dal@stag.UUCP (Dale Schumacher) (02/15/88)
<Thomas_E_Zerucha@cup.portal.com> writes... > Arkanoid uses a series of locations where GEM stores the current mouse > X,Y, and button state, somewhere in 0x00002000 - 0x00002fff range, and > you can find the locations easily and patch them. I have the new ROMs > and a copy of ARKANOIDS that runs on them. When will programmers use > the documented methods of doing these things <groan>? I picked up some information a while ago about these values actually being referencable as an offset from the a-line base address (like lots of other information posted in Bammi's ALINE2.H). I haven't tested these values on the Megas, but they should work. Perhaps someone could substantiate their usefulness (or failure) on the Mega ROMs. #define MOUSEX *((WORD *)((char *)aline + (char *)-344L)) #define MOUSEY *((WORD *)((char *)aline + (char *)-342L)) #define MOUSESTATE *((BYTE *)((char *)aline + (char *)-348L)) The mouse buttons appear to be (MOUSESTATE & 1) for left and (MOUSESTATE & 2) for right. The higher order bits of MOUSESTATE seem to hacve something to do with the mouse being moved. If anyone can expand on this information, (or make corrections) please do. Dale Schumacher ..ihnp4!meccts!stag!syntel!dal (alias: Dalnefre')
apratt@atari.UUCP (Allan Pratt) (02/20/88)
in article <338@stag.UUCP>, syntel!dal@stag.UUCP (Dale Schumacher) says: > #define MOUSEX *((WORD *)((char *)aline + -344L)) > #define MOUSEY *((WORD *)((char *)aline + -342L)) > #define MOUSESTATE see below > > The mouse buttons appear to be (MOUSESTATE & 1) for left and (MOUSESTATE & 2) > for right. The higher order bits of MOUSESTATE seem to hacve something to > do with the mouse being moved. If anyone can expand on this information, > (or make corrections) please do. The mousex and mousey values above are correct (if a little over-casted). But the button state can better be read from MOUSE_BT, at offset -596L from the "aline" base. This variable doesn't have any bits except the button state bits (bit 0 = button 0, bit 1 = button 1), so there's nothing else to check. #define MOUSE_BT *((WORD *)((char *)aline + -596L)) This one is a word, not a byte. Also, you can't cast the constant to a (char *): it's OK to add a constant to a character pointer, but adding two pointers is undefined in C. Subtracting two pointers gives the distance between them, but adding two pointers is illegal. (Naturally, the Alcyon compiler not only doesn't tell you this is an error, but at least it generates correct code for what you wanted it to do. The defines in the quote from dal have been edited by me to reflect this.) Note that these values are READ ONLY. If you write to them, bad things will happen and the system will lose track of the mouse state. All of these "negative line-A variables" were published in the developer section of CompUServe some time ago. They work for all ROMs. ============================================ Opinions expressed above do not necessarily -- Allan Pratt, Atari Corp. reflect those of Atari Corp. or anyone else. ...ames!atari!apratt