WebGL(2)

第四章 Camera

These matrices represent transformations that when applied to our scene, allow us to move thing around.

用matrices代表camera物件

每次移動camera時,需要去更新4-4matrix根據camera新的位置

Homogeneous coordinate

h(x,y,z,w)=v(x/w,y/w,z/w)

v(x,y,z)=h(x,y,z,1)

View origin 視點eye或camera相對位於world origin

NDC(Normalize device Coordinate)

In NDC space, the x and y coordinate represent the location of your vertices on a normalized 2D scene, while the z-coordinate encodes depth information.

因為物件縮放,法向量不再垂直90度角

S'=MS

N'=KN

N'.S'=0

(KN).(MS)=0

(KN)^T(MS)=0

N^TK^TMS=0

N^T(K^TM)S=0

因為N^TS=0

所以K^TM=I

1.The Model-View Matrix that groups the model and view transform in one single matrix.

2.The Normal matrix is obtained by inverting and transposing the Model-View Matrix.
3.The perspective matrix groups the projection transformation and the perspective division.

uMVMatrix the model-view matrix

uPMatrix the perspective matrix
uNMatrix the normal Matrix