Introduction - If you have any usage issues, please Google them yourself
DirectX Lighting vs. Real World Lighting (DX light illumination of the real world) in the DX, we can create different types of light, to make scenes look more realistic. Bear in mind, however, DX in the light only in the approximation to simulate natural light. In nature, light from light source (such as light bulbs) to issue, and then the extension of a straight line, until the consumption of finished or imported into the eyes-ray object in the face of reflection will occur, each reflection will have energy consumption in fact, light can be inter-reflection in the object of millions of times, and the smooth surface than the non-smooth surface reflects more light. All full-count in. If so, computation is enormous, so, DX only approximate to imitate.