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Fix widescreen letterbox/divider left-edge clipping on ARM64 (#709)

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* Fix widescreen letterbox/divider left-edge clipping on ARM64

The race-intro letterbox bars (draw_box_fill_wide) and the splitscreen
divider lines fed the float OTRGetDimensionFromLeftEdge result into
gDPFillWideRectangle, whose _SHIFTL packing casts float->unsigned.
Converting a negative float to unsigned is UB: x86 wraps (and the
wide-rect handler's sign extension recovers the value, so the bug is
invisible there), but ARM64 fcvtzu saturates negatives to zero — so on
Apple Silicon the fills started at the 4:3 left edge instead of the
true left edge, leaving a strip of sky visible left of the intro bars
in widescreen. Use the integer OTRGetRectDimensionFrom*Edge getters,
matching the sibling draw_box_wide helpers.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Shorten the fix comment

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
quarrel07
2026-07-20 03:14:36 -07:00
committed by GitHub
parent 582900a1b9
commit b3e0fe248d
2 changed files with 12 additions and 4 deletions
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src/menu_items.c
+5 -2
View File
@@ -3476,8 +3476,11 @@ Gfx* draw_box_fill_wide(Gfx* displayListHead, s32 ulx, s32 uly, s32 lrx, s32 lry
gSPDisplayList(displayListHead++, D_02008030);
gDPSetFillColor(displayListHead++, (GPACK_RGBA5551(red, green, (u32) blue, alpha) << 0x10 |
GPACK_RGBA5551(red, green, (u32) blue, alpha)));
gDPFillWideRectangle(displayListHead++, OTRGetDimensionFromLeftEdge(ulx) - 1, uly, OTRGetDimensionFromRightEdge(lrx) + 1,
lry);
// Use the integer Rect getters: the float getters' negative left edge goes
// through a float->unsigned cast in _SHIFTL (UB) that ARM64 saturates to 0,
// pushing the fill's left edge to the 4:3 boundary in widescreen.
gDPFillWideRectangle(displayListHead++, OTRGetRectDimensionFromLeftEdge(ulx) - 1, uly,
OTRGetRectDimensionFromRightEdge(lrx) + 1, lry);
gDPFillRectangle(displayListHead++, ulx, uly, lrx, lry);
gSPDisplayList(displayListHead++, D_02008058);
return displayListHead;
src/racing/skybox_and_splitscreen.c
+7 -2
View File
@@ -308,11 +308,16 @@ void func_802A4300(void) {
gDPFillRectangle(gDisplayListHead++, 157, 0, 159, 239);
break;
case SCREEN_MODE_2P_SPLITSCREEN_HORIZONTAL:
gDPFillWideRectangle(gDisplayListHead++, OTRGetDimensionFromLeftEdge(0), 119, OTRGetGameRenderWidth(), 121);
// Integer Rect getter: the float getter's negative result through
// _SHIFTL is float->unsigned UB, which saturates to 0 on ARM64 and
// clips the divider's left extension (see draw_box_fill_wide).
gDPFillWideRectangle(gDisplayListHead++, OTRGetRectDimensionFromLeftEdge(0), 119,
OTRGetGameRenderWidth(), 121);
break;
case SCREEN_MODE_3P_4P_SPLITSCREEN:
gDPFillRectangle(gDisplayListHead++, 157, 0, 159, 239);
gDPFillWideRectangle(gDisplayListHead++, OTRGetDimensionFromLeftEdge(0), 119, OTRGetGameRenderWidth(), 121);
gDPFillWideRectangle(gDisplayListHead++, OTRGetRectDimensionFromLeftEdge(0), 119,
OTRGetGameRenderWidth(), 121);
break;
}
gDPPipeSync(gDisplayListHead++);