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/*
* Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2EdgeAndCircleContact.h"
#include "../b2Body.h"
#include "../b2WorldCallbacks.h"
#include "../../Common/b2BlockAllocator.h"
#include "../../Collision/Shapes/b2EdgeShape.h"
#include <new>
#include <cstring>
b2Contact* b2EdgeAndCircleContact::Create(b2Shape* shape1, b2Shape* shape2, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2EdgeAndCircleContact));
return new (mem) b2EdgeAndCircleContact(shape1, shape2);
}
void b2EdgeAndCircleContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2EdgeAndCircleContact*)contact)->~b2EdgeAndCircleContact();
allocator->Free(contact, sizeof(b2EdgeAndCircleContact));
}
b2EdgeAndCircleContact::b2EdgeAndCircleContact(b2Shape* s1, b2Shape* s2)
: b2Contact(s1, s2)
{
b2Assert(m_shape1->GetType() == e_edgeShape);
b2Assert(m_shape2->GetType() == e_circleShape);
m_manifold.pointCount = 0;
m_manifold.points[0].normalImpulse = 0.0f;
m_manifold.points[0].tangentImpulse = 0.0f;
}
void b2EdgeAndCircleContact::Evaluate(b2ContactListener* listener)
{
b2Body* b1 = m_shape1->GetBody();
b2Body* b2 = m_shape2->GetBody();
b2Manifold m0;
memcpy(&m0, &m_manifold, sizeof(b2Manifold));
b2CollideEdgeAndCircle(&m_manifold, (b2EdgeShape*)m_shape1, b1->GetXForm(), (b2CircleShape*)m_shape2, b2->GetXForm());
b2ContactPoint cp;
cp.shape1 = m_shape1;
cp.shape2 = m_shape2;
cp.friction = b2MixFriction(m_shape1->GetFriction(), m_shape2->GetFriction());
cp.restitution = b2MixRestitution(m_shape1->GetRestitution(), m_shape2->GetRestitution());
if (m_manifold.pointCount > 0)
{
m_manifoldCount = 1;
b2ManifoldPoint* mp = m_manifold.points + 0;
if (m0.pointCount == 0)
{
mp->normalImpulse = 0.0f;
mp->tangentImpulse = 0.0f;
if (listener)
{
cp.position = b1->GetWorldPoint(mp->localPoint1);
b2Vec2 v1 = b1->GetLinearVelocityFromLocalPoint(mp->localPoint1);
b2Vec2 v2 = b2->GetLinearVelocityFromLocalPoint(mp->localPoint2);
cp.velocity = v2 - v1;
cp.normal = m_manifold.normal;
cp.separation = mp->separation;
cp.id = mp->id;
listener->Add(&cp);
}
}
else
{
b2ManifoldPoint* mp0 = m0.points + 0;
mp->normalImpulse = mp0->normalImpulse;
mp->tangentImpulse = mp0->tangentImpulse;
if (listener)
{
cp.position = b1->GetWorldPoint(mp->localPoint1);
b2Vec2 v1 = b1->GetLinearVelocityFromLocalPoint(mp->localPoint1);
b2Vec2 v2 = b2->GetLinearVelocityFromLocalPoint(mp->localPoint2);
cp.velocity = v2 - v1;
cp.normal = m_manifold.normal;
cp.separation = mp->separation;
cp.id = mp->id;
listener->Persist(&cp);
}
}
}
else
{
m_manifoldCount = 0;
if (m0.pointCount > 0 && listener)
{
b2ManifoldPoint* mp0 = m0.points + 0;
cp.position = b1->GetWorldPoint(mp0->localPoint1);
b2Vec2 v1 = b1->GetLinearVelocityFromLocalPoint(mp0->localPoint1);
b2Vec2 v2 = b2->GetLinearVelocityFromLocalPoint(mp0->localPoint2);
cp.velocity = v2 - v1;
cp.normal = m0.normal;
cp.separation = mp0->separation;
cp.id = mp0->id;
listener->Remove(&cp);
}
}
}
void b2EdgeAndCircleContact::b2CollideEdgeAndCircle(b2Manifold* manifold,
const b2EdgeShape* edge,
const b2XForm& xf1,
const b2CircleShape* circle,
const b2XForm& xf2)
{
manifold->pointCount = 0;
b2Vec2 d;
b2Vec2 c = b2Mul(xf2, circle->GetLocalPosition());
b2Vec2 cLocal = b2MulT(xf1, c);
b2Vec2 n = edge->GetNormalVector();
b2Vec2 v1 = edge->GetVertex1();
b2Vec2 v2 = edge->GetVertex2();
float32 radius = circle->GetRadius();
float32 separation;
float32 dirDist = b2Dot((cLocal - v1), edge->GetDirectionVector());
if (dirDist <= 0) {
d = cLocal - v1;
if (b2Dot(d, edge->GetCorner1Vector()) < 0) {
return;
}
d = c - b2Mul(xf1, v1);
} else if (dirDist >= edge->GetLength()) {
d = cLocal - v2;
if (b2Dot(d, edge->GetCorner2Vector()) > 0) {
return;
}
d = c - b2Mul(xf1, v2);
} else {
separation = b2Dot(cLocal - v1, n);
if (separation > radius || separation < -radius) {
return;
}
separation -= radius;
manifold->normal = b2Mul(xf1.R, n);
manifold->pointCount = 1;
manifold->points[0].id.key = 0;
manifold->points[0].separation = separation;
c = c - radius * manifold->normal;
manifold->points[0].localPoint1 = b2MulT(xf1, c);
manifold->points[0].localPoint2 = b2MulT(xf2, c);
return;
}
float32 distSqr = b2Dot(d,d);
if (distSqr > radius * radius)
{
return;
}
if (distSqr < B2_FLT_EPSILON)
{
separation = -radius;
manifold->normal = b2Mul(xf1.R, n);
}
else
{
separation = d.Normalize() - radius;
manifold->normal = d;
}
manifold->pointCount = 1;
manifold->points[0].id.key = 0;
manifold->points[0].separation = separation;
c = c - radius * manifold->normal;
manifold->points[0].localPoint1 = b2MulT(xf1, c);
manifold->points[0].localPoint2 = b2MulT(xf2, c);
}
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