Any way to free sprite 0 (mouse pointer)?

[StingRay]

As the title suggests I'm looking for a way to completely free sprite 0 so it can be used for other stuff. Tried quite a few things so far and was satisfied with none. Is it even possible to claim sprite 0 when system is still intact?
And no, just changing the sprite to something invisible is not enough, I really need to have full control of sprite 0, i.e. it must not handle any mouse movements any longer.

Any hints welcome!

[ross]

Chain to VBL IRQ and tamper gfxBase->copper stuff?

[StingRay]

Well, that still wouldn't fix the problem with the system still handling the mouse movements. And if possible I'm looking for a "clean" (i.e. less hacky) solution.

[Toni Wilen]

Add high priority input.device/IND_ADDHANDLER and swallow all events? (or all mouse events only).

[StingRay]

That might indeed work. Will try it, thanks.

[ross]

But this not solve the freeing of sprite..
(you got a stuck sprite0 on screen if you ignore each event)

Seems that a mix of the two techniques is required.

How about:
- intuition->LockIBase (a bit extreme..)
- high priority input.device/IND_ADDHANDLER (all events to NIL)
- chain to VBL IRQ and tamper gfxBase->copper->spritepointer
(maintaining wb/system copperlist, yes is hacky..)

Logically if don't need Intuition and don't need to inject mouse movement
What's your purpose?

[mark_k]

How system-legal are you wanting to be? You could eat all mouse movement events and use SetPointer() to set the sprite 0 [i.e. mouse pointer] image which would apply while your window is active.

Or you could call SetPrefs() to set the system-wide mouse pointer image. But that will work on Kickstart 1.x only; on 2.x or later you could replace the pointer ILBM image in ENV: maybe.

Moving the sprite would require injecting fake mouse movement input events.

[Samurai_Crow]

This could be handy for a more system friendly AmosPro runtime environment and others as well!

Sent from my Prism II using Tapatalk

[mark_k]

Digging into this subject some more...

A thread from comp.sys.amiga.programmer in 1993

From postings by Chris Green (Commodore graphics software engineer):
See the source code for AABoing on amiga.physik.unizh.ch. This
contains a fragment of how to use sprite 0 more-or-less safely.
I am using 64 bit wide sprites (os 3.0, AA chips), but the
same technique works under previous kickstarts.

The "trick" is to obtain another sprite, and set the spritenum
field in the SimpleSprite (or ExtSprite) structure to zero. Then when
this sprite is moved or changed, it will replace sprite 0. If intuition
moves the sprite (in response to a mouse click, for instance), it will
steal the sprite back temporarily, but this can be fixed by preventing
intuition from seeing mousemove events (via an input handler).

AABoing on Aminet

[meynaf]

For using sprite 0 I would start by trying to overwrite its pointer ($dff120) with mine in a custom copper list. The OS would still maintain the old sprite with the mouse position but that data just wouldn't be displayed anymore. If you use an Intuition screen you can do that by using Screen.ViewPort.UCopIns.