PianoLED-Circle-Edition/src/pianoleds.cpp

//
// pianoleds.cpp
//
#include "pianoleds.h"
#include <string.h>
#include <assert.h>

// MIDI status nibbles
#define MIDI_NOTE_OFF		0x80
#define MIDI_NOTE_ON		0x90
#define MIDI_CONTROL_CHANGE	0xB0

// Control numbers that mean "stop everything"
#define MIDI_CC_ALL_SOUND_OFF	120
#define MIDI_CC_ALL_NOTES_OFF	123

CPianoLEDs::CPianoLEDs (ILEDStrip &Strip)
:	m_Strip (Strip),
	m_bDirty (true),
	m_bHostConnected (false),
	m_nCalibPattern (CALIB_PATTERN_OFF),
	m_nCalibIndex (0),
	m_nCalibIndexHi (0)
{
	memset ((void *) m_KeyVelocity, 0, sizeof m_KeyVelocity);
	memset ((void *) m_HintVelocity, 0, sizeof m_HintVelocity);
}

CPianoLEDs::~CPianoLEDs (void)
{
}

bool CPianoLEDs::Initialize (void)
{
	if (!m_Strip.Initialize ())
	{
		return false;
	}

	assert (m_Strip.GetLEDCount () >= LED_COUNT);

	BuildKeyMap ();

	// Start from a known-dark strip rather than whatever the pixels held
	// when power came up.
	return m_Strip.Blackout ();
}

void CPianoLEDs::OnMIDIPacket (const uint8_t *pPacket, unsigned nLength)
{
	// The platform hands us one already-framed MIDI message of 1-3 bytes.
	// Anything
	// shorter than a channel message cannot be a note event.
	if (nLength < 3)
	{
		return;
	}

	uint8_t ucStatus  = pPacket[0] & 0xF0;
	uint8_t ucChannel = pPacket[0] & 0x0F;

	switch (ucStatus)
	{
	case MIDI_NOTE_ON:
		// Note On with velocity 0 is the conventional Note Off.
		SetKey (pPacket[1], pPacket[2], ChannelMatches (ucChannel, HINT_MIDI_CHANNEL));
		break;

	case MIDI_NOTE_OFF:
		SetKey (pPacket[1], 0, ChannelMatches (ucChannel, HINT_MIDI_CHANNEL));
		break;

	case MIDI_CONTROL_CHANGE:
		switch (pPacket[1])
		{
		case MIDI_CC_ALL_SOUND_OFF:
		case MIDI_CC_ALL_NOTES_OFF:
			AllOff ();
			break;

		case CALIB_CC_PATTERN:
			// Leaving calibration must not strand a lit pattern.
			m_nCalibPattern = pPacket[2];
			m_bDirty = true;
			break;

		case CALIB_CC_INDEX_HI:
			m_nCalibIndexHi = pPacket[2];
			break;

		case CALIB_CC_INDEX_LO:
			// Low byte last, so the 14-bit value updates atomically
			// from the renderer's point of view.
			m_nCalibIndex = (m_nCalibIndexHi << 7) | pPacket[2];
			m_bDirty = true;
			break;

		default:
			break;
		}
		break;

	default:
		break;
	}
}

// Pitch classes of the white keys, C through B.
static bool IsWhiteKey (uint8_t ucNote)
{
	switch (ucNote % 12)
	{
	case 0: case 2: case 4: case 5: case 7: case 9: case 11:
		return true;
	default:
		return false;
	}
}

void CPianoLEDs::BuildKeyMap (void)
{
#if NOTE_MAP_GEOMETRIC
	// A white key is LED_COUNT / WHITE_KEY_COUNT pixels wide - 3.38 at the
	// nominal 176 LEDs, not 2. Held as a 1/256 fixed-point value so the
	// mapping needs no floating point.
	const unsigned nWhitePitch = (LED_COUNT * 256u) / WHITE_KEY_COUNT;

	unsigned nWhitesBelow = 0;
#endif

	for (unsigned nKey = 0; nKey < KEY_COUNT; nKey++)
	{
		uint8_t ucNote = (uint8_t) (MIDI_NOTE_MIN + nKey);

#if NOTE_MAP_GEOMETRIC
		// A white key's centre sits half a key past the whites below it;
		// a black key sits on the boundary between its neighbours.
		unsigned nCentre = nWhitesBelow * nWhitePitch;
		if (IsWhiteKey (ucNote))
		{
			nCentre += nWhitePitch / 2;
			nWhitesBelow++;
		}

		// Round to the nearest pixel, then centre the lit span on it.
		int nCentreLED = (int) ((nCentre + 128) / 256);
		int nStart = nCentreLED - (int) (LEDS_PER_KEY / 2);
#else
		(void) ucNote;
		int nStart = (int) (nKey * LEDS_PER_KEY);
#endif

		nStart += LED_OFFSET;

