  A fully discrete approximation of the semi-linear stochastic wave equation
driven by multiplicative noise is presented. A standard linear finite element
approximation is used in space and a stochastic trigonometric method for the
temporal approximation. This explicit time integrator allows for mean-square
error bounds independent of the space discretisation and thus do not suffer
from a step size restriction as in the often used St\"ormer-Verlet-leap-frog
scheme. Furthermore, it satisfies an almost trace formula (i.e., a linear drift
of the expected value of the energy of the problem). Numerical experiments are
presented and confirm the theoretical results.
