BT411/engine/MUNGA_L4/L4GLASSWIN.cpp

#include "mungal4.h"
#pragma hdrstop

//###########################################################################
// L4GLASSWIN -- per-display glass cockpit windows.  Design + layout rules:
// l4glasswin.h.  Each pod secondary display is its OWN GDI window carrying
// the display surface (CPU-blit from the shared gauge buffer) with its RIO
// button bank placed around it; a Flight Controls window hosts the
// no-display banks.  Modeled on L4PADPANEL (GDI cells + lamp decode) and
// L4PLASMAWIN (CPU pixelBuffer -> StretchDIBits), so no D3D is involved.
//###########################################################################

#include "l4glasswin.h"
#include "l4padrio.h"
#include "l4vb16.h"
#include "l4riobank.h"		// the shared button-bank geometry (with the surround)
#include "../munga/gaugrend.h"

#include <windows.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

// The main game window (for pod-faithful placement) is reached via
// BTResolveMainWindow() (l4vb16.h) -- NOT the `ghWnd` global directly, which this
// newly-added engine TU can bind as the NULL /FORCE-duplicate copy.

//###########################################################################
// Mode gate
//###########################################################################

int
	BTGlassPanelsActive()
{
	static int v = -1;
	if (v < 0)
	{
		const char *e = getenv("BT_GLASS_PANELS");
		v = (e != NULL && e[0] != '0') ? 1 : 0;
	}
	return v;
}

//###########################################################################
// Window constants.  The BUTTON GEOMETRY (how far a bank reaches under the
// glass, the lamp strip, the column pitch, the per-column nudge against the
// imagery legends) moved to L4RIOBANK on 2026-07-26 so the cockpit surround
// draws the identical field; what is left here is this window's own chrome.
//###########################################################################

enum
{
	CellW       = 58,			// flight-controls cell (no glass behind it)
	CellH       = 28,
	Gap         = 4,
	MfdSurfW    = 640, MfdSurfH = 480,	// mono MFD surface at native 640x480
	RadarSurfW  = 480, RadarSurfH = 640,	// portrait secondary/radar CRT at native (rotated 640x480)
	RepaintTimerId       = 1,
	RepaintMilliseconds  = 62,			// == L4PADPANEL (half the fastest lamp half-period)
	MfdMonoTint = 0x00FFFFFF				// mono MFD phosphor colour (BGRA); tunable
};

enum ColorClass { ClrRed, ClrYellow, ClrBlue };

struct GButton
{
	int         address;
	ColorClass  color;
	RECT        rect;		// client-space
};

struct GWin
{
	const char *title;
	HWND        hwnd;

	// Surface (portPrimary == NULL -> no surface, e.g. Flight Controls).
	const char *portPrimary;
	const char *portAlt;	// the Eng<n> preset plane sibling, or NULL
	int         monoTint;	// -1 = palette-expand (radar); else BGRA mono tint
	int         rotate;		// 0 / 1 / 3 (portrait secondary)
	RECT        surfaceRect;

	GButton     buttons[24];
	int         buttonCount;
	int         showLabels;		// draw the hex/name on each button? (Flight Controls only)

	int         clientW, clientH;
	int         frameW, frameH;
	int         wantX, wantY;
};

static GWin  gWins[8];
static int   gWinCount = 0;

static int            pressedAddress = -1;
static unsigned char  latched[128];
static int            gRadarRot = 3;			// BT_GAUGE_SEC_ROT (default CW, upright)
static bool           sRepositionedToMain = false;
static unsigned long *gStage = NULL;			// 640*480 BGRA staging (shared, main-thread)

static HFONT titleFont  = NULL;
static HFONT buttonFont = NULL;
static HFONT subFont    = NULL;

//###########################################################################
// Named handle/joystick buttons (the Flight Controls window)
//###########################################################################

struct NamedButton { int address; const char *name; };
static const NamedButton namedButtons[] =
{
	{ 0x3D, "Panic" }, { 0x3F, "Throttle" },
	{ 0x40, "Main"  }, { 0x41, "Look Bk" }, { 0x42, "Torso Ctr" },
	{ 0x43, "Look R" }, { 0x44, "Look L" }, { 0x45, "Pinky"  },
	{ 0x46, "Middle"}, { 0x47, "Upper"  },
};
enum { NamedButtonCount = sizeof(namedButtons) / sizeof(namedButtons[0]) };

static const char *
	PhysicalName(int address)
{
	for (int i = 0; i < NamedButtonCount; ++i)
		if (namedButtons[i].address == address)
			return namedButtons[i].name;
	return NULL;
}

