compare to infinity fev (notes below)

Looking at the test_collision_parabola_edge_north_from_ne test:
- Inifinity fev seems to return an incorrect value `Face(FaceVert(SubmeshFaceId(1), SubmeshVertId(7)))`, but despite that, the face crawler works.
- the new md algorithm seems to return the correct value `Vert(VertVert(SubmeshVertId(1), SubmeshVertId(6)))`, but the face crawler breaks.

Cargo.lock

@@ -1974,9 +1974,9 @@ dependencies = [
 
 [[package]]
 name = "luau0-src"
-version = "0.15.11+luau697"
+version = "0.17.0+luau701"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bdbf698d77af7b846fab212ca666c5d597b9ff445ef1a647e181d3392e13dfdf"
+checksum = "ed8f8edd8aba9654a9eeb62b2fe7461589f2faf2d0a1bc04bd64c0123319b3fc"
 dependencies = [
  "cc",
 ]
@@ -2149,12 +2149,13 @@ dependencies = [
 
 [[package]]
 name = "mlua"
-version = "0.11.4"
+version = "0.11.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9be1c2bfc684b8a228fbaebf954af7a47a98ec27721986654a4cc2c40a20cc7e"
+checksum = "935ac67539907efcd7198137eb7358e052555f77fe1b2916600a2249351f2b33"
 dependencies = [
  "bstr",
  "either",
+ "libc",
  "mlua-sys",
  "num-traits",
  "parking_lot",
@@ -2164,9 +2165,9 @@ dependencies = [
 
 [[package]]
 name = "mlua-sys"
-version = "0.8.3"
+version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3d4dc9cfc5a7698899802e97480617d9726f7da78c910db989d4d0fd4991d900"
+checksum = "8c968af21bf6b19fc9ca8e7b85ee16f86e4c9e3d0591de101a5608086bda0ad8"
 dependencies = [
  "cc",
  "cfg-if",
@@ -3814,6 +3815,7 @@ dependencies = [
  "arrayvec",
  "glam",
  "id",
+ "mlua",
  "strafesnet_common",
 ]
 

engine/physics/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2024"
 arrayvec = "0.7.6"
 glam = "0.30.0"
 id = { version = "0.1.0", registry = "strafesnet" }
+mlua = { version = "0.11.5", features = ["luau"] }
 strafesnet_common = { path = "../../lib/common", registry = "strafesnet" }
 
 [lints]

engine/physics/src/face_crawler.rs

@@ -21,6 +21,12 @@ impl<M:MeshQuery> CrawlResult<M>{
 			CrawlResult::Hit(face,time)=>Some((face,time)),
 		}
 	}
+	pub fn miss(self)->Option<FEV<M>>{
+		match self{
+			CrawlResult::Miss(fev)=>Some(fev),
+			CrawlResult::Hit(_,_)=>None,
+		}
+	}
 }
 
 // TODO: move predict_collision_face_out algorithm in here or something

engine/physics/src/lib.rs

@@ -3,6 +3,7 @@ mod face_crawler;
 mod model;
 mod push_solve;
 mod minimum_difference;
+mod minimum_difference_lua;
 
 pub mod physics;
 

engine/physics/src/minimum_difference.rs

@@ -870,6 +870,13 @@ mod test{
 	fn test_cube_points(){
 		let mesh=PhysicsMesh::unit_cube();
 		let mesh_view=mesh.complete_mesh_view();
-		assert!(mesh_contains_point(mesh_view,vec3::NEG_Z));
+		for x in -2..=2{
+			for y in -2..=2{
+				for z in -2..=2{
+					let point=vec3::int(x,y,z)>>1;
+					assert!(mesh_contains_point(mesh_view,point),"Mesh did not contain point {point}");
+				}
+			}
+		}
 	}
 }

