// Display checker board background
MaterialCell checkerBackgroundHit(Ray r, HitRecord hit) {
// Find the t value where z = scene.camera.far
hit.t = -scene.camera.far / r.dir.z;
if (hit.t < 0) // Only put it on the background, not behind the camera too
return black;
hit.hitP = r.pointAtParameter(hit.t);
hit.normal = new Double3D(0, 0, 1);
hit.hitP.x = (hit.hitP.x > 0) ? hit.hitP.x : -hit.hitP.x + checkerFreq / 2;
hit.hitP.y = (hit.hitP.y > 0) ? hit.hitP.y : -hit.hitP.y + checkerFreq / 2;
if (hit.hitP.x % checkerFreq < checkerFreq / 2) // && p.x < scene.camera.windowRight)
if (hit.hitP.y % checkerFreq < checkerFreq / 2) // && p.y < scene.camera.windowTop)
return white;
else return black;
else if (hit.hitP.y % checkerFreq < checkerFreq / 2) // && p.y < scene.camera.windowTop)
return black;
else return white;
}
