opc_aabbcollider.cpp

opcode是功能强大

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/*
 *	OPCODE - Optimized Collision Detection
 *	Copyright (C) 2001 Pierre Terdiman
 *	Homepage: http://www.codercorner.com/Opcode.htm
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Contains code for an AABB collider.
 *	\file		OPC_AABBCollider.cpp
 *	\author		Pierre Terdiman
 *	\date		January, 1st, 2002
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Contains an AABB-vs-tree collider.
 *
 *	\class		AABBCollider
 *	\author		Pierre Terdiman
 *	\version	1.3
 *	\date		January, 1st, 2002
*/
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Precompiled Header
#include "Opcode/Stdafx.h"

using namespace Opcode;

#include "Opcode/OPC_BoxBoxOverlap.h"
#include "Opcode/OPC_TriBoxOverlap.h"

#define SET_CONTACT(prim_index, flag)						\
	/* Set contact status */								\
	mFlags |= flag;											\
	mTouchedPrimitives->Add(prim_index);

//! AABB-triangle test
#define AABB_PRIM(prim_index, flag)							\
	/* Request vertices from the app */						\
	VertexPointers VP;	mIMesh->GetTriangle(VP, prim_index);\
	mLeafVerts[0] = *VP.Vertex[0];							\
	mLeafVerts[1] = *VP.Vertex[1];							\
	mLeafVerts[2] = *VP.Vertex[2];							\
	/* Perform triangle-box overlap test */					\
	if(TriBoxOverlap())										\
	{														\
		SET_CONTACT(prim_index, flag)						\
	}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Constructor.
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
AABBCollider::AABBCollider()
{
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Destructor.
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
AABBCollider::~AABBCollider()
{
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Generic collision query for generic OPCODE models. After the call, access the results:
 *	- with GetContactStatus()
 *	- with GetNbTouchedPrimitives()
 *	- with GetTouchedPrimitives()
 *
 *	\param		cache		[in/out] a box cache
 *	\param		box			[in] collision AABB in world space
 *	\param		model		[in] Opcode model to collide with
 *	\return		true if success
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
bool AABBCollider::Collide(AABBCache& cache, const CollisionAABB& box, const Model& model)
{
	// Checkings
	if(!Setup(&model))	return false;

	// Init collision query
	if(InitQuery(cache, box))	return true;

	if(!model.HasLeafNodes())
	{
		if(model.IsQuantized())
		{
			const AABBQuantizedNoLeafTree* Tree = (const AABBQuantizedNoLeafTree*)model.GetTree();

			// Setup dequantization coeffs
			mCenterCoeff	= Tree->mCenterCoeff;
			mExtentsCoeff	= Tree->mExtentsCoeff;

			// Perform collision query
			if(SkipPrimitiveTests())	_CollideNoPrimitiveTest(Tree->GetNodes());
			else						_Collide(Tree->GetNodes());
		}
		else
		{
			const AABBNoLeafTree* Tree = (const AABBNoLeafTree*)model.GetTree();

			// Perform collision query
			if(SkipPrimitiveTests())	_CollideNoPrimitiveTest(Tree->GetNodes());
			else						_Collide(Tree->GetNodes());
		}
	}
	else
	{
		if(model.IsQuantized())
		{
			const AABBQuantizedTree* Tree = (const AABBQuantizedTree*)model.GetTree();

			// Setup dequantization coeffs
			mCenterCoeff	= Tree->mCenterCoeff;
			mExtentsCoeff	= Tree->mExtentsCoeff;

			// Perform collision query
			if(SkipPrimitiveTests())	_CollideNoPrimitiveTest(Tree->GetNodes());
			else						_Collide(Tree->GetNodes());
		}
		else
		{
			const AABBCollisionTree* Tree = (const AABBCollisionTree*)model.GetTree();

			// Perform collision query
			if(SkipPrimitiveTests())	_CollideNoPrimitiveTest(Tree->GetNodes());
			else						_Collide(Tree->GetNodes());
		}
	}
	return true;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Initializes a collision query :
 *	- reset stats & contact status
 *	- check temporal coherence
 *
 *	\param		cache		[in/out] a box cache
 *	\param		box			[in] AABB in world space
 *	\return		TRUE if we can return immediately
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
BOOL AABBCollider::InitQuery(AABBCache& cache, const CollisionAABB& box)
{
	// 1) Call the base method
	VolumeCollider::InitQuery();

	// 2) Keep track of the query box
	mBox = box;

	// 3) Setup destination pointer
	mTouchedPrimitives = &cache.TouchedPrimitives;

	// 4) Special case: 1-triangle meshes [Opcode 1.3]
	if(mCurrentModel && mCurrentModel->HasSingleNode())
	{
		if(!SkipPrimitiveTests())
		{
			// We simply perform the BV-Prim overlap test each time. We assume single triangle has index 0.
			mTouchedPrimitives->Reset();

			// Perform overlap test between the unique triangle and the box (and set contact status if needed)
			AABB_PRIM(udword(0), OPC_CONTACT)

