forked from arti/vt1200
SDD
571850e564
MAME's TMS34010 renderer does not read VRAM: tms340x0_ind16 calls the driver's scanline callback for the active region and paints only the blanking regions. Our callback drew nothing, so the active area was never painted and every frame dump was all-black. Add render_active_line(), called from scanline(): it reads the framebuffer out of the video-RAM share at bit 0x04000000 with a measured 1024-bit (0x40-word, 128-byte) row pitch and LSB-first bit order within each 16-bit word. The pitch comes from the firmware's own character blitter (PIXBLT at pc=3FDF9A00 advances its destination by 0x40 words per glyph row); at the 160-byte pitch MAME derived from HEBLNK/HSBLNK/HTOTAL the text is sheared and unreadable. Validated: frame 160 shows the level-1 CP437 character table legibly, frame 600 the level-1 error screen. VT1200_DPYLOG added as an opt-in per-scanline display-params dump. Regression (no VT1200_* env): PC=3FDCE400 samples=199 -- holds. See harness/mame/RENDER_REPORT.md.