hyperion.ng/libsrc/leddevice/dev_spi/LedDeviceAPA102.cpp

#include "LedDeviceAPA102.h"

// Constants
namespace {

/// The value that determines the higher bits of the APA102 brightness control field
const int APA102_LEDFRAME_UPPER_BITS = 0xE0;

} //End of constants


LedDeviceAPA102::LedDeviceAPA102(const QJsonObject &deviceConfig)
	: ProviderSpi(deviceConfig)
{
	// Overwrite non supported/required features
	_latchTime_ms = 0;
}

LedDevice* LedDeviceAPA102::construct(const QJsonObject &deviceConfig)
{
	return new LedDeviceAPA102(deviceConfig);
}

bool LedDeviceAPA102::init(const QJsonObject &deviceConfig)
{
	bool isInitOK = false;

	// Initialise sub-class
	if ( ProviderSpi::init(deviceConfig) )
	{
		_brightnessControlMaxLevel = deviceConfig["brightnessControlMaxLevel"].toInt(APA102_BRIGHTNESS_MAX_LEVEL);
		Info(_log, "[%s] Setting maximum brightness to [%d] = %d%%", QSTRING_CSTR(_activeDeviceType), _brightnessControlMaxLevel, _brightnessControlMaxLevel * 100 / APA102_BRIGHTNESS_MAX_LEVEL);

		const unsigned int startFrameSize = 4;
		//Endframe, add additional 4 bytes to cover SK9922 Reset frame (in case SK9922 were sold as AP102) -  has no effect on APA102
		const unsigned int endFrameSize = (_ledCount/32) * 4 + 4;
		const unsigned int APAbufferSize = (_ledCount * 4) + startFrameSize + endFrameSize;

		_ledBuffer.resize(APAbufferSize, 0x00);

		isInitOK = true;
	}
	return isInitOK;
}

void LedDeviceAPA102::bufferWithBrightness(std::vector<uint8_t> &txBuf, const std::vector<ColorRgb> & ledValues, const int brightness) {
	const int ledCount = static_cast<int>(_ledCount);

	for (int iLed = 0; iLed < ledCount; ++iLed)
	{
		const ColorRgb &rgb = ledValues[iLed];
		const uint8_t red = rgb.red;
		const uint8_t green = rgb.green;
		const uint8_t blue = rgb.blue;

		/// The LED index in the buffer
		const int b = 4 + iLed * 4;

		txBuf[b + 0] = brightness | APA102_LEDFRAME_UPPER_BITS;
		txBuf[b + 1] = blue;
		txBuf[b + 2] = green;
		txBuf[b + 3] = red;
	}
}

int LedDeviceAPA102::write(const std::vector<ColorRgb> &ledValues)
{
	this->bufferWithBrightness(_ledBuffer, ledValues, _brightnessControlMaxLevel);

	return writeBytes(_ledBuffer.size(), _ledBuffer.data());
}