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;
}
/**
* Checks if there is a shadow
* @param r The ray
* @return Returns 1 if there is a shadow, 0 if there isn't
*/
int Shadow (Ray r, double tmax)
{
if (intersect (r, tmax))
return 0;
return 1;
}
bool intersect (Ray r, double maxt)
{
Isect tp;
int i, nhits;
nhits = 0;
inter.t = 1e9;
for (i = 0; i < prim.Length; i++) {
// uses global temporary Prim (tp) as temp.object for speedup
tp = prim [i].intersect (r);
if (tp != null && tp.t < inter.t) {
inter.t = tp.t;
inter.prim = tp.prim;
inter.surf = tp.surf;
inter.enter = tp.enter;
nhits++;
}
}
return nhits > 0 ? true : false;
}
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++;
}
}
}
public abstract Isect intersect (Ray ry);