engine/physics/src/minimum_difference_lua.rs

@@ -0,0 +1,173 @@
+use mlua::{Lua,FromLuaMulti,IntoLuaMulti,Function,Result as LuaResult,Vector};
+use strafesnet_common::integer::{Planar64,Planar64Vec3,FixedFromFloatError};
+
+use crate::model::{MeshQuery,MinkowskiMesh};
+
+pub fn contains_point(
+	mesh:&MinkowskiMesh,
+	point:Planar64Vec3,
+)->LuaResult<bool>{
+	Ok(minimum_difference(mesh,point,true)?.hits)
+}
+pub fn minimum_difference_details(
+	mesh:&MinkowskiMesh,
+	point:Planar64Vec3,
+)->LuaResult<(bool,Option<Details>)>{
+	let md=minimum_difference(mesh,point,false)?;
+	Ok((md.hits,md.details))
+}
+fn p64v3(v:Vector)->Result<Planar64Vec3,FixedFromFloatError>{
+	Ok(Planar64Vec3::new([
+		v.x().try_into()?,
+		v.y().try_into()?,
+		v.z().try_into()?,
+	]))
+}
+fn vec(v:Planar64Vec3)->Vector{
+	Vector::new(v.x.into(),v.y.into(),v.z.into())
+}
+struct MinimumDifference{
+	hits:bool,
+	details:Option<Details>
+}
+pub struct Details{
+	pub distance:Planar64,
+	pub p_pos:Planar64Vec3,
+	pub p_norm:Planar64Vec3,
+	pub q_pos:Planar64Vec3,
+	pub q_norm:Planar64Vec3,
+}
+impl FromLuaMulti for MinimumDifference{
+	fn from_lua_multi(mut values:mlua::MultiValue,_lua:&Lua)->LuaResult<Self>{
+		match values.make_contiguous(){
+			&mut [
+				mlua::Value::Boolean(hits),
+				mlua::Value::Nil,
+				mlua::Value::Nil,
+				mlua::Value::Nil,
+				mlua::Value::Nil,
+				mlua::Value::Nil,
+			]=>Ok(Self{hits,details:None}),
+			&mut [
+				mlua::Value::Boolean(hits),
+				mlua::Value::Number(distance),
+				mlua::Value::Vector(p_pos),
+				mlua::Value::Vector(p_norm),
+				mlua::Value::Vector(q_pos),
+				mlua::Value::Vector(q_norm),
+			]=>Ok(Self{
+				hits,
+				details:Some(Details{
+					distance:distance.try_into().unwrap(),
+					p_pos:p64v3(p_pos).unwrap(),
+					p_norm:p64v3(p_norm).unwrap(),
+					q_pos:p64v3(q_pos).unwrap(),
+					q_norm:p64v3(q_norm).unwrap(),
+				}),
+			}),
+			&mut [
+				mlua::Value::Boolean(hits),
+				mlua::Value::Integer(distance),
+				mlua::Value::Vector(p_pos),
+				mlua::Value::Vector(p_norm),
+				mlua::Value::Vector(q_pos),
+				mlua::Value::Vector(q_norm),
+			]=>Ok(Self{
+				hits,
+				details:Some(Details{
+					distance:distance.into(),
+					p_pos:p64v3(p_pos).unwrap(),
+					p_norm:p64v3(p_norm).unwrap(),
+					q_pos:p64v3(q_pos).unwrap(),
+					q_norm:p64v3(q_norm).unwrap(),
+				}),
+			}),
+			values=>Err(mlua::Error::runtime(format!("Invalid return values: {values:?}"))),
+		}
+	}
+}
+
+struct Args{
+	query_p:Function,
+	radius_p:f64,
+	query_q:Function,
+	radius_q:f64,
+	test_intersection:bool,
+}
+impl Args{
+	fn new(
+		lua:&Lua,
+		mesh:&'static MinkowskiMesh<'static>,
+		point:Planar64Vec3,
+		test_intersection:bool,
+	)->LuaResult<Self>{
+		let radius_p=0.0;
+		let radius_q=0.0;
+		// Query the farthest point on the mesh in the given direction.
+		let query_p=lua.create_function(move|_,dir:Option<Vector>|{
+			let Some(dir)=dir else{
+				return Ok(vec(mesh.mesh0.hint_point()));
+			};
+			let dir=p64v3(dir).unwrap();
+			let vert_id=mesh.mesh0.farthest_vert(dir);
+			let dir=mesh.mesh0.vert(vert_id);
+			Ok(vec(dir))
+		})?;
+		// query_q is different since it includes the test point offset.
+		let query_q=lua.create_function(move|_,dir:Option<Vector>|{
+			let Some(dir)=dir else{
+				return Ok(vec(mesh.mesh1.hint_point()+point));
+			};
+			let dir=p64v3(dir).unwrap();
+			let vert_id=mesh.mesh1.farthest_vert(dir);
+			let dir=mesh.mesh1.vert(vert_id)+point;
+			Ok(vec(dir))
+		})?;
+		Ok(Args{
+			query_p,
+			radius_p,
+			query_q,
+			radius_q,
+			test_intersection,
+		})
+	}
+}
+impl IntoLuaMulti for Args{
+	fn into_lua_multi(self,lua:&Lua)->LuaResult<mlua::MultiValue>{
+		use mlua::IntoLua;
+		Ok(mlua::MultiValue::from_vec(vec![
+			self.query_p.into_lua(lua)?,
+			self.radius_p.into_lua(lua)?,
+			self.query_q.into_lua(lua)?,
+			self.radius_q.into_lua(lua)?,
+			mlua::Value::Nil,
+			self.test_intersection.into_lua(lua)?,
+		]))
+	}
+}
+
+fn minimum_difference(
+	mesh:&MinkowskiMesh,
+	point:Planar64Vec3,
+	test_intersection:bool,
+)->LuaResult<MinimumDifference>{
+	let ctx=init_lua()?;
+	// SAFETY: mesh lifetime must outlive args usages
+	let mesh=unsafe{core::mem::transmute(mesh)};
+	let args=Args::new(&ctx.lua,mesh,point,test_intersection)?;
+	ctx.f.call(args)
+}
+
+struct Ctx{
+	lua:Lua,
+	f:Function,
+}
+fn init_lua()->LuaResult<Ctx>{
+	static SOURCE:std::sync::LazyLock<String>=std::sync::LazyLock::new(||std::fs::read_to_string("/home/quat/strafesnet/game/src/ReplicatedStorage/Shared/Trey-MinimumDifference.lua").unwrap());
+	let lua=Lua::new();
+	lua.sandbox(true)?;
+	let lib_f=lua.load(SOURCE.as_str()).set_name("Trey-MinimumDifference").into_function()?;
+	let lib:mlua::Table=lib_f.call(())?;
+	let f=lib.raw_get("difference")?;
+	Ok(Ctx{lua,f})
+}

