+
+static int getAngleFromTouchDelta(int dx, int dy)
+{
+ double pi = 3.141592653;
+ double rad = atan2((double)-dy, (double)dx);
+ double rad2 = (rad < 0 ? rad + 2 * pi : rad);
+ double deg = rad2 * 180.0 / pi;
+
+ return (int)(deg * 16.0 / 360.0 + 0.5) % 16;
+}
+
+int getButtonFromTouchPosition(int x, int y, int dst_mx, int dst_my)
+{
+ // calculate start (source) position to be at the middle of the tile
+ int src_mx = SX + x * TILESIZE_VAR + TILESIZE_VAR / 2;
+ int src_my = SY + y * TILESIZE_VAR + TILESIZE_VAR / 2;
+ int dx = dst_mx - src_mx;
+ int dy = dst_my - src_my;
+ int element;
+ int angle_old = -1;
+ int angle_new = -1;
+ int button = 0;
+ int i;
+
+ if (!IN_LEV_FIELD(x, y))
+ return 0;
+
+ element = Feld[x][y];
+
+ if (!IS_MCDUFFIN(element) &&
+ !IS_LASER(element) &&
+ !IS_MIRROR(element) &&
+ !IS_BEAMER(element) &&
+ !IS_POLAR(element) &&
+ !IS_POLAR_CROSS(element) &&
+ !IS_DF_MIRROR(element) &&
+ !IS_DF_MIRROR_AUTO(element))
+ return 0;
+
+ if (IS_MCDUFFIN(element) ||
+ IS_LASER(element))
+ {
+ angle_old = laser.start_angle;
+ angle_new = (dx > 0 && ABS(dy) < ABS(dx) ? ANG_RAY_RIGHT :
+ dy < 0 && ABS(dx) < ABS(dy) ? ANG_RAY_UP :
+ dx < 0 && ABS(dy) < ABS(dx) ? ANG_RAY_LEFT :
+ dy > 0 && ABS(dx) < ABS(dy) ? ANG_RAY_DOWN :
+ -1);
+ }
+ else
+ {
+ for (i = 0; i < laser.num_damages; i++)
+ {
+ if (laser.damage[i].x == x &&
+ laser.damage[i].y == y &&
+ ObjHit(x, y, HIT_POS_CENTER))
+ {
+ angle_old = laser.damage[i].angle;
+
+ break;
+ }
+ }
+
+ if (angle_old == -1)
+ return 0;
+
+ angle_old = get_mirrored_angle(angle_old, get_element_angle(element));
+ angle_new = getAngleFromTouchDelta(dx, dy);
+ }
+
+ button = (angle_new == angle_old ? 0 :
+ (angle_new - angle_old + 16) % 16 < 8 ? MB_LEFTBUTTON :
+ MB_RIGHTBUTTON);
+
+ return button;
+}