Android OpenGL ES coordinate system and Android view Coordinate System

FromArticle: [Android source code] Android graphic rendering (skia EGL OpenGL ES)

Android OpenGL ES coordinate system: it is three-dimensional (of course there are also two-dimensional, but there is no Z axis, there is no difference), the coordinate origin of the coordinate system is in the center of the screen, the X axis is horizontal to the right, Y axis vertical up, Z axis vertical screen, forward outward. The coordinate system of gles can be understood as follows. The XOZ plane is a ground plane, and the Y axis represents the height. We will try to maintain this style in future development. Otherwise, you will encounter many problems in coordinate transformation.

Android view coordinate system: in the upper left corner of the screen, the coordinates are (0, 0), the right is the positive direction of the X axis, and the downward is the positive direction of the Y axis.

Note: The coordinates and locations described above are all based on the mobile phone placement method.