From 7a615449c535f132ed06d747acce7bd920b3c4b4 Mon Sep 17 00:00:00 2001 From: Cyd Date: Fri, 3 Jul 2026 20:09:36 -0500 Subject: [PATCH] VDB decode SOLVED: six displays bit-packed in the 16bpp pixel The gauge framebuffer is an encoded stream: each 16bpp pixel packs all six cockpit displays. Decoded live into per-display windows: bits 0-5 = the COLOR radar/tactical display, as 6-bit RGB (2 bits/channel) bits 6-7 = mono display 1 (nav scope) bits 8-9 = mono display 2 (weapons/systems) bits 10-11 = mono display 3 (sensor cluster) bits 12-13 = mono display 4 bits 14-15 = mono display 5 That's 6 + 5x2 = 16 bits exactly -> six displays (1 color + 5 mono), matching the pod hardware. A 7th window (bits 16-17) confirms the budget: it's black. Each display now renders in its own 640x480 window from the shared framebuffer (vga.mem.linear). Mono screens show as brightness; the three VDB palettes are the per-display color maps (next: apply them). Co-Authored-By: Claude Opus 4.8 --- emulator/vpx-device/vpxlog.cpp | 43 +++++++++++++++++++++++----------- 1 file changed, 29 insertions(+), 14 deletions(-) diff --git a/emulator/vpx-device/vpxlog.cpp b/emulator/vpx-device/vpxlog.cpp index 1bab383..1a68de8 100644 --- a/emulator/vpx-device/vpxlog.cpp +++ b/emulator/vpx-device/vpxlog.cpp @@ -669,20 +669,30 @@ static void pal_draw(HDC dc, int g, int cw, int ch) { Bitu start = vga.config.real_start; /* visible page start (bytes) */ Bitu stride = (Bitu)W * 2; /* 16bpp */ if (fb) { + /* The six displays are bit-packed into each 16bpp pixel: + * window 0 = the COLOR radar = bits 0-5 as 6-bit RGB (2 bits/chan) + * window g>=1 = a mono display = the 2-bit field at bit (4 + 2*g) + * (g=1 -> bits 6-7, ... g=5 -> bits 14-15) + * rendered as brightness. */ + unsigned shift = 4u + 2u * (unsigned)g; /* used for g>=1 */ for (int y = 0; y < H; y++) { Bitu ofs = start + (Bitu)y * stride; unsigned char *d = &img[(size_t)y * W * 3]; for (int x = 0; x < W; x++, ofs += 2, d += 3) { uint16_t px = *(const uint16_t *)(fb + (ofs & mask)); - d[0] = (unsigned char)(((px >> 11) & 0x1F) * 255 / 31); - d[1] = (unsigned char)(((px >> 5) & 0x3F) * 255 / 63); - d[2] = (unsigned char)(( px & 0x1F) * 255 / 31); + if (g == 0) { + d[0] = (unsigned char)(( px & 0x3u) * 85u); /* R: bits 0-1 */ + d[1] = (unsigned char)(((px >> 2u) & 0x3u) * 85u); /* G: bits 2-3 */ + d[2] = (unsigned char)(((px >> 4u) & 0x3u) * 85u); /* B: bits 4-5 */ + } else { + unsigned char v = (unsigned char)(((px >> shift) & 0x3u) * 85u); + d[0] = d[1] = d[2] = v; + } } } } else { memset(img, 0, sizeof img); } - (void)g; glViewport(0, 0, cw, ch); glClearColor(0, 0, 0, 1); glClear(GL_COLOR_BUFFER_BIT); glDisable(GL_DEPTH_TEST); glDisable(GL_TEXTURE_2D); glDisable(GL_LIGHTING); @@ -732,15 +742,20 @@ static DWORD WINAPI rt_main(LPVOID) { if (!make_gl_window("VPX VelociRender (emulated)", 832, 512, 40, 40, &wnd, &dc, &gl)) return 1; - /* three 640x480 windows, one per VDB display palette */ - static const char *pal_titles[3] = { - "VDB palette 0 - secondary", "VDB palette 1 - aux1", - "VDB palette 2 - aux2" }; - HWND pwnd[3]; HDC pdc[3]; HGLRC pgl[3]; - bool phave[3] = { false, false, false }; - for (int g = 0; g < 3; g++) + /* one 640x480 window per decoded display: window 0 = color radar + * (bits 0-5 RGB), windows 1-6 = the mono displays (2-bit fields). */ + const int NPAL = 7; + static const char *pal_titles[7] = { + "display 0 - radar (bits 0-5 RGB)", "display 1 (bits 6-7)", + "display 2 (bits 8-9)", "display 3 (bits 10-11)", + "display 4 (bits 12-13)", "display 5 (bits 14-15)", + "display 6 (bits 16-17)" }; + HWND pwnd[7]; HDC pdc[7]; HGLRC pgl[7]; + bool phave[7] = { false, false, false, false, false, false, false }; + for (int g = 0; g < NPAL; g++) phave[g] = make_gl_window(pal_titles[g], 640, 480, - 920, 40 + g * 500, &pwnd[g], &pdc[g], &pgl[g]); + 880 + (g % 3) * 650, 30 + (g / 3) * 470, + &pwnd[g], &pdc[g], &pgl[g]); VFrame cur; for (;;) { @@ -765,8 +780,8 @@ static DWORD WINAPI rt_main(LPVOID) { rt_frames++; } } - /* redraw the palette windows every tick (live) */ - for (int g = 0; g < 3; g++) { + /* redraw the display windows every tick (live) */ + for (int g = 0; g < NPAL; g++) { if (!phave[g]) continue; wglMakeCurrent(pdc[g], pgl[g]); RECT cr; GetClientRect(pwnd[g], &cr);