// Bresenham's line algorithm
public void DrawLine(Triangle triangle, Vertex from, Vertex to)
{
Color lineColor = Color.RoyalBlue;
int d, dx, dy, ai, bi, xi, yi;
int x1 = from.projectionX, y1 = from.projectionY, x2 = to.projectionX, y2 = to.projectionY;
int x = x1, y = y1;
// ustalenie kierunku rysowania
dx = Math.Abs(x2 - x1);
xi = Math.Sign(x2 - x1);
dy = Math.Abs(y2 - y1);
yi = Math.Sign(y2 - y1);
// pierwszy piksel
SetPixel(triangle, x, y, lineColor);
// oś wiodąca OX
if (dx > dy)
{
ai = (dy - dx) * 2;
bi = dy * 2;
d = bi - dx;
// pętla po kolejnych x
while (x != x2)
{
// test współczynnika
if (d >= 0)
{
x += xi;
y += yi;
d += ai;
}
else
{
d += bi;
x += xi;
}
SetPixel(triangle, x, y, lineColor);
}
}
// oś wiodąca OY
else
{
ai = (dx - dy) * 2;
bi = dx * 2;
d = bi - dy;
// pętla po kolejnych y
while (y != y2)
{
// test współczynnika
if (d >= 0)
{
x += xi;
y += yi;
d += ai;
}
else
{
d += bi;
y += yi;
}
SetPixel(triangle, x, y, lineColor);
}
}
}
public void Fill(IModel model, Triangle triangle)
{
var indexes = triangle.GetSortedIndexes();
var AET = new List <AETNode>();
int k = 0;
Vector <double> N = null;
Color constantColor = Color.Empty;
Color[] gouraudColors = null;
if (model is Cuboid)
{
N = (model as Cuboid).N(triangle);
}
switch (shaderType)
{
case ShaderType.Constant:
{
var coordinates = Vector <double> .Build.Dense(new double[3]
{
(triangle.points[0].worldX + triangle.points[1].worldX + triangle.points[2].worldX) / 3.0,
(triangle.points[0].worldY + triangle.points[1].worldY + triangle.points[2].worldY) / 3.0,
(triangle.points[0].worldZ + triangle.points[1].worldZ + triangle.points[2].worldZ) / 3.0
});
N = triangle.InterpolateN(0.333, 0.333, 0.333);
constantColor = ColorCalculation.Phong(coordinates, N, model.Color);
break;
}
case ShaderType.Gouraud:
{
gouraudColors = new Color[3]
{
ColorCalculation.Phong(triangle.points[0], model.Color),
ColorCalculation.Phong(triangle.points[1], model.Color),
ColorCalculation.Phong(triangle.points[2], model.Color)
};
break;
}
}
int lowerBound = triangle.points[indexes[0]].projectionY;
int upperBound = triangle.points[indexes[2]].projectionY >= canvas.Height ? canvas.Height - 1 : triangle.points[indexes[2]].projectionY;
if (lowerBound < 0)
{
if (upperBound < 0)
{
return;
}
lowerBound = 0;
AET.Add(new AETNode(triangle.points[indexes[2]], triangle.points[indexes[0]]));
if (triangle.points[indexes[1]].projectionY < 0)
{
AET.Add(new AETNode(triangle.points[indexes[1]], triangle.points[indexes[2]]));
k = 2;
}
else
{
AET.Add(new AETNode(triangle.points[indexes[0]], triangle.points[indexes[1]]));
k = 1;
}
foreach (var aetNode in AET)
{
aetNode.x += aetNode.xd * -aetNode.p1.projectionY;
}
AET.Sort((p1, p2) => (int)(p1.x - p2.x));
}
for (int y = lowerBound; y <= upperBound; y++)
{
while (triangle.points[indexes[k]].projectionY == y - 1)
{
var prev = triangle.points[Triangle.Prev(indexes[k])];
var current = triangle.points[indexes[k]];
var next = triangle.points[Triangle.Next(indexes[k])];
if (prev.projectionY > current.projectionY)
{
AET.Add(new AETNode(prev, current));
}
else
{
AET.RemoveAll(aetn => aetn.p2.projectionY == current.projectionY);
}
if (next.projectionY > current.projectionY)
{
AET.Add(new AETNode(current, next));
}
else
{
AET.RemoveAll(aetn => aetn.p2.projectionY == current.projectionY);
}
k++;
}
if (AET.Count > 0 && AET[1].x < AET[0].x)
{
AET.Add(AET[0]);
AET.RemoveAt(0);
}
for (int i = 0; i < AET.Count; i += 2)
{
int xLowerBound = (int)AET[i].x >= 0 ? (int)AET[i].x : 0;
int xUpperBound = (int)Math.Round(AET[i + 1].x) < canvas.Width ? (int)Math.Round(AET[i + 1].x) : canvas.Width;
for (int x = xLowerBound; x < xUpperBound; x++)
{
double w0, w1, w2;
(w0, w1, w2) = triangle.GetWeights(x, y);
double z = triangle.Z(w0, w1, w2);
if (z >= zBuffor[x, y])
{
zBuffor[x, y] = z;
switch (shaderType)
{
case ShaderType.Constant:
canvas.SetPixel(x, y, constantColor);
break;
case ShaderType.Gouraud:
Color gouraudColor = ColorCalculation.Gouraud(gouraudColors, w0, w1, w2);
canvas.SetPixel(x, y, gouraudColor);
break;
case ShaderType.Phong:
N = triangle.InterpolateN(w0, w1, w2);
Color phongColor = ColorCalculation.Phong(triangle.InterpolateXYZ(w0, w1, w2), N, model.Color);
canvas.SetPixel(x, y, phongColor);
break;
}
}
}
}
foreach (var aetn in AET)
{
aetn.x += aetn.xd;
}
}
if (drawTriangleEdges)
{
DrawLine(triangle, triangle.points[0], triangle.points[1]);
DrawLine(triangle, triangle.points[0], triangle.points[2]);
DrawLine(triangle, triangle.points[1], triangle.points[2]);
}
}
