bool Eagle::ShouldWeShoot(RobotState ourRobotState, RobotState enemyRobotState, Vector2 ballPos)
{
// In simplistic terms, we should shoot if we're close enough to the goal,
// we've got the ball, and there is clear line-of-sight to goal
Vector2 goalPosition;
if (m_pitchSide == eLeftSide)
{
goalPosition = GoalCentrePosition(eRightSide);
}
else
{
goalPosition = GoalCentrePosition(eLeftSide);
}
Vector2 ourRobotPos = ourRobotState.Position();
const float angleThresh = M_PI_4;
float distToGoal = ourRobotState.Position().Distance(&goalPosition);
// Ian reckons this should be 1/4 of the pitch, but I'm living dangerously and have gone for 1/3.
float distanceThreshold = KICKING_THRESHOLD * m_pitchSizeX;
// Commenting this out now - we need to account for the ball being invisible.
//bool weHaveBall = DoWeHaveBall(ourRobotState, ballPos);
bool closeToGoal = distToGoal < distanceThreshold;
// Check that the enemy robot isn't obstructing the ball.
bool isGoalClear = false;
float angleToGoal = fmod(ourRobotPos.GetAngleTo(&goalPosition), 2*M_PI);
float ourOrientation = fmod(ourRobotState.Orientation(), 2*M_PI);
float angleDifference = fmod(fabs(angleToGoal - ourOrientation), 2*M_PI);
//bool isFacingGoal = (angleDifference < angleThresh) || (angleDifference > (2*M_PI) - angleThresh);
// Check if we're facing somewhere into the goal.
// Extrapolate to the goal-line position we're facing.
float extrapolatedYCoord = ourRobotPos.Y() + (ourRobotPos.Gradient(&ballPos) * (goalPosition.X() - ourRobotPos.X()));
// The goal is in the middle of the pitch, constituting half its length.
float goalTop = 0.75 * m_pitchSizeY;
float goalBottom = 0.25 * m_pitchSizeY;
bool isFacingGoal = (extrapolatedYCoord >= goalBottom) && (extrapolatedYCoord <= goalTop);
// The position we're aiming for.
Vector2 goalTarget(m_pitchSizeX, extrapolatedYCoord);
if (!m_intersection.LineCircleIntersection(ourRobotPos, goalTarget, enemyRobotState.Position(), ROBOT_RADIUS))
{
isGoalClear = true;
}
if (closeToGoal && isGoalClear && isFacingGoal)
{
return true;
}
return false;
}
/*!
* Identify the target state that we wish the robot to be in. This will be the target which the A* algorithm plots towards.
*/
RobotState Eagle::IdentifyTarget(RobotState &ourRobotState, RobotState &enemyRobotState, Vector2 ballPos, bool doWeHaveBall, bool &isMovingToBall)
{
RobotState targetState;
Vector2 ourRobotPos = ourRobotState.Position();
Vector2 enemyRobotPos = enemyRobotState.Position();
Vector2 ourGoalCentre = GoalCentrePosition(m_pitchSide);
Vector2 enemyGoalCentre;
if (m_pitchSide == eLeftSide)
{
enemyGoalCentre = GoalCentrePosition(eRightSide);
}
else
{
enemyGoalCentre = GoalCentrePosition(eLeftSide);
}
ballPos.Clamp(Vector2(0,0), Vector2(m_pitchSizeX-1, m_pitchSizeY-1));
isMovingToBall = false;
// doWeHaveBall is a value which comes from the robot's rotational sensors.
//ourRobotState.SetHasBall(doWeHaveBall);
ourRobotState.SetHasBall(DoesRobotHaveBall(ourRobotState, ballPos));
enemyRobotState.SetHasBall(DoesRobotHaveBall(enemyRobotState, ballPos));
if (m_state == ePenaltyAttack)
{
m_isKickingPosSet = false;
// When taking a penalty, we want to find a free position to kick to.
// Position should stay the same - we only want to re-orientate.
targetState.SetPosition(ourRobotPos);
// We'll do this by checking for intersections between us and three positions on the goal line.
Vector2 targetPositions[3];
targetPositions[0] = enemyGoalCentre;
targetPositions[1] = enemyGoalCentre - Vector2(0,50);
targetPositions[2] = enemyGoalCentre + Vector2(0,50);
int arrayLength = sizeof(targetPositions)/sizeof(Vector2);
Vector2 optimalShootingTarget;
float bestDistanceFromEnemy = 0;
// Iterate through the positions, finding the best one, based on if it's unblocked and how far it is from the enemy robot.
for (int i=0; i < arrayLength; i++)
{
// Check if the target is unblocked.
bool isBlocked = m_intersection.LineCircleIntersection(ourRobotPos, targetPositions[i], enemyRobotPos, ROBOT_RADIUS);
if (isBlocked)
{
continue;
}
float distanceSqdToEnemy = enemyRobotPos.DistanceSquared(&targetPositions[i]);
// Check if this beats our previous best distance.
if (distanceSqdToEnemy > bestDistanceFromEnemy)
{
bestDistanceFromEnemy = distanceSqdToEnemy;
optimalShootingTarget = targetPositions[i];
}
// Check that we do actually have a target set.
if (optimalShootingTarget.IsSet())
{
float angleToTarget = ourRobotPos.GetAngleTo(&optimalShootingTarget);
targetState.SetOrientation(angleToTarget);
}
else
{
targetState.SetOrientation(ourRobotState.Orientation());
}
}
}
else if (m_state == ePenaltyDefend)
{
m_isKickingPosSet = false;
// When defending, we're permitted to move up and down the goalline.
