public static Geometry.Ray_Test_Result TestOBBLine(OBB obb, LineSegment ls, Geometry.Ray_Test_Mode mode)
{
var result = new Geometry.Ray_Test_Result();
var pos2 = obb.Point_W_To_L(ls.end);
var pos1 = obb.Point_W_To_L(ls.start);
var dir = pos2 - pos1;
if (Math.Abs(dir.X) < 0.01f)
{
if (Math.Abs(pos1.X) > obb.HalfAxisWidth.X)
{
result.Did_It_Hit = false;
return(result);
}
}
var tleftx = (-obb.HalfAxisWidth.X - pos1.X) / dir.X;
var trightx = (obb.HalfAxisWidth.X - pos1.X) / dir.X;
var tenterx = tleftx < trightx ? tleftx : trightx;
var texitx = tleftx < trightx ? trightx : tleftx;
if (Math.Abs(dir.Y) < 0.01f)
{
if (Math.Abs(pos1.Y) > obb.HalfAxisWidth.Y)
{
result.Did_It_Hit = false;
return(result);
}
}
var tlefty = (-obb.HalfAxisWidth.Y - pos1.Y) / dir.Y;
var trighty = (obb.HalfAxisWidth.Y - pos1.Y) / dir.Y;
var tentery = tlefty < trighty ? tlefty : trighty;
var texity = tlefty < trighty ? trighty : tlefty;
var tmaxmin = tentery > tenterx ? tentery : tenterx;
var tminmax = texity < texitx ? texity : texitx;
result.enter = tmaxmin;
result.exit = tminmax;
switch (mode)
{
case Geometry.Ray_Test_Mode.Line: result.Did_It_Hit = (tmaxmin < tminmax);
break;
case Geometry.Ray_Test_Mode.Ray: result.Did_It_Hit = (tmaxmin < tminmax) && (tmaxmin >= 0);
break;
case Geometry.Ray_Test_Mode.Segment: result.Did_It_Hit = (tmaxmin < tminmax) && (tmaxmin >= 0) && (tmaxmin <= 1);
break;
}
return(result);
}
/// <summary>
/// xekinas me deiktes i j
/// kai kataligeis se final_i, final_j //elegxe to an piaseis esto ena einai ok
/// exeis kati times tx ty pou deixnoun "se ti pososto os pros monada apo to sinoliko manhattan x kai y antistoixa eisai tora"
/// diladi xekinane apo miden ftanoun 1 alla kai pali me ta final stamatas
/// </summary>
//this method performs a bersenhaam algorithm like traversal of the "neutral" grid using a linesegment.
//until it hits with an obstacle reporting the ray's/segment's parameter at the point of entering and leaving it
public static Geometry.Ray_Test_Result Trace_Line(LineSegment ls, Geometry.Ray_Test_Mode mode)
{
var direction = ls.end - ls.start;
if (mode == Geometry.Ray_Test_Mode.Line)
{
throw new Exception();
}
Grid_Query_Counter.Counter++;
var grid = GELib.Managers.Spatial_Partitioning_Management.main_spatial_grid.neutral;// grids[(int)Col_Slot.Neutral];
var cell_size = World_Info.Collision_Cellsize;
var cell_coords_start = Spatial.Grid_Func.Grid_Coords(ls.start, cell_size);
Spatial.Grid_Coord cell_coords_end;
cell_coords_end = Spatial.Grid_Func.Grid_Coords(ls.end, cell_size);
var i = cell_coords_start.col;
var j = cell_coords_start.row;
var final_i = cell_coords_end.col;
var final_j = cell_coords_end.row;
var y_manh_dist_inv = direction.Y == 0 ? Single.MaxValue : (float)1 / Math.Abs(direction.Y);
var x_manh_dist_inv = direction.X == 0 ? Single.MaxValue : (float)1 / Math.Abs(direction.X);
//an to cell afxanei -1,0,1 kathos proxoras analoga pou koitas
int di = ((ls.start.X < ls.end.X) ? 1 : ((ls.start.X > ls.end.X) ? -1 : 0));
int dj = ((ls.start.Y < ls.end.Y) ? 1 : ((ls.start.Y > ls.end.Y) ? -1 : 0));
//se ti posostioso ton manh_dist xekinises,
//xekinises oxi h arxiki timi pou einai miden
//alla ta t deixnoun "to epomeno toixaki"
//kai mallon me ta midenika sta di pou vazo pio pano ktl h idea einai oti
//den tha peraseis dyo tixakia mias sintetagmenis seri
//ex ou kai h anisotita sto for(;;)
var tx = (ls.start.X > ls.end.X ? ls.start.X - (i * cell_size) : (i + 1) * cell_size - ls.start.X) * x_manh_dist_inv;
var ty = (ls.start.Y > ls.end.Y ? ls.start.Y - (j * cell_size) : (j + 1) * cell_size - ls.start.Y) * y_manh_dist_inv;
//ta vimata pou kaneis sthn timi tou tx kathos proxoras
var dtx = cell_size * x_manh_dist_inv;
var dty = cell_size * y_manh_dist_inv;
while (true)
{
var aa = grid.getBucket(i, j);
Geometry.Ray_Test_Result Min = new Geometry.Ray_Test_Result(); Min.enter = Single.MaxValue;
for (int ib = 0; ib < aa.Count; ib++)
{
var g_obj = aa[ib];
if (g_obj.g.Last_Query >= Grid_Query_Counter.Counter || g_obj.col != i || g_obj.row != j)
{
continue;
}
g_obj.g.Last_Query = Grid_Query_Counter.Counter;
var collidable = g_obj.g.Coll;
if (collidable.RTII == RTI.Firing || collidable.RTII == RTI.Just_A_Triangle || collidable.RTII == RTI.Chain_Rectangle)
{
continue;
}
var obb = collidable.OBB;
var inner_res = Geometry_Func.TestOBBLine(obb, ls, mode);
if (inner_res.Did_It_Hit)
{
if (inner_res.enter < Min.enter)
{
Min = inner_res;
last_trace = obb;
}
}
}
if (Min.enter != Single.MaxValue)
{
return(Min);
}
if (tx <= ty)
{ // tx smallest, step in x
if (i == final_i)
{
break;
}
tx += dtx;
i += di;
}
else
{ // ty smallest, step in y
if (j == final_j)
{
break;
}
ty += dty;
j += dj;
}
}
var res = new Geometry.Ray_Test_Result(); res.Did_It_Hit = false;
return(res);
}