Method Initialize

GTE/Samples/Physics/BallHill/PhysicsModule.cpp:24–59

}

void PhysicsModule::Initialize(float time, float deltaTime, float y1, float y2, float y1Dot, float y2Dot)
{
    mTime = time;

    // state variables
    mState[0] = y1;     // y1(0)
    mState[1] = y1Dot;  // y1'(0)
    mState[2] = y2;     // y2(0)
    mState[3] = y2Dot;  // y2'(0)

    // auxiliary variables
    mAux[0] = a1 * a1;  // a1^2
    mAux[1] = a2 * a2;  // a2^2
    mAux[2] = gravity;  // g

    // RK4 differential equation solver.
    std::function<Vector4<float>(float, Vector4<float> const&)> odeFunction
        =
        [this](float, Vector4<float> const& input) -> Vector4<float>
        {
            float mat00 = mAux[0] + 4.0f * input[0] * input[0];
            float mat01 = 4.0f * input[0] * input[2];
            float mat11 = mAux[1] + 4.0f * input[2] * input[2];
            float invDet = 1.0f / (mat00*mat11 - mat01*mat01);
            float sqrLen = input[1] * input[1] + input[3] * input[3];
            float rhs0 = 2.0f * input[0] * (mAux[2] - 2.0f * input[0] * sqrLen);
            float rhs1 = 2.0f * input[2] * (mAux[2] - 2.0f * input[2] * sqrLen);
            float y1Dot = (mat11 * rhs0 - mat01 * rhs1) * invDet;
            float y2Dot = (mat00 * rhs1 - mat01 * rhs0) * invDet;

            // (y1, dot(y1), y2, dot(y2))
            return Vector4<float>{ input[1], y1Dot, input[3], y2Dot };
        };

    mSolver = std::make_unique<Solver>(deltaTime, odeFunction);
}

void PhysicsModule::GetData(Vector4<float>& center, Matrix4x4<float>& incrRot) const
{