示例#1
0
        public static StateDerivative EulerEvaluate(ObjectState initial, float t, float dt, StateDerivative der, Func<ObjectState, float, Vector4> acceleration )
        {
            ObjectState state;
            state.Value = initial.Value + der.Velocity * dt;
            state.Velocity = initial.Velocity + der.Acceletaion * dt;

            StateDerivative output;
            output.Velocity = state.Velocity;
            output.Acceletaion = acceleration(state, t + dt);
            return output;
        }
示例#2
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        /// <summary>
        /// Uses Runge-Kutta fourth order integration
        ///
        /// </summary>
        /// <remarks>Reference: Integration Basics by Glenn Fiedler
        /// http://gafferongames.com/game-physics/integration-basics/</remarks>
        /// <param name="state">Physics state</param>
        /// <param name="t">Time</param>
        /// <param name="dt">Time derived (step)</param>
        /// <param name="acceleration">Acceleration function</param>
        public static void RK4Integrate(ref ObjectState state, float t, float dt, Func <ObjectState, float, Vector4> acceleration)
        {
            StateDerivative a = EulerEvaluate(state, t, 0.0f, new StateDerivative(), acceleration);
            StateDerivative b = EulerEvaluate(state, t + dt * .5f, dt * .5f, a, acceleration);
            StateDerivative c = EulerEvaluate(state, t + dt * .5f, dt * .5f, b, acceleration);
            StateDerivative d = EulerEvaluate(state, t + dt, dt, c, acceleration);

            Vector4 dxdt = 1f / 6 * (a.Velocity + 2 * (b.Velocity + c.Velocity) + d.Velocity);
            Vector4 dvdt = 1f / 6 * (a.Acceletaion + 2 * (b.Acceletaion + c.Acceletaion) + d.Acceletaion);

            state.Value    = state.Value + dxdt * dt;
            state.Velocity = state.Velocity + dvdt * dt;
        }
示例#3
0
        public static StateDerivative EulerEvaluate(ObjectState initial, float t, float dt, StateDerivative der, Func <ObjectState, float, Vector4> acceleration)
        {
            ObjectState state;

            state.Value    = initial.Value + der.Velocity * dt;
            state.Velocity = initial.Velocity + der.Acceletaion * dt;

            StateDerivative output;

            output.Velocity    = state.Velocity;
            output.Acceletaion = acceleration(state, t + dt);
            return(output);
        }