b2TensorDampingController.h
上传用户:gb3593
上传日期:2022-01-07
资源大小:3028k
文件大小:3k
源码类别:
游戏引擎
开发平台:
Visual C++
- /*
- * Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
- *
- * 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.
- */
- #ifndef B2_TENSORDAMPINGCONTROLLER_H
- #define B2_TENSORDAMPINGCONTROLLER_H
- #include "b2Controller.h"
- class b2TensorDampingControllerDef;
- /// Applies top down linear damping to the controlled bodies
- /// The damping is calculated by multiplying velocity by a matrix in local co-ordinates.
- class b2TensorDampingController : public b2Controller{
- public:
- /// Tensor to use in damping model
- b2Mat22 T;
- /*Some examples (matrixes in format (row1; row2) )
- (-a 0;0 -a) Standard isotropic damping with strength a
- (0 a;-a 0) Electron in fixed field - a force at right angles to velocity with proportional magnitude
- (-a 0;0 -b) Differing x and y damping. Useful e.g. for top-down wheels.
- */
- //By the way, tensor in this case just means matrix, don't let the terminology get you down.
- /// Set this to a positive number to clamp the maximum amount of damping done.
- float32 maxTimestep;
- // Typically one wants maxTimestep to be 1/(max eigenvalue of T), so that damping will never cause something to reverse direction
- /// @see b2Controller::Step
- void Step(const b2TimeStep& step);
- protected:
- void Destroy(b2BlockAllocator* allocator);
- private:
- friend class b2TensorDampingControllerDef;
- b2TensorDampingController(const b2TensorDampingControllerDef* def);
- };
- /// This class is used to build tensor damping controllers
- class b2TensorDampingControllerDef : public b2ControllerDef
- {
- public:
- /// Tensor to use in damping model
- b2Mat22 T;
- /// Set this to a positive number to clamp the maximum amount of damping done.
- float32 maxTimestep;
- /// Sets damping independantly along the x and y axes
- void SetAxisAligned(float32 xDamping,float32 yDamping);
- private:
- b2TensorDampingController* Create(b2BlockAllocator* allocator) const;
- };
- #endif