Adding matrices

Two matrices can be added together by component. To add two matrices together, sum their respective components and store the result in a new matrix. Matrix addition can be used with scalar multiplication to interpolate or blend between multiple matrices. Later, you will learn how to use this property to implement animation skinning.

Implement the matrix addition function in mat4.cpp. Don't forget to add the function declaration to mat4.h:

mat4 operator+(const mat4& a, const mat4& b) {

    return mat4(

        a.xx+b.xx, a.xy+b.xy, a.xz+b.xz, a.xw+b.xw,

        a.yx+b.yx, a.yy+b.yy, a.yz+b.yz, a.yw+b.yw,

        a.zx+b.zx, a.zy+b.zy, a.zz+b.zz, a.zw+b.zw,

        a.tx+b.tx, a.ty+b.ty, a.tz+b.tz, a.tw+b.tw

    );

}

Matrix addition is simple but it will play a big role in displaying an animated mesh. In the next section, you will learn how to scale a matrix by a scalar value.