Tencent Game Academy Game Programming Chapter 8 (Personal Summary)-Material Shading and Lighting

Chapter 8 Material Shading and Illumination Learning Check-in

In this chapter, the teacher’s mouth speed is a bit quick...Follow-up supplement

Physical review

What is rendering

• The art of balancing physics and limited computing resources
• Physically based rendering (material + lighting) = interaction between light and matter
• Movie screen: offline rendering
• Base logistics rendering: PBR (lighting is rendered based on a more accurate physical model)
• The characteristics of the generated waves also reflect the characteristics of the particles

Material

Light interacts with particles

• Particles are polarized. The electrons absorb part of the energy of the light. The electrons inside the atom transition from a low-energy state to a high-energy state, and absorb visible light at certain frequencies. When you see a red object, it is because the object has wavelengths other than red. Absorbed, only red is left to reflect human eyes
• Luminous flux: light energy produced per unit time
• Luminous intensity:
• brightness

• Measure the coefficient of Fresnel reflection with experimental instruments: a common phenomenon, most metals are greater than 0.5, and most non-metals are less than 0.5

Global illumination

• method

• Offline rendering

  • Path tracking
    • Violent method, the real calculation of the result of a rebound of each light path in the game scene through computing power. Generally, the starting point will start from the camera and emit rays into the scene. The BRDF probability function is used to calculate the direction of each rebound. Bounce in the other direction of the scene and continue to bounce. If it does not hit the light source, the contribution of this ray is completely black. Generally, at the last bounce, it is forcibly connected to the light source, and then it depends on whether If there is an object blocked, if there is an object, it will become a shadow. If it is not blocked, it will contribute to the calculation of the light source.

  

  

  • Photo Mapping
    • Path tracking will not store any information, but the photon mapping will store the energy every time it bounces, and emit photons from the light source point to the scene, and then let a structure of the scene save the result of each bounce Then, when the camera observes the scene during the collection phase, these results are interpolated, and the photon mapping and path tracking effects can be essentially the same
  • Radiance

• Real-time rendering

  • Screen space

    • Screen ambient light shading

      • Cryengine 的Screen space ambient occlusion（SSAO）
      • HBAO+ (Use screen space to simulate an AO phenomenon)

    • Screen space reflection

      • HI-Z Tracing (Frost Engine)
        • Min-Z Pass, Battlefield Series, Star Wars Series
      • PBR brdf-Stochastic Monte Carlo sampling sampling method + denoise (noise reduction)

      

  • World space

    • Voxel Cone Tracing

    • Distance Field

    • Real-time ray tracing

      • Calculate the focus of light and geometry

      

    • Indirect lighting

    • Bent Normal

    • Surface light source (the light source that comes with the melt)

    • Indirect Shadow

    • Ambient light shading

    • GGX normal distribution function

• storage

  • Lightmap
  • Reflection probe
    • Diffuse reflection
    • Specular reflection

F is the Fresnel effect

Local illumination

Point light source

Image-based lighting

• Light probe