File content as of revision 4:ee635fc62b6e:

#ifndef _TPIXY_H
#define _TPIXY_H
#include "mbed.h"
#include "TPixyInterface.h"

// Communication/misc parameters
#define PIXY_INITIAL_ARRAYSIZE      30
#define PIXY_MAXIMUM_ARRAYSIZE      130
#define PIXY_START_WORD             0xaa55
#define PIXY_START_WORD_CC          0xaa56
#define PIXY_START_WORDX            0x55aa
#define PIXY_MAX_SIGNATURE          7
#define PIXY_DEFAULT_ARGVAL         0xffff

// Pixy x-y position values
#define PIXY_MIN_X                  0L
#define PIXY_MAX_X                  319L
#define PIXY_MIN_Y                  0L
#define PIXY_MAX_Y                  199L
#define PIXY_CENTER_X               ((PIXY_MAX_X-PIXY_MIN_X)/2)
// RC-servo values
#define PIXY_RCS_MIN_POS            650L
#define PIXY_RCS_MAX_POS            1000L
#define PIXY_RCS_CENTER_POS         ((PIXY_RCS_MAX_POS-PIXY_RCS_MIN_POS)/2)

enum BlockType {
    NORMAL_BLOCK,
    CC_BLOCK
};

struct Block {
    uint16_t signature;
    uint16_t x;
    uint16_t y;
    uint16_t width;
    uint16_t height;
    uint16_t angle;
};

template <class TPixyInterface> class TPixy
{
public:
    Serial* serial;
    Block *blocks;
    TPixy(TPixyInterface* type, Serial* serialOut = NULL, uint16_t arg = PIXY_DEFAULT_ARGVAL);
    ~TPixy();
    uint16_t getBlocks(uint16_t maxBlocks = 1000);
    int8_t setServos(uint16_t s0, uint16_t s1);
    void init();

private:
    TPixyInterface* link;
    BlockType blockType;
    bool getStart();
    void resize();
    bool skipStart;
    uint16_t blockCount;
    uint16_t blockArraySize;
};

template <class TPixyInterface> void TPixy<TPixyInterface>::init()
{
    link->init();
}


template <class TPixyInterface> TPixy<TPixyInterface>::TPixy(TPixyInterface* type, Serial* serialOut, uint16_t arg) : serial(serialOut), link(type)
{
    skipStart = false;
    blockCount = 0;
    blockArraySize = PIXY_INITIAL_ARRAYSIZE;
    blocks = (Block *)malloc(sizeof(Block)*blockArraySize);
    link->setArg(arg);
}

template <class TPixyInterface> TPixy<TPixyInterface>::~TPixy()
{
    free(blocks);
}

template <class TPixyInterface> bool TPixy<TPixyInterface>::getStart()
{
    uint16_t w, lastw;
    lastw = 0xffff;
    while(true) {
        w = link->getWord();
        if (w == 0 && lastw == 0) {
            wait_ms(10);
            return false;
        } else if (w == PIXY_START_WORD && lastw == PIXY_START_WORD) {
            blockType = NORMAL_BLOCK;
            return true;
        } else if (w == PIXY_START_WORD_CC && lastw == PIXY_START_WORD) {
            blockType = CC_BLOCK;
            return true;
        } else if (w == PIXY_START_WORDX) {
            if (serial != NULL) {
                serial->printf("reorder");
            }
            link->getByte(); // resync
        }
        lastw = w;
    }
}

template <class TPixyInterface> void TPixy<TPixyInterface>::resize()
{
    blockArraySize += PIXY_INITIAL_ARRAYSIZE;
    blocks = (Block *)realloc(blocks, sizeof(Block)*blockArraySize);
}

template <class TPixyInterface> uint16_t TPixy<TPixyInterface>::getBlocks(uint16_t maxBlocks)
{
    uint8_t i;
    uint16_t w, checksum, sum;
    Block *block;

    if (!skipStart) {
        if (getStart() == false) {
            return 0;
        }
    } else {
        skipStart = false;
    }
    for(blockCount = 0; blockCount < maxBlocks && blockCount < PIXY_MAXIMUM_ARRAYSIZE;) {
        checksum = link->getWord();
        if (checksum == PIXY_START_WORD) { 
            skipStart = true;
            blockType = NORMAL_BLOCK;
            if (serial != NULL) {
                serial->printf("skip");
            }
            return blockCount;
        } else if (checksum == PIXY_START_WORD_CC) {
            skipStart = true;
            blockType = CC_BLOCK;
            return blockCount;
        } else if (checksum == 0) {
            return blockCount;
        }
        if (blockCount > blockArraySize) {
            resize();
        }
        block = blocks + blockCount;

        for (i = 0, sum = 0; i < sizeof(Block)/sizeof(uint16_t); i++) {
            if (blockType == NORMAL_BLOCK && i >= 5) { // skip
                block->angle = 0;
                break;
            }
            w = link->getWord();
            sum += w;
            *((uint16_t *)block + i) = w;
        }

        if (checksum == sum) {
            blockCount++;
        } else {
            w = link->getWord();
            if (serial != NULL) {
                serial->printf("cs error");
            }
        }
        if (w == PIXY_START_WORD) {
            blockType = NORMAL_BLOCK;
        } else if (w == PIXY_START_WORD_CC) {
            blockType = CC_BLOCK;
        } else {
            return blockCount;
        }
    }
    return blockCount;
}

template <class TPixyInterface> int8_t TPixy<TPixyInterface>::setServos(uint16_t s0, uint16_t s1)
{
    uint8_t outBuf[6];
    outBuf[0] = 0x00;
    outBuf[1] = 0xff;
    *(uint16_t *)(outBuf + 2) = s0;
    *(uint16_t *)(outBuf + 4) = s1;
    return link->send(outBuf, 6);
}

#endif