//###########################################################################
// Lamp decode: the ONE copy lives in l4vb16.h (BTLampBrightnessOf).  This TU
// used to carry its own, as did L4PADPANEL -- three copies of the same
// formula, all three carrying the same dim-to-bright flash bug (see the
// header's 2026-07-26 note).
//###########################################################################

static int
	LampBrightnessOf(int state, unsigned long tick)
{
	return BTLampBrightnessOf(state, tick);
}

//###########################################################################
// Layout builders
//###########################################################################

// (The local PlaceCellAt / PlaceLine / PlaceRect placers retired 2026-07-26 --
// the geometry they carried now comes from L4RIOBANK, shared with the cockpit
// surround.  AdoptBank below is the only thing that writes GButton rects.)

//---------------------------------------------------------------------------
// Copy a laid-out bank into this window at the given offset.  A glass window
// passes -bounds so the bank's bounding box lands at the client origin (the
// bank reaches OUTSIDE the display, so its rects arrive with coordinates
// left of / above it); the flight window, which has no glass, passes 0.
//---------------------------------------------------------------------------
static void
	AdoptBank(GWin &w, const BTRioBank &bank, ColorClass color, int dx, int dy)
{
	for (int i = 0; i < bank.buttonCount &&
		 w.buttonCount < (int)(sizeof(w.buttons) / sizeof(w.buttons[0])); ++i)
	{
		const BTRioButton &src = bank.buttons[i];
		GButton &b = w.buttons[w.buttonCount++];
		b.address = src.address;
		b.color   = (src.colorClass == 1) ? ClrYellow
				  : (src.colorClass == 2) ? ClrBlue : color;
		b.rect.left   = src.x + dx;
		b.rect.top    = src.y + dy;
		b.rect.right  = src.x + dx + src.w;
		b.rect.bottom = src.y + dy + src.h;
	}
}

// An MFD display: 8 red buttons split 4 above / 4 below the surface (top row =
// the high 4 addresses descending, matching the L4PADPANEL cluster order).
// Geometry is L4RIOBANK's -- the under-glass rule, shared with the surround.
static void
	BuildMfd(GWin &w, const char *title, const char *portP, const char *portA, int bankHi)
{
	memset(&w, 0, sizeof(w));
	w.title = title;
	w.portPrimary = portP;
	w.portAlt = portA;
	w.monoTint = MfdMonoTint;
	w.rotate = 0;

	BTRioBankMetrics metrics;
	BTRioBankMetricsFor(MfdSurfW, MfdSurfH, &metrics);

	BTRioBank bank;
	BTRioBankLayout(BTRioBankMfd, 0, 0, MfdSurfW, MfdSurfH,
		bankHi, 0, &metrics, 0, &bank);

	BTRioBankDump(title, &bank);
	int dx = -bank.boundsX, dy = -bank.boundsY;
	AdoptBank(w, bank, ClrRed, dx, dy);
	SetRect(&w.surfaceRect, dx, dy, dx + MfdSurfW, dy + MfdSurfH);
	w.clientW = bank.boundsW;
	w.clientH = bank.boundsH;
}

// The secondary/radar display: 12 yellow Secondary buttons split left / right
// of the portrait surface (0x10-0x15 left, 0x16-0x1B right).
static void
	BuildRadar(GWin &w)
{
	memset(&w, 0, sizeof(w));
	w.title = "Secondary / Radar";
	w.portPrimary = "sec";
	w.portAlt = NULL;
	w.monoTint = -1;			// palette
	w.rotate = gRadarRot;

	// Left column 0x10-0x15, right 0x18-0x1D, foot row 0x16/0x17/0x1F/0x1E.
	// (0x15 sits on the left column -- Cyd listed 0x10-0x14; move it if wanted.)
	static const int bottomAddrs[4] = { 0x16, 0x17, 0x1F, 0x1E };