engine/physics/src/model.rs

@@ -641,8 +641,19 @@ pub enum MinkowskiFace{
 
 #[derive(Debug)]
 pub struct MinkowskiMesh<'a>{
-	mesh0:TransformedMesh<'a>,
-	mesh1:TransformedMesh<'a>,
+	pub mesh0:TransformedMesh<'a>,
+	pub mesh1:TransformedMesh<'a>,
+}
+
+//infinity fev algorithm state transition
+#[derive(Debug)]
+enum Transition{
+	Done,//found closest vert, no edges are better
+	Vert(MinkowskiVert),//transition to vert
+}
+enum EV{
+	Vert(MinkowskiVert),
+	Edge(MinkowskiEdge),
 }
 
 pub type GigaTime=Ratio<Fixed<4,128>,Fixed<4,128>>;
@@ -666,8 +677,128 @@ impl MinkowskiMesh<'_>{
 			mesh1,
 		}
 	}
+	fn farthest_vert(&self,dir:Planar64Vec3)->MinkowskiVert{
+		MinkowskiVert::VertVert(self.mesh0.farthest_vert(dir),self.mesh1.farthest_vert(-dir))
+	}
+	fn next_transition_vert(&self,vert_id:MinkowskiVert,best_distance_squared:&mut Fixed<2,64>,infinity_dir:Planar64Vec3,point:Planar64Vec3)->Transition{
+		let mut best_transition=Transition::Done;
+		for &directed_edge_id in self.vert_edges(vert_id).as_ref(){
+			let edge_n=self.directed_edge_n(directed_edge_id);
+			//is boundary uncrossable by a crawl from infinity
+			let edge_verts=self.edge_verts(directed_edge_id.as_undirected());
+			//select opposite vertex
+			let test_vert_id=edge_verts.as_ref()[directed_edge_id.parity() as usize];
+			//test if it's closer
+			let diff=point-self.vert(test_vert_id);
+			if edge_n.dot(infinity_dir).is_zero(){
+				let distance_squared=diff.dot(diff);
+				if distance_squared<*best_distance_squared{
+					best_transition=Transition::Vert(test_vert_id);
+					*best_distance_squared=distance_squared;
+				}
+			}
+		}
+		best_transition
+	}
+	fn final_ev(&self,vert_id:MinkowskiVert,best_distance_squared:&mut Fixed<2,64>,infinity_dir:Planar64Vec3,point:Planar64Vec3)->EV{
+		let mut best_transition=EV::Vert(vert_id);
+		let diff=point-self.vert(vert_id);
+		for &directed_edge_id in self.vert_edges(vert_id).as_ref(){
+			let edge_n=self.directed_edge_n(directed_edge_id);
+			//is boundary uncrossable by a crawl from infinity
+			//check if time of collision is outside Time::MIN..Time::MAX
+			if edge_n.dot(infinity_dir).is_zero(){
+				let d=edge_n.dot(diff);
+				//test the edge
+				let edge_nn=edge_n.dot(edge_n);
+				if !d.is_negative()&&d<=edge_nn{
+					let distance_squared={
+						let c=diff.cross(edge_n);
+						//wrap for speed
+						(c.dot(c)/edge_nn).divide().wrap_2()
+					};
+					if distance_squared<=*best_distance_squared{
+						best_transition=EV::Edge(directed_edge_id.as_undirected());
+						*best_distance_squared=distance_squared;
+					}
+				}
+			}
+		}
+		best_transition
+	}
+	fn crawl_boundaries(&self,mut vert_id:MinkowskiVert,infinity_dir:Planar64Vec3,point:Planar64Vec3)->EV{
+		let mut best_distance_squared={
+			let diff=point-self.vert(vert_id);
+			diff.dot(diff)
+		};
+		loop{
+			match self.next_transition_vert(vert_id,&mut best_distance_squared,infinity_dir,point){
+				Transition::Done=>return self.final_ev(vert_id,&mut best_distance_squared,infinity_dir,point),
+				Transition::Vert(new_vert_id)=>vert_id=new_vert_id,
+			}
+		}
+	}
+	/// This function drops a vertex down to an edge or a face if the path from infinity did not cross any vertex-edge boundaries but the point is supposed to have already crossed a boundary down from a vertex
