question: public Matrix4 multiplyByScale ( double xScale , double yScale , double zScale ) { double [ ] m = this . m ; m [ 0 ] *= xScale ; m [ 4 ] *= xScale ; m [ 8 ] *= xScale ; m [ 12 ] *= xScale ; m [ 1 ] *= yScale ; m [ 5 ] *= yScale ; m [ 9 ] *= yScale ; m [ 13 ] *= yScale ; m [ 2 ] *= zScale ; m [ 6 ] *= zScale ; m [ 10 ] *= zScale ; m [ 14 ] *= zScale ; return this ; }
target:  Multiplies this matrix by a scale matrix with specified values.