void Game::HandleAI(float msecs)
{
// Run AI for computer planes
for (int i = activePlayers_; i < TotalPlayers(); i ++)
{
// Bail if it's dying or stalled. We're not allowing sniping while stalling, the
// bots are just too good a shot
Plane *current = &players_[i];
if (current->IsDying() || current->IsStalled())
continue;
// Find the closets enemy plane
Plane *target = NULL;
float currentRange = 9999;
for (int j = 0; j < TotalPlayers(); j ++)
{
if (j == i) // Can't target self
continue;
// We're currently ignoring respawning players. May remove this later to make
// the AI more aggressive
if (currentRange > current->GetPosition().Distance(players_[j].GetPosition())
&& !players_[j].IsDying() && !players_[j].IsStalled() && !players_[j].IsInvincible())
{
target = &players_[j];
currentRange = current->GetPosition().Distance(target->GetPosition());
}
}
if (target == NULL) // Level off if we don't have a target
{
float targetAngle = 0;
if (targetAngle > current->GetRotation())
current->TurnLeft(msecs);
else
current->TurnRight(msecs);
}
else
{
// Plot an intercept course!
Vector2 currentPosition = current->GetPosition();
Vector2 targetPosition = target->GetPosition();
Vector2 interceptPoint = Vector2::CollisionPoint(currentPosition, current->GetVelocity(), targetPosition, target->GetVelocity());
// If the target is running parallel to us, go for them
//if (interceptPoint.x == 0 && interceptPoint.y == 0)
// interceptPoint = targetPosition;
// If the target is in front of us, try and lead it
// Calculate time for bullet to reach intercept point
Vector2 bulletStartPos = currentPosition + current->GetVelocity().Normalise() * (20 + MAX_SPEED + 0.5f);
float bulletTravelTime = (bulletStartPos - interceptPoint).Length() / BULLET_SPEED;
// Calculate target position at that time
Vector2 projectedTargetPos = targetPosition + (target->GetVelocity() * bulletTravelTime);
// Decide if it's worth a shot
if (interceptPoint.Distance(projectedTargetPos) < 20)
{
Bullet *bullet = current->Fire();
if (bullet != NULL)
bullets_.push_back(bullet);
}
// Don't play chicken
// TODO: Turn away from collisions
// Don't derp
// TODO: Don't run into the ground
// Attempt to maneuver for a better shot
Vector2 currentVelocity = current->GetVelocity().Normalise();
Vector2 targetVelocity = (currentPosition - projectedTargetPos).Normalise();
float diffAngle = currentVelocity.Cross(targetVelocity);
if (diffAngle < 0)
current->TurnLeft(msecs);
else
current->TurnRight(msecs);
if (DEBUG_RENDERER)
{
glBegin(GL_QUADS);
glColor3f(0, 0, 0);
glVertex2f(interceptPoint.x - 2, interceptPoint.y - 2);
glVertex2f(interceptPoint.x + 2, interceptPoint.y - 2);
glVertex2f(interceptPoint.x + 2, interceptPoint.y + 2);
glVertex2f(interceptPoint.x - 2, interceptPoint.y + 2);
glEnd();
glBegin(GL_QUADS);
glColor3f(1, 0, 1);
glVertex2f(projectedTargetPos.x - 15, projectedTargetPos.y - 15);
glVertex2f(projectedTargetPos.x + 15, projectedTargetPos.y - 15);
glVertex2f(projectedTargetPos.x + 15, projectedTargetPos.y + 15);
glVertex2f(projectedTargetPos.x - 15, projectedTargetPos.y + 15);
glEnd();
}
}
}
}
//----------------------------------------------------------------------------
bool Mgc::SeparatePointSets2D (int iQuantity0, const Vector2* akVertex0,
int iQuantity1, const Vector2* akVertex1, Line2& rkSeprLine)
{
// construct convex hull of point set 0
ConvexHull2D kHull0(iQuantity0,akVertex0);
kHull0.ByDivideAndConquer();
int iEdgeQuantity0 = kHull0.GetQuantity();
const int* aiEdge0 = kHull0.GetIndices();
// construct convex hull of point set 1
ConvexHull2D kHull1(iQuantity1,akVertex1);
kHull1.ByDivideAndConquer();
int iEdgeQuantity1 = kHull1.GetQuantity();
const int* aiEdge1 = kHull1.GetIndices();
// test edges of hull 0 for possible separation of points
int j0, j1, iI0, iI1, iSide0, iSide1;
Vector2 kDiff;
for (j1 = 0, j0 = iEdgeQuantity0-1; j1 < iEdgeQuantity0; j0 = j1++)
{
// lookup edge (assert: iI0 != iI1 )
iI0 = aiEdge0[j0];
iI1 = aiEdge0[j1];
// compute potential separating line (assert: (xNor,yNor) != (0,0))
kDiff = akVertex0[iI1] - akVertex0[iI0];
rkSeprLine.Normal() = kDiff.Cross();
rkSeprLine.Constant() = rkSeprLine.Normal().Dot(akVertex0[iI0]);
// determine if hull 1 is on same side of line
iSide1 = OnSameSide(rkSeprLine,iEdgeQuantity1,aiEdge1,akVertex1);
if ( iSide1 )
{
// determine which side of line hull 0 lies
iSide0 = WhichSide(rkSeprLine,iEdgeQuantity0,aiEdge0,akVertex0);
if ( iSide0*iSide1 <= 0 ) // line separates hulls
return true;
}
}
// test edges of hull 1 for possible separation of points
for (j1 = 0, j0 = iEdgeQuantity1-1; j1 < iEdgeQuantity1; j0 = j1++)
{
// lookup edge (assert: iI0 != iI1 )
iI0 = aiEdge1[j0];
iI1 = aiEdge1[j1];
// compute perpendicular to edge (assert: (xNor,yNor) != (0,0))
kDiff = akVertex1[iI1] - akVertex1[iI0];
rkSeprLine.Normal() = kDiff.Cross();
rkSeprLine.Constant() = rkSeprLine.Normal().Dot(akVertex1[iI0]);
// determine if hull 0 is on same side of line
iSide0 = OnSameSide(rkSeprLine,iEdgeQuantity0,aiEdge0,akVertex0);
if ( iSide0 )
{
// determine which side of line hull 1 lies
iSide1 = WhichSide(rkSeprLine,iEdgeQuantity1,aiEdge1,akVertex1);
if ( iSide0*iSide1 <= 0 ) // line separates hulls
return true;
}
}
return false;
}