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Diffstat (limited to 'Client/ThirdParty/Box2D/testbed/tests/apply_force.cpp')
| -rw-r--r-- | Client/ThirdParty/Box2D/testbed/tests/apply_force.cpp | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/Client/ThirdParty/Box2D/testbed/tests/apply_force.cpp b/Client/ThirdParty/Box2D/testbed/tests/apply_force.cpp new file mode 100644 index 0000000..65d8094 --- /dev/null +++ b/Client/ThirdParty/Box2D/testbed/tests/apply_force.cpp @@ -0,0 +1,203 @@ +// 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 "test.h" + +// This test shows how to apply forces and torques to a body. +// It also shows how to use the friction joint that can be useful +// for overhead games. +class ApplyForce : public Test +{ +public: + ApplyForce() + { + m_world->SetGravity(b2Vec2(0.0f, 0.0f)); + + const float k_restitution = 0.4f; + + b2Body* ground; + { + b2BodyDef bd; + bd.position.Set(0.0f, 20.0f); + ground = m_world->CreateBody(&bd); + + b2EdgeShape shape; + + b2FixtureDef sd; + sd.shape = &shape; + sd.density = 0.0f; + sd.restitution = k_restitution; + + // Left vertical + shape.SetTwoSided(b2Vec2(-20.0f, -20.0f), b2Vec2(-20.0f, 20.0f)); + ground->CreateFixture(&sd); + + // Right vertical + shape.SetTwoSided(b2Vec2(20.0f, -20.0f), b2Vec2(20.0f, 20.0f)); + ground->CreateFixture(&sd); + + // Top horizontal + shape.SetTwoSided(b2Vec2(-20.0f, 20.0f), b2Vec2(20.0f, 20.0f)); + ground->CreateFixture(&sd); + + // Bottom horizontal + shape.SetTwoSided(b2Vec2(-20.0f, -20.0f), b2Vec2(20.0f, -20.0f)); + ground->CreateFixture(&sd); + } + + { + b2Transform xf1; + xf1.q.Set(0.3524f * b2_pi); + xf1.p = xf1.q.GetXAxis(); + + b2Vec2 vertices[3]; + vertices[0] = b2Mul(xf1, b2Vec2(-1.0f, 0.0f)); + vertices[1] = b2Mul(xf1, b2Vec2(1.0f, 0.0f)); + vertices[2] = b2Mul(xf1, b2Vec2(0.0f, 0.5f)); + + b2PolygonShape poly1; + poly1.Set(vertices, 3); + + b2FixtureDef sd1; + sd1.shape = &poly1; + sd1.density = 2.0f; + + b2Transform xf2; + xf2.q.Set(-0.3524f * b2_pi); + xf2.p = -xf2.q.GetXAxis(); + + vertices[0] = b2Mul(xf2, b2Vec2(-1.0f, 0.0f)); + vertices[1] = b2Mul(xf2, b2Vec2(1.0f, 0.0f)); + vertices[2] = b2Mul(xf2, b2Vec2(0.0f, 0.5f)); + + b2PolygonShape poly2; + poly2.Set(vertices, 3); + + b2FixtureDef sd2; + sd2.shape = &poly2; + sd2.density = 2.0f; + + b2BodyDef bd; + bd.type = b2_dynamicBody; + + bd.position.Set(0.0f, 3.0); + bd.angle = b2_pi; + bd.allowSleep = false; + m_body = m_world->CreateBody(&bd); + m_body->CreateFixture(&sd1); + m_body->CreateFixture(&sd2); + + float gravity = 10.0f; + float I = m_body->GetInertia(); + float mass = m_body->GetMass(); + + // Compute an effective radius that can be used to + // set the max torque for a friction joint + // For a circle: I = 0.5 * m * r * r ==> r = sqrt(2 * I / m) + float radius = b2Sqrt(2.0f * I / mass); + + b2FrictionJointDef jd; + jd.bodyA = ground; + jd.bodyB = m_body; + jd.localAnchorA.SetZero(); + jd.localAnchorB = m_body->GetLocalCenter(); + jd.collideConnected = true; + jd.maxForce = 0.5f * mass * gravity; + jd.maxTorque = 0.2f * mass * radius * gravity; + + m_world->CreateJoint(&jd); + } + + { + b2PolygonShape shape; + shape.SetAsBox(0.5f, 0.5f); + + b2FixtureDef fd; + fd.shape = &shape; + fd.density = 1.0f; + fd.friction = 0.3f; + + for (int i = 0; i < 10; ++i) + { + b2BodyDef bd; + bd.type = b2_dynamicBody; + + bd.position.Set(0.0f, 7.0f + 1.54f * i); + b2Body* body = m_world->CreateBody(&bd); + + body->CreateFixture(&fd); + + float gravity = 10.0f; + float I = body->GetInertia(); + float mass = body->GetMass(); + + // For a circle: I = 0.5 * m * r * r ==> r = sqrt(2 * I / m) + float radius = b2Sqrt(2.0f * I / mass); + + b2FrictionJointDef jd; + jd.localAnchorA.SetZero(); + jd.localAnchorB.SetZero(); + jd.bodyA = ground; + jd.bodyB = body; + jd.collideConnected = true; + jd.maxForce = mass * gravity; + jd.maxTorque = 0.1f * mass * radius * gravity; + + m_world->CreateJoint(&jd); + } + } + } + + void Step(Settings& settings) override + { + g_debugDraw.DrawString(5, m_textLine, "Forward (W), Turn (A) and (D)"); + m_textLine += m_textIncrement; + + if (glfwGetKey(g_mainWindow, GLFW_KEY_W) == GLFW_PRESS) + { + b2Vec2 f = m_body->GetWorldVector(b2Vec2(0.0f, -50.0f)); + b2Vec2 p = m_body->GetWorldPoint(b2Vec2(0.0f, 3.0f)); + m_body->ApplyForce(f, p, true); + } + + if (glfwGetKey(g_mainWindow, GLFW_KEY_A) == GLFW_PRESS) + { + m_body->ApplyTorque(10.0f, true); + } + + if (glfwGetKey(g_mainWindow, GLFW_KEY_D) == GLFW_PRESS) + { + m_body->ApplyTorque(-10.0f, true); + } + + Test::Step(settings); + } + + static Test* Create() + { + return new ApplyForce; + } + + b2Body* m_body; +}; + +static int testIndex = RegisterTest("Forces", "Apply Force", ApplyForce::Create); |