Method update

tests/cpp-tests/Source/TerrainTest/TerrainTest.cpp:211–275

}

void Player::update(float dt)
{
    auto player = (MeshRenderer*)this;
    switch (_playerState)
    {
    case PLAYER_STATE_IDLE:
        break;
    case PLAYER_STATE_FORWARD:
    {
        Vec3 curPos     = player->getPosition3D();
        Vec3 newFaceDir = _targetPos - curPos;
        newFaceDir.y    = 0.0f;
        newFaceDir.normalize();
        Vec3 offset = newFaceDir * 25.0f * dt;
        curPos += offset;
        player->setPosition3D(curPos);
    }
    break;
    case PLAYER_STATE_BACKWARD:
    {
        Vec3 forward_vec;
        player->getNodeToWorldTransform().getForwardVector(&forward_vec);
        forward_vec.normalize();
        player->setPosition3D(player->getPosition3D() - forward_vec * 15 * dt);
    }
    break;
    case PLAYER_STATE_LEFT:
    {
        player->setRotation3D(player->getRotation3D() + Vec3(0, 25 * dt, 0));
    }
    break;
    case PLAYER_STATE_RIGHT:
    {
        player->setRotation3D(player->getRotation3D() + Vec3(0, -25 * dt, 0));
    }
    break;
    default:
        break;
    }
    // transform player position to world coord
    auto playerPos      = player->getPosition3D();
    auto playerModelMat = player->getParent()->getNodeToWorldTransform();
    playerModelMat.transformPoint(&playerPos);
    Vec3 Normal;
    float player_h = _terrain->getHeight(playerPos.x, playerPos.z, &Normal);
    if (Normal.isZero())  // check the player whether is out of the terrain
    {
        player_h = playerPos.y;
    }
    else
    {
        player_h += PLAYER_HEIGHT;
    }
    player->setPositionY(player_h);
    Quaternion q2;
    q2.createFromAxisAngle(Vec3(0, 1, 0), (float)-M_PI, &q2);

    Quaternion headingQ;