public class rt extends PixApplet {
public double focalLength = 3;
public final static int X = 0;
public final static int Y = 1;
public final static int Z = 2;
public final static int R = 3;
public final static int RED = 4;
public final static int GREEN = 5;
public final static int BLUE = 6;
public double[][] spheres;
public double[][] lights;
private booolean printlog = false;
public rt () {
super();
spheres = new double[10][7];
for(int i=0;i<spheres.length;i++){
spheres[i][0] = 5*(Math.random()-0.5);
spheres[i][1] = 5*(Math.random()-0.5);
spheres[i][2] = -30*(Math.random()+2);
spheres[i][3] = Math.random() * 3;
spheres[i][4] = Math.random();
spheres[i][5] = Math.random();
spheres[i][6] = Math.random();
}
lights = new double[5][6];
for(int i=0;i<lights.length;i++){
lights[i][0] = Math.random()*100;
lights[i][1] = Math.random()*100;
lights[i][2] = Math.random()*100;
lights[i][3] = Math.random();
lights[i][4] = Math.random();
lights[i][5] = Math.random();
}
}
// print log
public void log(String s){
if(printlog)
System.out.println(s);
}
// trace a ray
public void rayTrace(double[] v, double[] w, double[] rgb){
double t = 100000.0; // <--- infinity :-)
double[] obj = null;
double[] s = null;
double t1,t2;
double[] tmp = {0,0,0};
for(int i=0;i<spheres.length;i++){
s = spheres[i];
double A = dotProduct(w,w);
vectorSubtract(v,s,tmp);
double B = 2.0 * dotProduct(tmp,w);
double C = dotProduct(tmp,tmp) - s[R]*s[R];
// did we miss the sphere?
double b24ac = B*B - 4.0*A*C;
if(b24ac <= 0)
continue;
double sq_b24ac = Math.sqrt(b24ac);
t1 = -B - sq_b24ac/(2.0*A);
// is sphere in front of the ray?
if(t1 > 0 && t1 < t){
t = t1;
obj = s;
}
}
if(obj == null){
rgb[0] = 0.5; // 0.5*Math.cos(w[0]*Math.PI/2.0);
rgb[1] = 0.5; // 0.5*Math.cos(w[1]*Math.PI/2.0);
rgb[2] = 0.5; // 0.5*Math.cos(w[2]*Math.PI/2.0);
return;
}
// Compute surface point S = v + tw
double[] S = {
v[0]+t*w[0],
v[1]+t*w[1],
v[2]+t*w[2],
};
// Compute surface normal n = (S-[cx,cy,cz])/r
double[] n = {
(S[X]-obj[X])/obj[R],
(S[Y]-obj[Y])/obj[R],
(S[Z]-obj[Z])/obj[R],
};
vectorNormalize(n,n);
// Compute reflection vector R = -2(w * n)n + w
double wn = dotProduct(w,n);
//double wn = dotProduct(new double[]{1,0,0},n);
double[] R = {
-2 * wn * n[X] + w[X],
-2 * wn * n[Y] + w[Y],
-2 * wn * n[Z] + w[Z],
};
vectorNormalize(R,R);
//Ambientcolor + SUMi ( LightColori * ( Diffusecolor * max(0,Li.n) + Specularcolor * (max(0,Hi.e)p ) )
// Hi = 2(Li . n) n - Li
// Create reflected ray with v = (S+eR) and w = R.
double[] Rv = {
S[X] + 0.02 * R[X],
S[Y] + 0.02 * R[Y],
S[Z] + 0.02 * R[Z],
};
rayTrace(Rv,R,rgb);
rgb[0] = (0.4 * (1.0 - obj[RED])) + ((0.6) * rgb[0]) * wn;
rgb[1] = (0.4 * (1.0 - obj[GREEN])) + ((0.6) * rgb[1]) * wn;
rgb[2] = (0.4 * (1.0 - obj[BLUE])) + ((0.6) * rgb[2]) * wn;
/*
rgb[0] = rgb[0] * obj[RED];
rgb[1] = rgb[1] * obj[GREEN];
rgb[2] = rgb[2] * obj[BLUE];
*/
}
/**
* SET PIXELS FOR THIS ANIMATION FRAME
* (THIS OVERRIDES A METHOD IN PIXAPPLET CLASS)
*/
public void setPix(int frame) {
double[] rgb = new double[]{0,0,0};
double[] v = new double[]{0,0,0};
double[] w = new double[]{0,0,0};
v[0] = 0;
v[1] = 0; // CAMERA EYEPOINT IS AT THE ORIGIN
v[2] = 0;
int n = 0;
for (int j = 0 ; j < H ; j++) // LOOP OVER IMAGE ROWS
for (int i = 0 ; i < W ; i++) { // LOOP OVER IMAGE COLUMNS
w[0] = (double)(i - W/2) / W; // COMPUTE RAY DIRECTION AT EACH PIXEL
w[1] = (double)(H/2 - j) / W; //
w[2] = -focalLength; // PLACE IMAGE PLANE AT z = -focalLength
vectorNormalize(w,w);
rayTrace(v, w, rgb); // RAY TRACE AT THIS PIXEL
pix[n++] = pack(
(int)(255 * rgb[0]),
(int)(255 * rgb[1]),
(int)(255 * rgb[2]));
}
}
/**
* given 2 points, find their difference
*/
void vectorSubtract (double[] va, double[] vb, double[] out){
out[0] = va[0]-vb[0];
out[1] = va[1]-vb[1];
out[2] = va[2]-vb[2];
}
/**
* cross product of two vectors
*/
void crossProduct(double[] v1, double[] v2, double[] cross ) {
cross[0] = v1[1]*v2[2] - v1[2]*v2[1];
cross[1] = v1[2]*v2[0] - v1[0]*v2[2];
cross[2] = v1[0]*v2[1] - v1[1]*v2[0];
}
/**
* normalize
*/
double vectorNormalize(double[] in, double[] out ) {
double length, ilength;
length = Math.sqrt(in[0]*in[0] + in[1]*in[1] + in[2]*in[2]);
if (length == 0){
return 0;
}
ilength = 1.0/length;
out[0] = in[0]*ilength;
out[1] = in[1]*ilength;
out[2] = in[2]*ilength;
return length;
}
/**
* dot product
*/
double dotProduct (double[] v1, double[] v2){
return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}
public boolean keyUp(java.awt.Event e,int key){
System.out.println("key: "+key);
if(key == 'a')
spheres[0][2]-=0.1;
if(key == 'z')
spheres[0][2]+=0.1;
if(key == 'f')
focalLength-=0.1;
if(key == 'v')
focalLength+=0.1;
damage = true;
return true;
}
}