			// Return immediately regardless of status
			return TRUE;
		}
	}

	// 5) Check temporal coherence :
	if(TemporalCoherenceEnabled())
	{
		// Here we use temporal coherence
		// => check results from previous frame before performing the collision query
		if(FirstContactEnabled())
		{
			// We're only interested in the first contact found => test the unique previously touched face
			if(mTouchedPrimitives->GetNbEntries())
			{
				// Get index of previously touched face = the first entry in the array
				udword PreviouslyTouchedFace = mTouchedPrimitives->GetEntry(0);

				// Then reset the array:
				// - if the overlap test below is successful, the index we'll get added back anyway
				// - if it isn't, then the array should be reset anyway for the normal query
				mTouchedPrimitives->Reset();

				// Perform overlap test between the cached triangle and the box (and set contact status if needed)
				AABB_PRIM(PreviouslyTouchedFace, OPC_TEMPORAL_CONTACT)

				// Return immediately if possible
				if(GetContactStatus())	return TRUE;
			}
			// else no face has been touched during previous query
			// => we'll have to perform a normal query
		}
		else
		{
			// We're interested in all contacts =>test the new real box N(ew) against the previous fat box P(revious):
			if(IsCacheValid(cache) && mBox.IsInside(cache.FatBox))
			{
				// - if N is included in P, return previous list
				// => we simply leave the list (mTouchedFaces) unchanged

				// Set contact status if needed
				if(mTouchedPrimitives->GetNbEntries())	mFlags |= OPC_TEMPORAL_CONTACT;

				// In any case we don't need to do a query
				return TRUE;
			}
			else
			{
				// - else do the query using a fat N

				// Reset cache since we'll about to perform a real query
				mTouchedPrimitives->Reset();

				// Make a fat box so that coherence will work for subsequent frames
				mBox.mExtents *= cache.FatCoeff;

				// Update cache with query data (signature for cached faces)
				cache.FatBox = mBox;
			}
		}
	}
	else
	{
		// Here we don't use temporal coherence => do a normal query
		mTouchedPrimitives->Reset();
	}

	// 5) Precompute min & max bounds if needed
	mMin = box.mCenter - box.mExtents;
	mMax = box.mCenter + box.mExtents;

	return FALSE;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Collision query for vanilla AABB trees.
 *	\param		cache		[in/out] a box cache
 *	\param		box			[in] collision AABB in world space
 *	\param		tree		[in] AABB tree
 *	\return		true if success
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
bool AABBCollider::Collide(AABBCache& cache, const CollisionAABB& box, const AABBTree* tree)
{
	// This is typically called for a scene tree, full of -AABBs-, not full of triangles.
	// So we don't really have "primitives" to deal with. Hence it doesn't work with
	// "FirstContact" + "TemporalCoherence".
	ASSERT( !(FirstContactEnabled() && TemporalCoherenceEnabled()) );

	// Checkings
	if(!tree)	return false;

	// Init collision query
	if(InitQuery(cache, box))	return true;

	// Perform collision query
	_Collide(tree);

	return true;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Checks the AABB completely contains the box. In which case we can end the query sooner.
 *	\param		bc	[in] box center
 *	\param		be	[in] box extents
 *	\return		true if the AABB contains the whole box
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
inline_ BOOL AABBCollider::AABBContainsBox(const IceMaths::Point& bc, const IceMaths::Point& be)
{
	if(mMin.x > bc.x - be.x)	return FALSE;
	if(mMin.y > bc.y - be.y)	return FALSE;
	if(mMin.z > bc.z - be.z)	return FALSE;

	if(mMax.x < bc.x + be.x)	return FALSE;
	if(mMax.y < bc.y + be.y)	return FALSE;
	if(mMax.z < bc.z + be.z)	return FALSE;

	return TRUE;
}

#define TEST_BOX_IN_AABB(center, extents)	\
	if(AABBContainsBox(center, extents))	\
	{										\
		/* Set contact status */			\
		mFlags |= OPC_CONTACT;				\
		_Dump(node);						\
		return;								\
	}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Recursive collision query for normal AABB trees.
 *	\param		node	[in] current collision node
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void AABBCollider::_Collide(const AABBCollisionNode* node)
{
	// Perform AABB-AABB overlap test
	if(!AABBAABBOverlap(node->mAABB.mExtents, node->mAABB.mCenter))	return;

	TEST_BOX_IN_AABB(node->mAABB.mCenter, node->mAABB.mExtents)

	if(node->IsLeaf())
	{
		AABB_PRIM(node->GetPrimitive(), OPC_CONTACT)
	}
	else
	{
		_Collide(node->GetPos());

		if(ContactFound()) return;

		_Collide(node->GetNeg());
	}
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Recursive collision query for normal AABB trees, without primitive tests.
 *	\param		node	[in] current collision node
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void AABBCollider::_CollideNoPrimitiveTest(const AABBCollisionNode* node)
{
	// Perform AABB-AABB overlap test
	if(!AABBAABBOverlap(node->mAABB.mExtents, node->mAABB.mCenter))	return;

	TEST_BOX_IN_AABB(node->mAABB.mCenter, node->mAABB.mExtents)