diff options
Diffstat (limited to 'Source/3rdParty/Box2D/Rope/b2Rope.cpp')
-rw-r--r-- | Source/3rdParty/Box2D/Rope/b2Rope.cpp | 259 |
1 files changed, 0 insertions, 259 deletions
diff --git a/Source/3rdParty/Box2D/Rope/b2Rope.cpp b/Source/3rdParty/Box2D/Rope/b2Rope.cpp deleted file mode 100644 index 847b11d..0000000 --- a/Source/3rdParty/Box2D/Rope/b2Rope.cpp +++ /dev/null @@ -1,259 +0,0 @@ -/* -* Copyright (c) 2011 Erin Catto http://box2d.org -* -* 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 "Box2D/Rope/b2Rope.h" -#include "Box2D/Common/b2Draw.h" - -b2Rope::b2Rope() -{ - m_count = 0; - m_ps = nullptr; - m_p0s = nullptr; - m_vs = nullptr; - m_ims = nullptr; - m_Ls = nullptr; - m_as = nullptr; - m_gravity.SetZero(); - m_k2 = 1.0f; - m_k3 = 0.1f; -} - -b2Rope::~b2Rope() -{ - b2Free(m_ps); - b2Free(m_p0s); - b2Free(m_vs); - b2Free(m_ims); - b2Free(m_Ls); - b2Free(m_as); -} - -void b2Rope::Initialize(const b2RopeDef* def) -{ - b2Assert(def->count >= 3); - m_count = def->count; - m_ps = (b2Vec2*)b2Alloc(m_count * sizeof(b2Vec2)); - m_p0s = (b2Vec2*)b2Alloc(m_count * sizeof(b2Vec2)); - m_vs = (b2Vec2*)b2Alloc(m_count * sizeof(b2Vec2)); - m_ims = (float32*)b2Alloc(m_count * sizeof(float32)); - - for (int32 i = 0; i < m_count; ++i) - { - m_ps[i] = def->vertices[i]; - m_p0s[i] = def->vertices[i]; - m_vs[i].SetZero(); - - float32 m = def->masses[i]; - if (m > 0.0f) - { - m_ims[i] = 1.0f / m; - } - else - { - m_ims[i] = 0.0f; - } - } - - int32 count2 = m_count - 1; - int32 count3 = m_count - 2; - m_Ls = (float32*)b2Alloc(count2 * sizeof(float32)); - m_as = (float32*)b2Alloc(count3 * sizeof(float32)); - - for (int32 i = 0; i < count2; ++i) - { - b2Vec2 p1 = m_ps[i]; - b2Vec2 p2 = m_ps[i+1]; - m_Ls[i] = b2Distance(p1, p2); - } - - for (int32 i = 0; i < count3; ++i) - { - b2Vec2 p1 = m_ps[i]; - b2Vec2 p2 = m_ps[i + 1]; - b2Vec2 p3 = m_ps[i + 2]; - - b2Vec2 d1 = p2 - p1; - b2Vec2 d2 = p3 - p2; - - float32 a = b2Cross(d1, d2); - float32 b = b2Dot(d1, d2); - - m_as[i] = b2Atan2(a, b); - } - - m_gravity = def->gravity; - m_damping = def->damping; - m_k2 = def->k2; - m_k3 = def->k3; -} - -void b2Rope::Step(float32 h, int32 iterations) -{ - if (h == 0.0) - { - return; - } - - float32 d = expf(- h * m_damping); - - for (int32 i = 0; i < m_count; ++i) - { - m_p0s[i] = m_ps[i]; - if (m_ims[i] > 0.0f) - { - m_vs[i] += h * m_gravity; - } - m_vs[i] *= d; - m_ps[i] += h * m_vs[i]; - - } - - for (int32 i = 0; i < iterations; ++i) - { - SolveC2(); - SolveC3(); - SolveC2(); - } - - float32 inv_h = 1.0f / h; - for (int32 i = 0; i < m_count; ++i) - { - m_vs[i] = inv_h * (m_ps[i] - m_p0s[i]); - } -} - -void b2Rope::SolveC2() -{ - int32 count2 = m_count - 1; - - for (int32 i = 0; i < count2; ++i) - { - b2Vec2 p1 = m_ps[i]; - b2Vec2 p2 = m_ps[i + 1]; - - b2Vec2 d = p2 - p1; - float32 L = d.Normalize(); - - float32 im1 = m_ims[i]; - float32 im2 = m_ims[i + 1]; - - if (im1 + im2 == 0.0f) - { - continue; - } - - float32 s1 = im1 / (im1 + im2); - float32 s2 = im2 / (im1 + im2); - - p1 -= m_k2 * s1 * (m_Ls[i] - L) * d; - p2 += m_k2 * s2 * (m_Ls[i] - L) * d; - - m_ps[i] = p1; - m_ps[i + 1] = p2; - } -} - -void b2Rope::SetAngle(float32 angle) -{ - int32 count3 = m_count - 2; - for (int32 i = 0; i < count3; ++i) - { - m_as[i] = angle; - } -} - -void b2Rope::SolveC3() -{ - int32 count3 = m_count - 2; - - for (int32 i = 0; i < count3; ++i) - { - b2Vec2 p1 = m_ps[i]; - b2Vec2 p2 = m_ps[i + 1]; - b2Vec2 p3 = m_ps[i + 2]; - - float32 m1 = m_ims[i]; - float32 m2 = m_ims[i + 1]; - float32 m3 = m_ims[i + 2]; - - b2Vec2 d1 = p2 - p1; - b2Vec2 d2 = p3 - p2; - - float32 L1sqr = d1.LengthSquared(); - float32 L2sqr = d2.LengthSquared(); - - if (L1sqr * L2sqr == 0.0f) - { - continue; - } - - float32 a = b2Cross(d1, d2); - float32 b = b2Dot(d1, d2); - - float32 angle = b2Atan2(a, b); - - b2Vec2 Jd1 = (-1.0f / L1sqr) * d1.Skew(); - b2Vec2 Jd2 = (1.0f / L2sqr) * d2.Skew(); - - b2Vec2 J1 = -Jd1; - b2Vec2 J2 = Jd1 - Jd2; - b2Vec2 J3 = Jd2; - - float32 mass = m1 * b2Dot(J1, J1) + m2 * b2Dot(J2, J2) + m3 * b2Dot(J3, J3); - if (mass == 0.0f) - { - continue; - } - - mass = 1.0f / mass; - - float32 C = angle - m_as[i]; - - while (C > b2_pi) - { - angle -= 2 * b2_pi; - C = angle - m_as[i]; - } - - while (C < -b2_pi) - { - angle += 2.0f * b2_pi; - C = angle - m_as[i]; - } - - float32 impulse = - m_k3 * mass * C; - - p1 += (m1 * impulse) * J1; - p2 += (m2 * impulse) * J2; - p3 += (m3 * impulse) * J3; - - m_ps[i] = p1; - m_ps[i + 1] = p2; - m_ps[i + 2] = p3; - } -} - -void b2Rope::Draw(b2Draw* draw) const -{ - b2Color c(0.4f, 0.5f, 0.7f); - - for (int32 i = 0; i < m_count - 1; ++i) - { - draw->DrawSegment(m_ps[i], m_ps[i+1], c); - } -} |