Games101 Lesson 7 shading 1 Notes

One 、 The depth of the cache （Z-buffering）

（1） Painter algorithm ： Like an oil painter painting , Draw the farthest first , Paint and cover from far to near .

① Painter's algorithm works in most cases , You need to arrange the distance first .
② But if there is partial coverage of each other , There will be problems with the painter's Algorithm , Here's the picture .

（2） The depth of the cache

① The depth of the cache Z-buffer The algorithm records the depth of each pixel , In addition to recording the color of each pixel , The depth of each pixel is also recorded .
② The pseudo code of deep cache is as follows .

③ An example of deep caching is as follows .

④ The complexity of the deep cache algorithm is O(n).

Two 、 To color （Shading）

（1） Coloring in this course refers to applying different materials to objects .

（2） A simple coloring model ：Blinn-Phong Reflectance Model

① Highlights are shown from top to bottom 、 Diffuse reflection 、 Three parts of ambient light .
（3） Shading point
① These inputs are required ： Observation direction 、 normal 、 The direction of the light 、 Surface parameters （ Such as color 、 Brightness, etc ）.
② Observation direction 、 normal 、 The illumination directions are unit vectors .
③ Shading discussed in this section does not consider shadows .

3、 ... and 、 Diffuse reflection （Diffuse Reflection）

（1） Definition of diffuse reflection

① Light will be reflected evenly to all angles .
② The color is the same in all observation directions .
（2） The energy that light at different angles can accept

（3） Light attenuation

① The farther away the point is, the energy of light will be attenuated .
② For example, light radiates a circle , The length of the circumference near , The circumference in the distance is long , According to the conservation of energy , Distant points should get less energy .
（4）Lambertian Shading

① Combined with the energy received by light at different angles and the light attenuation formula, the coloring of a point can be obtained .
（5） Different diffuse reflection coefficients kd Examples of different coloring situations obtained .

reference

Course video link : GAMES101 Lecture07 Shading 1