opc_raycollider.cpp

opcode是功能强大

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/*
 *	OPCODE - Optimized Collision Detection
 *	Copyright (C) 2001 Pierre Terdiman
 *	Homepage: http://www.codercorner.com/Opcode.htm
 *
 *  OPCODE modifications for scaled model support (and other things)
 *  Copyright (C) 2004 Gilvan Maia (gilvan 'at' vdl.ufc.br)
 *	Check http://www.vdl.ufc.br/gilvan/coll/opcode/index.htm for updates.
 *
 */
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/**
 *	Contains code for a ray collider.
 *	\file		OPC_RayCollider.cpp
 *	\author		Pierre Terdiman
 *	\date		June, 2, 2001
 */
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/**
 *	Contains a ray-vs-tree collider.
 *	This class performs a stabbing query on an AABB tree, i.e. does a ray-mesh collision.
 *
 *	HIGHER DISTANCE BOUND:
 *
 *		If P0 and P1 are two 3D points, let's define:
 *		- d = distance between P0 and P1
 *		- Origin	= P0
 *		- Direction	= (P1 - P0) / d = normalized direction vector
 *		- A parameter t such as a point P on the line (P0,P1) is P = Origin + t * Direction
 *		- t = 0  -->  P = P0
 *		- t = d  -->  P = P1
 *
 *		Then we can define a general "ray" as:
 *
 *			struct Ray
 *			{
 *				Point	Origin;
 *				Point	Direction;
 *			};
 *
 *		But it actually maps three different things:
 *		- a segment,   when 0 <= t <= d
 *		- a half-line, when 0 <= t < +infinity, or -infinity < t <= d
 *		- a line,      when -infinity < t < +infinity
 *
 *		In Opcode, we support segment queries, which yield half-line queries by setting d = +infinity.
 *		We don't support line-queries. If you need them, shift the origin along the ray by an appropriate margin.
 *
 *		In short, the lower bound is always 0, and you can setup the higher bound "d" with RayCollider::SetMaxDist().
 *
 *		Query	|segment			|half-line		|line
 *		--------|-------------------|---------------|----------------
 *		Usages	|-shadow feelers	|-raytracing	|-
 *				|-sweep tests		|-in/out tests	|
 *
 *	FIRST CONTACT:
 *
 *		- You can setup "first contact" mode or "all contacts" mode with RayCollider::SetFirstContact().
 *		- In "first contact" mode we return as soon as the ray hits one face. If can be useful e.g. for shadow feelers, where
 *		you want to know whether the path to the light is free or not (a boolean answer is enough).
 *		- In "all contacts" mode we return all faces hit by the ray.
 *
 *	TEMPORAL COHERENCE:
 *
 *		- You can enable or disable temporal coherence with RayCollider::SetTemporalCoherence().
 *		- It currently only works in "first contact" mode.
 *		- If temporal coherence is enabled, the previously hit triangle is cached during the first query. Then, next queries
 *		start by colliding the ray against the cached triangle. If they still collide, we return immediately.
 *
 *	CLOSEST HIT:
 *
 *		- You can enable or disable "closest hit" with RayCollider::SetClosestHit().
 *		- It currently only works in "all contacts" mode.
 *		- If closest hit is enabled, faces are sorted by distance on-the-fly and the closest one only is reported.
 *
 *	BACKFACE CULLING:
 *
 *		- You can enable or disable backface culling with RayCollider::SetCulling().
 *		- If culling is enabled, ray will not hit back faces (only front faces).
 *		
 *
 *
 *	\class		RayCollider
 *	\author		Pierre Terdiman
 *	\version	1.3
 *	\date		June, 2, 2001
*/
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/**
 *	This class describes a face hit by a ray or segment.
 *	This is a particular class dedicated to stabbing queries.
 *
 *	\class		CollisionFace
 *	\author		Pierre Terdiman
 *	\version	1.3
 *	\date		March, 20, 2001
*/
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/**
 *	This class is a dedicated collection of CollisionFace.
 *
 *	\class		CollisionFaces
 *	\author		Pierre Terdiman
 *	\version	1.3
 *	\date		March, 20, 2001
*/
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// Precompiled Header
#include "Opcode/Stdafx.h"

using namespace Opcode;
using namespace IceMaths;

// When this macro is set, the overlap tests considers an scaling on AABBs/tris.
// This means that the ray/line is not entirely in the model's local space when collision
// tests take places.
// #define OPC_RAYCOLLIDER_SCALE_BEFORE_OVERLAP

#include "Opcode/OPC_RayAABBOverlap.h"
#include "Opcode/OPC_RayTriOverlap.h"

#define SET_CONTACT(prim_index, flag)											\
	mNbIntersections++;															\
	/* Set contact status */													\
	mFlags |= flag;																\
	/* In any case the contact has been found and recorded in mStabbedFace  */	\
	mStabbedFace.mFaceID = prim_index;

