frustum function
Generates a frustum matrix with the given bounds
@param {mat4} out mat4 frustum matrix will be written into @param {Number} left Left bound of the frustum @param {Number} right Right bound of the frustum @param {Number} bottom Bottom bound of the frustum @param {Number} top Top bound of the frustum @param {Number} near Near bound of the frustum @param {Number} far Far bound of the frustum @returns {mat4} out
Implementation
List<double> frustum(List<double> out, double left, double right, double bottom, double top, double near, double far) {
final rl = 1 / (right - left);
final tb = 1 / (top - bottom);
final nf = 1 / (near - far);
out[0] = near * 2 * rl;
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 0;
out[5] = near * 2 * tb;
out[6] = 0;
out[7] = 0;
out[8] = (right + left) * rl;
out[9] = (top + bottom) * tb;
out[10] = (far + near) * nf;
out[11] = -1;
out[12] = 0;
out[13] = 0;
out[14] = far * near * 2 * nf;
out[15] = 0;
return out;
}