https://gitlab.synchro.net/main/sbbs/-/commit/584161fa8330cab0bde7c024
Modified Files:
xtrn/syncivision/syncretro.example.ini xtrn/syncnes/syncretro.example.ini
Log Message:
syncretro: record why aspect 1.5 is right, and default the NES to it

"Why is the aspect 1.5 and not 4:3?" is the question the next sysop will
ask, and the answer is not in the door: it is in the TERMINAL.

The door emits pixels. Whether they are square when they reach the eye is
the screen mode the player picked. SyncTERM's classic VGA modes ("80x25")
are the mode 13h shape -- a 640x400 canvas shown as a 4:3 picture -- so
every canvas pixel is 1.3333/1.6 = 0.8333 as wide as it is tall, and every image the door draws is squeezed horizontally by that factor before anyone
sees it. The "LCD 80x25" modes are the square-pixel variants and squeeze nothing. The door can tell that it is talking to SyncTERM, but not which
mode the player chose, so no single number is right for both.

Measured on the Dr. Mario title screen -- whose checkerboard is drawn from square NES tiles, so its shape on screen IS the pixel shape:

SyncTERM "80x25" (VGA) NES pixel 1.178, picture 1.250
SyncTERM "LCD 80x25", NES pixel 1.403, picture 1.500
Windows Terminal

A real NES is 1.143 pixels / 1.219 picture (the 8:7 convention), or 1.250 / 1.333 (a 4:3 television). So in the VGA modes an emitted 1.5 pre-compensates for the squeeze and lands between the two references -- which is why it looks right, and why the "correct" 4:3 looks too NARROW there: 1.333 x 0.8333 = 1.111, nearly square.

Default the NES template to 1.5 accordingly. The old default, `core` (the
NES's reported 1.219), comes out at 1.016 in the VGA modes: essentially
square pixels, and visibly wrong for most of the people who will dial in.

The Intellivision keeps its default, and the same arithmetic says why it was never a problem: FreeIntv's native 352x224 is 1.571, which the VGA squeeze turns into 1.31 -- the 4:3 that console really output. Right by luck, and
only in those modes; its template now says so.

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