igc_array.py implements the array model from PXPL5SUP/IGCOPS.C + IGCTYPES.H:
the screen is partitioned into 64x128 tiles; every pixel owns a 26-byte
bit-addressable memory + enable bit; all pixels evaluate the same linear
tree eval_ltree(x,y,A,B,C)=(int)(x*A+y*B+C) in lockstep. A triangle is drawn
exactly as the hardware does (PXPL5GEO tri_zb_rgb): three edge trees -> the
enable register, then z + r/g/b planes interpolated per pixel, z-buffered via
MEM2geMEM2, writes gated by enable, read back out of pixel memory.
Driven by the captured 9x5 surface it lights 18/50 tiles and produces pixels
that match shade_render.py to ~1% (edge anti-aliasing only) -- validating the
array against the reference rasteriser. This is the array's computational
model, not a decode of the compiled bit-serial micro-code (that binary
encoding is still undecoded); it produces the pixels that micro-code would.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CydandClaude Opus 4.8
9d8de701f6
