fix [#36685] crash calculating tangent space data on degenerate geometry

the error was that the range check was done on the float before converting to an int.
now convert to and int first and ensure a valid range on that.

1 files changed, 2 insertions, 2 deletions

diff --git a/intern/mikktspace/mikktspace.c b/intern/mikktspace/mikktspace.c
index 018869f36b6..62aa2da2517 100644
--- a/intern/mikktspace/mikktspace.c
+++ b/intern/mikktspace/mikktspace.c
@@ -440,8 +440,8 @@ static const int g_iCells = 2048;
 static NOINLINE int FindGridCell(const float fMin, const float fMax, const float fVal)
 {
 	const float fIndex = g_iCells * ((fVal-fMin)/(fMax-fMin));
-	const int iIndex = fIndex<0?0:((int)fIndex);
-	return iIndex<g_iCells?iIndex:(g_iCells-1);
+	const int iIndex = (int)fIndex;
+	return iIndex < g_iCells ? (iIndex >= 0 ? iIndex : 0) : (g_iCells - 1);
 }
 
 static void MergeVertsFast(int piTriList_in_and_out[], STmpVert pTmpVert[], const SMikkTSpaceContext * pContext, const int iL_in, const int iR_in);