private bool GetPolygen(My3DPolygon PG)
{
int d;
int i = 0;
do
{
d = (int)((PG.Points[i].X - PG.Points[i + 2].X) * (PG.Points[i].Y - PG.Points[i + 1].Y)
- (PG.Points[i].X - PG.Points[i + 1].X) * (PG.Points[i].Y - PG.Points[i + 2].Y));
i++;
} while (d == 0 || i + 2 < PG.number);
if (d != 0)
{
i--;
A = ((PG.Points[i].Z - PG.Points[i + 2].Z) * (PG.Points[i].Y - PG.Points[i + 1].Y)
- (PG.Points[i].Z - PG.Points[i + 1].Z) * (PG.Points[i].Y - PG.Points[i + 2].Y)) / d;
B = ((PG.Points[i].Z - PG.Points[i + 1].Z) * (PG.Points[i].X - PG.Points[i + 2].X)
- (PG.Points[i].Z - PG.Points[i + 2].Z) * (PG.Points[i].X - PG.Points[i + 1].X)) / d;
C = PG.Points[i].Z - A * PG.Points[i].X - B * PG.Points[i].Y;
return(true);
}
else
{
return(false);
}
}
private void ZBufferPolygon(My3DPolygon PG, double[,] Z)
{
if (!GetPolygen(PG))
{
return;
}
Point[] g1 = new Point[100];
EdgeInfo[] edgelist = new EdgeInfo[100];
int j = 0, yu = 0, yd = 1024;
for (int i = 0; i < PG.number; i++)
{
g1[i].X = (int)(PG.Points[i].X + 0.5);
g1[i].Y = (int)(PG.Points[i].Y + 0.5);
}
g1[PG.number].X = (int)(PG.Points[0].X + 0.5);
g1[PG.number].Y = (int)(PG.Points[0].Y + 0.5);
for (int i = 0; i < PG.number; i++)
{
if (g1[i].Y > yu)
{
yu = g1[i].Y;
}
if (g1[i].Y < yd)
{
yd = g1[i].Y;
}
if (g1[i].Y != g1[i + 1].Y)
{
if (g1[i].Y > g1[i + 1].Y)
{
edgelist[j++] = new EdgeInfo(g1[i + 1].X, g1[i + 1].Y, g1[i].X, g1[i].Y);
}
else
{
edgelist[j++] = new EdgeInfo(g1[i].X, g1[i].Y, g1[i + 1].X, g1[i + 1].Y);
}
}
}
Graphics g = CreateGraphics();
for (int y = yd; y < yu; y++)
{
var sorted =
from item in edgelist
where y < item.YMax && y >= item.YMin
orderby item.XMin, item.K
select item;
int flag = 0;
foreach (var item in sorted)
{
if (flag == 0)
{
FirstX = (int)(item.XMin + 0.5);
flag++;
}
else
{
Pen p = new Pen(PG.pcolor);
for (int x = FirstX; x < (int)(item.XMin + 0.5); x++)
{
double z = A * x + B * y + C;
if (z > Z[x, y])
{
Z[x, y] = z;
g.DrawRectangle(p, x, y, 1, 1);
}
}
flag = 0;
}
}
for (int i = 0; i < j; i++)
{
if (y < edgelist[i].YMax - 1 && y > edgelist[i].YMin)
{
edgelist[i].XMin += edgelist[i].K;
}
}
}
}
