Getting enemy vehicle to follow player vehicle C++ - c++

Question

I'm currently building a game where the played drives a semi truck and is followed and attacked by enemy cars by attempted slamming. I got some help from one of my teachers on how to get the enemy to choose which direction to go in order to follow and attack the player. Upon implementing what she gave me I got weird behavior and feel like I'm missing something.
When I place an enemy car in game near the player and pass the player's position into the function the enemy car simply spins in circles. If I add velocity to it i drives in large circles. Generally it never chooses a direction to drive straight in.
After debugging it seems like my if statement doesn't ever resolve and upon every update it keeps trying to get back towards 0 but for some reason it can't.
I am not sure if the coordinates of the player are creating the issue or if my math calculations or going wonky.
void EnemySpeedy::playerTracking(float posX, float posY)
{
//Direction choosing
dir.x = posX - pos.x;
dir.y = posY - pos.y;
//plus maybe this?
goalAngle = atan2f(dir.y, dir.x);
//I think this is the problem code?//
if (angle < goalAngle) angle -= sfw::getDeltaTime() * angularSpeed;
else angle += sfw::getDeltaTime() * angularSpeed;
//AI Movement alla adding velocity
acc = speed;
vel = vel + (acc - dragVel) * sfw::getDeltaTime();
vel = std::fmaxf(0, vel);
vel = std::fminf(vel, maxVel);
pos = { pos.x + vel * cosf(angle * PI / 180) * sfw::getDeltaTime(),
pos.y + vel * sinf(angle * PI / 180) * sfw::getDeltaTime() };
}

Answer 1

atan2f returns radians, so your goalAngle is in the range [-Pi,Pi].
I don't know if your angle and the angularSpeed use the same metric, but when you calculate the sinf and cosf you are converting angle from degrees to radians.
I suggest to keep all your angles in radians and check them:
#include <cmath>
inline float normAngle ( float ang ) {
return ang < -M_PI ? ang + 2.0*M_PI : ( ang > M_PI ? ang - 2.0*M_PI : ang);
}
inline float limitValue ( float x, float min, float max ) {
return x < min ? min : ( x > max ? max : x );
}
Then, you can try this logic:
void EnemySpeedy::playerTracking(float posX, float posY)
{
//Direction choosing, pos is a member of EnemySpeedy
float dirX = posX - pos.x;
float dirY = posY - pos.y;
//Angle choosing; angle, angularSpeed and angularSpeedMax are members of EnemySpeedy
float goalAngle = atan2(dirY, dirX);
float difAngle = normAngle(angle - goalAngle);
angularSpeed = limitValue(-difAngle,-angularSpeedMax,angularSpeedMax);
float dt = sfw::getDeltaTime();
angle = normAngle(angle + dt * angularSpeed);
// Update speed; acc, vel, etc. are members of EnemySpeedy class
// acc = speed; // it seems odd to me...
// vel = limitValue(vel + (acc - dragVel) * dt, 0.0, maxVel);
// what about:
acc = (difAngle > 1.5 || difAngle < -1.5) ? -maxAcc/2.0 : maxAcc*(maxVel - vel)/maxVel;
// brake if direction is wrong, go to limit velocity otherwise
acc = limitValue(acc, -maxAcc, maxAcc);
vel = limitValue(vel + acc * dt, 0.0, maxVel);
// Update position
pos.x += vel * cos(angle) * dt;
pos.y += vel * sin(angle) * dt;
}