#146 Out of range error in GLGraphics.pas

[Yann Papouin]

Since rev 1.63 of GLGraphics.pas (Integer -> PtrUInt), Delphi throw an "Out of range" exception

In:
rowOffset := PtrUInt(BitmapScanLine(aBitmap, Height - 2)) - PtrUInt(pSrc)
The result can be negative.

We should revert all PtrUInt to ptrInt ?

[YarUnderoaker]

In 64-bit platforms an arifmetic operations with pointer must be doing with conversion it's to PtrUInt type. So maybe need to complitly rewrite this code.
Besides, rowOffset is 32-bit integer and PtrUInt is 64-bit on x64 - not very correct assignment operation.

[Yann Papouin]

The main problem comes from the operation, by example the following line
temp := Byte(1) - Byte(1);
will raise an exception when range check is enabled even if temp is an integer

[Yann Papouin]

Ok my previous assertion was wrong
delta := Int64(Byte(250) - Byte(254));
do not raise any exception the result is valid.

BUT

delta:= int64(PtrUInt(newbase) - PtrUInt(oldbase));
is raising an out of range exception
(tested with
newbase := Pointer(2140012872);
oldbase := Pointer(2144797000);
)

the same thing with
delta:= int64(PtrUInt(newbase)) - int64(PtrUInt(oldbase));
do not raise any exception the result is valid.

To my mind it's delphi int64 error, but I can be fixed by casting both arguments
delta:= int64(PtrUInt(newbase)) - int64(PtrUInt(oldbase));

[YarUnderoaker]

ok, go fix :)