Vec3D CSceneData::getVertexNormal(int x, int y)const
{
float a = getVertexHeight(x, y);
float b = getVertexHeight(x, y+1);
float c = getVertexHeight(x+1, y);
Vec3D vVector0(0,(b-a),1);
Vec3D vVector1(1,(c-a),0);
Vec3D vN = vVector0.cross(vVector1);
return vN.normalize();
}
Vec3D CTerrainData::getVertexNormal(int nCellX, int nCellY)const
{
float a = getVertexHeight(nCellX, nCellY);
float b = getVertexHeight(nCellX, nCellY+1);
float c = getVertexHeight(nCellX+1, nCellY);
Vec3D vVector0(0,(b-a),1);
Vec3D vVector1(1,(c-a),0);
Vec3D vN = vVector0.cross(vVector1);
return vN.normalize();
}
float CSceneData::getHeight(float fX, float fY)const
{
int nCellX = fX;
int nCellY = fY;
float u = fX - nCellX;
float v = fY - nCellY;
float a = getVertexHeight(nCellX, nCellY);
float b = getVertexHeight(nCellX+1, nCellY);
float c = getVertexHeight(nCellX, nCellY+1);
float d = getVertexHeight(nCellX+1, nCellY+1);
return bilinearInterpolation(a,b,c,d,u,v);
}
//---------------------------------------------------------------------------
float Terrain::getLowestVertex( long& tileR, long& tileC )
{
float lowest = 9999999.; // an absurdly big number
for ( int i = 0; i < realVerticesMapSide * realVerticesMapSide; ++i )
{
float tmp = getVertexHeight( i );
if ( tmp < lowest )
{
lowest = tmp;
tileR = i/realVerticesMapSide;
tileC = i % realVerticesMapSide;
}
}
return lowest;
}
//---------------------------------------------------------------------------
float Terrain::getHighestVertex( long& tileR, long& tileC )
{
float highest = -9999999.; // an absurdly small number
for ( int i = 0; i < realVerticesMapSide * realVerticesMapSide; ++i )
{
float tmp = getVertexHeight( i );
if ( tmp > highest )
{
highest = tmp;
tileR = i/realVerticesMapSide;
tileC = i % realVerticesMapSide;
}
}
return highest;
}
float Storage::getHeightAt(const osg::Vec3f &worldPos)
{
int cellX = static_cast<int>(std::floor(worldPos.x() / 8192.f));
int cellY = static_cast<int>(std::floor(worldPos.y() / 8192.f));
ESM::Land* land = getLand(cellX, cellY);
if (!land || !(land->mDataTypes&ESM::Land::DATA_VHGT))
return -2048;
// Mostly lifted from Ogre::Terrain::getHeightAtTerrainPosition
// Normalized position in the cell
float nX = (worldPos.x() - (cellX * 8192))/8192.f;
float nY = (worldPos.y() - (cellY * 8192))/8192.f;
// get left / bottom points (rounded down)
float factor = ESM::Land::LAND_SIZE - 1.0f;
float invFactor = 1.0f / factor;
int startX = static_cast<int>(nX * factor);
int startY = static_cast<int>(nY * factor);
int endX = startX + 1;
int endY = startY + 1;
endX = std::min(endX, ESM::Land::LAND_SIZE-1);
endY = std::min(endY, ESM::Land::LAND_SIZE-1);
// now get points in terrain space (effectively rounding them to boundaries)
float startXTS = startX * invFactor;
float startYTS = startY * invFactor;
float endXTS = endX * invFactor;
float endYTS = endY * invFactor;
// get parametric from start coord to next point
float xParam = (nX - startXTS) * factor;
float yParam = (nY - startYTS) * factor;
/* For even / odd tri strip rows, triangles are this shape:
even odd
3---2 3---2
| / | | \ |
0---1 0---1
*/
// Build all 4 positions in normalized cell space, using point-sampled height
osg::Vec3f v0 (startXTS, startYTS, getVertexHeight(land, startX, startY) / 8192.f);
osg::Vec3f v1 (endXTS, startYTS, getVertexHeight(land, endX, startY) / 8192.f);
osg::Vec3f v2 (endXTS, endYTS, getVertexHeight(land, endX, endY) / 8192.f);
osg::Vec3f v3 (startXTS, endYTS, getVertexHeight(land, startX, endY) / 8192.f);
// define this plane in terrain space
osg::Plane plane;
// FIXME: deal with differing triangle alignment
if (true)
{
// odd row
bool secondTri = ((1.0 - yParam) > xParam);
if (secondTri)
plane = osg::Plane(v0, v1, v3);
else
plane = osg::Plane(v1, v2, v3);
}
/*
else
{
// even row
bool secondTri = (yParam > xParam);
if (secondTri)
plane.redefine(v0, v2, v3);
else
plane.redefine(v0, v1, v2);
}
*/
// Solve plane equation for z
return (-plane.getNormal().x() * nX
-plane.getNormal().y() * nY
- plane[3]) / plane.getNormal().z() * 8192;
}