2. Reference

typedef struct MthXy {
     Fixed32 x; / * X coordinate * /
     Fixed32 y; / * Y coordinate * /
} MthXy;

typedef struct MthXyz {
     Fixed32 x; / * X coordinate * /
     Fixed32 y; / * Y coordinate * /
     Fixed32 z; / * Z coordinate * /
} MthXyz;

Typedef struct MthMatrix{
     Fixed32 val [3] [4]; / ​​* 3 rows and 4 columns fixed-point data * /
}MthMatrix

typedef struct MthMatrixTbl {
     Uint16 stackSize; / * Number of entries in the matrix stack * /
     MthMatrix * current; / * Current matrix pointer * /
     MthMatrix * stack; / * Matrix stack pointer * /
} MthMatrixTbl;