0
           0       0       0     1
          
          c_m =
           3       48       70        0
          30        4       75        0
          33       52        5        0
           0        0        0        1
          
d_m is unchanged.

Transform operator* (const Transform t) const operator
Multiplication of a Transform by another Transform without assignment. The return value is a Transform whose matrix contains values that are the result of the matrix multiplication of matrix and t.matrix.