double p = pow(l % r * (b > 0), 99);

var p:Double = pow(l % r * (if (b > 0) 1.0 else 0.0), 99.0)

import java.io
import java.io.{Writer, PrintWriter, OutputStream, FileOutputStream}
import java.lang.Math._

object CardRaytracer(out_:OutputStream,width_:Int,height_:Int) {

    val WIDTH       = 512
    val HEIGHT      = 512
    val SUB_SAMPLES = 64

    var width  = WIDTH
    var height = HEIGHT

    def out:Writer

    // .................................................. bla-bla ...................

    def this(out_:OutputStream,width_:Int, height_:Int) {
        this.width  = width_
        this.height = height_
        this.out    = out_
    }

    def this(out_:OutputStream) {
        this.out = out_;
    }

    def main(args: Array[String]): Unit = {
        def begin = System.currentTimeMillis();
        if (args.length == 0) {
            new CardRaytracer(System.out).process();
            System.err.printf("Elapsed time : %d sec\n",(System.currentTimeMillis()-begin)/1000);
            System.exit(1);
        } else if (args.length == 1) {
            def os = new FileOutputStream(args(0));
            new CardRaytracer(os).process();
            os.close();
            System.err.printf("Elapsed time : %d sec\n", (System.currentTimeMillis() - begin) / 1000);
            System.exit(2);
        } else if (args.length == 3) {
            def os = new FileOutputStream(args(0));
            new CardRaytracer(os, valueOf(args(1)), valueOf(args(2))).process();
            os.close();
            System.err.printf("Elapsed time : %d sec\n", (System.currentTimeMillis() - begin) / 1000);
            System.exit(2);
        }
        System.exit(0);
    }

}

Error:(61, 21) traits or objects may not have parameters
object CardRaytracer(out_:OutputStream,width_:Int,height_:Int) {
                    ^

$ scala\CardRaytracer.scala:180: error: overloaded method value printf with alternatives:

  (x$1: java.util.Locale,x$2: String,x$3: Object*)java.io.PrintWriter <and>
  (x$1: String,x$2: Object*)java.io.PrintWriter
 cannot be applied to (String, Int, Int)
        wr.printf("P6 %d %d 255 ", width, height)
           ^