acceleration.h

00001 /* Copyright 2011 Adam Green (http://mbed.org/users/AdamGreen/)
00002 
00003    Licensed under the Apache License, Version 2.0 (the "License");
00004    you may not use this file except in compliance with the License.
00005    You may obtain a copy of the License at
00006 
00007        http://www.apache.org/licenses/LICENSE-2.0
00008 
00009    Unless required by applicable law or agreed to in writing, software
00010    distributed under the License is distributed on an "AS IS" BASIS,
00011    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00012    See the License for the specific language governing permissions and
00013    limitations under the License.
00014 */
00015 /* Classes to apply acceleration to input from Sparkfun's Blackberry Trackball
00016    Breakout board.
00017 */
00018 #ifndef _ACCELERATION_H_
00019 #define _ACCELERATION_H_
00020 
00021 #include <mbed.h>
00022 #include <limits.h>
00023 #include "BBTrackball.h"
00024 
00025 
00026 
00027 /* Class which can apply acceleration to each of the roller inputs from the
00028    Sparkfun Blackberry Trackball device.
00029 */
00030 template<size_t SampleCount,
00031          int    DecelerateThreshold,
00032          int    AccelerateThreshold,
00033          int    MaxAcceleration>
00034 class CAcceleratedRoller
00035 {
00036 public:
00037     CAcceleratedRoller(void)
00038     {
00039         m_Acceleration = 1;
00040         m_VelocitySum = 0;
00041         m_SampleIndex = 0;
00042         memset(m_Samples, 0, sizeof(m_Samples));
00043     }
00044 
00045     void AccumulateSample(short CurrVelocity);
00046     int  Acceleration(void) const
00047     {
00048         return m_Acceleration;
00049     }
00050     
00051 protected:
00052     unsigned char   ClampToUChar(short Value);
00053     int             m_Acceleration;
00054     int             m_VelocitySum;
00055     size_t          m_SampleIndex;
00056     unsigned char   m_Samples[SampleCount];
00057 };
00058 
00059 
00060 class CAcceleratedTrackball : public CBBTrackball
00061 {
00062 public:
00063     CAcceleratedTrackball(PinName BluePin,
00064                           PinName RedPin,
00065                           PinName GreenPin,
00066                           PinName WhitePin,
00067                           PinName UpPin,
00068                           PinName DownPin,
00069                           PinName LeftPin,
00070                           PinName RightPin,
00071                           PinName ButtonPin) : CBBTrackball(BluePin,
00072                                                             RedPin,
00073                                                             GreenPin,
00074                                                             WhitePin,
00075                                                             UpPin,
00076                                                             DownPin,
00077                                                             LeftPin,
00078                                                             RightPin,
00079                                                             ButtonPin),
00080                                                m_IterationsSinceLastMotion(INT_MAX)
00081     {
00082     }                                                            
00083     void GetState(int& DeltaX, int& DeltaY, int& ButtonPressed);
00084 
00085 protected:
00086     void    UpdateLEDColourBasedOnMotion(int VelocityX, 
00087                                          int VelocityY, 
00088                                          int ButtonPressed);
00089     
00090     int                                 m_IterationsSinceLastMotion;
00091     CAcceleratedRoller<250, 4, 4, 40>   m_UpAcceleration;
00092     CAcceleratedRoller<250, 4, 4, 40>   m_DownAcceleration;
00093     CAcceleratedRoller<250, 4, 4, 30>   m_LeftAcceleration;
00094     CAcceleratedRoller<250, 4, 4, 30>   m_RightAcceleration;
00095 };
00096 
00097 #endif // _ACCELERATION_H_