	BTRioBankMetrics metrics;
	BTRioBankMetricsFor(RadarSurfW, RadarSurfH, &metrics);

	BTRioBank bank;
	BTRioBankLayout(BTRioBankRadar, 0, 0, RadarSurfW, RadarSurfH,
		0x10, 0x18, &metrics, bottomAddrs, &bank);

	BTRioBankDump("Secondary / Radar", &bank);
	int dx = -bank.boundsX, dy = -bank.boundsY;
	AdoptBank(w, bank, ClrYellow, dx, dy);
	SetRect(&w.surfaceRect, dx, dy, dx + RadarSurfW, dy + RadarSurfH);
	w.clientW = bank.boundsW;
	w.clientH = bank.boundsH;
}

// The Flight Controls window: the no-display banks -- throttle/panic/door/icom
// (0x38-0x3F) and joystick/fire (0x40-0x47), two neutral columns.
static void
	BuildFlight(GWin &w)
{
	memset(&w, 0, sizeof(w));
	w.title = "Flight Controls";
	w.portPrimary = NULL;
	w.showLabels = 1;			// the only window that shows hex/name on its buttons

	// No glass to hide behind, so these cells carry their own size (see
	// l4riobank.h) -- two 1-wide columns, eight rows each.  Cell minus the
	// 4px gap keeps the historical CellW/CellH PITCH and the 2px inset the
	// old PlaceCellAt drew, so the window is pixel-identical.
	BTRioBankMetrics metrics;
	metrics.strip = 0;
	metrics.gap   = Gap;
	metrics.cellW = CellW - Gap;
	metrics.cellH = CellH - Gap;

	BTRioBank bank;
	memset(&bank, 0, sizeof(bank));
	BTRioBankFlightGrid(2, 2, 0x38, 8, 1, 0, 0, &metrics, &bank);	// throttle/panic/door/icom
	BTRioBankFlightGrid(CellW + Gap + 2, 2, 0x40, 8, 1, 0, 0, &metrics, &bank);	// joystick + fire

	BTRioBankDump("Flight Controls", &bank);
	AdoptBank(w, bank, ClrBlue, 0, 0);
	// no translation here (the cells are already at their 2px inset); the
	// client is the historical two-column extent
	w.clientW = CellW + Gap + CellW;
	w.clientH = 8 * CellH;
}

//###########################################################################
// Placement -- pod-faithful ring around the main game window
//###########################################################################

static void
	WorkArea(RECT *wa)
{
	if (!SystemParametersInfoW(SPI_GETWORKAREA, 0, wa, 0))
	{
		wa->left = 0; wa->top = 0;
		wa->right = GetSystemMetrics(SM_CXSCREEN);
		wa->bottom = GetSystemMetrics(SM_CYSCREEN);
	}
}

static bool
	GetMainRect(RECT *out)
{
	HWND mh = (HWND)BTResolveMainWindow();
	if (mh != NULL && IsWindow(mh) && GetWindowRect(mh, out))
		return true;
	// Fallback before the main window exists: assume 800x600 centered.
	RECT wa; WorkArea(&wa);
	int cw = 800, ch = 600;
	out->left = (wa.left + wa.right - cw) / 2;
	out->top  = (wa.top + wa.bottom - ch) / 2;
	out->right = out->left + cw;
	out->bottom = out->top + ch;
	return false;
}

static void
	ComputeLayout()
{
	RECT m; GetMainRect(&m);
	RECT wa; WorkArea(&wa);
	int gap = 10;
	int cx = (m.left + m.right) / 2;
	int cy = (m.top + m.bottom) / 2;

