fix RGBUnboundedSpectrum

src/main/java/eu/jonahbauer/raytracing/render/spectrum/RGBUnboundedSpectrum.java

@@ -15,7 +15,7 @@ public final class RGBUnboundedSpectrum implements Spectrum {
         }
         var max = Math.max(rgb.r(), Math.max(rgb.g(), rgb.b()));
         this.scale = 2 * max;
-        this.polynomial = cs.toSpectrum(scale == 0 ? rgb.div(scale) : ColorRGB.BLACK);
+        this.polynomial = cs.toSpectrum(scale != 0 ? rgb.div(scale) : ColorRGB.BLACK);
     }
 
     @Override