public void A_translation_matrix_should_translate_each_component_of_the_point()
{
var matrix = new Matrix(
1, 0, 0, 1,
0, 1, 0, 3,
0, 0, 1, -2,
0, 0, 0, 1);
Assert.Equal(new Point(2, 5, 1), matrix * new Point(1, 2, 3));
}
public void A_scaling_matrix_should_scale_each_component_of_the_point()
{
var matrix = new Matrix(
1, 0, 0, 0,
0, 2, 0, 0,
0, 0, 3, 0,
0, 0, 0, 1);
Assert.Equal(new Point(2, 6, 12), matrix * new Point(2, 3, 4));
}
public void The_zero_vector_should_result_in_the_zero_vector()
{
var matrix = new Matrix(
1, 3, 4, 15,
0, 5, 0, 2,
0, 0, 3, 5,
0, 0, 0, 1);
Assert.Equal(Vector.Zero, matrix * Vector.Zero);
}
public void The_resulting_matrix_should_contain_the_elements_of_the_original_matrix_with_the_rows_and_columns_interchanged()
{
var expectedTranspose = new Matrix(
1, 5, 9, 13,
2, 6, 10, 14,
3, 7, 11, 15,
4, 8, 12, 16
);
Assert.Equal(expectedTranspose, MatrixHelper.SequentialMatrix.Transpose());
}
public void A_translation_matrix_should_result_in_the_same_vector()
{
var vector = new Vector(1, 2, 3);
var matrix = new Matrix(
1, 0, 0, 1,
0, 1, 0, 2,
0, 0, 1, 3,
0, 0, 0, 1);
Assert.Equal(vector, matrix * vector);
}
public static Matrix operator *(Matrix left, Matrix right)
{
var result = new Matrix();
for (var row = 0; row < 4; row++) {
for (var col = 0; col < 4; col++) {
result[row, col]
= left[row, 0] * right[0, col]
+ left[row, 1] * right[1, col]
+ left[row, 2] * right[2, col]
+ left[row, 3] * right[3, col];
}
}
return result;
}
