public void render(Interval interval)
{
// Screen variables
int[] row = new int[interval.width * (interval.yto - interval.yfrom)];
int pixCounter = 0; //iterator
// Rendering variables
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();
// Header for .ppm file
// System.out.println("P3");
// System.out.println(width + " " + height);
// System.out.println("255");
// All loops are reversed for 'speedup' (cf. thinking in java p331)
// For each line
for (y = interval.yfrom; y < interval.yto; y++)
{
ylen = (double)(2.0 * y) / (double)interval.width - 1.0;
// System.out.println("Doing line " + y);
// For each pixel of the line
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;
// RGB values for .ppm file
// System.out.println(red + " " + green + " " + blue);
// Sets the pixels
row[pixCounter++] = alpha | (red << 16) | (green << 8) | (blue);
} // end for (x)
} // end for (y)
}
public static void Main()
{
RayTracer rt = new RayTracer();
// create the objects to be rendered
rt.scene = rt.createScene();
// get lights, objects etc. from scene.
rt.setScene(rt.scene);
// Set interval to be rendered to the whole picture
// (overkill, but will be useful to retain this for parallel versions)
Interval interval = new Interval(0, rt.width, rt.height, 0, rt.height, 1);
// Do the business!
rt.render(interval);
}