[FEAT] Matrix add dertminant

raytracing/src/matrix.cpp

@@ -190,6 +190,13 @@ bool Matrix::transpose(void)
 
 /* ------------------------------------------------------------------------- */
 
+double Matrix::determinant(void)
+{
+    return (m_data[0][0] * m_data[1][1]) - (m_data[0][1] * m_data[1][0]);
+}
+
+/* ------------------------------------------------------------------------- */
+
 Matrix Matrix::identity(void)
 {
     Matrix the_identity = {

raytracing/src/matrix.h

@@ -58,6 +58,7 @@ namespace Raytracer
         const Tuple operator*(const Tuple &a_tuple) const;
 
         bool transpose(void);
+        double determinant(void);
 
         static Matrix identity(void);
 

tests/03_matrix.cpp

@@ -227,3 +227,15 @@ TEST_CASE("[Matrix] Transposing the identity matrix", "[Matrix]")
 
     REQUIRE(a == Matrix::identity());
 }
+
+/* ------------------------------------------------------------------------- */
+
+TEST_CASE("[Matrix] Calculating the determinant of a 2x2 matrix", "[Matrix]")
+{
+    Matrix a = {
+        { 1, 5},
+        {-3, 2}
+    };
+
+    REQUIRE(a.determinant() == 17);
+}