Lower case folders

src/libraries/box2d/collision/b2_circle_shape.cpp

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+// 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));
+}