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// This code contains NVIDIA Confidential Information and is disclosed to you
// under a form of NVIDIA software license agreement provided separately to you.
//
// Notice
// NVIDIA Corporation and its licensors retain all intellectual property and
// proprietary rights in and to this software and related documentation and
// any modifications thereto. Any use, reproduction, disclosure, or
// distribution of this software and related documentation without an express
// license agreement from NVIDIA Corporation is strictly prohibited.
//
// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES
// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO
// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT,
// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.
//
// Information and code furnished is believed to be accurate and reliable.
// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such
// information or for any infringement of patents or other rights of third parties that may
// result from its use. No license is granted by implication or otherwise under any patent
// or patent rights of NVIDIA Corporation. Details are subject to change without notice.
// This code supersedes and replaces all information previously supplied.
// NVIDIA Corporation products are not authorized for use as critical
// components in life support devices or systems without express written approval of
// NVIDIA Corporation.
//
// Copyright (c) 2008-2018 NVIDIA Corporation. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
#ifndef GU_INTERSECTION_RAY_TRIANGLE_H
#define GU_INTERSECTION_RAY_TRIANGLE_H
#include "foundation/PxVec3.h"
#include "PxPhysXCommonConfig.h"
#include "CmPhysXCommon.h"
namespace physx
{
namespace Gu
{
// PT: this is used for backface culling. It existed in Moller's original code already. Basically this is only to avoid dividing by zero.
// This should not depend on what units are used, and neither should it depend on the size of triangles. A large triangle with the same
// orientation as a small triangle should be backface culled the same way. A triangle whose orientation does not change should not suddenly
// become culled or visible when we scale it.
//
// An absolute epsilon is fine here. The computation will work fine for small triangles, and large triangles will simply make 'det' larger,
// more and more inaccurate, but it won't suddenly make it negative.
//
// Using FLT_EPSILON^2 ensures that triangles whose edges are smaller than FLT_EPSILON long are rejected. This epsilon makes the code work
// for very small triangles, while still preventing divisions by too small values.
#define GU_CULLING_EPSILON_RAY_TRIANGLE FLT_EPSILON*FLT_EPSILON
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Computes a ray-triangle intersection test.
* From Tomas Moeller's "Fast Minimum Storage Ray-Triangle Intersection"
* Could be optimized and cut into 2 methods (culled or not). Should make a batch one too to avoid the call overhead, or make it inline.
*
* \param orig [in] ray origin
* \param dir [in] ray direction
* \param vert0 [in] triangle vertex
* \param vert1 [in] triangle vertex
* \param vert2 [in] triangle vertex
* \param at [out] distance
* \param au [out] impact barycentric coordinate
* \param av [out] impact barycentric coordinate
* \param cull [in] true to use backface culling
* \param enlarge [in] enlarge triangle by specified epsilon in UV space to avoid false near-edge rejections
* \return true on overlap
* \note u, v and t will remain unchanged if false is returned.
*/
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
PX_FORCE_INLINE bool intersectRayTriangle( const PxVec3& orig, const PxVec3& dir,
const PxVec3& vert0, const PxVec3& vert1, const PxVec3& vert2,
PxReal& at, PxReal& au, PxReal& av,
bool cull, float enlarge=0.0f)
{
// Find vectors for two edges sharing vert0
const PxVec3 edge1 = vert1 - vert0;
const PxVec3 edge2 = vert2 - vert0;
// Begin calculating determinant - also used to calculate U parameter
const PxVec3 pvec = dir.cross(edge2); // error ~ |v2-v0|
// If determinant is near zero, ray lies in plane of triangle
const PxReal det = edge1.dot(pvec); // error ~ |v2-v0|*|v1-v0|
if(cull)
{
if(det<GU_CULLING_EPSILON_RAY_TRIANGLE)
return false;
// Calculate distance from vert0 to ray origin
const PxVec3 tvec = orig - vert0;
// Calculate U parameter and test bounds
const PxReal u = tvec.dot(pvec);
const PxReal enlargeCoeff = enlarge*det;
const PxReal uvlimit = -enlargeCoeff;
const PxReal uvlimit2 = det + enlargeCoeff;
if(u<uvlimit || u>uvlimit2)
return false;
// Prepare to test V parameter
const PxVec3 qvec = tvec.cross(edge1);
// Calculate V parameter and test bounds
const PxReal v = dir.dot(qvec);
if(v<uvlimit || (u+v)>uvlimit2)
return false;
// Calculate t, scale parameters, ray intersects triangle
const PxReal t = edge2.dot(qvec);
const PxReal inv_det = 1.0f / det;
at = t*inv_det;
au = u*inv_det;
av = v*inv_det;
}
else
{
// the non-culling branch
if(PxAbs(det)<GU_CULLING_EPSILON_RAY_TRIANGLE)
return false;
const PxReal inv_det = 1.0f / det;
// Calculate distance from vert0 to ray origin
const PxVec3 tvec = orig - vert0; // error ~ |orig-v0|
// Calculate U parameter and test bounds
const PxReal u = tvec.dot(pvec) * inv_det;
if(u<-enlarge || u>1.0f+enlarge)
return false;
// prepare to test V parameter
const PxVec3 qvec = tvec.cross(edge1);
// Calculate V parameter and test bounds
const PxReal v = dir.dot(qvec) * inv_det;
if(v<-enlarge || (u+v)>1.0f+enlarge)
return false;
// Calculate t, ray intersects triangle
const PxReal t = edge2.dot(qvec) * inv_det;
at = t;
au = u;
av = v;
}
return true;
}
/* \note u, v and t will remain unchanged if false is returned. */
PX_FORCE_INLINE bool intersectRayTriangleCulling( const PxVec3& orig, const PxVec3& dir,
const PxVec3& vert0, const PxVec3& vert1, const PxVec3& vert2,
PxReal& t, PxReal& u, PxReal& v,
float enlarge=0.0f)
{
return intersectRayTriangle(orig, dir, vert0, vert1, vert2, t, u, v, true, enlarge);
}
/* \note u, v and t will remain unchanged if false is returned. */
PX_FORCE_INLINE bool intersectRayTriangleNoCulling( const PxVec3& orig, const PxVec3& dir,
const PxVec3& vert0, const PxVec3& vert1, const PxVec3& vert2,
PxReal& t, PxReal& u, PxReal& v,
float enlarge=0.0f)
{
return intersectRayTriangle(orig, dir, vert0, vert1, vert2, t, u, v, false, enlarge);
}
} // namespace Gu
}
#endif
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