summaryrefslogtreecommitdiff
path: root/Client/ThirdParty/Box2D/testbed/tests/wrecking_ball.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'Client/ThirdParty/Box2D/testbed/tests/wrecking_ball.cpp')
-rw-r--r--Client/ThirdParty/Box2D/testbed/tests/wrecking_ball.cpp165
1 files changed, 165 insertions, 0 deletions
diff --git a/Client/ThirdParty/Box2D/testbed/tests/wrecking_ball.cpp b/Client/ThirdParty/Box2D/testbed/tests/wrecking_ball.cpp
new file mode 100644
index 0000000..74a61b4
--- /dev/null
+++ b/Client/ThirdParty/Box2D/testbed/tests/wrecking_ball.cpp
@@ -0,0 +1,165 @@
+// 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"
+#include "imgui/imgui.h"
+
+/// This test shows how a distance joint can be used to stabilize a chain of
+/// bodies with a heavy payload. Notice that the distance joint just prevents
+/// excessive stretching and has no other effect.
+/// By disabling the distance joint you can see that the Box2D solver has trouble
+/// supporting heavy bodies with light bodies. Try playing around with the
+/// densities, time step, and iterations to see how they affect stability.
+/// This test also shows how to use contact filtering. Filtering is configured
+/// so that the payload does not collide with the chain.
+class WreckingBall : public Test
+{
+public:
+ WreckingBall()
+ {
+ b2Body* ground = NULL;
+ {
+ b2BodyDef bd;
+ ground = m_world->CreateBody(&bd);
+
+ b2EdgeShape shape;
+ shape.SetTwoSided(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f));
+ ground->CreateFixture(&shape, 0.0f);
+ }
+
+ {
+ b2PolygonShape shape;
+ shape.SetAsBox(0.5f, 0.125f);
+
+ b2FixtureDef fd;
+ fd.shape = &shape;
+ fd.density = 20.0f;
+ fd.friction = 0.2f;
+ fd.filter.categoryBits = 0x0001;
+ fd.filter.maskBits = 0xFFFF & ~0x0002;
+
+ b2RevoluteJointDef jd;
+ jd.collideConnected = false;
+
+ const int32 N = 10;
+ const float y = 15.0f;
+ m_distanceJointDef.localAnchorA.Set(0.0f, y);
+
+ b2Body* prevBody = ground;
+ for (int32 i = 0; i < N; ++i)
+ {
+ b2BodyDef bd;
+ bd.type = b2_dynamicBody;
+ bd.position.Set(0.5f + 1.0f * i, y);
+ if (i == N - 1)
+ {
+ bd.position.Set(1.0f * i, y);
+ bd.angularDamping = 0.4f;
+ }
+
+ b2Body* body = m_world->CreateBody(&bd);
+
+ if (i == N - 1)
+ {
+ b2CircleShape circleShape;
+ circleShape.m_radius = 1.5f;
+ b2FixtureDef sfd;
+ sfd.shape = &circleShape;
+ sfd.density = 100.0f;
+ sfd.filter.categoryBits = 0x0002;
+ body->CreateFixture(&sfd);
+ }
+ else
+ {
+ body->CreateFixture(&fd);
+ }
+
+ b2Vec2 anchor(float(i), y);
+ jd.Initialize(prevBody, body, anchor);
+ m_world->CreateJoint(&jd);
+
+ prevBody = body;
+ }
+
+ m_distanceJointDef.localAnchorB.SetZero();
+
+ float extraLength = 0.01f;
+ m_distanceJointDef.minLength = 0.0f;
+ m_distanceJointDef.maxLength = N - 1.0f + extraLength;
+ m_distanceJointDef.bodyB = prevBody;
+ }
+
+ {
+ m_distanceJointDef.bodyA = ground;
+ m_distanceJoint = m_world->CreateJoint(&m_distanceJointDef);
+ m_stabilize = true;
+ }
+ }
+
+ void UpdateUI() override
+ {
+ ImGui::SetNextWindowPos(ImVec2(10.0f, 100.0f));
+ ImGui::SetNextWindowSize(ImVec2(200.0f, 100.0f));
+ ImGui::Begin("Wrecking Ball Controls", nullptr, ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize);
+
+ if (ImGui::Checkbox("Stabilize", &m_stabilize))
+ {
+ if (m_stabilize == true && m_distanceJoint == nullptr)
+ {
+ m_distanceJoint = m_world->CreateJoint(&m_distanceJointDef);
+ }
+ else if (m_stabilize == false && m_distanceJoint != nullptr)
+ {
+ m_world->DestroyJoint(m_distanceJoint);
+ m_distanceJoint = nullptr;
+ }
+ }
+
+ ImGui::End();
+ }
+
+ void Step(Settings& settings) override
+ {
+ Test::Step(settings);
+
+ if (m_distanceJoint)
+ {
+ g_debugDraw.DrawString(5, m_textLine, "Distance Joint ON");
+ }
+ else
+ {
+ g_debugDraw.DrawString(5, m_textLine, "Distance Joint OFF");
+ }
+ m_textLine += m_textIncrement;
+ }
+
+ static Test* Create()
+ {
+ return new WreckingBall;
+ }
+
+ b2DistanceJointDef m_distanceJointDef;
+ b2Joint* m_distanceJoint;
+ bool m_stabilize;
+};
+
+static int testIndex = RegisterTest("Examples", "Wrecking Ball", WreckingBall::Create);