public void SetPixel(int x, int y, MyColor color)
{
if (x >= m_Width || y >= m_Height)
{
return;
}
Color setColor = Color.FromArgb(color.R, color.G, color.B);
m_FrameBuffer.SetPixel(x, y, setColor);
}
private void DrawSpansBetweenEdges(Edge e1, Edge e2)
{
// calculate difference between the y coordinates
// of the first edge and return if 0
float e1ydiff = (float)(e1.Y2 - e1.Y1);
if (e1ydiff == 0.0f)
{
return;
}
// calculate difference between the y coordinates
// of the second edge and return if 0
float e2ydiff = (float)(e2.Y2 - e2.Y1);
if (e2ydiff == 0.0f)
{
return;
}
// calculate differences between the x coordinates
// and colors of the points of the edges
float e1xdiff = (float)(e1.X2 - e1.X1);
float e2xdiff = (float)(e2.X2 - e2.X1);
MyColor e1colordiff = e1.Color2 - e1.Color1;
MyColor e2colordiff = e2.Color2 - e2.Color1;
// calculate factors to use for interpolation
// with the edges and the step values to increase
// them by after drawing each span
float factor1 = (float)(e2.Y1 - e1.Y1) / e1ydiff;
float factorStep1 = 1.0f / e1ydiff;
float factor2 = 0.0f;
float factorStep2 = 1.0f / e2ydiff;
// loop through the lines between the edges and draw spans
for (int y = e2.Y1; y < e2.Y2; y++)
{
// create and draw span
Span span = new Span(e1.Color1 + (e1colordiff * factor1),
e1.X1 + (int)(e1xdiff * factor1),
e2.Color1 + (e2colordiff * factor2),
e2.X1 + (int)(e2xdiff * factor2)
);
DrawSpan(span, y);
// increase factors
factor1 += factorStep1;
factor2 += factorStep2;
}
}
public Span(MyColor color1, int x1, MyColor color2, int x2)
{
if (x1 < x2)
{
Color1 = color1;
X1 = x1;
Color2 = color2;
X2 = x2;
}
else
{
Color1 = color2;
X1 = x2;
Color2 = color1;
X2 = x1;
}
}
public Edge(MyColor color1, int x1, int y1, MyColor color2, int x2, int y2)
{
if (y1 < y2)
{
Color1 = color1;
X1 = x1;
Y1 = y1;
Color2 = color2;
X2 = x2;
Y2 = y2;
}
else
{
Color1 = color2;
X1 = x2;
Y1 = y2;
Color2 = color1;
X2 = x1;
Y2 = y1;
}
}
private void DrawSpan(Span span, int y)
{
int xdiff = span.X2 - span.X1;
if (xdiff == 0)
{
return;
}
MyColor colordiff = span.Color2 - span.Color1;
float factor = 0.0f;
float factorStep = 1.0f / (float)xdiff;
// draw each pixel in the span
for (int x = span.X1; x < span.X2; x++)
{
SetPixel(x, y, span.Color1 + (colordiff * factor));
factor += factorStep;
}
}
public void DrawLine(MyColor color1, float x1, float y1, MyColor color2, float x2, float y2)
{
float xdiff = (x2 - x1);
float ydiff = (y2 - y1);
if (xdiff == 0.0f && ydiff == 0.0f)
{
SetPixel((int)x1, (int)y1, color1);
return;
}
if (Math.Abs(xdiff) > Math.Abs(ydiff))
{
float xmin, xmax;
// set xmin to the lower x value given
// and xmax to the higher value
if (x1 < x2)
{
xmin = x1;
xmax = x2;
}
else
{
xmin = x2;
xmax = x1;
}
// draw line in terms of y slope
float slope = ydiff / xdiff;
for (float x = xmin; x <= xmax; x += 1.0f)
{
float y = y1 + ((x - x1) * slope);
MyColor color = color1 + ((color2 - color1) * ((x - x1) / xdiff));
SetPixel((int)x, (int)y, color);
}
}
else
{
float ymin, ymax;
// set ymin to the lower y value given
// and ymax to the higher value
if (y1 < y2)
{
ymin = y1;
