Pressing any button causes the vehicle's maximum speed to change

[capp-adocia]

Hello, I have used the PhysX5.5.0 SnippetVehicle2FourWheelDrive project for reference and completed the function of simulating the movement of the car. However, when I get the linear velocity of the vehicle through the function gVehicle.mPhysXState.physxActor.rigidBody->getLinearVelocity(), a strange phenomenon occurs. When I press the forward button, the vehicle accelerates to a maximum speed of 46.9km/h. This looks good, but as long as I press any key (the forward key is kept pressed), such as "T", the vehicle's speed will increase until it reaches 186km/h. I checked which keys I pressed would trigger events, but the "T" I entered did not trigger any corresponding events. What's going on?

Here are some relevant codes

• Key events:

void OnKey(int key, int scancode, int action, int mods) {
	if (action == SDL_KEYDOWN || action == SDL_KEYUP) {
		// 处理油门、后退、转向
		switch (key) {
		case SDLK_KP_8:
			handleThrottle(action);
			break;
		case SDLK_KP_2:
			handleBackward(action);
			break;
		case SDLK_KP_4:
			handleSteering(action, true); // true 左转
			break;
		case SDLK_KP_6:
			handleSteering(action, false); // false 右转
			break;
		case SDLK_SPACE:
			createDynamic(PxTransform(PxVec3(0, 20, 2), PxQuat(1.0f, 0.0f, 0.0f, 0.0f)), PxSphereGeometry(0.5f), PxVec3(0., 1., 0.) * 10.0f);
			break;
		case SDLK_LSHIFT:
			VehicleShift(action);
			break;
		// 加速
		case SDLK_LCTRL:
			VehicleAccelerate(action);
			break;
		default:
			break;
		}
		// 调用相机控制
		cameraControl->onKey(key, action, mods);
	}
}

• Forward function

// 方向键按键函数
void handleThrottle(int action) {
	if (action == SDL_KEYDOWN) {
		throttle();
	}
	else if (action == SDL_KEYUP) {
		brake();
	}
}

// 设置前进
void throttle()
{
	// 设置油门
	gVehicle.mCommandState.throttle = 1.0f;  // 油门
	gVehicle.mCommandState.brakes[0] = 0.0f;  // 刹车保持关闭
	gVehicle.mCommandState.brakes[1] = 0.0f;  // 刹车保持关闭

	gVehicle.mEngineDriveState.gearboxState.currentGear = 2;
	gVehicle.mEngineDriveState.gearboxState.targetGear = 2;
	gVehicle.mTransmissionCommandState.targetGear = PxVehicleEngineDriveTransmissionCommandState::eAUTOMATIC_GEAR;
}
// 刹车
void brake()
{
	gVehicle.mCommandState.throttle = 0.0f;  // 油门完全关闭
}

• ImGui display speed

void renderIMGUI()
{
	// 1. 创建一个新的IMGUI帧
	ImGui_ImplOpenGL3_NewFrame();
	ImGui_ImplSDL2_NewFrame();
	ImGui::NewFrame();
	ImGuiIO& io = ImGui::GetIO(); (void)io;
	io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
	io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls

	// 2. 创建UI并放置一些控件
	ImGui::Begin("OpenGL"); // 创建一个新的窗口
	ImGui::Text("FPS: %.2f", io.Framerate); // 显示帧率
	// 坐标
	{
		// 获取小车的位置
		glm::mat4 model = scene->getChildren()[2]->getModelMatrixV2();
		glm::vec3 targetPosition = glm::vec3(model[3]); // 获取模型矩阵的平移部分，即物体的位置
		ImGui::Text("Position: (%.2f, %.2f, %.2f)", targetPosition.x, targetPosition.y, targetPosition.z);
	}
	// 速度
	{
		// 获取小车的线性速度
		const PxVec3 linVel1 = gVehicle.mPhysXState.physxActor.rigidBody->getLinearVelocity();
		ImGui::Text("Velocity: (%.2f, %.2f, %.2f)", linVel1.x, linVel1.y, linVel1.z);

