92 lines
3.3 KiB
C++
92 lines
3.3 KiB
C++
// Copyright Epic Games, Inc. All Rights Reserved.
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#include "ProceduralFoliageBroadphase.h"
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#include "FoliageType_InstancedStaticMesh.h"
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FProceduralFoliageBroadphase::FProceduralFoliageBroadphase(float TileSize, float MinimumQuadTreeSize)
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: QuadTree(FBox2D(FVector2D(-TileSize * 2.f, -TileSize * 2.f), FVector2D(TileSize * 2.f, TileSize * 2.f)), MinimumQuadTreeSize)
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{
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}
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FProceduralFoliageBroadphase::FProceduralFoliageBroadphase(const FProceduralFoliageBroadphase& OtherBroadphase)
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: QuadTree(FBox2D(FVector2D(0, 0), FVector2D(0, 0)))
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{
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OtherBroadphase.QuadTree.Duplicate(QuadTree);
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}
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// Perhaps this should copy the QuadTree like the copy constructor does...?
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FProceduralFoliageBroadphase& FProceduralFoliageBroadphase::operator=(const FProceduralFoliageBroadphase& OtherBroadphase) = default;
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void FProceduralFoliageBroadphase::Empty()
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{
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QuadTree.Empty();
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}
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/*Takes the instance and returns the AABB that contains both its shade and collision radius*/
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FBox2D GetMaxAABB(FProceduralFoliageInstance* Instance)
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{
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const float Radius = Instance->GetMaxRadius();
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const FVector2D Location(Instance->Location);
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const FVector2D Offset(Radius, Radius);
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const FBox2D AABB(Location - Offset, Location + Offset);
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return AABB;
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}
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bool FProceduralFoliageBroadphase::TestAgainstAABB(FProceduralFoliageInstance* Instance)
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{
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const FBox2D MaxAABB = GetMaxAABB(Instance);
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return MaxAABB.Intersect(QuadTree.GetTreeBox());
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}
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void FProceduralFoliageBroadphase::Insert(FProceduralFoliageInstance* Instance)
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{
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const FBox2D MaxAABB = GetMaxAABB(Instance);
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QuadTree.Insert(Instance, MaxAABB);
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}
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bool CircleOverlap(const FVector& ALocation, float ARadius, const FVector& BLocation, float BRadius)
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{
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return (ALocation - BLocation).SizeSquared2D() <= (ARadius + BRadius)*(ARadius + BRadius);
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}
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bool FProceduralFoliageBroadphase::GetOverlaps(FProceduralFoliageInstance* Instance, TArray<FProceduralFoliageOverlap>& Overlaps) const
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{
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const float AShadeRadius = Instance->GetShadeRadius();
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const float ACollisionRadius = Instance->GetCollisionRadius();
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TArray<FProceduralFoliageInstance*> PossibleOverlaps;
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const FBox2D AABB = GetMaxAABB(Instance);
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QuadTree.GetElements(AABB, PossibleOverlaps);
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Overlaps.Reserve(Overlaps.Num() + PossibleOverlaps.Num());
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for (FProceduralFoliageInstance* Overlap : PossibleOverlaps)
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{
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if (Overlap != Instance)
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{
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//We must determine if this is an overlap of shade or an overlap of collision. If both the collision overlap wins
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bool bCollisionOverlap = CircleOverlap(Instance->Location, ACollisionRadius, Overlap->Location, Overlap->GetCollisionRadius());
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bool bShadeOverlap = CircleOverlap(Instance->Location, AShadeRadius, Overlap->Location, Overlap->GetShadeRadius());
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if (bCollisionOverlap || bShadeOverlap)
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{
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new (Overlaps)FProceduralFoliageOverlap(Instance, Overlap, bCollisionOverlap ? ESimulationOverlap::CollisionOverlap : ESimulationOverlap::ShadeOverlap);
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}
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}
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}
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return Overlaps.Num() > 0;
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}
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void FProceduralFoliageBroadphase::Remove(FProceduralFoliageInstance* Instance)
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{
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const FBox2D AABB = GetMaxAABB(Instance);
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const bool bRemoved = QuadTree.Remove(Instance, AABB);
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check(bRemoved);
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}
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void FProceduralFoliageBroadphase::GetInstancesInBox(const FBox2D& Box, TArray<FProceduralFoliageInstance*>& Instances) const
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{
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QuadTree.GetElements(Box, Instances);
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}
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