#if STRIP_REVERSED
		// Mirror the whole strip, keeping the span left-to-right.
		nStart = (int) LED_COUNT - nStart - (int) LEDS_PER_KEY;
#endif

		m_KeyLED[nKey] = nStart;
	}
}

void CPianoLEDs::SetKey (uint8_t ucNote, uint8_t ucVelocity, bool bHint)
{
	// Drop anything off the ends of the keybed rather than trusting the
	// input; an out-of-range note would index past the strip.
	if (   ucNote < MIDI_NOTE_MIN
	    || ucNote > MIDI_NOTE_MAX)
	{
		return;
	}

	unsigned nKey = ucNote - MIDI_NOTE_MIN;

	if (bHint)
	{
		m_HintVelocity[nKey] = ucVelocity;
	}
	else
	{
		m_KeyVelocity[nKey] = ucVelocity;
	}

	m_bDirty = true;
}

void CPianoLEDs::SetHostConnected (bool bConnected)
{
	if (m_bHostConnected != bConnected)
	{
		m_bHostConnected = bConnected;
		m_bDirty = true;
	}
}

void CPianoLEDs::RunSelfTest (TDelayMs *pDelay)
{
#if BOOT_SELF_TEST
	assert (pDelay != nullptr);

	// Sweep in strip order, not key order, so what you watch is the strip's
	// own geometry: it starts at pixel 0 wherever that physically is.
	for (unsigned i = 0; i < LED_COUNT; i++)
	{
		if (i > 0)
		{
			m_Strip.SetLED (i - 1, 0, 0, 0);
		}

		m_Strip.SetLED (i, GLOBAL_BRIGHTNESS, GLOBAL_BRIGHTNESS,
				   GLOBAL_BRIGHTNESS);
		m_Strip.Update ();

		pDelay (BOOT_SELF_TEST_MS);
	}

	m_Strip.Blackout ();

	// The sweep left the strip in a state the renderer does not know about.
	m_bDirty = true;
#else
	(void) pDelay;
#endif
}

void CPianoLEDs::RenderIdle (void)
{
#if IDLE_INDICATOR
	// One dim pixel at the strip's start: powered and running, no host yet.
	const uint8_t B = GLOBAL_BRIGHTNESS / 8 ? GLOBAL_BRIGHTNESS / 8 : 1;

	PaintPixel (0, B, B, B);
#endif
}

void CPianoLEDs::AllOff (void)
{
	memset ((void *) m_KeyVelocity, 0, sizeof m_KeyVelocity);
	memset ((void *) m_HintVelocity, 0, sizeof m_HintVelocity);

	m_bDirty = true;
}

bool CPianoLEDs::ChannelMatches (uint8_t ucChannel, uint8_t ucWanted)
{
	if (ucWanted == MIDI_CHANNEL_NONE)
	{
		return false;
	}

	if (ucWanted == MIDI_CHANNEL_ANY)
	{
		return true;
	}

	return ucChannel == ucWanted;
}

uint8_t CPianoLEDs::Scale (uint8_t ucChannel, uint8_t ucVelocity)
{
	unsigned nValue = ucChannel;

	// Global brightness ceiling. This is the clamp that keeps a whited-out
	// strip inside the supply's current budget; see config.h.
	nValue = nValue * GLOBAL_BRIGHTNESS / 255;

#if VELOCITY_SENSITIVE
	// Map velocity 1-127 onto [VELOCITY_FLOOR_PCT, 100] percent, so even the
	// softest note stays visible.
	unsigned nPercent =   VELOCITY_FLOOR_PCT
			    + (100 - VELOCITY_FLOOR_PCT) * ucVelocity / 127;
	nValue = nValue * nPercent / 100;
#endif

	return (uint8_t) nValue;
}

void CPianoLEDs::PaintPixel (int nLED, uint8_t nRed, uint8_t nGreen, uint8_t nBlue)
{
	// A non-zero LED_OFFSET can push a key's span off either end. Drop
	// those pixels rather than wrapping them to the wrong end of the strip.
	if (   nLED < 0
	    || nLED >= (int) LED_COUNT)
	{
		return;
	}

	m_Strip.SetLED ((unsigned) nLED, nRed, nGreen, nBlue);
}

void CPianoLEDs::PaintKey (unsigned nKey, uint8_t nRed, uint8_t nGreen, uint8_t nBlue)
{
	assert (nKey < KEY_COUNT);

	for (unsigned i = 0; i < LEDS_PER_KEY; i++)
	{
		PaintPixel (m_KeyLED[nKey] + (int) i, nRed, nGreen, nBlue);
	}
}

void CPianoLEDs::RenderNotes (void)
{
	unsigned nLit = 0;

	for (unsigned nKey = 0; nKey < KEY_COUNT; nKey++)
	{
		uint8_t ucVelocity = m_KeyVelocity[nKey];
		bool bHint = false;

		if (ucVelocity == 0)
		{
			// A key being played wins over a "next note" hint on it.
			ucVelocity = m_HintVelocity[nKey];
			bHint = true;
		}

