Creating the Full No Tanks! Game - The Essential Guide to Flash Games - page 298

}else {
difference = 0;
}

checkCol = predator.currCol;
checkRow = predator.currRow;

for (differenceCtr = 0; differenceCtr <= difference; differenceCtr++) {
checkCol += testDX;
checkRow += testDY;

if (checkCol < 0 || checkCol == mapColumnCount) {
break;
//trace("col hit border");

}else if (checkRow < 0 || checkRow == mapRowCount) {
break;
//trace("row hit border");

}else if (tileSheetData[levelTileMap[checkRow][checkCol]] == TILE_WALL) {
//trace("hit wall");
break;

}else if (checkCol == player.currCol && checkRow == player.currRow) {
//if predator is facing the player then fire
if (predator.rotation == testRotation) {
fireMissileAtPlayer(predator);
}
break;

}else {
//trace("hit nothing");
}
}
}
}

//** end added in iteration #6
These are the main points in the checkLineOfSight function:

1. The predator and prey are passed in just as they are in the chaseObject function.

2. If the predator and the prey are already in the same region , the local act variable is

set to true to force the later code to test line of sight.

3. If the predator and prey are not in the same region, the enemyIntel value is used to

decide whether the predator object will test line of sight against the prey . The act
variable is set to true if they share the same region or if the random generated value
is less than enemyIntel ). Also, the predator is rotated toward the prey , so it looks
smart and the player can tell it is working.

4. If act is true, we first check to see of the predator and prey are in the same column. If

so, we set the local difference variable to be the absolute value of the difference