	for (int i = 0; i < gWinCount; ++i)
	{
		GWin &w = gWins[i];
		int fw = w.frameW, fh = w.frameH;
		int x = m.left, y = m.top;
		switch (i)
		{
		case 0: x = m.left;            y = m.top - fh - gap;   break;	// Heat  (UL)
		case 1: x = cx - fw / 2;       y = m.top - fh - gap;   break;	// Mfd2  (UC)
		case 2: x = m.right - fw;      y = m.top - fh - gap;   break;	// Comm  (UR)
		case 3: x = m.left - fw - gap; y = m.bottom - fh;      break;	// Mfd1  (LL)
		case 4: x = m.right + gap;     y = m.bottom - fh;      break;	// Mfd3  (LR)
		case 5: x = cx - fw / 2;       y = m.bottom + gap;     break;	// Radar (center)
		case 6: x = m.left - fw - gap; y = cy - fh / 2;        break;	// Flight (left of seat)
		}
		// Clamp fully on-screen (small desktops -> panels pile at the edges).
		if (x + fw > wa.right)  x = wa.right - fw;
		if (y + fh > wa.bottom) y = wa.bottom - fh;
		if (x < wa.left) x = wa.left;
		if (y < wa.top)  y = wa.top;
		w.wantX = x;
		w.wantY = y;
	}
}

static void
	ApplyLayout()
{
	for (int i = 0; i < gWinCount; ++i)
		if (gWins[i].hwnd != NULL)
			SetWindowPos(gWins[i].hwnd, HWND_TOPMOST, gWins[i].wantX, gWins[i].wantY,
				0, 0, SWP_NOSIZE | SWP_NOACTIVATE);
}

//###########################################################################
// Painting
//###########################################################################

static void
	DrawLabelText(HDC dc, const char *text, HFONT font, RECT *rect,
		COLORREF color, UINT format)
{
	WCHAR wide[32];
	int n = 0;
	for (const char *s = text; *s && n < 31; ++s)
		wide[n++] = (WCHAR)*s;
	wide[n] = 0;
	HFONT old_font = (HFONT)SelectObject(dc, font);
	SetTextColor(dc, color);
	DrawTextW(dc, wide, -1, rect, format);
	SelectObject(dc, old_font);
}

static int   sGlassLog = -1;
static unsigned long sBlitCalls = 0;

static void
	BlitSurface(HDC dc, GWin *w)
{
	if (sGlassLog < 0)
		sGlassLog = getenv("BT_GLASS_LOG") ? 1 : 0;
	int log = sGlassLog && ((sBlitCalls++ % 240) == 0);

	// Reach the renderer via BTResolveGaugeRenderer (l4vb16.h; DEFINED in
	// game/btl4main.cpp off the real btl4App pointer), NOT the `application` global
	// directly -- a fresh engine TU can bind the NULL /FORCE-duplicate copy.
	GaugeRenderer *gr = BTResolveGaugeRenderer();
	if (gr == NULL)
	{
		if (log) DEBUG_STREAM << "[glass] '" << w->title << "' gauge renderer not ready\n" << std::flush;
		return;
	}

	L4GraphicsPort *port = static_cast<L4GraphicsPort*>(gr->GetGraphicsPort(w->portPrimary));
	if (w->portAlt != NULL)
	{
		L4GraphicsPort *alt = static_cast<L4GraphicsPort*>(gr->GetGraphicsPort(w->portAlt));
		// Show whichever of the Mfd<n>/Eng<n> pair is the live (non-blank) plane,
		// exactly like the pod monitor + BTDrawGaugeSurfaces (Gitea #9).
		bool primaryBlank = (port == NULL) ||
			(port->GetEnableID() == L4GraphicsPort::BlankColor);
		if (primaryBlank && alt != NULL &&
			alt->GetEnableID() != L4GraphicsPort::BlankColor)
			port = alt;
		else if (port == NULL)
			port = alt;
	}
	if (port == NULL)
	{
		if (log) DEBUG_STREAM << "[glass] '" << w->title << "' port '" << w->portPrimary
			<< "' NULL (not installed)\n" << std::flush;
		return;
	}

	SVGA16 *svga = static_cast<SVGA16*>(port->graphicsDisplay);
	if (svga == NULL || gStage == NULL)
	{
		if (log) DEBUG_STREAM << "[glass] '" << w->title << "' svga=" << (void*)svga
			<< " stage=" << (void*)gStage << "\n" << std::flush;
		return;
	}

