ImplementationsVec4.go

func (mat *T) MulVec4(v *vec4.T) vec4.T {
	return vec4.T{
		mat[0][0]*v[0] + mat[1][0]*v[1] + mat[2][0]*v[2] + mat[3][0]*v[3],
		mat[0][1]*v[0] + mat[1][1]*v[1] + mat[2][1]*v[2] + mat[3][1]*v[3],
		mat[0][2]*v[0] + mat[1][2]*v[1] + mat[2][2]*v[2] + mat[3][2]*v[3],
		mat[0][3]*v[0] + mat[1][3]*v[1] + mat[2][3]*v[2] + mat[3][3]*v[3],
	}
}

// Strangely, this is the slowest of the three.
func (mat *T) AltMulVec4(v *vec4.T) vec4.T {
	result := *v
	mat.TransformVec4(&result)
	return result
}

// MulVec3 multiplies v with mat with w as fourth component of the vector.
func (mat *T) TransformVec4(v *vec4.T) {
	// use intermediate variables to not alter further computations
	x := mat[0][0]*v[0] + mat[1][0]*v[1] + mat[2][0]*v[2] + mat[3][0]*v[3]
	y := mat[0][1]*v[0] + mat[1][1]*v[1] + mat[2][1]*v[2] + mat[3][1]*v[3]
	z := mat[0][2]*v[0] + mat[1][2]*v[1] + mat[2][2]*v[2] + mat[3][2]*v[3]
	v[3] = mat[0][3]*v[0] + mat[1][3]*v[1] + mat[2][3]*v[2] + mat[3][3]*v[3]
	v[0] = x
	v[1] = y
	v[2] = z
}

PASS
BenchmarkMulVec4    50000000            35.5 ns/op
BenchmarkAltMulVec4 30000000            53.1 ns/op
BenchmarkTransformVec4  50000000            24.5 ns/op
ok      github.com/ungerik/go3d/mat4    4.720s