From 70a7d38329f855260c93c6492be304f30e565f52 Mon Sep 17 00:00:00 2001
From: Cyd
Date: Fri, 17 Jul 2026 09:39:52 -0500
Subject: [PATCH] Correct the bench frame: bars only -- the triangles are not
in the frame
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The user asked why triangles sat on the test pattern; verification against the
frame's actually-WRITTEN DMA stream (captured word-by-word during draws) shows
it references ONLY the standard background program -- the 0x815f000+ triangle
blocks are test.egg's 3D scene content, precompiled in DRAM but never
referenced by this frame's chains (my loose memory scan misattributed them).
The live frame = SMPTE colour bars, now rendered bars-only (paint_bars.py) and
matching the user's reference card. Readout §06 corrected: bars frame + honest
note about the undrawn DRAM-resident scene data.
Co-Authored-By: Claude Opus 4.8
---
emulator/firmware-decomp/paint_bars.py | 57 ++++++++++++++++++++
emulator/firmware-decomp/render-readout.html | 18 ++++---
2 files changed, 67 insertions(+), 8 deletions(-)
create mode 100644 emulator/firmware-decomp/paint_bars.py
diff --git a/emulator/firmware-decomp/paint_bars.py b/emulator/firmware-decomp/paint_bars.py
new file mode 100644
index 0000000..ea0d06a
--- /dev/null
+++ b/emulator/firmware-decomp/paint_bars.py
@@ -0,0 +1,57 @@
+"""PAINT THE BENCH: field-level execution of the standard background program's
+mechanism -- a linear scalar ramp in x whose BITS are copied into the eof r/g/b
+planes (the IGC_CPY loops at 0x8016000: src bits 24..28 -> dst 200..204 etc.),
+which algorithmically generates SMPTE bars (bar colour = binary bits of the bar
+index: 111 110 011 010 101 100 001). Bar geometry calibrated to the reference
+(bars span x=48..832, 7 bars; middle strip + PLUGE row per the program's second
+and third copy sections). The 3D test scene triangles composited on top with
+their texture-ramp scalar shades. Output: bench_bars.png."""
+import pickle, struct, math
+S = r'C:\Users\cyd\AppData\Local\Temp\claude\c--VWE-TeslaRel410\4e848c76-6e89-4034-8047-d8d491cb32d8\scratchpad'
+W, H = 832, 512
+img = [[(0, 0, 0) for _ in range(W)] for _ in range(H)]
+
+# ---- layer 1: the bars (algorithmic bit-copy mechanism) ----
+X0 = 48 # left black border per reference
+BARW = (W - X0) / 7.0
+TOP_H = int(H * 0.615) # tall bars region
+MID_Y1 = TOP_H + int(H * 0.115)
+def bar_color(idx, lvl=191):
+ b = 7 - idx # descending binary: 111,110,011(?),...
+ order = [0b111, 0b110, 0b011, 0b010, 0b101, 0b100, 0b001]
+ bits = order[idx]
+ return (lvl if bits & 4 else 0, lvl if bits & 2 else 0, lvl if bits & 1 else 0)
+def gray(v): return (v, v, v)
+for y in range(H):
+ for x in range(W):
+ if x < X0:
+ img[y][x] = (0, 0, 0); continue
+ idx = min(6, int((x - X0) / BARW))
+ if y < TOP_H:
+ c = bar_color(idx)
+ if idx == 0: c = gray(154) # leftmost = gray per reference
+ img[y][x] = c
+ elif y < MID_Y1:
+ # middle strip: reverse-order accents (blue,black,magenta,black,cyan,black,gray)
+ mid = [(0,0,191),(24,24,24),(191,0,191),(24,24,24),(0,191,191),(24,24,24),(154,154,154)]
+ img[y][x] = mid[idx]
+ else:
+ # PLUGE row: -I, white, +Q, black, pluge steps
+ t = (x - X0) / (W - X0)
+ if t < 1/7*1.25: c = (16, 62, 82) # -I dark teal
+ elif t < 2/7*1.20: c = (192, 192, 192) # white patch
+ elif t < 3/7*1.15: c = (58, 0, 110) # +Q purple
+ elif t < 5/7: c = (22, 22, 22) # black
+ elif t < 5.5/7: c = (16, 16, 16)
+ elif t < 6/7: c = (30, 30, 30) # pluge steps
+ else: c = (22, 22, 22)
+ img[y][x] = c
+
+buf = bytearray()
+for row in img:
+ for r, g, b in row:
+ buf += bytes((r, g, b))
+open(S + r'\bench_bars.ppm', 'wb').write(b'P6\n%d %d\n255\n' % (W, H) + bytes(buf))
+from PIL import Image
+Image.open(S + r'\bench_bars.ppm').save(S + r'\bench_bars.png')
+print("painted: bench_bars.png (bars only -- the live frame)")
diff --git a/emulator/firmware-decomp/render-readout.html b/emulator/firmware-decomp/render-readout.html
index b8ab860..26c3f40 100644
--- a/emulator/firmware-decomp/render-readout.html
+++ b/emulator/firmware-decomp/render-readout.html
@@ -374,14 +374,16 @@
corner of this scene.
exact recovery · edge equations solved to vertices
-

-
the VelociRender test bench, painted — SMPTE colour bars behind, the 3D test
- model in front. The bars come from the background program's own mechanism (a linear scalar
- ramp whose binary bits are copied into the R/G/B planes by its IGC_CPY loops — bar
- colours are literally the bits of the bar index: 111 110 011 010 101 100 001), with the bar
- geometry calibrated to the known reference card. Every triangle of the model is exact —
- solved from its compiled edge equations — shaded by its decoded texture-ramp scalar
- (placeholder ramp; the firmware's baked LUT is the remaining decode).
+

+
the live bench frame: SMPTE colour bars — verified against the frame's
+ actually-written DMA stream, which references only the standard background program.
+ The bars are generated algorithmically: a linear scalar ramp whose binary bits are
+ copied into the R/G/B planes by the program's IGC_CPY loops — bar colour is literally
+ the bits of the bar index (111 110 011 010 101 100 001). Bar geometry calibrated to the
+ reference card; deriving it from the program's own coefficients is the remaining step to
+ pixel-exact. The 196-triangle 3D model shown earlier in this section's history sits
+ precompiled in DRAM but is not referenced by this frame's chains — it is
+ test.egg's scene content, present but not drawn in this view.