Intro to 3D graphics week 3

This week i have been implementing a Matrix class into my program. Here are some of the Matrix transforms

Matrix Transforms

Translation

x     100 xshift
y  = 010 yshift
z     001 z shift
w    0001

To move along the x,y or z axis you just change the x,y,z shift to the value you want to move by you can use minus to move one direction and positive for the other direction.

Scaling

x   xscale      0  0   0
y   0     yscale     0  0
z   0   0    zscale     0
w  0   0     0            1

Scaling is simply increasing the x,y,z scale in the direction you want to increase.

Rotation

Transform function

passing in the transform matrix and the vector to be transformed and also a blank vector for the result. The matrix gets applied to the vector your passing in and stores it in a result vector giving you the transformed vector. In the method below it performs a dot product to give the result in vector form

void Matrix::Transform(const Matrix& m, const Vector& v, Vector& result)
{

result._x =  v._x * m._m[0][0] + v._y * m._m[1][0] + v._z * m._m[2][0] + v._w * m._m[3][0];
result._y =  v._x * m._m[0][1] + v._y * m._m[1][1] + v._z * m._m[2][1] + v._w * m._m[3][1];
result._z =  v._x * m._m[0][2] + v._y * m._m[1][2] + v._z * m._m[2][2] + v._w * m._m[3][2];