	// Surface expand.  BT_GLASS_MFD_PAL (experiment): render the mono MFD windows
	// through the palette LUT (low byte, secondary palette) instead of the 1-bit
	// mono tint, to compare.  NB the MFD's own graphics live in a HIGH bit-plane
	// the 256-entry palette can't index, so this shows the shared low-byte content.
	int mask = port->GetBitMask();
	int palId = port->paletteID;
	int tint = w->monoTint;
	static int sMfdPal = -1;
	if (sMfdPal < 0) sMfdPal = getenv("BT_GLASS_MFD_PAL") ? 1 : 0;
	if (sMfdPal && tint >= 0)
	{
		tint = -1;						// palette-expand
		mask = 0xFF;					// index the low (palette) byte
		palId = SVGA16::SecondaryPalette;
	}
	int ow = 0, oh = 0;
	svga->ExpandPlaneToBGRA(mask, palId, tint, w->rotate, gStage, &ow, &oh);
	if (log)
	{
		int nz = 0, n = ow * oh;
		for (int i = 0; i < n; ++i) if (gStage[i] != 0) nz++;
		DEBUG_STREAM << "[glass] '" << w->title << "' port=" << w->portPrimary
			<< " mask=0x" << std::hex << port->GetBitMask() << std::dec
			<< " pal=" << port->paletteID << " enable=" << port->GetEnableID()
			<< " ow=" << ow << " oh=" << oh << " nonzero=" << nz << "/" << n
			<< "\n" << std::flush;
	}
	if (ow <= 0 || oh <= 0)
		return;

	BITMAPINFO info;
	memset(&info, 0, sizeof(info));
	info.bmiHeader.biSize        = sizeof(BITMAPINFOHEADER);
	info.bmiHeader.biWidth       = ow;
	info.bmiHeader.biHeight      = -oh;		// top-down
	info.bmiHeader.biPlanes      = 1;
	info.bmiHeader.biBitCount    = 32;
	info.bmiHeader.biCompression = BI_RGB;

	const RECT &r = w->surfaceRect;
	SetStretchBltMode(dc, HALFTONE);
	SetBrushOrgEx(dc, 0, 0, NULL);
	StretchDIBits(dc,
		r.left, r.top, r.right - r.left, r.bottom - r.top,
		0, 0, ow, oh,
		gStage, &info, DIB_RGB_COLORS, SRCCOPY);
}

static void
	PaintGlass(HWND window, GWin *w)
{
	PAINTSTRUCT paint;
	HDC winDC = BeginPaint(window, &paint);
	unsigned long tick = GetTickCount();

	RECT client;
	GetClientRect(window, &client);

	// Double-buffer the whole frame (== L4PADPANEL issue #13).
	HDC dc = CreateCompatibleDC(winDC);
	HBITMAP backing = CreateCompatibleBitmap(winDC,
		client.right - client.left, client.bottom - client.top);
	HBITMAP oldBacking = (HBITMAP)SelectObject(dc, backing);
	HBRUSH background = CreateSolidBrush(RGB(24, 24, 24));
	FillRect(dc, &client, background);
	DeleteObject(background);
	SetBkMode(dc, TRANSPARENT);

	// (No in-client title -- the OS window caption labels each window.)

	// Buttons are drawn FIRST (UNDER the display).  Each is a big clickable rect;
	// the surface blit further down masks the part inside the display, leaving only
	// the bit that protrudes past the display edge visible -- a solid lamp light.
	// (The Flight Controls window has no surface, so its buttons show in full.)
	for (int i = 0; i < w->buttonCount; ++i)
	{
		const GButton &b = w->buttons[i];
		const RECT &r = b.rect;
		int held = (b.address == pressedAddress) || latched[b.address & 0x7F];
		int shade = LampBrightnessOf(PadRIO::GetLampState(b.address), tick);
		if (held)
			shade = 3;

