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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 "settings.h"
#include "test.h"
#include "imgui/imgui.h"
// Test the wheel joint with motor, spring, and limit options.
class WheelJoint : public Test
{
public:
WheelJoint()
{
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);
}
m_enableLimit = true;
m_enableMotor = false;
m_motorSpeed = 10.0f;
{
b2CircleShape shape;
shape.m_radius = 2.0f;
b2BodyDef bd;
bd.type = b2_dynamicBody;
bd.position.Set(0.0f, 10.0f);
bd.allowSleep = false;
b2Body* body = m_world->CreateBody(&bd);
body->CreateFixture(&shape, 5.0f);
b2WheelJointDef jd;
// Horizontal
jd.Initialize(ground, body, bd.position, b2Vec2(0.0f, 1.0f));
jd.motorSpeed = m_motorSpeed;
jd.maxMotorTorque = 10000.0f;
jd.enableMotor = m_enableMotor;
jd.lowerTranslation = -3.0f;
jd.upperTranslation = 3.0f;
jd.enableLimit = m_enableLimit;
float hertz = 1.0f;
float dampingRatio = 0.7f;
b2LinearStiffness(jd.stiffness, jd.damping, hertz, dampingRatio, ground, body);
m_joint = (b2WheelJoint*)m_world->CreateJoint(&jd);
}
}
void Step(Settings& settings) override
{
Test::Step(settings);
float torque = m_joint->GetMotorTorque(settings.m_hertz);
g_debugDraw.DrawString(5, m_textLine, "Motor Torque = %4.0f", torque);
m_textLine += m_textIncrement;
b2Vec2 F = m_joint->GetReactionForce(settings.m_hertz);
g_debugDraw.DrawString(5, m_textLine, "Reaction Force = (%4.1f, %4.1f)", F.x, F.y);
m_textLine += m_textIncrement;
}
void UpdateUI() override
{
ImGui::SetNextWindowPos(ImVec2(10.0f, 100.0f));
ImGui::SetNextWindowSize(ImVec2(200.0f, 100.0f));
ImGui::Begin("Joint Controls", nullptr, ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize);
if (ImGui::Checkbox("Limit", &m_enableLimit))
{
m_joint->EnableLimit(m_enableLimit);
}
if (ImGui::Checkbox("Motor", &m_enableMotor))
{
m_joint->EnableMotor(m_enableMotor);
}
if (ImGui::SliderFloat("Speed", &m_motorSpeed, -100.0f, 100.0f, "%.0f"))
{
m_joint->SetMotorSpeed(m_motorSpeed);
}
ImGui::End();
}
static Test* Create()
{
return new WheelJoint;
}
b2WheelJoint* m_joint;
float m_motorSpeed;
bool m_enableMotor;
bool m_enableLimit;
};
static int testIndex = RegisterTest("Joints", "Wheel", WheelJoint::Create);
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