		// 计算速度的大小（即速度的模长）
		float speedMagnitude = linVel1.magnitude();
		float speedKmh = speedMagnitude * 3.6f; // 转成km/h
        ImGui::Text("Speed: %.2f Km/h", speedKmh); // 显示速度的大小
	}

	ImGui::End();
	// 3. 执行UI渲染
	ImGui::Render();
	// 获取当前窗口的宽高
	int display_w = 0, display_h = 0;
	SDL_GL_GetDrawableSize(glApp.getWindow(), &display_w, &display_h);
	glViewport(0, 0, display_w, display_h);
	// 渲染ImGui的绘制数据
	ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
}

• Initialization and updating of PhysX vehicles

The vehicle parameters in the initVehicles() function are consistent with those in the SnippetVehicle2FourWheelDrive project.

PxVehiclePhysXSimulationContext gVehicleSimulationContext;
//The vehicle with engine drivetrain
EngineDriveVehicle gVehicle; // 第一辆车

bool initVehicles()
{
	// 现有的第一辆车的初始化
	LoadBaseParams(gVehicle.mBaseParams);
	setPhysXIntegrationParams(gVehicle.mBaseParams.axleDescription, gPhysXMaterialFrictions, gNbPhysXMaterialFrictions, gPhysXDefaultMaterialFriction, gVehicle.mPhysXParams);

	LoadEngineDrivertrainParams(gVehicle.mEngineDriveParams);
	if (!gVehicle.initialize(*gPhysics, PxCookingParams(PxTolerancesScale()), *gMaterial, EngineDriveVehicle::eDIFFTYPE_FOURWHEELDRIVE))
	{
		return false;
	}
	// 设置车辆的初始位置和方向
	PxTransform pose1(PxVec3(0.0f, 0.2f, 0.0f), PxQuat(PxIdentity));  // 第一辆车
	gVehicle.setUpActor(*gScene, pose1, "EngineDrive1");

	// 初始化模拟上下文
	gVehicleSimulationContext.setToDefault();
	gVehicleSimulationContext.frame.lngAxis = PxVehicleAxes::ePosZ;
	gVehicleSimulationContext.frame.latAxis = PxVehicleAxes::ePosX;
	gVehicleSimulationContext.frame.vrtAxis = PxVehicleAxes::ePosY;
	gVehicleSimulationContext.scale.scale = 2.0f;
	gVehicleSimulationContext.gravity = gGravity;
	gVehicleSimulationContext.physxScene = gScene;
	gVehicleSimulationContext.physxActorUpdateMode = PxVehiclePhysXActorUpdateMode::eAPPLY_ACCELERATION;

	return true;
}

void stepPhysics()
{
	const PxReal timestep = 1.0f / 60.0f;

	// 第一辆车的物理步进
	gVehicle.mCommandState.nbBrakes = 1; // 设置刹车数量为1
	const PxVec3 linVel1 = gVehicle.mPhysXState.physxActor.rigidBody->getLinearVelocity();
	const PxVec3 forwardDir1 = gVehicle.mPhysXState.physxActor.rigidBody->getGlobalPose().q.getBasisVector2();
	const PxReal forwardSpeed1 = linVel1.dot(forwardDir1);

	const PxU8 nbSubsteps1 = (forwardSpeed1 < 5.0f ? 3 : 1);
	gVehicle.mComponentSequence.setSubsteps(gVehicle.mComponentSequenceSubstepGroupHandle, nbSubsteps1);
	gVehicle.step(timestep, gVehicleSimulationContext);

	gScene->simulate(timestep);
	gScene->fetchResults(true);
}

Here is my video demonstration

2.13.mp4

At about 13 seconds in the video, I pressed the "T" key, and then it started to accelerate until it reached about 186km/h. I spent an afternoon troubleshooting, but still couldn't find the real problem. I obviously didn't have any key events related to "T", but in fact it did trigger a certain event. This is really a weird problem.