function raycast(angle,ColumnX,OriginX,OriginY){
//how far to move the ray
var stepX = (cos[angle] * MapSize);  
var stepY = -(sin[angle] * MapSize);
//center point of current block
var rayX=(((OriginX+stepX)>>6)<<6)+(MapSize>>1);
var rayY=(((OriginY+stepY)>>6)<<6)+(MapSize>>1);
//length of the ray
var rayLen=Infinity;

while(1){
  //see whats in the current block
  block=MapPeek(rayX,rayY);
  //if the ray has gone out of bounds then exit
  if(block[0]==OUT_OF_BOUNDS)break
  //if it's hit a wall then...
  else if(block[0]==WALL){
  //get the lines stored within this block
  segments=block[1];
			
  i=0;  //and loop through them
  while(i<segments.length){
    //check an intersection between this line and the ray
    intersection=GetIntersection(OriginX, OriginY, rayX+(stepX), rayY+(stepY), segments[0], segments[1], segments[2], segments[3]);
    //if there was an intersection then..
    if(intersection!=null){
      //see how far away it is
      tmp=(Abs(intersection[0] - OriginX)*abscos[angle]) + (Abs(intersection[1] - OriginY)*abssin[angle]);
      //if it's nearer than the last intersection then keep it
      if(tmp<rayLen)rayLen=tmp;
      }
    i++;
    }
  }
  //if an intersection was found then stop checking
  if(rayLen!=Infinity)break;
    //extend the ray
    rayX+=stepX;
    rayY+=stepY;
}

function cast_through_sector(LINE ray, SECTOR sector) returns nothing    for each wall in sector        intersection = intersect_line(ray, wall)        if intersection then            if wall is portal then                cast_through_sector(ray, wall.portal_sector)            else                length = line_length(ray.point1, intersection)                if length < ray.length then                    ray.length = length                end if            end if        end if    next wallend functionfunction raycast(POINT eye, ANGLE eye_angle, ANGLE fov, INT columns) returns nothing    LINE rays[columns] = create_rays(eye, eye_angle, fov, columns)        for each ray in rays        ray.length = INFINITE        cast_through_sector(ray, eye.current_sector)        ray.length = correct_fish_eye(ray.length, ray.angle)    nextend function