		// Bound the number of simultaneously lit keys, so no sequence of
		// MIDI events can drive the strip past the supply's budget.
		if (   ucVelocity == 0
		    || nLit >= MAX_LIT_KEYS)
		{
			continue;
		}

		nLit++;

		// Only lit keys are painted. Under the geometric map adjacent
		// keys' spans overlap, so painting unlit keys black here would
		// erase a lit neighbour's pixels.
		if (bHint)
		{
			PaintKey (nKey, Scale (HINT_COLOR_R, ucVelocity),
					Scale (HINT_COLOR_G, ucVelocity),
					Scale (HINT_COLOR_B, ucVelocity));
		}
		else
		{
			PaintKey (nKey, Scale (NOTE_COLOR_R, ucVelocity),
					Scale (NOTE_COLOR_G, ucVelocity),
					Scale (NOTE_COLOR_B, ucVelocity));
		}
	}
}

void CPianoLEDs::RenderCalibration (void)
{
	// Patterns run at the same ceiling as normal operation, so nothing here
	// can draw more current than the design already allows.
	const uint8_t W = GLOBAL_BRIGHTNESS;

	switch (m_nCalibPattern)
	{
	case CALIB_PATTERN_ENDS:
		// Confirms orientation and that LED_COUNT matches the strip you
		// actually cut. Red is pixel 0, green is the last pixel.
		PaintPixel (0, W, 0, 0);
		PaintPixel ((int) LED_COUNT - 1, 0, W, 0);
		break;

	case CALIB_PATTERN_OCTAVES:
		// Every C. Mapping drift shows up immediately as the marks
		// walking off the keys; middle C is picked out in red.
		for (unsigned nKey = 0; nKey < KEY_COUNT; nKey++)
		{
			uint8_t ucNote = (uint8_t) (MIDI_NOTE_MIN + nKey);
			if (ucNote % 12 != 0)
			{
				continue;
			}

			if (ucNote == 60)
			{
				PaintKey (nKey, W, 0, 0);
			}
			else
			{
				PaintKey (nKey, 0, 0, W);
			}
		}
		break;

	case CALIB_PATTERN_KEYS:
		// Every key, white keys and black keys in different colours, so
		// the whole mapping can be checked against the keybed at once.
		for (unsigned nKey = 0; nKey < KEY_COUNT; nKey++)
		{
			if (IsWhiteKey ((uint8_t) (MIDI_NOTE_MIN + nKey)))
			{
				PaintKey (nKey, 0, W, 0);
			}
			else
			{
				PaintKey (nKey, 0, 0, W);
			}
		}
		break;

	case CALIB_PATTERN_WALK:
		// One pixel at a time, stepped from the PC. This is how
		// LED_OFFSET gets its value: walk to the pixel sitting over A0.
		PaintPixel ((int) m_nCalibIndex, W, W, W);
		break;

	case CALIB_PATTERN_ALL:
		// Voltage droop test. Every pixel lit is well beyond normal
		// operation, which caps at MAX_LIT_KEYS, so watch the far end
		// for the colour shifting warm - that is the injection point
		// telling you it is needed.
		for (unsigned i = 0; i < LED_COUNT; i++)
		{
			PaintPixel ((int) i, W, W, W);
		}
		break;

	default:
		break;
	}
}

void CPianoLEDs::Update (void)
{
	if (!m_bDirty)
	{
		return;
	}

	// Clear the flag before reading state, not after. An event arriving
	// mid-render then leaves the flag set and we render again next pass,
	// rather than being dropped.
	m_bDirty = false;

	// Start from black, then paint only what should be lit. Key spans can
	// overlap under the geometric map, so nothing may paint black over a
	// region a neighbour has already claimed.
	for (unsigned i = 0; i < LED_COUNT; i++)
	{
		m_Strip.SetLED (i, 0, 0, 0);
	}

	if (m_nCalibPattern != CALIB_PATTERN_OFF)
	{
		RenderCalibration ();
	}
	else if (!m_bHostConnected)
	{
		// No host means no notes can arrive, so show a heartbeat rather
		// than a strip that looks identical to an unpowered one.
		RenderIdle ();
	}
	else
	{
		RenderNotes ();
	}

	m_Strip.Update ();
}