#ifdef OPC_RAYHIT_CALLBACK

	#define HANDLE_CONTACT(prim_index, flag)													\
		SET_CONTACT(prim_index, flag)															\
																								\
		if(mHitCallback)	(mHitCallback)(mStabbedFace, mUserData);

	#define UPDATE_CACHE					\
		if(cache && GetContactStatus())		\
		{									\
			*cache	= mStabbedFace.mFaceID;	\
		}
#else

	#define HANDLE_CONTACT(prim_index, flag)													\
		SET_CONTACT(prim_index, flag)															\
																								\
		/* Now we can also record it in mStabbedFaces if available */							\
		if(mStabbedFaces)																		\
		{																						\
			/* If we want all faces or if that's the first one we hit */						\
			if(!mClosestHit || !mStabbedFaces->GetNbFaces())									\
			{																					\
				mStabbedFaces->AddFace(mStabbedFace);											\
			}																					\
			else																				\
			{																					\
				/* We only keep closest hit */													\
				CollisionFace* Current = const_cast<CollisionFace*>(mStabbedFaces->GetFaces());	\
				if(Current && mStabbedFace.mDistance<Current->mDistance)						\
				{																				\
					*Current = mStabbedFace;													\
				}																				\
			}																					\
		}

	#define UPDATE_CACHE												\
		if(cache && GetContactStatus() && mStabbedFaces)				\
		{																\
			const CollisionFace* Current = mStabbedFaces->GetFaces();	\
			if(Current)	*cache	= Current->mFaceID;						\
			else		*cache	= INVALID_ID;							\
		}
#endif

#define SEGMENT_PRIM(prim_index, flag)														\
	/* Request vertices from the app */														\
	VertexPointers VP;	mIMesh->GetTriangle(VP, prim_index);								\
																							\
	/* Perform ray-tri overlap test and return */											\
	if(RayTriOverlap(*VP.Vertex[0], *VP.Vertex[1], *VP.Vertex[2]))							\
	{																						\
		/* Intersection point is valid if dist < segment's length */						\
		/* We know dist>0 so we can use integers */											\
		if(IR(mStabbedFace.mDistance)<IR(mMaxDist))											\
		{																					\
			HANDLE_CONTACT(prim_index, flag)												\
		}																					\
	}

#define RAY_PRIM(prim_index, flag)															\
	/* Request vertices from the app */														\
	VertexPointers VP;	mIMesh->GetTriangle(VP, prim_index);								\
																							\
	/* Perform ray-tri overlap test and return */											\
	if(RayTriOverlap(*VP.Vertex[0], *VP.Vertex[1], *VP.Vertex[2]))							\
	{																						\
		HANDLE_CONTACT(prim_index, flag)													\
	}


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/**
 *	Constructor.
 */
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RayCollider::RayCollider() :
	mNbRayBVTests		(0),
	mNbRayPrimTests		(0),
	mNbIntersections	(0),
	mCulling			(true),
#ifdef OPC_RAYHIT_CALLBACK
	mHitCallback		(null),
	mUserData			(0),
#else
	mClosestHit			(false),
	mStabbedFaces		(null),
#endif
	mMaxDist			(MAX_FLOAT)
{
}

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

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/**
 *	Validates current settings. You should call this method after all the settings and callbacks have been defined.
 *	\return		null if everything is ok, else a string describing the problem
 */
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const char* RayCollider::ValidateSettings()
{
	if(mMaxDist<0.0f)											return "Higher distance bound must be positive!";
	if(TemporalCoherenceEnabled() && !FirstContactEnabled())	return "Temporal coherence only works with ""First contact"" mode!";
#ifndef OPC_RAYHIT_CALLBACK
	if(mClosestHit && FirstContactEnabled())					return "Closest hit doesn't work with ""First contact"" mode!";
	if(TemporalCoherenceEnabled() && mClosestHit)				return "Temporal coherence can't guarantee to report closest hit!";
#endif
	if(SkipPrimitiveTests())									return "SkipPrimitiveTests not possible for RayCollider ! (not implemented)";
	return null;
}

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/**
 *	Generic stabbing query for generic OPCODE models. After the call, access the results:
 *	- with GetContactStatus()
 *	- in the user-provided destination array
 *
 *	\param		world_ray		[in] stabbing ray in world space
 *	\param		model			[in] Opcode model to collide with
 *	\param		world			[in] model's world matrix, or null
 *	\param		cache			[in] a possibly cached face index, or null
 *	\return		true if success
 */
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bool RayCollider::Collide(const IceMaths::Ray& world_ray, const Model& model, const IceMaths::Matrix4x4* world, udword* cache)
{