This commit contains a wrong solution for the 0.1 problem before we knew of coth function

- fix the 0.1 speed problem that we went to low, but still havent solve the -0.1 acceleration problem

common/systems/tests/phys/basic.rs

@@ -299,7 +299,7 @@ fn cant_run_during_fall() -> Result<(), Box<dyn Error>> {
 
 #[test]
 fn physics_theory() -> Result<(), Box<dyn Error>> {
-    let tick = |i: usize, move_dir: f64, vel: f64, pos: f64, dt: f64| {
+    let tick = |i: usize, move_dir: f64, acc: f64, vel: f64, pos: f64, dt: f64| {
         /*
             ROLLING_FRICTION_FORCE + AIR_FRICTION_FORCE + TILT_FRICT_FORCE + ACCEL_FORCE = TOTAL_FORCE
 
@@ -326,7 +326,7 @@ fn physics_theory() -> Result<(), Box<dyn Error>> {
         let air_friction_co = 0.9_f64;
         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 c = air_friction_co * air_friction_area * 0.5 * air_density * mass ;
 
         let acc = 9.2_f64 * move_dir; // btw: cant accelerate faster than gravity on foot
         let old_vel = vel;
@@ -334,17 +334,21 @@ fn physics_theory() -> Result<(), Box<dyn Error>> {
         // 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 = if acc == 0.0 {
+
-            vel
+        // The function besically takes its last result calculates the inverse* of it, adds the newly get speed to it and then run tanh again
-        } else {
+        // *inverse of the tanh and the factors before.
-            (mass * acc.abs() / c).sqrt() * ( ( (c / acc.abs() / mass ).sqrt() * old_vel ).atanh() + acc.signum() * (c * acc.abs() / mass).sqrt() * dt ).tanh()
+        let past_fak = (c / (mass * acc.abs() ) ).sqrt() * old_vel;
-        };
+        // the original algorithm isn't able to keep a speed over the terminal velocity based on acc. however that is necessary, e.g. for pushbacks, falling, external factors and stopping (because of we stop acc would be 0 and the  terminal vel would be 0 too)
+        // here we decide to reduce that factor by c each second.
+        let over_vel_keep = (past_fak * c.powf(dt)).max(1.0) * past_fak.signum(); //TODO signum needed
+        let vel = ( ((mass * acc.abs() ) / c ).sqrt() * over_vel_keep) * ( ( past_fak.clamp(-1.0, 1.0) ).atanh() + acc.signum() * (c * acc.abs() / mass).sqrt() * dt ).tanh();
+        //let vel =  ((mass * acc.abs() + old_acc ) / c).sqrt() * ( ( ( (c / (mass * acc.abs() ) ).sqrt() * old_vel).clamp(-1.0, 1.0) ).atanh() + acc.signum() * (c * acc.abs() / mass).sqrt() * dt ).tanh();
 
         //physics
         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() {
+        let diff = if !diff.is_finite() {
             0.0
         } else {
             diff
@@ -353,10 +357,16 @@ fn physics_theory() -> Result<(), Box<dyn Error>> {
         let pos = pos + diff;
 
 
+        let ending = ((i+1) as f64 *dt * 10.0).round() as i64;
+        let line = format!("[{:0>2.1}]:    move_dir: {:0>1.1},    over_vel_keep: {:0>4.4},    acc: {:0>4.4},    vel: {:0>4.4},    dist: {:0>7.4},    dist: {:0>7.4},    pos: {:0>7.4},    c: {:0>4.4}", (i+1) as f64 *dt, move_dir, over_vel_keep, acc, vel, distance_last, distance, pos, c);
+        if ending % 10 == 0 {
+            println!("\x1b[91m{}\x1b[0m", line)
+        } else if ending % 2 != 0 {
+            println!("\x1b[94m{}\x1b[0m", line)
+        } else {
+            println!("{}", line)
+        }
 
-        //if ((i+1) as f64 *dt * 10.0).round() as i64 % 2 == 0 {
-            println!("[{:0>2.1}]:    move_dir: {:0>1.1},    acc: {:0>4.4},    vel: {:0>4.4},    dist: {:0>7.4},    dist: {:0>7.4},    pos: {:0>7.4},    c: {:0>4.4}", (i+1) as f64 *dt, move_dir, acc, vel, distance_last, distance, pos, c);
-        //}
         (acc, vel, pos)
     };
 
@@ -364,18 +374,18 @@ fn physics_theory() -> Result<(), Box<dyn Error>> {
         let dt = 1.0 / tps as f64;
         println!("");
         println!("dt: {}", dt);
-        let (_acc, mut vel, mut pos) = (0.0, 0.0, 0.0);
+        let (mut acc, mut vel, mut pos) = (0.0, 0.0, 0.0);
         let mut i = 0;
-        for _ in 0..tps {
+        for _ in 0..tps*2 {
-            (_, vel, pos) = tick(i, 1.0, vel, pos, dt);
+            (acc, vel, pos) = tick(i, 1.0, acc, vel, pos, dt);
+            i += 1;
+        }
+        for _ in 0..tps*2 {
+            (acc, vel, pos) = tick(i, 0.1, acc, vel, pos, dt);
             i += 1;
         }
         for _ in 0..tps {
-            (_, vel, pos) = tick(i, -1.0, vel, pos, dt);
+            (acc, vel, pos) = tick(i, 1.0, acc, vel, pos, dt);
-            i += 1;
-        }
-        for _ in 0..tps {
-            (_, vel, pos) = tick(i, 1.0, vel, pos, dt);
             i += 1;
         }
         (vel, pos)