		COLORREF fill, text_color;
		if (b.color == ClrYellow)
		{
			fill = (shade == 3) ? RGB(245, 210, 60)
				 : (shade != 0) ? RGB(140, 118, 38)
				                : RGB(70, 60, 24);
			text_color = RGB(0, 0, 0);
		}
		else if (b.color == ClrBlue)
		{
			fill = (shade == 3) ? RGB(205, 228, 255)
				 : (shade != 0) ? RGB(110, 135, 180)
				                : RGB(70, 86, 120);
			text_color = RGB(0, 0, 0);
		}
		else	// ClrRed (MFD)
		{
			fill = (shade == 3) ? RGB(230, 70, 70)
				 : (shade != 0) ? RGB(120, 50, 50)
				                : RGB(64, 40, 40);
			text_color = RGB(255, 255, 255);
		}
		// Solid lamp fill + a bright border.  Under the imagery, only the protruding
		// edge shows once the surface is blitted on top.
		{
			COLORREF bright = (b.color == ClrYellow) ? RGB(245, 210, 60)
			                : (b.color == ClrBlue)   ? RGB(205, 228, 255)
			                                         : RGB(230, 70, 70);
			HBRUSH face = CreateSolidBrush(fill);
			FillRect(dc, &r, face);
			DeleteObject(face);
			HPEN pen = CreatePen(PS_SOLID, 1, bright);
			HGDIOBJ oldPen = SelectObject(dc, pen);
			HGDIOBJ oldBr = SelectObject(dc, GetStockObject(NULL_BRUSH));
			Rectangle(dc, r.left, r.top, r.right, r.bottom);
			SelectObject(dc, oldBr);
			SelectObject(dc, oldPen);
			DeleteObject(pen);
		}

		// Labels only on the Flight Controls window; MFD/radar buttons are bare.
		if (w->showLabels)
		{
			char hex[8];
			sprintf(hex, "%02X", b.address);
			const char *name = PhysicalName(b.address);
			if (name != NULL)
			{
				RECT top_rect = { r.left, r.top + 1, r.right, (r.top + r.bottom) / 2 + 3 };
				RECT bottom_rect = { r.left, (r.top + r.bottom) / 2, r.right, r.bottom - 1 };
				DrawLabelText(dc, name, buttonFont, &top_rect, text_color,
					DT_CENTER | DT_TOP | DT_SINGLELINE | DT_END_ELLIPSIS);
				DrawLabelText(dc, hex, subFont, &bottom_rect, text_color,
					DT_CENTER | DT_BOTTOM | DT_SINGLELINE);
			}
			else
			{
				RECT cell_rect = r;
				DrawLabelText(dc, hex, buttonFont, &cell_rect, text_color,
					DT_CENTER | DT_VCENTER | DT_SINGLELINE);
			}
		}

		// Latch = gold outline; momentary held = white outline (== L4PADPANEL).
		if (latched[b.address & 0x7F])
		{
			HBRUSH gold = CreateSolidBrush(RGB(255, 215, 0));
			RECT o = r;
			FrameRect(dc, &o, gold);
			DeleteObject(gold);
		}
		else if (held)
		{
			RECT o = r;
			FrameRect(dc, &o, (HBRUSH)GetStockObject(WHITE_BRUSH));
		}
	}

	// Surface (imagery) LAST -- ON TOP of the buttons, masking their inside so only
	// the protruding lamp edges show.  (No-op for the Flight Controls window.)
	if (w->portPrimary != NULL)
	{
		BlitSurface(dc, w);
		HPEN pen = CreatePen(PS_SOLID, 1, RGB(70, 70, 70));
		HPEN oldPen = (HPEN)SelectObject(dc, pen);
		HBRUSH oldBrush = (HBRUSH)SelectObject(dc, GetStockObject(NULL_BRUSH));
		Rectangle(dc, w->surfaceRect.left - 1, w->surfaceRect.top - 1,
			w->surfaceRect.right + 1, w->surfaceRect.bottom + 1);
		SelectObject(dc, oldBrush);
		SelectObject(dc, oldPen);
		DeleteObject(pen);
	}

	BitBlt(winDC, 0, 0, client.right - client.left, client.bottom - client.top,
		dc, 0, 0, SRCCOPY);
	SelectObject(dc, oldBacking);
	DeleteObject(backing);
	DeleteDC(dc);
	EndPaint(window, &paint);
}

