public override Isect intersect(Ray ry)
{
double b, disc, t;
Isect ip;
v.sub2(c, ry.P);
b = Vec.dot(v, ry.D);
disc = b * b - Vec.dot(v, v) + r2;
if (disc < 0.0)
{
return(null);
}
disc = Math.Sqrt(disc);
t = (b - disc < 1e-6) ? b + disc : b - disc;
if (t < 1e-6)
{
return(null);
}
ip = new Isect();
ip.t = t;
ip.enter = Vec.dot(v, v) > r2 + 1e-6 ? 1 : 0;
ip.prim = this;
ip.surf = surf;
return(ip);
}
/**
* Launches a ray
*/
Vec trace(int level, double weight, Ray r)
{
Vec P, N;
bool hit;
// Checks the recursion level
if (level > 6)
{
return(new Vec());
}
hit = intersect(r, 1e6);
if (hit)
{
P = r.point(inter.t);
N = inter.prim.normal(P);
if (Vec.dot(r.D, N) >= 0.0)
{
N.negate();
}
return(shade(level, weight, P, N, r.D, inter));
}
// no intersection --> col = 0,0,0
return(voidVec);
}
/**
* Return the Vector's reflection direction
* @return The specular direction
*/
Vec SpecularDirection(Vec I, Vec N)
{
Vec r;
r = Vec.comb(1.0 / Math.Abs(Vec.dot(I, N)), I, 2.0, N);
r.normalize();
return(r);
}
/**
* Return the Vector's transmission direction
*/
Vec TransDir(Surface m1, Surface m2, Vec I, Vec N)
{
double n1, n2, eta, c1, cs2;
Vec r;
n1 = m1 == null ? 1.0 : m1.ior;
n2 = m2 == null ? 1.0 : m2.ior;
eta = n1 / n2;
c1 = -Vec.dot(I, N);
cs2 = 1.0 - eta * eta * (1.0 - c1 * c1);
if (cs2 < 0.0)
{
return(null);
}
r = Vec.comb(eta, I, eta * c1 - Math.Sqrt(cs2), N);
r.normalize();
return(r);
}
/**
* Returns the shaded color
* @return The color in Vec form (rgb)
*/
Vec shade(int level, double weight, Vec P, Vec N, Vec I, Isect hit)
{
Vec tcol;
Vec R;
double t, diff, spec;
Surface surf;
Vec col;
int l;
col = new Vec();
surf = hit.surf;
R = new Vec();
if (surf.shine > 1e-6)
{
R = SpecularDirection(I, N);
}
// Computes the effectof each light
for (l = 0; l < lights.Length; l++)
{
L.sub2(lights [l].pos, P);
if (Vec.dot(N, L) >= 0.0)
{
t = L.normalize();
tRay.P = P;
tRay.D = L;
// Checks if there is a shadow
if (Shadow(tRay, t) > 0)
{
diff = Vec.dot(N, L) * surf.kd *
lights [l].brightness;
col.adds(diff, surf.color);
if (surf.shine > 1e-6)
{
spec = Vec.dot(R, L);
if (spec > 1e-6)
{
spec = Math.Pow(spec, surf.shine);
col.x += spec;
col.y += spec;
col.z += spec;
}
}
}
}
}
tRay.P = P;
if (surf.ks * weight > 1e-3)
{
tRay.D = SpecularDirection(I, N);
tcol = trace(level + 1, surf.ks * weight, tRay);
col.adds(surf.ks, tcol);
}
if (surf.kt * weight > 1e-3)
{
if (hit.enter > 0)
{
tRay.D = TransDir(null, surf, I, N);
}
else
{
tRay.D = TransDir(surf, null, I, N);
}
tcol = trace(level + 1, surf.kt * weight, tRay);
col.adds(surf.kt, tcol);
}
// garbaging...
tcol = null;
surf = null;
return(col);
}
public void render(Interval interval)
{
int[] row = new int[interval.width * (interval.yto - interval.yfrom)];
int pixCounter = 0; //iterator
int x, y, red, green, blue;
double xlen, ylen;
Vec viewVec;
viewVec = Vec.sub(view.at, view.from);
viewVec.normalize();
Vec tmpVec = new Vec(viewVec);
tmpVec.scale(Vec.dot(view.up, viewVec));
Vec upVec = Vec.sub(view.up, tmpVec);
upVec.normalize();
Vec leftVec = Vec.cross(view.up, viewVec);
leftVec.normalize();
double frustrumwidth = view.dist * Math.Tan(view.angle);
upVec.scale(-frustrumwidth);
leftVec.scale(view.aspect * frustrumwidth);
Ray r = new Ray(view.from, voidVec);
Vec col = new Vec();
// For each line
for (y = interval.yfrom; y < interval.yto; y++)
{
ylen = (double)(2.0 * y) / (double)interval.width - 1.0;
for (x = 0; x < interval.width; x++)
{
xlen = (double)(2.0 * x) / (double)interval.width - 1.0;
r.D = Vec.comb(xlen, leftVec, ylen, upVec);
r.D.add(viewVec);
r.D.normalize();
col = trace(0, 1.0, r);
// computes the color of the ray
red = (int)(col.x * 255.0);
if (red > 255)
{
red = 255;
}
green = (int)(col.y * 255.0);
if (green > 255)
{
green = 255;
}
blue = (int)(col.z * 255.0);
if (blue > 255)
{
blue = 255;
}
checksum += red;
checksum += green;
checksum += blue;
// Sets the pixels
row [pixCounter] = alpha | (red << 16) | (green << 8) | (blue);
pixCounter++;
}
}
}