// Orientation should stay the same.
targetState.SetOrientation(ourRobotState.Orientation());
// X-axis position should be the same, y-axis should be a position extrapolated in the direction of the enemy robot.
//float extrapolationGradient = tan(enemyRobotState.Orientation());
// I'm experimenting with extrapolating on a line between the robot and ball instead.
float extrapolationGradient = enemyRobotPos.Gradient(&ballPos);
int extrapolatedY = enemyRobotPos.Y() + ((ourRobotPos.X() - enemyRobotPos.X()) * extrapolationGradient);
Vector2 proposedPosition(ourRobotPos.X(), extrapolatedY);
proposedPosition.Clamp(Vector2(0,0), Vector2(m_pitchSizeX-1, m_pitchSizeY-1));
targetState.SetPosition(proposedPosition);
}
else
{
// If we're here, assume we're in open play.
if (!ourRobotState.HasBall())
{
m_isKickingPosSet = false;
// Check if the enemy robot has the ball.
if (enemyRobotState.HasBall())
{
if (m_pitchSide == eLeftSide)
{
targetState.SetPosition(ourGoalCentre.X() + 50, ourGoalCentre.Y());
targetState.SetOrientation(0);
}
else
{
targetState.SetPosition(ourGoalCentre.X() - 50, ourGoalCentre.Y());
targetState.SetOrientation(M_PI);
}
}
else
{
// If we don't have the ball, the aim should be to move to the ball.
isMovingToBall = true;
targetState.SetPosition(ballPos);
if (m_pitchSide == eLeftSide)
{
targetState.SetOrientation(0);
}
else
{
targetState.SetOrientation(M_PI);
}
}
}
else
{
// Check if the previously calculated target pos is appropriate or if we need to recalc.
if ((m_isKickingPosSet) && ((m_kickingPos.Distance(&ourRobotPos) < 30) || (m_kickingPos.Distance(&enemyRobotPos) < 40)))
{
m_isKickingPosSet = false;
}
if (!m_isKickingPosSet)
{
// If we have the ball, let's move to a more appropriate place.
// This is done regardless of whether we're shooting or not.
/*
This should depend on:
1. The opposite half of the pitch to the enemy robot.
2. Within the kicking threshold.
3. Fairly central, but outside of the enemy robot's radius
4. Orientated towards the goal
*/
bool isEnemyOnBottomSide;
// Determine which half of the pitch the enemy robot is on.
if (enemyRobotState.Position().Y() < m_pitchSizeY/2)
{
isEnemyOnBottomSide = true;
}
else
{
isEnemyOnBottomSide = false;
}
// Determine where the kicking threshold is for this side of the pitch.
float kickingPositionX;
float kickingPositionY;
if (m_pitchSide == eLeftSide)
{
kickingPositionX = m_pitchSizeX - ((KICKING_THRESHOLD/2)*m_pitchSizeX);
}
else
{
kickingPositionX = (KICKING_THRESHOLD/2)*m_pitchSizeX;
}
if (isEnemyOnBottomSide)
{
kickingPositionY = m_pitchSizeY/2 + 80;
}
else
{
kickingPositionY = m_pitchSizeY/2 - 80;
}
// Check if the position is within two robot radii of the enemy.
Vector2 proposedPosition = Vector2(kickingPositionX,kickingPositionY);
// Check if the proposed position is too close to the enemy robot to be used.
if (proposedPosition.Distance(&enemyRobotPos) < 2*ROBOT_RADIUS)
{
float adjustedYPosition;
if (isEnemyOnBottomSide)
{
adjustedYPosition = proposedPosition.Y() + 2*ROBOT_RADIUS;
}
else
{
adjustedYPosition = proposedPosition.Y() - 2*ROBOT_RADIUS;
}
proposedPosition = Vector2( proposedPosition.X(), adjustedYPosition);
}
proposedPosition.Clamp(Vector2(0,0), Vector2(m_pitchSizeX-1, m_pitchSizeY-1));
m_kickingPos = proposedPosition;
m_isKickingPosSet = true;
}
targetState.SetPosition(m_kickingPos);
// We'll do this by checking for intersections between us and three positions on the goal line.
Vector2 targetPositions[3];
targetPositions[0] = enemyGoalCentre;
targetPositions[1] = enemyGoalCentre - Vector2(0,50);
targetPositions[2] = enemyGoalCentre + Vector2(0,50);
int arrayLength = sizeof(targetPositions)/sizeof(Vector2);
Vector2 optimalShootingTarget;
float bestDistanceFromEnemy = 0;
// Iterate through the positions, finding the best one, based on if it's unblocked and how far it is from the enemy robot.
for (int i=0; i < arrayLength; i++)
{
// Check if the target is unblocked.
bool isBlocked = m_intersection.LineCircleIntersection(m_kickingPos, targetPositions[i], enemyRobotPos, ROBOT_RADIUS);
if (isBlocked)
{
continue;
}
float distanceSqdToEnemy = enemyRobotPos.DistanceSquared(&targetPositions[i]);
// Check if this beats our previous best distance.
if (distanceSqdToEnemy > bestDistanceFromEnemy)
{
bestDistanceFromEnemy = distanceSqdToEnemy;
optimalShootingTarget = targetPositions[i];
}
// Check that we do actually have a target set.
if (optimalShootingTarget.IsSet())
{
float angleToTarget = m_kickingPos.GetAngleTo(&optimalShootingTarget);
targetState.SetOrientation(angleToTarget);
}
else
{
targetState.SetOrientation(ourRobotState.Orientation());
}
}
}
targetState.SetPosition((int)targetState.Position().X(), (int)targetState.Position().Y());
}
return targetState;
}