Posted 09 March 2012 - 12:52 AM
Your system should have a constant g, should it not? Your entire world would have some form of gravity, and your character that is finished will probably be using the same constant.
At mid jump, the apex, your V0y would be 0. At the start and the finish, your V0y would be 0. Mid-jump, your V0y would be your previous Vy. I may be wrong on that very last statement, but I don't think so. If V0y was to consider your initial jump's starting velocity, the character is not moving, so that would fully eliminate V0y * t.
EDIT: As an afterthought, and due to it being late, V0y would be a function included in your equation for y, and each point during the jump would recalculate the equation with a different t: y = (g * t + V0y) * t - ((g * t^2) / 2) where V0y is the very first velocity you want to give the character to jump.
-- To clarify: (g * t + V0y) is the velocity the character is at at the end of the last update.