public void Draw1(int w, int h, Matrix3D projection,
Mesh mesh,
Action <int, int, int> setFacePixel,
Action <int, int, int> setEdgePixel
)
{
for (var fi = 0; fi < mesh.Indices.Count; ++fi)
{
var face = mesh.Indices[fi];
if (face.Count < 3)
{
continue; // nothing to draw
}
// check normal
var v0 = projection * mesh.Points[face[0]];
var v1 = projection * mesh.Points[face[1]];
var v2 = projection * mesh.Points[face[2]];
if (Vector3D.Cross(v0 - v1, v2 - v1).Z < 0)
{
continue;
}
// projected points
var ppts = new List <Vector3D>();
for (var i = 0; i < face.Count; ++i)
{
ppts.Add(projection * mesh.Points[face[i]]);
}
ppts.Add(ppts[0]); // double up on last one
// draw filled polygon
// get min, max y
int minY = int.MaxValue, maxY = int.MinValue;
foreach (var pt in ppts)
{
minY = Math.Min(minY, (int)pt.Y);
maxY = Math.Max(maxY, (int)pt.Y);
}
// space for left, right ends
var left = new int[maxY - minY + 1];
var right = new int[maxY - minY + 1];
// initialize them
for (var i = 0; i < left.Length; ++i)
{
left[i] = int.MaxValue;
right[i] = int.MinValue;
}
// now walk all edges, setting left and right at each y value
for (var i = 0; i < ppts.Count - 1; ++i)
{
var p1 = ppts[i];
var p2 = ppts[i + 1];
int x1 = (int)p1.X, y1 = (int)p1.Y;
int x2 = (int)p2.X, y2 = (int)p2.Y;
DDA.Compute(x1, y1, x2, y2, (x, y) =>
{
left[y - minY] = Math.Min(left[y - minY], x);
right[y - minY] = Math.Max(right[y - minY], x);
}
);
}
// now walk and fill
var color = mesh.FaceColors[fi];
for (var j = 0; j < left.Length; ++j)
{
for (var i = left[j]; i <= right[j]; ++i)
{
setFacePixel(i, j + minY, fi);
}
}
// draw wireframe
for (var i = 0; i < ppts.Count - 1; ++i)
{
var p1 = ppts[i];
var p2 = ppts[i + 1];
int x1 = (int)p1.X, y1 = (int)p1.Y;
int x2 = (int)p2.X, y2 = (int)p2.Y;
Draw.Line(x1, y1, x2, y2, (i1, j1) => setEdgePixel(i1, j1, fi));
}
}
}
public static void Line(int x1, int y1, int x2, int y2, Action <int, int> setPixel)
{
DDA.Compute(x1, y1, x2, y2, (x, y) => setPixel(x, y));
}