tlc_fades.h

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/*  Copyright (c) 2009 by Alex Leone <acleone ~AT~ gmail.com>

    This file is part of the Arduino TLC5940 Library.

    The Arduino TLC5940 Library is free software: you can redistribute it
    and/or modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    The Arduino TLC5940 Library is distributed in the hope that it will be
    useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with The Arduino TLC5940 Library.  If not, see
    <http://www.gnu.org/licenses/>. */

#ifndef TLC_FADES_H
#define TLC_FADES_H

#include <avr/interrupt.h>

#include "Tlc5940.h"
#include "WProgram.h"

#ifndef TLC_FADE_BUFFER_LENGTH

#define TLC_FADE_BUFFER_LENGTH    24
#endif

struct Tlc_Fade {
    TLC_CHANNEL_TYPE channel; 
    int16_t startValue;       
    int16_t changeValue;      
    uint32_t startMillis;     
    uint32_t endMillis;       
} tlc_fadeBuffer[TLC_FADE_BUFFER_LENGTH];

uint8_t tlc_fadeBufferSize;

uint8_t tlc_updateFades();
uint8_t tlc_updateFades(uint32_t currentMillis);
uint8_t tlc_addFade(struct Tlc_Fade *fade);
uint8_t tlc_addFade(TLC_CHANNEL_TYPE channel, int16_t startValue,
                    int16_t endValue, uint32_t startMillis, uint32_t endMillis);
uint8_t tlc_isFading(TLC_CHANNEL_TYPE channel);
uint8_t tlc_removeFades(TLC_CHANNEL_TYPE channel);
static void tlc_removeFadeFromBuffer(Tlc_Fade *current, Tlc_Fade *end);

/* @{ */

uint8_t tlc_addFade(struct Tlc_Fade *fade)
{
    if (tlc_fadeBufferSize == TLC_FADE_BUFFER_LENGTH) {
        return 0; // fade buffer full
    }
    struct Tlc_Fade *p = tlc_fadeBuffer + tlc_fadeBufferSize++;
    p->channel = fade->channel;
    p->startValue = fade->startValue;
    p->changeValue = fade->changeValue;
    p->startMillis = fade->startMillis;
    p->endMillis = fade->endMillis;
    return tlc_fadeBufferSize;
}

uint8_t tlc_addFade(TLC_CHANNEL_TYPE channel, int16_t startValue,
                    int16_t endValue, uint32_t startMillis, uint32_t endMillis)
{
    if (tlc_fadeBufferSize == TLC_FADE_BUFFER_LENGTH) {
        return 0; // fade buffer full
    }
    struct Tlc_Fade *p = tlc_fadeBuffer + tlc_fadeBufferSize++;
    p->channel = channel;
    p->startValue = startValue;
    p->changeValue = endValue - startValue;
    p->startMillis = startMillis;
    p->endMillis = endMillis;
    return tlc_fadeBufferSize;
}

uint8_t tlc_isFading(TLC_CHANNEL_TYPE channel)
{
    struct Tlc_Fade *end = tlc_fadeBuffer + tlc_fadeBufferSize;
    for (struct Tlc_Fade *p = tlc_fadeBuffer; p < end; p++) {
        if (p->channel == channel) {
            return 1;
        }
    }
    return 0;
}

uint8_t tlc_removeFades(TLC_CHANNEL_TYPE channel)
{
    uint8_t removed = 0;
    struct Tlc_Fade *end = tlc_fadeBuffer + tlc_fadeBufferSize;
    for (struct Tlc_Fade *p = tlc_fadeBuffer; p < end; p++) {
        if (p->channel == channel) {
            removed++;
            tlc_removeFadeFromBuffer(p, --end);
        }
    }
    return removed;
}

static void tlc_removeFadeFromBuffer(struct Tlc_Fade *current,
                                     struct Tlc_Fade *endp)
{
    if (endp != current) { // if this is not the last fade
        current->channel = endp->channel;
        current->startValue = endp->startValue;
        current->changeValue = endp->changeValue;
        current->startMillis = endp->startMillis;
        current->endMillis = endp->endMillis;
    }
    tlc_fadeBufferSize--;
}

uint8_t tlc_updateFades()
{
    return tlc_updateFades(millis());
}

uint8_t tlc_updateFades(uint32_t currentMillis)
{
    struct Tlc_Fade *end = tlc_fadeBuffer + tlc_fadeBufferSize;
    uint8_t needsUpdate = 0;
    for (struct Tlc_Fade *p = tlc_fadeBuffer; p < end;){
        if (currentMillis >= p->endMillis) { // fade done
            Tlc.set(p->channel, p->startValue + p->changeValue);
            needsUpdate = 1;
            tlc_removeFadeFromBuffer(p, --end);
            continue;
        } else {
            uint32_t startMillis = p->startMillis;
            if (currentMillis >= startMillis) {
                Tlc.set(p->channel, p->startValue + p->changeValue
                        * (int32_t)(currentMillis - startMillis)
                        / (int32_t)(p->endMillis - startMillis));
                needsUpdate = 1;
            }
        }
        p++;
    }
    if (needsUpdate) {
        Tlc.update();
        if (tlc_fadeBufferSize == 0) {
            while (tlc_needXLAT)
                ;
        }
    }
    return tlc_fadeBufferSize;
}

/* @} */

#endif

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