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Kaleidoscope/src/kaleidoscope/plugin/LEDEffect-Chase.cpp

71 lines
2.6 KiB

/* Kaleidoscope-LEDEffect-Chase - A Chase LED effect for Kaleidoscope.
* Copyright (C) 2017-2018 Keyboard.io, Inc.
*
* This program 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, version 3.
*
* This program 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
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "Kaleidoscope-LEDEffect-Chase.h"
namespace kaleidoscope {
namespace plugin {
void LEDChaseEffect::update(void) {
if (!Kaleidoscope.has_leds)
return;
uint16_t now = Kaleidoscope.millisAtCycleStart();
if ((now - last_update_) < update_delay_) {
return;
}
last_update_ = now;
// The red LED is at `pos_`; the blue one follows behind. `direction_` is
// either +1 or -1; `distance_` is the gap between them.
int8_t pos2 = pos_ - (direction_ * distance_);
// First, we turn off the LEDs that were turned on in the previous update.
// `pos_` is always in the valid range (0 <= pos_ < LED_COUNT), but after it
// changes direction, for the first few updates, `pos2` will be out of bounds.
// Since it's an unsigned integer, even when it would have a value below zero,
// it underflows and so one test is good for both ends of the range.
::LEDControl.setCrgbAt(pos_, CRGB(0, 0, 0));
if (pos2 < LED_COUNT)
::LEDControl.setCrgbAt(pos2, CRGB(0, 0, 0));
// Next, we adjust the red light's position. If the direction hasn't changed (the red
// light isn't out of bounds), we also adjust the blue light's position to match the red
// one. If the new position puts it out of bounds, we reverse the direction, and bring
// it back in bounds. When this happens, the blue light "jumps" behind the red one, and
// will be out of bounds. The simplest way to do this is to assign it a value that is
// known to be invalid (LED_COUNT).
pos_ += direction_;
if (pos_ < LED_COUNT && pos_ > 0) {
pos2 += direction_;
} else {
direction_ = -direction_;
pos_ += direction_;
pos2 = LED_COUNT;
}
// Last, we turn on the LEDs at their new positions. As before, the blue light (pos2) is
// only set if it's in the valid LED range.
::LEDControl.setCrgbAt(pos_, CRGB(255, 0, 0));
if (pos2 < LED_COUNT)
::LEDControl.setCrgbAt(pos2, CRGB(0, 0, 255));
}
}
}
kaleidoscope::plugin::LEDChaseEffect LEDChaseEffect;