波动方程水面模拟（简版）

　　具体推导详见

　　Mathematics.for.3D.Game.Programming.and.Computer.Graphics.3Ed 的第十五章 布料和流体模拟

　

　初始化水面顶点参数

void waveNode::InitWaterData()
{
    //float count = 10.0;
    //极限0.7071
    m_fC = 0.3;
    m_fD = 1.0;
    m_fT = 1.0;
    m_fMU = 0.20;
    m_fK1 = (4.0 - 8.0 * m_fC * m_fC * m_fT * m_fT / (m_fD * m_fD)) / (m_fMU * m_fT + 2.0);
    m_fK2 = (m_fMU - 2.0) / (m_fMU + 2.0);
    m_fK3 = (2.0 * m_fC * m_fC * m_fT * m_fT / (m_fD * m_fD)) / (m_fMU * m_fT + 2.0);
}

　更新水面顶点高度

void waveNode::CalculateWave()
{
    //边界不动
    for (int y = 1; y < m_iNumTileY - 1; y++)
    {
        for (int x = 1; x < m_iNumTileX - 1; x++)
        {
            //当前和之前的顶点位置
            pVERTEX pCntVertex = m_vecAllVertex.at(y * m_iNumTileX + x);
            pVERTEX pPreVertex = m_vecAllVertexPre.at(y * m_iNumTileX + x);
            osg::Vec3 cntPos = pCntVertex->pos;
            osg::Vec3 prePos = pPreVertex->pos;
            //前后左右当前顶点位置
            osg::Vec3 leftPos = m_vecAllVertex.at(y * m_iNumTileX + x - 1)->pos;
            osg::Vec3 rightPos = m_vecAllVertex.at(y * m_iNumTileX + x + 1)->pos;
            osg::Vec3 upPos = m_vecAllVertex.at((y + 1) * m_iNumTileX + x)->pos;
            osg::Vec3 downPos = m_vecAllVertex.at((y - 1) * m_iNumTileX + x)->pos;

            float nextZ = m_fK1 * (cntPos.z()) + m_fK2 * (prePos.z()) +
                m_fK3 * (leftPos.z() + rightPos.z() + upPos.z() + downPos.z());
            //更新上一次与这一次以及下一次的顶点位置信息
            pPreVertex->pos = pCntVertex->pos;
            pCntVertex->pos = osg::Vec3(cntPos.x(), cntPos.y(), nextZ);
        }
    }
}