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working on 0 and negative numbers

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This commit is contained in:
Marcel Märtens 2022-06-10 14:31:51 +02:00
parent fa14d96428
commit 597fc1b147
1 changed files with 29 additions and 31 deletions
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60
common/systems/tests/phys/basic.rs
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@ -327,22 +327,28 @@ fn physics_theory() -> Result<(), Box<dyn Error>> {
let air_friction_area = 0.75_f64;
let air_density = 1.225_f64;
let c = air_friction_co * air_friction_area * 0.5 * air_density * mass;
//let acc = accel_force / mass * move_dir;
let acc = 9.2_f64; // btw: cant accelerate faster than gravity on foot
let acc = 9.2_f64 * move_dir; // btw: cant accelerate faster than gravity on foot
let old_vel = vel;
// controller
// I know what you think, wtf, yep: https://math.stackexchange.com/questions/1929436/line-integral-of-force-of-air-resistanc
// basically an integral of the air resistance formula which scales with v^2 transformed with an ODE.
let vel = (mass * acc / c).sqrt() * ( ( (c / acc / mass ).sqrt() * old_vel ).atanh() + (c * acc / mass).sqrt() * dt ).tanh();
let vel = if acc == 0.0 {
vel
} else {
(mass * acc.abs() / c).sqrt() * ( ( (c / acc.abs() / mass ).sqrt() * old_vel ).atanh() + acc.signum() * (c * acc.abs() / mass).sqrt() * dt ).tanh()
};
//physics
//let acc2 = (vel - old_vel) / dt;
//let distance = 0.5 * vel * dt - 0.5 * acc2 * dt * dt;
let distance_last = mass / c * ( ( ( old_vel * (c/acc / mass).sqrt()).atanh() ).cosh() ).ln();
let distance = mass / c * ( ( ( old_vel * (c/acc / mass).sqrt()).atanh() + dt* (c * acc / mass).sqrt()).cosh() ).ln();
let diff = distance - distance_last;
let diff = if diff.is_nan() {
0.0
} else {
diff
};
let pos = pos + diff;
@ -354,38 +360,30 @@ fn physics_theory() -> Result<(), Box<dyn Error>> {
(acc, vel, pos)
};
let (vel_final_01, pos_final_01) = {
let test_run = |tps: u32| {
let dt = 1.0 / tps as f64;
println!("");
const DT: f64 = 0.1;
println!("dt: {}", DT);
println!("dt: {}", dt);
let (_acc, mut vel, mut pos) = (0.0, 0.0, 0.0);
for i in 0..30 {
(_, vel, pos) = tick(i, 1.0, vel, pos, DT);
let mut i = 0;
for _ in 0..tps {
(_, vel, pos) = tick(i, 1.0, vel, pos, dt);
i += 1;
}
for _ in 0..tps {
(_, vel, pos) = tick(i, -1.0, vel, pos, dt);
i += 1;
}
for _ in 0..tps {
(_, vel, pos) = tick(i, 1.0, vel, pos, dt);
i += 1;
}
(vel, pos)
};
let (vel_final_02, pos_final_02) = {
println!("");
const DT: f64 = 0.2;
println!("dt: {}", DT);
let (_acc, mut vel, mut pos) = (0.0, 0.0, 0.0);
for i in 0..15 {
(_, vel, pos) = tick(i, 1.0, vel, pos, DT);
}
(vel, pos)
};
let (vel_final_10, pos_final_10) = {
println!("");
const DT: f64 = 1.0;
println!("dt: {}", DT);
let (_acc, mut vel, mut pos) = (0.0, 0.0, 0.0);
for i in 0..3 {
(_, vel, pos) = tick(i, 1.0, vel, pos, DT);
}
(vel, pos)
};
let (vel_final_01, pos_final_01) = test_run(10);
let (vel_final_02, pos_final_02) = test_run(5);
let (vel_final_10, pos_final_10) = test_run(1);
let vel_diff = (vel_final_02 - vel_final_01).abs();
let pos_diff = (pos_final_02 - pos_final_01).abs();