Inside Macintosh: 3D Graphics Programming With QuickDraw 3D /

Chapter 4 - Geometric Objects / Geometric Objects Reference

Data Structures

Matrices

QuickDraw 3D defines 3-by-3 and 4-by-4 matrices as structures containing two-dimensional arrays of floating-point numbers as the single field in the structure. This convention allows for easy structure copying and for passing matrix parameters either by value or by reference. In a C language two-dimensional array, the second index varies fastest; accordingly, you can think of the first index as representing the matrix row and the second index as representing the matrix column. For example, consider the 3-by-3 matrix A defined like this: $A\; =\; MATRIX\; (not\; implemented)$

Here, A[0][0] is the matrix element a, and A[2][1] is the matrix element h.

Matrices are defined by the TQ3Matrix3x3 and TQ3Matrix4x4 data types.

Note

Remember that arrays in C are indexed starting with 0.

typedef struct TQ3Matrix3x3 {
   float                      value[3][3];
} TQ3Matrix3x3;
typedef struct TQ3Matrix4x4 {
   float                      value[4][4];
} TQ3Matrix4x4;

Field Description

value

An array of floating-point values that define the matrix.