Add comment clarifying shape of parabola
@@ -205,7 +205,9 @@ void derive_single_parabola_with_custom_knots(CuTest *tc)
tsReal slope = 3.f;
tsReal span = 5.f;
- /* Set the initial position, slope, and final position. */
+ /* Set the initial position, slope, and final position.
+ * Note that this defines a parabola by degree, but a line
+ * by shape. */
ctrlp[0] = -7.f;
ctrlp[1] = ctrlp[0] + slope * span / degree;
ctrlp[2] = ctrlp[0] + slope * span;
