Open source

js/codes/contributions/draivins_can_move.js

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+function can_move(map, cur_x, cur_y, target_x, target_y) {
+    var x_lines = map.x_lines || [];
+    var y_lines = map.y_lines || [];
+
+    var min_x = min(cur_x, target_x);
+    var max_x = max(cur_x, target_x);
+    var min_y = min(cur_y, target_y);
+    var max_y = max(cur_y, target_y);
+
+    var dx = target_x - cur_x;
+    var dy = target_y - cur_y;
+
+    var dydx = dy / (dx + EPS);
+    var dxdy = 1 / dydx;
+
+    for (var i = 0; i < x_lines.length; i++) {
+        var line = x_lines[i];
+        var line_x = line[0];
+        if (max_x < line_x || min_x > line_x || max_y < line[1] || min_y > line[2]) {
+            continue;
+        }
+
+        var y_intersect = cur_y + (line_x - cur_x) * dydx;
+
+        if (y_intersect < line[1] || y_intersect > line[2]) {
+            continue;
+        }
+
+        return false;
+    }
+
+    for (var i = 0; i < y_lines.length; i++) {
+        var line = y_lines[i];
+        var line_y = line[0];
+        if (max_y < line_y || min_y > line_y || max_x < line[1] || min_x > line[2]) {
+            continue;
+        }
+
+        var x_intersect = cur_x + (line_y - cur_y) * dxdy;
+
+        if (x_intersect < line[1] || x_intersect > line[2]) {
+            continue;
+        }
+
+        return false;
+    }
+
+    return true;
+}