/* sniper */ /* strategy: since a scan of the entire battlefield can be done in 90 */ /* degrees from a corner, sniper can scan the field quickly. */ /* external variables, that can be used by any function */ int corner; /* current corner 0, 1, 2, or 2 */ int c1x, c1y; /* corner 1 x and y */ int c2x, c2y; /* " 2 " " " */ int c3x, c3y; /* " 3 " " " */ int c4x, c4y; /* " 4 " " " */ int s1, s2, s3, s4; /* starting scan position for corner 1 - 4 */ int sc; /* current scan start */ int d; /* last damage check */ /* main */ main() { int closest; /* check for targets in range */ int range; /* range to target */ int dir; /* scan direction */ /* initialize the corner info */ /* x and y location of a corner, and starting scan degree */ c1x = 10; c1y = 10; s1 = 0; c2x = 10; c2y = 990; s2 = 270; c3x = 990; c3y = 990; s3 = 180; c4x = 990; c4y = 10; s4 = 90; closest = 9999; new_corner(); /* start at a random corner */ d = damage(); /* get current damage */ dir = sc; /* starting scan direction */ while (1) { /* loop is executed forever */ while (dir < sc + 90) { /* scan through 90 degree range */ range = scan(dir,1); /* look at a direction */ if (range <= 700 && range > 0) { while (range > 0) { /* keep firing while in range */ closest = range; /* set closest flag */ cannon(dir,range); /* fire! */ range = scan(dir,1); /* check target again */ if (d + 15 > damage()) /* sustained several hits, */ range = 0; /* goto new corner */ } dir -= 10; /* back up scan, in case */ } dir += 2; /* increment scan */ if (d != damage()) { /* check for damage incurred */ new_corner(); /* we're hit, move now */ d = damage(); dir = sc; } } if (closest == 9999) { /* check for any targets in range */ new_corner(); /* nothing, move to new corner */ d = damage(); dir = sc; } else /* targets in range, resume */ dir = sc; closest = 9999; } } /* end of main */ /* new corner function to move to a different corner */ new_corner() { int x, y; int angle; int new; new = rand(4); /* pick a random corner */ if (new == corner) /* but make it different than the */ corner = (new + 1) % 4;/* current corner */ else corner = new; if (corner == 0) { /* set new x,y and scan start */ x = c1x; y = c1y; sc = s1; } if (corner == 1) { x = c2x; y = c2y; sc = s2; } if (corner == 2) { x = c3x; y = c3y; sc = s3; } if (corner == 3) { x = c4x; y = c4y; sc = s4; } /* find the heading we need to get to the desired corner */ angle = plot_course(x,y); /* start drive train, full speed */ drive(angle,100); /* keep traveling until we are within 100 meters */ /* speed is checked in case we run into wall, other robot */ /* not terribly great, since were are doing nothing while moving */ while (distance(loc_x(),loc_y(),x,y) > 100 && speed() > 0) ; /* cut speed, and creep the rest of the way */ drive(angle,20); while (distance(loc_x(),loc_y(),x,y) > 10 && speed() > 0) ; /* stop drive, should coast in the rest of the way */ drive(angle,0); } /* end of new_corner */ /* classical pythagorean distance formula */ distance(x1,y1,x2,y2) int x1; int y1; int x2; int y2; { int x, y; x = x1 - x2; y = y1 - y2; d = sqrt((x*x) + (y*y)); return(d); } /* plot course function, return degree heading to */ /* reach destination x, y; uses atan() trig function */ plot_course(xx,yy) int xx, yy; { int d; int x,y; int scale; int curx, cury; scale = 100000; /* scale for trig functions */ curx = loc_x(); /* get current location */ cury = loc_y(); x = curx - xx; y = cury - yy; /* atan only returns -90 to +90, so figure out how to use */ /* the atan() value */ if (x == 0) { /* x is zero, we either move due north or south */ if (yy > cury) d = 90; /* north */ else d = 270; /* south */ } else { if (yy < cury) { if (xx > curx) d = 360 + atan((scale * y) / x); /* south-east, quadrant 4 */ else d = 180 + atan((scale * y) / x); /* south-west, quadrant 3 */ } else { if (xx > curx) d = atan((scale * y) / x); /* north-east, quadrant 1 */ else d = 180 + atan((scale * y) / x); /* north-west, quadrant 2 */ } } return (d); }