/// <summary>
/// Returns the linearly interpolated height for a given position in the grid. Safe to use in systems.
/// </summary>
/// <returns></returns>
public static float GetGroundLevel(float3 position, NativeArray <float> heightMap, GridData grid)
{
// Use linear interpolation to avoid staircase-like movement
int2 position2D = grid.GetGridPosition(position);
if (!grid.IsInBounds(position2D))
{
return(0);
}
float xU = position.x - position2D.x;
float zU = (position.z - position2D.y);
xU = xU / grid.CellSize;
zU = zU / grid.CellSize;
int2 bottomRight = new int2(position2D.x + 1, position2D.y);
int2 topLeft = new int2(position2D.x, position2D.y + 1);
int2 topRight = new int2(position2D.x + 1, position2D.y + 1);
int2 origin = position2D;
if (xU + zU > 1f && grid.IsInBounds(topRight))
{
// On second triangle in this cell. Invert and switch xU and zU
origin = topRight;
xU = 1f - zU;
zU = 1f - xU;
}
float xHeight;
float zHeight;
if (grid.IsInBounds(bottomRight))
{
xHeight = math.lerp(heightMap[grid.GetCellIndex(origin)],
heightMap[grid.GetCellIndex(bottomRight)], xU);
}
else
{
xHeight = heightMap[grid.GetCellIndex(position)];
}
if (grid.IsInBounds(topLeft))
{
zHeight = math.lerp(heightMap[grid.GetCellIndex(origin)],
heightMap[grid.GetCellIndex(topLeft)], zU);
}
else
{
zHeight = heightMap[grid.GetCellIndex(position)];
}
return((xHeight + zHeight) / 2f);
}
