60 lines
2.1 KiB
C++
60 lines
2.1 KiB
C++
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#ifndef _BODYENVIRONMENT_HPP
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#define _BODYENVIRONMENT_HPP
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#include "RigidBody.hpp"
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namespace yasim {
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// The values for position and orientation within the global reference
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// frame, along with their first and second time derivatives. The
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// orientation is stored as a matrix for simplicity. Note that
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// because it is orthonormal, its inverse is simply its transpose.
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// You can get local->global transformations by calling Math::tmul33()
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// and using the same matrix.
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struct State {
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double pos[3]; // position
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float orient[9]; // global->local xform matrix
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float v[3]; // velocity
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float rot[3]; // rotational velocity
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float acc[3]; // acceleration
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float racc[3]; // rotational acceleration
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// Simple initialization
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State() {
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for(int i=0; i<3; i++) {
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pos[i] = v[i] = rot[i] = acc[i] = racc[i] = 0;
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for(int j=0; j<3; j++)
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orient[3*i+j] = i==j ? 1 : 0;
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}
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}
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};
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//
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// Objects implementing this interface are responsible for calculating
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// external forces on a RigidBody object. These will then be used by
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// an Integrator to decide on a new solution to the state equations,
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// which will be reported to the BodyEnvironment for further action.
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//
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class BodyEnvironment
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{
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public:
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// This method inspects the "environment" in which a RigidBody
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// exists, calculates forces and torques on the body, and sets
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// them via addForce()/addTorque(). Because this method is called
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// multiple times ("trials") as part of a Runge-Kutta integration,
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// this is NOT the place to make decisions about anything but the
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// forces on the object. Note that the acc and racc fields of the
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// passed-in State object are undefined! (They are calculed BY
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// this method).
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virtual void calcForces(State* state) = 0;
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// Called when the RK4 integrator has determined a "real" new
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// point on the curve of life. Any side-effect producing checks
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// of body state vs. the environment can happen here (crashes,
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// etc...).
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virtual void newState(State* state) = 0;
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};
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}; // namespace yasim
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#endif // _BODYENVIRONMENT_HPP
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