+	fn infinity_fev(&self,infinity_dir:Planar64Vec3,point:Planar64Vec3)->FEV::<MinkowskiMesh<'_>>{
+		//start on any vertex
+		//cross uncrossable vertex-edge boundaries until you find the closest vertex or edge
+		//cross edge-face boundary if it's uncrossable
+		match self.crawl_boundaries(self.farthest_vert(infinity_dir),infinity_dir,point){
+			//if a vert is returned, it is the closest point to the infinity point
+			EV::Vert(vert_id)=>FEV::Vert(vert_id),
+			EV::Edge(edge_id)=>{
+				//cross to face if the boundary is not crossable and we are on the wrong side
+				let edge_n=self.edge_n(edge_id);
+				// point is multiplied by two because vert_sum sums two vertices.
+				let delta_pos=point*2-{
+					let &[v0,v1]=self.edge_verts(edge_id).as_ref();
+					self.vert(v0)+self.vert(v1)
+				};
+				for (i,&face_id) in self.edge_faces(edge_id).as_ref().iter().enumerate(){
+					let face_n=self.face_nd(face_id).0;
+					//edge-face boundary nd, n facing out of the face towards the edge
+					let boundary_n=face_n.cross(edge_n)*(i as i64*2-1);
+					let boundary_d=boundary_n.dot(delta_pos);
+					//check if time of collision is outside Time::MIN..Time::MAX
+					//infinity_dir can always be treated as a velocity
+					if !boundary_d.is_positive()&&boundary_n.dot(infinity_dir).is_zero(){
+						//both faces cannot pass this condition, return early if one does.
+						return FEV::Face(face_id);
+					}
+				}
+				FEV::Edge(edge_id)
+			},
+		}
+	}
+	// TODO: fundamentally improve this algorithm.
+	// All it needs to do is find the closest point on the mesh
+	// and return the FEV which the point resides on.
+	//
+	// What it actually does is use the above functions to trace a ray in from infinity,
+	// crawling the closest point along the mesh surface until the ray reaches
+	// the starting point to discover the final FEV.
+	//
+	// The actual collision prediction probably does a single test
+	// and then immediately returns with 0 FEV transitions on average,
+	// because of the strict time_limit constraint.
+	//
+	// Most of the calculation time is just calculating the starting point
+	// for the "actual" crawling algorithm below (predict_collision_{in|out}).
+	fn closest_fev_not_inside(&self,mut infinity_body:Body,start_time:Bound<&Time>)->Option<FEV<MinkowskiMesh<'_>>>{
+		infinity_body.infinity_dir().and_then(|dir|{
+			let infinity_fev=self.infinity_fev(-dir,infinity_body.position);
+			//a line is simpler to solve than a parabola
+			infinity_body.velocity=dir;
+			infinity_body.acceleration=vec3::zero();
+			//crawl in from negative infinity along a tangent line to get the closest fev
+			infinity_fev.crawl(self,&infinity_body,Bound::Unbounded,start_time).miss()
+		})
+	}
 	pub fn predict_collision_in(&self,relative_body:&Body,range:impl RangeBounds<Time>)->Option<(MinkowskiFace,GigaTime)>{
+		let old_fev=self.closest_fev_not_inside(*relative_body,range.start_bound());
 		let fev=crate::minimum_difference::closest_fev_not_inside(self,relative_body.position)?;
+		println!("old_fev={old_fev:?}");
+		println!("fev={fev:?}");
 		//continue forwards along the body parabola
 		fev.crawl(self,relative_body,range.start_bound(),range.end_bound()).hit()
 	}