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hzeller / rpi-rgb-led-matrix

Controlling up to three chains of 64x64, 32x32, 16x32 or similar RGB LED displays using Raspberry Pi GPIO
GNU General Public License v2.0
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Vmapper:Z requires physical re-mapping and rewiring of panels when switching from odd to even number in height #1663

Closed marcmerlin closed 1 day ago

marcmerlin commented 1 month ago

You can currently wire things so that they work whether you have odd or even, but if you try to add a panel, everything gets flipped around https://github.com/hzeller/rpi-rgb-led-matrix/pull/1014 still works, but is fairly suboptimal

marcmerlin commented 1 month ago

This is with --led-chain=4 PXL_20240611_154150807

and with --led-chain=5, everything is reversed and all the panels need to be re-wired for the new order. PXL_20240611_154215361

As per my upcoming PR, the problem and solution

+    // because the panel you plug into ends up being the "bottom" panel and coordinates
+    // start from the top panel, and you typically don't wire the bottom panel (first in
+    // the chain) upside down, whether each panel gets swapped depends on this.
+    // Without this, if you wire for 4 panels high and add a 5h panel, without this
+    // code everything would get reversed and you'd have to re-layout all the panels
+    bool is_height_even_panels = ( matrix_width / panel_width) % 2;
marcmerlin commented 1 month ago

this is now fixed in https://github.com/hzeller/rpi-rgb-led-matrix/pull/1664