Optimize Neopixel library for maximum performance

This commit is contained in:
Daniel Öster 2025-08-17 00:19:45 +03:00
parent 9a898b72e2
commit ce7547f71e
4 changed files with 33 additions and 503 deletions

View file

@ -1,368 +1,38 @@
/*!
* @file Adafruit_NeoPixel.cpp
*
* @mainpage Arduino Library for driving Adafruit NeoPixel addressable LEDs,
* FLORA RGB Smart Pixels and compatible devicess -- WS2811, WS2812, WS2812B,
* SK6812, etc.
*
* @section intro_sec Introduction
*
* This is the documentation for Adafruit's NeoPixel library for the
* Arduino platform, allowing a broad range of microcontroller boards
* (most AVR boards, many ARM devices, ESP8266 and ESP32, among others)
* to control Adafruit NeoPixels, FLORA RGB Smart Pixels and compatible
* devices -- WS2811, WS2812, WS2812B, SK6812, etc.
*
* Adafruit invests time and resources providing this open source code,
* please support Adafruit and open-source hardware by purchasing products
* from Adafruit!
*
* @section author Author
*
* Written by Phil "Paint Your Dragon" Burgess for Adafruit Industries,
* with contributions by PJRC, Michael Miller and other members of the
* open source community.
*
* @section license License
*
* This file is part of the Adafruit_NeoPixel library.
*
* Adafruit_NeoPixel is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* Adafruit_NeoPixel 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with NeoPixel. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
/*Based on the Adafruit Neopixel library, which has been heavily modified to support only 1x RGB LED for lowest possible CPU usage*/
#include "Adafruit_NeoPixel.h"
/*!
@brief NeoPixel constructor when length, pin and pixel type are known
at compile-time.
@param n Number of NeoPixels in strand.
@param p Arduino pin number which will drive the NeoPixel data in.
@param t Pixel type -- add together NEO_* constants defined in
Adafruit_NeoPixel.h, for example NEO_GRB+NEO_KHZ800 for
NeoPixels expecting an 800 KHz (vs 400 KHz) data stream
with color bytes expressed in green, red, blue order per
pixel.
@return Adafruit_NeoPixel object. Call the begin() function before use.
*/
Adafruit_NeoPixel::Adafruit_NeoPixel(uint16_t n, int16_t p, neoPixelType t)
: begun(false), brightness(0), pixels(NULL), endTime(0) {
updateType(t);
updateLength(n);
extern "C" void espShow(uint16_t pin, uint8_t *pixels, uint8_t numBytes);
Adafruit_NeoPixel::Adafruit_NeoPixel(int16_t p) : pixels(NULL) {
updateLength();
setPin(p);
}
/*!
@brief "Empty" NeoPixel constructor when length, pin and/or pixel type
are not known at compile-time, and must be initialized later with
updateType(), updateLength() and setPin().
@return Adafruit_NeoPixel object. Call the begin() function before use.
@note This function is deprecated, here only for old projects that
may still be calling it. New projects should instead use the
'new' keyword with the first constructor syntax (length, pin,
type).
*/
Adafruit_NeoPixel::Adafruit_NeoPixel()
:
begun(false), numLEDs(0), numBytes(0), pin(-1), brightness(0),
pixels(NULL), rOffset(1), gOffset(0), bOffset(2), wOffset(1), endTime(0) {
}
/*!
@brief Deallocate Adafruit_NeoPixel object, set data pin back to INPUT.
*/
Adafruit_NeoPixel::~Adafruit_NeoPixel() {
void Adafruit_NeoPixel::updateLength(void) {
free(pixels);
if (pin >= 0)
pinMode(pin, INPUT);
pixels = (uint8_t *)malloc(numBytes);
if (pixels) memset(pixels, 0, numBytes);
}
/*!
@brief Configure NeoPixel pin for output.
*/
void Adafruit_NeoPixel::begin(void) {
if (pin >= 0) {
pinMode(pin, OUTPUT);
digitalWrite(pin, LOW);
}
begun = true;
}
/*!
@brief Change the length of a previously-declared Adafruit_NeoPixel
strip object. Old data is deallocated and new data is cleared.
Pin number and pixel format are unchanged.
@param n New length of strip, in pixels.
@note This function is deprecated, here only for old projects that
may still be calling it. New projects should instead use the
'new' keyword with the first constructor syntax (length, pin,
type).
*/
void Adafruit_NeoPixel::updateLength(uint16_t n) {
free(pixels); // Free existing data (if any)
// Allocate new data -- note: ALL PIXELS ARE CLEARED
numBytes = n * ((wOffset == rOffset) ? 3 : 4);
if ((pixels = (uint8_t *)malloc(numBytes))) {
memset(pixels, 0, numBytes);
numLEDs = n;
} else {
numLEDs = numBytes = 0;
}
}
/*!
@brief Change the pixel format of a previously-declared
Adafruit_NeoPixel strip object. If format changes from one of
the RGB variants to an RGBW variant (or RGBW to RGB), the old
data will be deallocated and new data is cleared. Otherwise,
the old data will remain in RAM and is not reordered to the
new format, so it's advisable to follow up with clear().
