/**
 * to see
 * By Raphael Rouvinov-Kats
 * 
 * Quick thang for pie point inter6tion
 **/

var player_x = 200, player_y = 200;
var object_x = 300, object_y = 300;
var player_r = 5, object_r = 5;
var inertia = 0.99; // [0,1] tendency to stay at place

var viewing_dist = 125;
var viewing_angle = 20;
var player_orientation = 0;

var draw = function() {
    // draw bg
    background(255, 255, 255);
    
    // draw orientation
    stroke(0, 0, 0, 0100);
    fill(255, 234, 0);
    arc(player_x, player_y, 
        viewing_dist*2, viewing_dist*2, 
        -viewing_angle/2 + player_orientation, viewing_angle/2 + player_orientation);
    
    // draw player
    stroke(0, 0, 0);
    fill(58, 135, 74);
    ellipse(player_x, player_y, player_r*2, player_r*2);
    
    // draw object, show stroke only if in viewing angle and distance
    var object_visible = false;
    var d = dist(player_x, player_y, object_x, object_y) - object_r;
    var a = atan2(object_y - player_y, object_x - player_x);
    if (d < viewing_dist) {
        if (abs(a - player_orientation) < viewing_angle/2 + atan(object_r/dist(player_x, player_y, object_x, object_y))) {
            object_visible = true;
        }
    }
    stroke(0, 0, 0, object_visible ? 255 : 0);
    fill(255, 0, 0);
    ellipse(object_x, object_y, object_r*2, object_r*2);
    
    // move player to mouse if mouse isn't already where player is
    if (dist(player_x, player_y, mouseX, mouseY) > player_r) {
        var old_player_x = player_x;
        var old_player_y = player_y;
        player_x = player_x*inertia + mouseX*(1-inertia);
        player_y = player_y*inertia + mouseY*(1-inertia);
        
        // update orientation
        player_orientation = atan2(player_y-old_player_y, player_x-old_player_x);
    }
};