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Diffstat (limited to 'Client/ThirdParty/Box2D/src/collision/b2_circle_shape.cpp')
-rw-r--r-- | Client/ThirdParty/Box2D/src/collision/b2_circle_shape.cpp | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/Client/ThirdParty/Box2D/src/collision/b2_circle_shape.cpp b/Client/ThirdParty/Box2D/src/collision/b2_circle_shape.cpp new file mode 100644 index 0000000..ecc6929 --- /dev/null +++ b/Client/ThirdParty/Box2D/src/collision/b2_circle_shape.cpp @@ -0,0 +1,105 @@ +// MIT License + +// Copyright (c) 2019 Erin Catto + +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: + +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. + +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. + +#include "box2d/b2_circle_shape.h" +#include "box2d/b2_block_allocator.h" + +#include <new> + +b2Shape* b2CircleShape::Clone(b2BlockAllocator* allocator) const +{ + void* mem = allocator->Allocate(sizeof(b2CircleShape)); + b2CircleShape* clone = new (mem) b2CircleShape; + *clone = *this; + return clone; +} + +int32 b2CircleShape::GetChildCount() const +{ + return 1; +} + +bool b2CircleShape::TestPoint(const b2Transform& transform, const b2Vec2& p) const +{ + b2Vec2 center = transform.p + b2Mul(transform.q, m_p); + b2Vec2 d = p - center; + return b2Dot(d, d) <= m_radius * m_radius; +} + +// Collision Detection in Interactive 3D Environments by Gino van den Bergen +// From Section 3.1.2 +// x = s + a * r +// norm(x) = radius +bool b2CircleShape::RayCast(b2RayCastOutput* output, const b2RayCastInput& input, + const b2Transform& transform, int32 childIndex) const +{ + B2_NOT_USED(childIndex); + + b2Vec2 position = transform.p + b2Mul(transform.q, m_p); + b2Vec2 s = input.p1 - position; + float b = b2Dot(s, s) - m_radius * m_radius; + + // Solve quadratic equation. + b2Vec2 r = input.p2 - input.p1; + float c = b2Dot(s, r); + float rr = b2Dot(r, r); + float sigma = c * c - rr * b; + + // Check for negative discriminant and short segment. + if (sigma < 0.0f || rr < b2_epsilon) + { + return false; + } + + // Find the point of intersection of the line with the circle. + float a = -(c + b2Sqrt(sigma)); + + // Is the intersection point on the segment? + if (0.0f <= a && a <= input.maxFraction * rr) + { + a /= rr; + output->fraction = a; + output->normal = s + a * r; + output->normal.Normalize(); + return true; + } + + return false; +} + +void b2CircleShape::ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const +{ + B2_NOT_USED(childIndex); + + b2Vec2 p = transform.p + b2Mul(transform.q, m_p); + aabb->lowerBound.Set(p.x - m_radius, p.y - m_radius); + aabb->upperBound.Set(p.x + m_radius, p.y + m_radius); +} + +void b2CircleShape::ComputeMass(b2MassData* massData, float density) const +{ + massData->mass = density * b2_pi * m_radius * m_radius; + massData->center = m_p; + + // inertia about the local origin + massData->I = massData->mass * (0.5f * m_radius * m_radius + b2Dot(m_p, m_p)); +} |