66 lines
1.8 KiB
Rust
66 lines
1.8 KiB
Rust
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pub struct Body {
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pub position: glam::Vec3,//I64 where 2^32 = 1 u
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pub velocity: glam::Vec3,//I64 where 2^32 = 1 u/s
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pub time: TIME,//nanoseconds x xxxxD!
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}
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pub struct PhysicsState {
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pub body: Body,
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pub time: TIME,
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pub strafe_tick_period: TIME,
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pub tick: u32,
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pub gravity: glam::Vec3,
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pub friction: f32,
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pub mv: f32,
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pub grounded: bool,
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pub walkspeed: f32,
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}
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pub type TIME = i64;
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const CONTROL_JUMP:u32 = 0b01000000;//temp
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impl PhysicsState {
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//delete this, we are tickless gamers
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pub fn run(&mut self, time: TIME, control_dir: glam::Vec3, controls: u32){
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let target_tick = (time/self.strafe_tick_period) as u32;//100t
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//the game code can run for 1 month before running out of ticks
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while self.tick<target_tick {
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self.tick += 1;
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let dt=0.01;
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let d=self.body.velocity.dot(control_dir);
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if d<self.mv {
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self.body.velocity+=(self.mv-d)*control_dir;
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}
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self.body.velocity+=self.gravity*dt;
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self.body.position+=self.body.velocity*dt;
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if self.body.position.y<0.0{
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self.body.position.y=0.0;
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self.body.velocity.y=0.0;
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self.grounded=true;
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}
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if self.grounded&&(controls&CONTROL_JUMP)!=0 {
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self.grounded=false;
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self.body.velocity+=glam::Vec3::new(0.0,0.715588/2.0*100.0,0.0);
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}
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if self.grounded {
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let applied_friction=self.friction*dt;
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let targetv=control_dir*self.walkspeed;
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let diffv=targetv-self.body.velocity;
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if applied_friction*applied_friction<diffv.length_squared() {
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self.body.velocity+=applied_friction*diffv.normalize();
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} else {
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self.body.velocity=targetv;
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}
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}
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}
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self.body.time=target_tick as TIME*self.strafe_tick_period;
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}
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//delete this
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pub fn extrapolate_position(&self, time: TIME) -> glam::Vec3 {
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let dt=(time-self.body.time) as f64/1_000_000_000f64;
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self.body.position+self.body.velocity*(dt as f32)+self.gravity*((0.5*dt*dt) as f32)
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}
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}
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