AI: aiming towards a moving target

Posted on 21 February 2023 14:22 by alv90

I would like to show a possible solution that I worked on for the aiming towards a moving target problem. Let P be the player, E the enemy, S the shot. P shoots towards E, but in the meantime E may be moved.

Let’s put ourselves in the reference system of P and consider polar coordinates. Let’s calculate the normal velocity of E against P. Let’s assume that the distance between P and E is constant over time.

We can compute the time that S takes to reach E from P. Then, we can use this time to compute the new angle of E against P.

In this way, we are able to make a rough prevision of where E will be when it will be reached by S. P just needs to shoot S in that direction.

Enjoy!

// argument0: P
// argument1: E
// argument2: shot speed

var vx_rel=argument1.vx-argument0.vx;
var vy_rel=argument1.vy-argument0.vy;

var radius=point_distance(argument0.x,argument0.y,argument1.x,argument1.y);
var ang=point_direction(argument0.x,argument0.y,argument1.x,argument1.y);

var time=radius/argument2;

var m=point_distance(0,0,vx_rel,vy_rel);
var d=point_direction(0,0,vx_rel,vy_rel);
d-=ang;
var vt=m*sin_deg(d);

var corr=(vt*time)/radius;

var ang2=ang+radtodeg(corr);
var xColl=argument0.x+radius*cos_deg(ang2);
var yColl=argument0.y-radius*sin_deg(ang2);

var ar;
ar[0]=ang2;
ar[1]=time;
ar[2]=xColl;
ar[3]=yColl;
return ar;

// argument0: P

// argument1: E

// argument2: shot speed

var vx_rel=argument1.vx-argument0.vx;

var vy_rel=argument1.vy-argument0.vy;

var radius=point_distance(argument0.x,argument0.y,argument1.x,argument1.y);

var ang=point_direction(argument0.x,argument0.y,argument1.x,argument1.y);

var time=radius/argument2;

var m=point_distance(0,0,vx_rel,vy_rel);

var d=point_direction(0,0,vx_rel,vy_rel);

d-=ang;

var vt=m*sin_deg(d);

var corr=(vt*time)/radius;

var ang2=ang+radtodeg(corr);

var xColl=argument0.x+radius*cos_deg(ang2);

var yColl=argument0.y-radius*sin_deg(ang2);

var ar;

ar[0]=ang2;

ar[1]=time;

ar[2]=xColl;

ar[3]=yColl;

return ar;

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