/**
* Returns the angle in degrees between the two vectors
*/
kmScalar kmVec2DegreesBetween(const kmVec2* v1, const kmVec2* v2) {
if(kmVec2AreEqual(v1, v2)) {
return 0.0;
}
kmVec2 t1, t2;
kmVec2Normalize(&t1, v1);
kmVec2Normalize(&t2, v2);
kmScalar cross = kmVec2Cross(&t1, &t2);
kmScalar dot = kmVec2Dot(&t1, &t2);
/*
* acos is only defined for -1 to 1. Outside the range we
* get NaN even if that's just because of a floating point error
* so we clamp to the -1 - 1 range
*/
if(dot > 1.0) dot = 1.0;
if(dot < -1.0) dot = -1.0;
return kmRadiansToDegrees(atan2(cross, dot));
}
void calculate_line_normal(kmVec2 p1, kmVec2 p2, kmVec2 other_point, kmVec2* normal_out) {
/*
A = (3,4)
B = (2,1)
C = (1,3)
AB = (2,1) - (3,4) = (-1,-3)
AC = (1,3) - (3,4) = (-2,-1)
N = n(AB) = (-3,1)
D = dot(N,AC) = 6 + -1 = 5
since D > 0:
N = -N = (3,-1)
*/
kmVec2 edge, other_edge;
kmScalar d;
kmVec2 n;
kmVec2Subtract(&edge, &p2, &p1);
kmVec2Subtract(&other_edge, &other_point, &p1);
kmVec2Normalize(&edge, &edge);
kmVec2Normalize(&other_edge, &other_edge);
n.x = edge.y;
n.y = -edge.x;
d = kmVec2Dot(&n, &other_edge);
if(d > 0.0f) {
n.x = -n.x;
n.y = -n.y;
}
normal_out->x = n.x;
normal_out->y = n.y;
kmVec2Normalize(normal_out, normal_out);
}
void BattleManagerScreen::onEntityEffectEvent( CCObject* e )
{
GameEntityEffectEvt* evt = dynamic_cast<GameEntityEffectEvt*>(e);
if(!evt) return;
if( evt->name.compare("Death Grip") == 0 ) {
CCLog("death grip");
kmVec2 pOrigin;
kmVec2 pTarget;
if( !GetEntityPosition(evt->origin, pOrigin) || !GetEntityPosition(evt->target, pTarget) )
{
CCLog("aborting death grip evt due to invalid target(s)");
}
kmVec2 toTarget;
kmVec2Subtract(&toTarget, &pTarget, &pOrigin);
kmVec2 u_toTarget;
kmVec2Normalize(&u_toTarget, &toTarget);
float leashDistance = 1; //one game unit
kmVec2 dv;
kmVec2Scale(&dv, &u_toTarget, leashDistance );
kmVec2 posEnd;
kmVec2Add(&posEnd, &pOrigin, &dv);
//convert back to screen coordinates
kmVec2Scale(&posEnd, &posEnd, VIEW_UNIT_CONVERSION);
GameEntityView* tView = getViewForEntity(evt->target);
tView->setPosition(posEnd.x, posEnd.y);
}
}
void BattleManagerScreen::enemyMovementAI( int enemyIdx, float dt )
{
float speed = 75.0f; //5 pixels/sec
EntityPair& enemy = m_enemies[enemyIdx];
std::vector<kmVec2> impulses; //x, y
std::vector<float> impulseWeights;
//TODO: select from closest player
EntityPair& player = m_players[0];
CCSize eSize = enemy.view->getContentSize();
CCPoint ePos = enemy.view->getPosition();
ePos.x += eSize.width/2;
ePos.y += eSize.height/2; //convert to center origin
CCSize pSize = player.view->getContentSize();
CCPoint pPos = player.view->getPosition();
pPos.x += pSize.width/2;
pPos.y += pSize.height/2; //convert to center origin
float playerLeash = pSize.width * 1.1f;
float playerLeashSq = playerLeash*playerLeash;
//impulse towards the player
kmVec2 toPlayer = { pPos.x - ePos.x, pPos.y - ePos.y };
kmVec2 u_toPlayer;
kmVec2Normalize( &u_toPlayer, &toPlayer);
if( kmVec2LengthSq( &toPlayer ) < (playerLeashSq * 0.75f) )
{
//impulse away from player (too close)
kmVec2 u_fromPlayer;
kmVec2Scale(&u_fromPlayer, &u_toPlayer, -1*0.75f); //flip the 'to player' vector
impulses.push_back(u_fromPlayer);
impulseWeights.push_back(100); //vastly overweigh the impulse to the player
}else {
if( kmVec2LengthSq(&toPlayer) > playerLeashSq )
{
//kmVec2Scale(&u_toPlayer, &u_toPlayer, 0.51f);
//impulse towards player
impulses.push_back(u_toPlayer);
impulseWeights.push_back(100);
}
}
//add impulses away from other enemies
for( int i=0; i< m_enemies.size(); i++) {
if( i == enemyIdx ) continue;
CCSize nSize = m_enemies[i].view->getContentSize();
CCPoint nPos = m_enemies[i].view->getPosition();
nPos.x += nSize.width/2;
nPos.y += nSize.height/2;
kmVec2 toNeighbor = { nPos.x - ePos.x, nPos.y - ePos.y };
float neighborLeash = nSize.width;
if( kmVec2LengthSq(&toNeighbor) < neighborLeash * neighborLeash ) {
kmVec2 u_toNeighbor;
kmVec2Normalize(&u_toNeighbor, &toNeighbor);
kmVec2 u_fromNeighbor;
kmVec2Scale(&u_fromNeighbor, &u_toNeighbor, -1);
impulses.push_back(u_fromNeighbor);
impulseWeights.push_back(50);
}
}
if( impulses.size() == 0 ) return;
//blend impulses
kmVec2 finalImpulse = impulses[0]; //zero always valid because its the impulse to the player
float finalImpulseWeight = impulseWeights[0];
for( int i=1; i< impulses.size(); i++) {
float w1 = finalImpulseWeight;
float w2 = impulseWeights[i];
float wTot = w1 + w2;
kmVec2 blend;
blend.x = (finalImpulse.x * w1 / wTot) + (impulses[i].x * w2 / wTot);
blend.y = (finalImpulse.y * w1 / wTot) + (impulses[i].y * w2 / wTot);
//run-length summation
finalImpulseWeight = wTot;
finalImpulse = blend;
}
kmVec2 scaledImpulse;
kmVec2Scale(&scaledImpulse, &finalImpulse, speed * dt);
//CCLog("impulse %.4f", kmVec2Length(& finalImpulse));
if( kmVec2Length(& finalImpulse) < (0.5f) )
{
//CCLog("ignore impulse %.4f", kmVec2Length(& finalImpulse));
return; //ignore very small changes to avoid leash jitter
}
ePos.x += scaledImpulse.x;
ePos.y += scaledImpulse.y;
ePos.x -= eSize.width/2;
ePos.y -= eSize.height/2; //back to original anchor coords
enemy.view->setPosition(ePos);
}