ymax = y2;
}
else
{
ymin = y2;
ymax = y1;
}
// draw line in terms of x slope
float slope = xdiff / ydiff;
for (float y = ymin; y <= ymax; y += 1.0f)
{
float x = x1 + ((y - y1) * slope);
MyColor color = color1 + ((color2 - color1) * ((y - y1) / ydiff));
SetPixel((int)x, (int)y, color);
}
}
}
public Span(MyColor color1, int x1, MyColor color2, int x2)
{
if (x1 < x2)
{
Color1 = color1;
X1 = x1;
Color2 = color2;
X2 = x2;
}
else
{
Color1 = color2;
X1 = x2;
Color2 = color1;
X2 = x1;
}
}
public Edge(MyColor color1, int x1, int y1, MyColor color2, int x2, int y2)
{
if (y1 < y2)
{
Color1 = color1;
X1 = x1;
Y1 = y1;
Color2 = color2;
X2 = x2;
Y2 = y2;
}
else
{
Color1 = color2;
X1 = x2;
Y1 = y2;
Color2 = color1;
X2 = x1;
Y2 = y1;
}
}
public void SetPixel(int x, int y, MyColor color)
{
if (x >= m_Width || y >= m_Height)
return;
Color setColor = Color.FromArgb(color.R, color.G, color.B);
m_FrameBuffer.SetPixel(x, y, setColor);
}
public void DrawTriangle(Color color1, float x1, float y1, Color color2, float x2, float y2, Color color3, float x3, float y3)
{
// create edges for the triangle
Edge[] edges = new Edge[3];
MyColor Mycolor1 = new MyColor(color1);
MyColor Mycolor2 = new MyColor(color2);
MyColor Mycolor3 = new MyColor(color3);
edges[0] = new Edge(Mycolor1, (int)x1, (int)y1, Mycolor2, (int)x2, (int)y2);
edges[1] = new Edge(Mycolor2, (int)x2, (int)y2, Mycolor3, (int)x3, (int)y3);
edges[2] = new Edge(Mycolor3, (int)x3, (int)y3, Mycolor1, (int)x1, (int)y1);
int maxLength = 0;
int longEdge = 0;
// find edge with the greatest length in the y axis
for(int i = 0; i < 3; i++)
{
int length = edges[i].Y2 - edges[i].Y1;
if(length > maxLength)
{
maxLength = length;
longEdge = i;
}
}
int shortEdge1 = (longEdge + 1) % 3;
int shortEdge2 = (longEdge + 2) % 3;
// draw spans between edges; the long edge can be drawn
// with the shorter edges to draw the full triangle
DrawSpansBetweenEdges(edges[longEdge], edges[shortEdge1]);
DrawSpansBetweenEdges(edges[longEdge], edges[shortEdge2]);
}
public void DrawLine(MyColor color1, float x1, float y1, MyColor color2, float x2, float y2)
{
float xdiff = (x2 - x1);
float ydiff = (y2 - y1);
if (xdiff == 0.0f && ydiff == 0.0f)
{
SetPixel((int)x1, (int)y1, color1);
return;
}
if (Math.Abs(xdiff) > Math.Abs(ydiff))
{
float xmin, xmax;
// set xmin to the lower x value given
// and xmax to the higher value
if (x1 < x2)
{
xmin = x1;
xmax = x2;
}
else
{
xmin = x2;
xmax = x1;
}
// draw line in terms of y slope
float slope = ydiff / xdiff;
for (float x = xmin; x <= xmax; x += 1.0f)
{
float y = y1 + ((x - x1) * slope);
MyColor color = color1 + ((color2 - color1) * ((x - x1) / xdiff));
SetPixel((int)x, (int)y, color);
}
}
else
{
float ymin, ymax;
// set ymin to the lower y value given
// and ymax to the higher value
if (y1 < y2)
{
ymin = y1;
ymax = y2;
}
else
{
ymin = y2;
ymax = y1;
}
// draw line in terms of x slope
float slope = xdiff / ydiff;
for (float y = ymin; y <= ymax; y += 1.0f)
{
float x = x1 + ((y - y1) * slope);
MyColor color = color1 + ((color2 - color1) * ((y - y1) / ydiff));
SetPixel((int)x, (int)y, color);
}
}
}