//###########################################################################
// WndProc / input
//###########################################################################

static int
	HitTest(GWin *w, int x, int y)
{
	for (int i = 0; i < w->buttonCount; ++i)
	{
		const RECT &r = w->buttons[i].rect;
		if (x >= r.left && x < r.right && y >= r.top && y < r.bottom)
			return w->buttons[i].address;
	}
	return -1;
}

static LRESULT CALLBACK
	GlassWndProc(HWND window, UINT message, WPARAM wparam, LPARAM lparam)
{
	GWin *w = (GWin*)GetWindowLongPtrW(window, GWLP_USERDATA);

	switch (message)
	{
	case WM_PAINT:
		if (w != NULL) { PaintGlass(window, w); return 0; }
		break;

	case WM_ERASEBKGND:
		return 1;	// PaintGlass fills the frame (double-buffered)

	case WM_TIMER:
		if (wparam == RepaintTimerId)
		{
			// One-shot: once the real main window is up, snap the ring onto it.
			HWND mh = (HWND)BTResolveMainWindow();
			if (!sRepositionedToMain && mh != NULL && IsWindow(mh))
			{
				ComputeLayout();
				ApplyLayout();
				sRepositionedToMain = true;
			}
			InvalidateRect(window, NULL, FALSE);
		}
		return 0;

	case WM_LBUTTONDOWN:
		if (w != NULL)
		{
			int a = HitTest(w, (int)(short)LOWORD(lparam), (int)(short)HIWORD(lparam));
			if (a >= 0)
			{
				// crash forensics (always-on, flushed BEFORE dispatch): if a
				// click kills the process, the last log line names the button.
				DEBUG_STREAM << "[glasswin] CLICK '" << (w->title ? w->title : "?")
					<< "' addr=0x" << std::hex << a << std::dec
					<< " at(" << (int)(short)LOWORD(lparam) << ","
					<< (int)(short)HIWORD(lparam) << ")"
					<< (latched[a & 0x7F] ? " unlatch" : " press")
					<< "\n" << std::flush;
				if (latched[a & 0x7F])
				{
					latched[a & 0x7F] = 0;
					PadRIO::SetScreenButton(a, 0);
				}
				else
				{
					pressedAddress = a;
					SetCapture(window);
					PadRIO::SetScreenButton(a, 1);
				}
				InvalidateRect(window, NULL, FALSE);
			}
		}
		return 0;

	case WM_LBUTTONUP:
		if (pressedAddress >= 0)
		{
			PadRIO::SetScreenButton(pressedAddress, 0);
			pressedAddress = -1;
			ReleaseCapture();
			InvalidateRect(window, NULL, FALSE);
		}
		return 0;

	case WM_RBUTTONDOWN:
		if (w != NULL)
		{
			int a = HitTest(w, (int)(short)LOWORD(lparam), (int)(short)HIWORD(lparam));
			if (a >= 0)
			{
				DEBUG_STREAM << "[glasswin] CLICK '" << (w->title ? w->title : "?")
					<< "' addr=0x" << std::hex << a << std::dec
					<< " latch-toggle\n" << std::flush;
				latched[a & 0x7F] = latched[a & 0x7F] ? 0 : 1;
				PadRIO::SetScreenButton(a, latched[a & 0x7F]);
				InvalidateRect(window, NULL, FALSE);
			}
		}
		return 0;

	case WM_CLOSE:
		ShowWindow(window, SW_HIDE);	// hide; the device owns the lifetime
		return 0;
	}
	return DefWindowProcW(window, message, wparam, lparam);
}

//###########################################################################
// Create / destroy
//###########################################################################

void
	BTGlassPanels_Create()
{
	if (gWinCount != 0)
		return;		// already up

	// BT_GAUGE_SEC_ROT: the portrait-CRT unrotation direction (shared with the
	// D3D dev path; default 3 = CW = user-verified upright).
	{
		const char *rv = getenv("BT_GAUGE_SEC_ROT");
		gRadarRot = (rv != NULL && rv[0] == '1') ? 1 : 3;
	}

	memset(latched, 0, sizeof(latched));
	pressedAddress = -1;
	sRepositionedToMain = false;
	if (gStage == NULL)
		gStage = new unsigned long[640 * 480];

