How-to guides
Prove a fix stayed in its region
Use diff to show exactly which pixels an edit changed.
When polishing a texture, each fix should touch only the region it is meant for. Keep the render from before the fix and compare:
cp out/lower.png before.png
# edit the grid, then:
texturescript grid lower.grid out/lower.png
texturescript diff out/lower.png before.png --sheet diff.png
diff prints a count and a map of the changed pixels:
mismatch 5/256 (missing 0, extra 5, wrong colour 0)
................
................
................
...........XX...
..........XXX...
................
--sheet writes the new texture, the old one and the changed pixels side by side, enlarged.
In a script or a check, add --check to exit with status 1 when any pixel differs, for example
to confirm a refactor of a grid changed nothing.