common: bvh: arbitrary traversal

lib/common/src/bvh.rs

@@ -3,7 +3,7 @@ use std::collections::BTreeMap;
 
 use crate::aabb::Aabb;
 use crate::ray::Ray;
-use crate::integer::{Ratio,Planar64};
+use crate::integer::{Ratio,Planar64,Planar64Vec3};
 use crate::instruction::{InstructionCollector,TimedInstruction};
 
 //da algaritum
@@ -140,33 +140,34 @@ impl<L> BvhNode<L>{
 			},
 		}
 	}
-	fn populate_nodes<'a,T,F>(
+	fn populate_nodes<'a,T,IntersectLeaf,IntersectAabb>(
 		&'a self,
-		collector:&mut InstructionCollector<&'a L,Ratio<Planar64,Planar64>>,
-		nodes:&mut BTreeMap<Ratio<Planar64,Planar64>,&'a BvhNode<L>>,
-		ray:&Ray,
-		start_time:Ratio<Planar64,Planar64>,
-		f:&F,
+		start_point:Planar64Vec3,
+		collector:&mut InstructionCollector<&'a L,T>,
+		nodes:&mut BTreeMap<T,&'a BvhNode<L>>,
+		start_time:T,
+		intersect_leaf:&IntersectLeaf,
+		intersect_aabb:&IntersectAabb,
 	)
 		where
 			T:Ord+Copy,
-			Ratio<Planar64,Planar64>:From<T>,
-			F:Fn(&L,&Ray)->Option<T>,
+			IntersectLeaf:Fn(&L)->Option<T>,
+			IntersectAabb:Fn(&Aabb)->Option<T>,
 	{
 		match &self.content{
-			RecursiveContent::Leaf(leaf)=>if let Some(time)=f(leaf,ray){
-				let ins=TimedInstruction{time:time.into(),instruction:leaf};
-				if start_time.lt_ratio(ins.time)&&ins.time.lt_ratio(collector.time()){
+			RecursiveContent::Leaf(leaf)=>if let Some(time)=intersect_leaf(leaf){
+				let ins=TimedInstruction{time,instruction:leaf};
+				if start_time<ins.time&&ins.time<collector.time(){
 					collector.collect(Some(ins));
 				}
 			},
 			RecursiveContent::Branch(children)=>for child in children{
-				if child.aabb.contains(ray.origin){
-					child.populate_nodes(collector,nodes,ray,start_time,f);
+				if child.aabb.contains(start_point){
+					child.populate_nodes(start_point,collector,nodes,start_time,intersect_leaf,intersect_aabb);
 				}else{
 					// Am I an upcoming superstar?
-					if let Some(t)=intersect_aabb(ray,&child.aabb){
-						if start_time.lt_ratio(t)&&t.lt_ratio(collector.time()){
+					if let Some(t)=intersect_aabb(&child.aabb){
+						if start_time<t&&t<collector.time(){
 							nodes.insert(t,child);
 						}
 					}
@@ -174,27 +175,29 @@ impl<L> BvhNode<L>{
 			},
 		}
 	}
-	pub fn sample_ray<T,F>(
+	/// Traverse the BVH using the given sampling functions.
+	/// Nodes are tested in order of T returned by IntersectAabb.
+	/// The algorithm ends when T for the next node to test is
+	/// greater than the current best collected T from IntersectLeaf.
+	pub fn traverse<T,IntersectLeaf,IntersectAabb>(
 		&self,
-		ray:&Ray,
+		start_point:Planar64Vec3,
 		start_time:T,
 		time_limit:T,
-		f:F,
+		intersect_leaf:IntersectLeaf,
+		intersect_aabb:IntersectAabb,
 	)->Option<(T,&L)>
 		where
 			T:Ord+Copy,
-			T:From<Ratio<Planar64,Planar64>>,
-			Ratio<Planar64,Planar64>:From<T>,
-			F:Fn(&L,&Ray)->Option<T>,
+			IntersectLeaf:Fn(&L)->Option<T>,
+			IntersectAabb:Fn(&Aabb)->Option<T>,
 	{
 		// source of nondeterminism when Aabb boundaries are coplanar
 		let mut nodes=BTreeMap::new();
 
-		let start_time=start_time.into();
-		let time_limit=time_limit.into();
 		let mut collector=InstructionCollector::new(time_limit);
 		// break open all nodes that contain ray.origin and populate nodes with future intersection times
-		self.populate_nodes(&mut collector,&mut nodes,ray,start_time,&f);
+		self.populate_nodes(start_point,&mut collector,&mut nodes,start_time,&intersect_leaf,&intersect_aabb);
 
 		// swim through nodes one at a time
 		while let Some((t,node))=nodes.pop_first(){
@@ -202,18 +205,18 @@ impl<L> BvhNode<L>{
 				break;
 			}
 			match &node.content{
-				RecursiveContent::Leaf(leaf)=>if let Some(time)=f(leaf,ray){
+				RecursiveContent::Leaf(leaf)=>if let Some(time)=intersect_leaf(leaf){
 					let ins=TimedInstruction{time:time.into(),instruction:leaf};
 					// this lower bound can also be omitted
 					// but it causes type inference errors lol
-					if start_time.lt_ratio(ins.time)&&ins.time.lt_ratio(collector.time()){
+					if start_time<ins.time&&ins.time<collector.time(){
 						collector.collect(Some(ins));
 					}
 				},
 				// break open the node and predict collisions with the child nodes
 				RecursiveContent::Branch(children)=>for child in children{
 					// Am I an upcoming superstar?
-					if let Some(t)=intersect_aabb(ray,&child.aabb){
+					if let Some(t)=intersect_aabb(&child.aabb){
 						// we don't need to check the lower bound
 						// because child aabbs are guaranteed to be within the parent bounds.
 						if t<collector.time(){