@param t Pixel type -- add together NEO_* constants defined in
Adafruit_NeoPixel.h, for example NEO_GRB+NEO_KHZ800 for
NeoPixels expecting an 800 KHz (vs 400 KHz) data stream
with color bytes expressed in green, red, blue order per
pixel.
@note This function is deprecated, here only for old projects that
may still be calling it. New projects should instead use the
'new' keyword with the first constructor syntax
(length, pin, type).
*/
void Adafruit_NeoPixel::updateType(neoPixelType t) {
bool oldThreeBytesPerPixel = (wOffset == rOffset); // false if RGBW
wOffset = (t >> 6) & 0b11; // See notes in header file
rOffset = (t >> 4) & 0b11; // regarding R/G/B/W offsets
gOffset = (t >> 2) & 0b11;
bOffset = t & 0b11;
// If bytes-per-pixel has changed (and pixel data was previously
// allocated), re-allocate to new size. Will clear any data.
if (pixels) {
bool newThreeBytesPerPixel = (wOffset == rOffset);
if (newThreeBytesPerPixel != oldThreeBytesPerPixel)
updateLength(numLEDs);
}
}
extern "C" void espShow(uint16_t pin, uint8_t *pixels, uint32_t numBytes);
/*!
@brief Transmit pixel data in RAM to NeoPixels.
@note On most architectures, interrupts are temporarily disabled in
order to achieve the correct NeoPixel signal timing. This means
that the Arduino millis() and micros() functions, which require
interrupts, will lose small intervals of time whenever this
function is called (about 30 microseconds per RGB pixel, 40 for
RGBW pixels). There's no easy fix for this, but a few
specialized alternative or companion libraries exist that use
very device-specific peripherals to work around it.
*/
void Adafruit_NeoPixel::show(void) {
if (!pixels)
return;
// Data latch = 300+ microsecond pause in the output stream. Rather than
// put a delay at the end of the function, the ending time is noted and
// the function will simply hold off (if needed) on issuing the
// subsequent round of data until the latch time has elapsed. This
// allows the mainline code to start generating the next frame of data
// rather than stalling for the latch.
while (!canShow())
;
// endTime is a private member (rather than global var) so that multiple
// instances on different pins can be quickly issued in succession (each
// instance doesn't delay the next).
// In order to make this code runtime-configurable to work with any pin,
// SBI/CBI instructions are eschewed in favor of full PORT writes via the
// OUT or ST instructions. It relies on two facts: that peripheral
// functions (such as PWM) take precedence on output pins, so our PORT-
// wide writes won't interfere, and that interrupts are globally disabled
// while data is being issued to the LEDs, so no other code will be
// accessing the PORT. The code takes an initial 'snapshot' of the PORT
// state, computes 'pin high' and 'pin low' values, and writes these back
// to the PORT register as needed.
// NRF52 may use PWM + DMA (if available), may not need to disable interrupt
// ESP32 may not disable interrupts because espShow() uses RMT which tries to acquire locks
espShow(pin, pixels, numBytes);
endTime = micros(); // Save EOD time for latch on next call
}
/*!
@brief Set/change the NeoPixel output pin number. Previous pin,
if any, is set to INPUT and the new pin is set to OUTPUT.
@param p Arduino pin number (-1 = no pin).
*/
void Adafruit_NeoPixel::setPin(int16_t p) {
if (begun && (pin >= 0))
pinMode(pin, INPUT); // Disable existing out pin
if (pin >= 0) pinMode(pin, INPUT);
pin = p;
if (begun) {
if ((p >= 0)) {
pinMode(p, OUTPUT);
digitalWrite(p, LOW);
}
}
/*!
@brief Set a pixel's color using separate red, green and blue
components. If using RGBW pixels, white will be set to 0.
@param n Pixel index, starting from 0.
@param r Red brightness, 0 = minimum (off), 255 = maximum.
@param g Green brightness, 0 = minimum (off), 255 = maximum.
@param b Blue brightness, 0 = minimum (off), 255 = maximum.
*/
void Adafruit_NeoPixel::setPixelColor(uint16_t n, uint8_t r, uint8_t g,
uint8_t b) {
if (n < numLEDs) {
if (brightness) { // See notes in setBrightness()
r = (r * brightness) >> 8;
g = (g * brightness) >> 8;
b = (b * brightness) >> 8;
}
uint8_t *p;
if (wOffset == rOffset) { // Is an RGB-type strip
p = &pixels[n * 3]; // 3 bytes per pixel
} else { // Is a WRGB-type strip
p = &pixels[n * 4]; // 4 bytes per pixel
p[wOffset] = 0; // But only R,G,B passed -- set W to 0
}
p[rOffset] = r; // R,G,B always stored
p[gOffset] = g;
p[bOffset] = b;
}
void Adafruit_NeoPixel::show(void) {
if (!pixels) return;
espShow(pin, pixels, numBytes);
}
/*!