	// Build the seven windows.  Order fixes the ComputeLayout roles (0..6).
	BuildMfd  (gWins[0], "Heat MFD",   "Heat", NULL,   0x2F);	// UL  0x28-0x2F
	BuildMfd  (gWins[1], "Engineering", "Mfd2", "Eng2", 0x27);	// UC  0x20-0x27
	BuildMfd  (gWins[2], "Comm MFD",   "Comm", NULL,   0x37);	// UR  0x30-0x37
	BuildMfd  (gWins[3], "Left Weapons", "Mfd1", "Eng1", 0x0F);	// LL  0x08-0x0F
	BuildMfd  (gWins[4], "Right Weapons", "Mfd3", "Eng3", 0x07);	// LR  0x00-0x07
	BuildRadar(gWins[5]);										// center 0x10-0x1B
	BuildFlight(gWins[6]);										// 0x38-0x47
	gWinCount = 7;

	titleFont = CreateFontW(-11, 0, 0, 0, FW_BOLD, 0, 0, 0,
		DEFAULT_CHARSET, 0, 0, CLEARTYPE_QUALITY, 0, L"Segoe UI");
	buttonFont = CreateFontW(-10, 0, 0, 0, FW_NORMAL, 0, 0, 0,
		DEFAULT_CHARSET, 0, 0, CLEARTYPE_QUALITY, 0, L"Segoe UI");
	subFont = CreateFontW(-9, 0, 0, 0, FW_NORMAL, 0, 0, 0,
		DEFAULT_CHARSET, 0, 0, CLEARTYPE_QUALITY, 0, L"Segoe UI");

	WNDCLASSW wc;
	memset(&wc, 0, sizeof(wc));
	wc.lpfnWndProc   = GlassWndProc;
	wc.hInstance     = GetModuleHandleW(NULL);
	wc.hCursor       = LoadCursorW(NULL, (LPCWSTR)IDC_ARROW);
	wc.lpszClassName = L"BTGlassWin";
	RegisterClassW(&wc);

	DWORD style = WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX;

	// Frame sizes first (ComputeLayout positions by frame dims).
	for (int i = 0; i < gWinCount; ++i)
	{
		RECT fr = { 0, 0, gWins[i].clientW, gWins[i].clientH };
		AdjustWindowRect(&fr, style, FALSE);
		gWins[i].frameW = fr.right - fr.left;
		gWins[i].frameH = fr.bottom - fr.top;
	}
	ComputeLayout();

	for (int i = 0; i < gWinCount; ++i)
	{
		GWin &w = gWins[i];
		WCHAR wtitle[64];
		int n = 0;
		for (const char *s = w.title; *s && n < 63; ++s) wtitle[n++] = (WCHAR)*s;
		wtitle[n] = 0;

		// Layered + topmost (== L4PADPANEL): DWM composites the panel independently
		// of the game's D3D swap chain, ending GDI-vs-D3D presentation strobing.
		w.hwnd = CreateWindowExW(
			WS_EX_TOPMOST | WS_EX_LAYERED,
			L"BTGlassWin", wtitle, style,
			w.wantX, w.wantY, w.frameW, w.frameH,
			NULL, NULL, GetModuleHandleW(NULL), NULL);
		if (w.hwnd == NULL)
		{
			DEBUG_STREAM << "[glasswin] CreateWindow failed for '" << w.title
				<< "'\n" << std::flush;
			continue;
		}
		SetWindowLongPtrW(w.hwnd, GWLP_USERDATA, (LONG_PTR)&w);
		SetLayeredWindowAttributes(w.hwnd, 0, 255, LWA_ALPHA);
		SetTimer(w.hwnd, RepaintTimerId, RepaintMilliseconds, NULL);
		ShowWindow(w.hwnd, SW_SHOWNOACTIVATE);
	}

	DEBUG_STREAM << "[glasswin] per-display cockpit up (" << gWinCount
		<< " windows: 5 MFD + radar + flight)\n" << std::flush;
}

void
	BTGlassPanels_Destroy()
{
	for (int i = 0; i < gWinCount; ++i)
	{
		if (gWins[i].hwnd != NULL)
		{
			KillTimer(gWins[i].hwnd, RepaintTimerId);
			DestroyWindow(gWins[i].hwnd);
			gWins[i].hwnd = NULL;
		}
	}
	gWinCount = 0;
	if (titleFont)  { DeleteObject(titleFont);  titleFont = NULL; }
	if (buttonFont) { DeleteObject(buttonFont); buttonFont = NULL; }
	if (subFont)    { DeleteObject(subFont);    subFont = NULL; }
	if (gStage)     { delete[] gStage; gStage = NULL; }
}