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rect: Avoid numeric overflow on massive lines in SDL_IntersectRectAndLine.

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Reference Issue #8301.
Reference Issue #8113.

(cherry picked from commit a391dd5fef)
This commit is contained in:
Ryan C. Gordon
2023-11-24 19:29:39 -05:00
parent e548044a82
commit db7f6425d0
2 changed files with 11 additions and 8 deletions
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17
src/video/SDL_rect_impl.h
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@@ -376,16 +376,16 @@ SDL_bool SDL_INTERSECTRECTANDLINE(const RECTTYPE *rect, SCALARTYPE *X1, SCALARTY
if (outcode1) {
if (outcode1 & CODE_TOP) {
y = recty1;
x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
x = (SCALARTYPE) (x1 + ((BIGSCALARTYPE)(x2 - x1) * (y - y1)) / (y2 - y1));
} else if (outcode1 & CODE_BOTTOM) {
y = recty2;
x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
x = (SCALARTYPE) (x1 + ((BIGSCALARTYPE)(x2 - x1) * (y - y1)) / (y2 - y1));
} else if (outcode1 & CODE_LEFT) {
x = rectx1;
y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
y = (SCALARTYPE) (y1 + ((BIGSCALARTYPE)(y2 - y1) * (x - x1)) / (x2 - x1));
} else if (outcode1 & CODE_RIGHT) {
x = rectx2;
y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
y = (SCALARTYPE) (y1 + ((BIGSCALARTYPE)(y2 - y1) * (x - x1)) / (x2 - x1));
}
x1 = x;
y1 = y;
@@ -394,23 +394,23 @@ SDL_bool SDL_INTERSECTRECTANDLINE(const RECTTYPE *rect, SCALARTYPE *X1, SCALARTY
if (outcode2 & CODE_TOP) {
SDL_assert(y2 != y1); /* if equal: division by zero. */
y = recty1;
x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
x = (SCALARTYPE) (x1 + ((BIGSCALARTYPE)(x2 - x1) * (y - y1)) / (y2 - y1));
} else if (outcode2 & CODE_BOTTOM) {
SDL_assert(y2 != y1); /* if equal: division by zero. */
y = recty2;
x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
x = (SCALARTYPE) (x1 + ((BIGSCALARTYPE)(x2 - x1) * (y - y1)) / (y2 - y1));
} else if (outcode2 & CODE_LEFT) {
/* If this assertion ever fires, here's the static analysis that warned about it:
http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-b0d01a.html#EndPath */
SDL_assert(x2 != x1); /* if equal: division by zero. */
x = rectx1;
y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
y = (SCALARTYPE) (y1 + ((BIGSCALARTYPE)(y2 - y1) * (x - x1)) / (x2 - x1));
} else if (outcode2 & CODE_RIGHT) {
/* If this assertion ever fires, here's the static analysis that warned about it:
http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-39b114.html#EndPath */
SDL_assert(x2 != x1); /* if equal: division by zero. */
x = rectx2;
y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
y = (SCALARTYPE) (y1 + ((BIGSCALARTYPE)(y2 - y1) * (x - x1)) / (x2 - x1));
}
x2 = x;
y2 = y;
@@ -427,6 +427,7 @@ SDL_bool SDL_INTERSECTRECTANDLINE(const RECTTYPE *rect, SCALARTYPE *X1, SCALARTY
#undef RECTTYPE
#undef POINTTYPE
#undef SCALARTYPE
#undef BIGSCALARTYPE
#undef COMPUTEOUTCODE
#undef SDL_HASINTERSECTION
#undef SDL_INTERSECTRECT