@brief Set a pixel's color using separate red, green, blue and white
components (for RGBW NeoPixels only).
@param n Pixel index, starting from 0.
@param r Red brightness, 0 = minimum (off), 255 = maximum.
@param g Green brightness, 0 = minimum (off), 255 = maximum.
@param b Blue brightness, 0 = minimum (off), 255 = maximum.
@param w White brightness, 0 = minimum (off), 255 = maximum, ignored
if using RGB pixels.
*/
void Adafruit_NeoPixel::setPixelColor(uint16_t n, uint8_t r, uint8_t g,
uint8_t b, uint8_t w) {
if (n < numLEDs) {
if (brightness) { // See notes in setBrightness()
r = (r * brightness) >> 8;
g = (g * brightness) >> 8;
b = (b * brightness) >> 8;
w = (w * brightness) >> 8;
}
uint8_t *p;
if (wOffset == rOffset) { // Is an RGB-type strip
p = &pixels[n * 3]; // 3 bytes per pixel (ignore W)
} else { // Is a WRGB-type strip
p = &pixels[n * 4]; // 4 bytes per pixel
p[wOffset] = w; // Store W
}
p[rOffset] = r; // Store R,G,B
p[gOffset] = g;
p[bOffset] = b;
}
}
/*!
@brief Set a pixel's color using a 32-bit 'packed' RGB or RGBW value.
@param n Pixel index, starting from 0.
@param c 32-bit color value. Most significant byte is white (for RGBW
pixels) or ignored (for RGB pixels), next is red, then green,
and least significant byte is blue.
*/
void Adafruit_NeoPixel::setPixelColor(uint16_t n, uint32_t c) {
if (n < numLEDs) {
uint8_t *p, r = (uint8_t)(c >> 16), g = (uint8_t)(c >> 8), b = (uint8_t)c;
if (brightness) { // See notes in setBrightness()
r = (r * brightness) >> 8;
g = (g * brightness) >> 8;
b = (b * brightness) >> 8;
}
if (wOffset == rOffset) {
p = &pixels[n * 3];
} else {
p = &pixels[n * 4];
uint8_t w = (uint8_t)(c >> 24);
p[wOffset] = brightness ? ((w * brightness) >> 8) : w;
}
p[rOffset] = r;
p[gOffset] = g;
p[bOffset] = b;
}
}
/*!
@brief Adjust output brightness. Does not immediately affect what's
currently displayed on the LEDs. The next call to show() will
refresh the LEDs at this level.
@param b Brightness setting, 0=minimum (off), 255=brightest.
@note This was intended for one-time use in one's setup() function,
not as an animation effect in itself. Because of the way this
library "pre-multiplies" LED colors in RAM, changing the
brightness is often a "lossy" operation -- what you write to
pixels isn't necessary the same as what you'll read back.
Repeated brightness changes using this function exacerbate the
problem. Smart programs therefore treat the strip as a
write-only resource, maintaining their own state to render each
frame of an animation, not relying on read-modify-write.
*/
void Adafruit_NeoPixel::setBrightness(uint8_t b) {
// Stored brightness value is different than what's passed.
// This simplifies the actual scaling math later, allowing a fast
// 8x8-bit multiply and taking the MSB. 'brightness' is a uint8_t,
// adding 1 here may (intentionally) roll over...so 0 = max brightness
// (color values are interpreted literally; no scaling), 1 = min
// brightness (off), 255 = just below max brightness.
uint8_t newBrightness = b + 1;
if (newBrightness != brightness) { // Compare against prior value
// Brightness has changed -- re-scale existing data in RAM,
// This process is potentially "lossy," especially when increasing
// brightness. The tight timing in the WS2811/WS2812 code means there
// aren't enough free cycles to perform this scaling on the fly as data
// is issued. So we make a pass through the existing color data in RAM
// and scale it (subsequent graphics commands also work at this
// brightness level). If there's a significant step up in brightness,
// the limited number of steps (quantization) in the old data will be
// quite visible in the re-scaled version. For a non-destructive
// change, you'll need to re-render the full strip data. C'est la vie.
uint8_t c, *ptr = pixels,
oldBrightness = brightness - 1; // De-wrap old brightness value
uint16_t scale;
if (oldBrightness == 0)
scale = 0; // Avoid /0
else if (b == 255)
scale = 65535 / oldBrightness;
else
scale = (((uint16_t)newBrightness << 8) - 1) / oldBrightness;
for (uint16_t i = 0; i < numBytes; i++) {
c = *ptr;
*ptr++ = (c * scale) >> 8;
}
brightness = newBrightness;
}
}
/*!
@brief Fill the whole NeoPixel strip with 0 / black / off.
*/
void Adafruit_NeoPixel::clear(void) { memset(pixels, 0, numBytes); }
void Adafruit_NeoPixel::setPixelColor(uint32_t c) {
uint8_t *p = pixels;
uint8_t r = (uint8_t)(c >> 16), g = (uint8_t)(c >> 8), b = (uint8_t)c;
p[rOffset] = r;
p[gOffset] = g;
p[bOffset] = b;
}