internal TerrainModel(int numPatchesX, int numPatchesY, Patch[,] patches, HeightMap heightMap, float tau, Effect effect)
{
HeightMap = heightMap;
_numPatchesX = numPatchesX;
_numPatchesY = numPatchesY;
_patches = patches;
_tau = tau;
Effect = effect;
}
internal TerrainModel(int numPatchesX, int numPatchesY, Patch[,] patches, HeightMap heightMap, Effect effect)
{
HeightMap = heightMap;
_numPatchesX = numPatchesX;
_numPatchesY = numPatchesY;
_patches = new List<Patch>(_numPatchesX * _numPatchesY);
_numLevels = 0;
for (int x = 0; x < _numPatchesX; x++)
for (int y = 0; y < _numPatchesY; y++)
{
_patches.Add(patches[x, y]);
_numLevels = Math.Max(_numLevels, patches[x, y].Levels);
}
_visiblePatches = new List<Patch>(_patches.Count);
MaxPatchesAtLevel = new int[_numLevels - 1];
MaxPatchesAtLevel[0] = 4;
for (int i = 1; i < _numLevels - 1; i++)
{
MaxPatchesAtLevel[i] = MaxPatchesAtLevel[i - 1] * 2;
}
Effect = effect;
}
internal void SetNeighbours(Patch pLeft, Patch pRight, Patch pTop, Patch pBottom)
{
_left = pLeft;
_right = pRight;
_top = pTop;
_bottom = pBottom;
}
public void Update(ICamera camera)
{
// TODO: Maybe don't need to update levels for invisible patches?
// set preferred tesselation levels for each patch
for (int y = 0; y < _numPatchesY; y++)
{
for (int x = 0; x < _numPatchesX; x++)
{
if (camera.BoundingFrustum.Contains(_patches[x, y].BoundingBox) != ContainmentType.Disjoint)
{
_patches[x, y].Visible = true;
_patches[x, y].UpdateLevelOfDetail(camera);
}
else
{
_patches[x, y].Visible = false;
}
}
}
// now, make sure that each patch is no more than 1 level different from its neighbours
// we loop through all patches, and if any are changed, set a flag. continue the outer
// loop until the "changed" flag is false for all patches
bool bChanged;
do
{
bChanged = false;
for (int y = 0; y < _numPatchesY; y++)
{
for (int x = 0; x < _numPatchesX; x++)
{
// get the minimum level for neighbouring patches
Patch pPatch = _patches[x, y];
int nLevel = pPatch.ActiveLevel;
int nLeft = pPatch.LeftActiveLevel;
int nRight = pPatch.RightActiveLevel;
int nTop = pPatch.TopActiveLevel;
int nBottom = pPatch.BottomActiveLevel;
int nMinimumNeighbouringLevel = Math.Min(Math.Min(nLeft, nRight), Math.Min(nTop, nBottom));
if (nLevel > nMinimumNeighbouringLevel + 1)
{
pPatch.ActiveLevel = nMinimumNeighbouringLevel + 1;
bChanged = true;
}
}
}
}while (bChanged);
// finally, update geometry to match LOD
for (int y = 0; y < _numPatchesY; y++)
{
for (int x = 0; x < _numPatchesX; x++)
{
_patches[x, y].UpdateTessellation();
}
}
/*int numVisible = 0;
* for (int y = 0; y < _numPatchesY; y++)
* for (int x = 0; x < _numPatchesX; x++)
* if (_patches[x, y].Visible)
* numVisible++;*/
}