private Color DiffuseShading(SinglePoint interscetionPoint, SinglePoint lightPoint)
{
//Unit normal vector
normalVector.X = (interscetionPoint.x - this.sampleSphere.Center.x) / this.sampleSphere.Radius;
normalVector.Y = (interscetionPoint.y - this.sampleSphere.Center.y) / this.sampleSphere.Radius;
normalVector.Z = (interscetionPoint.z - this.sampleSphere.Center.z) / this.sampleSphere.Radius;
//Vector from normal to the Light
lightVector.X = (lightPoint.x - interscetionPoint.x);// / Math.Abs(lightPoint.x - interscetionPoint.x);
lightVector.Y = (lightPoint.y - interscetionPoint.y);// / Math.Abs(lightPoint.y - interscetionPoint.y);
lightVector.Z = (lightPoint.z - interscetionPoint.z);// / Math.Abs(lightPoint.z - interscetionPoint.z);
lightVector.Normalize();
//constants
double kd = 0.8;
double ka = 0.2;
double fctr = Vector3D.DotProduct(normalVector, lightVector);
Color resultColor = new Color();
resultColor.R = (byte)(ka * this.sampleSphere.R + kd * fctr * this.sampleSphere.R);
resultColor.G = (byte)(ka * this.sampleSphere.G + kd * fctr * this.sampleSphere.G);
resultColor.B = (byte)(ka * this.sampleSphere.B + kd * fctr * this.sampleSphere.B);
resultColor.A = 1;
return resultColor;
}
private void ShiftCoordinates(ref SinglePoint p)
{
p.x += this.canvasWidth / 2;
p.y += this.canvasHeight / 2;
}
/* A sphere is given by its center (cx, cy, cz), its radius R, and its color (SR, SG, SB).
* line segment (ray) is given by its endpoints: P0 = (x0, y0, z0) and P1 = (x1, y1, z1).
* To find visible spheres, set P0 = viewer’s coordinates, VP = (VPx, VPy, VPz) and let P1 run through
* all the points (x1, y1, 0) where (x1, y1) is a pixel in the display area.
*
*/
private void SphereInterscetionCheck(SinglePoint p0, SinglePoint p1)
{
lightPoint.x = 0;
lightPoint.y = 50;
lightPoint.z = 0;
//p1.z = (double)Math.Sqrt(Math.Pow(p0.x - p1.x, 2) + Math.Pow(p0.y - p1.y, 2) + Math.Pow(p0.z - p1.z, 2));
dx = p1.x - p0.x;
dy = p1.y - p0.y;
dz = p1.z - p0.z;
a = dx * dx + dy * dy + dz * dz;
b = 2 * dx * (p0.x - this.sampleSphere.Center.x) + 2 * dy * (p0.y - this.sampleSphere.Center.y) + 2 * dz * (p0.z - this.sampleSphere.Center.z);
c = this.sampleSphere.Center.x * this.sampleSphere.Center.x + this.sampleSphere.Center.y * this.sampleSphere.Center.y
+ this.sampleSphere.Center.z * this.sampleSphere.Center.z + p0.x * p0.x + p0.y * p0.y + p0.z * p0.z
- 2 * (this.sampleSphere.Center.x * p0.x + this.sampleSphere.Center.y * p0.y + this.sampleSphere.Center.z * p0.z)
- this.sampleSphere.Radius * this.sampleSphere.Radius;
delta = b * b - 4 * a * c;
t = (-b - Math.Sqrt(delta)) / (2 * a);
SinglePoint diffuseShadingPoint = new SinglePoint { x = p0.x + t * dx, y = p0.y + t * dy, z = p0.z + t * dz };
pointsOfIntersection.Add(diffuseShadingPoint);
if (delta < 0) {
DrawPixel((p0.x + t * dx), (p0.y + t * dy), Colors.Black, 1);
} else if (delta == 0) {
//DrawPixel((int)p1.x, (int)p1.y, this.sampleSphere.SpehereColor, 1);
//this.grid.Add(new PointToCheck { x = (int)p1.x, y = (int)p1.y });
//DrawPixel((p0.x + t * dx), (p0.y + t * dy), Colors.Green, 1);
//this.grid.Add(new PointToCheck { x = (p0.x + t * dx), y = (p0.y + t * dy), delta = delta });
DrawPixel((p0.x + t * dx), (p0.y + t * dy), DiffuseShading(diffuseShadingPoint, lightPoint), 1);
this.grid.Add(new PointToCheck { x = (p0.x + t * dx), y = (p0.y + t * dy), delta = delta });
} else {
//DrawPixel((int)p1.x, (int)p1.y, this.sampleSphere.SpehereColor, 1);
//this.grid.Add(new PointToCheck { x = (int)p1.x, y = (int)p1.y });
//DrawPixel((p0.x + t * dx), (p0.y + t * dy), Colors.Red, 1);
//this.grid.Add(new PointToCheck { x = (p0.x + t * dx), y = (p0.y + t * dy), delta = delta });
DrawPixel((p0.x + t * dx), (p0.y + t * dy), DiffuseShading(diffuseShadingPoint, lightPoint), 1);
this.grid.Add(new PointToCheck { x = (p0.x + t * dx), y = (p0.y + t * dy), delta = delta });
}
}
private Color PhongIllumination(SinglePoint pointOfInterscetion, Vector3D normalVector)
{
vectorN = normalVector;
vectorL = lightVector;
vectorR.X = (this.sampleSphere.Center.x - pointOfInterscetion.x);
vectorR.Y = (this.sampleSphere.Center.y - pointOfInterscetion.y);
vectorR.Z = (this.sampleSphere.Center.z - pointOfInterscetion.z);
vectorV = -vectorR;
return new Color();
}
