Home Page Forums MAME MAME Emulating a Touchmaster tablet device

How would I go about emulating a Touchmaster device? These input devices were available for various 8-bit micros and I'm specifically looking at the one for the Dragon machines. There's plenty of detail, including ROM and software, at http://archive.worldofdragon.org/index.php?title=Touchmaster_Tablet. The owner of this device is on this forum and is willing to assist with any info required, provide scans for a bezel, and convert the overlays to SVG if required.

I'd like to see it as a second screen that we can apply a bezel and overlay to, then it's a point and click input device. I didn't find anything similar in MAME so am looking for suggestions. Is it even doable with what we have at the moment?

There are several touchscreen machines in MAME, but I don't know of any graphics tablets off the top of my head.

I'm the one with the tablet pictured on the Dragon Archive.

The tablet itself has a 6803 microcontroller with its own rom and a 6821 peripheral interface adaptor that communicates with the interface (which only contains another 6821).

The user guide contains test program for all supported machines.

As Pernod said, I can generate SVG files for the overlays (just need to know MAME's preferred method for generating them) and do testing on the real thing.

In general emulating a tablet is nice to pass absolute coordinates directly to the software inside the emulation. Sometimes that can only easily be done by emulating tablet hardware. This is why QEMU and VirtualBox emulate a USB tablet as well. A touchscreen is even better of course, but emulating a tablet similarly to a touchscreen to use with absolute coordinates may be more useful than having it as a separate screen.

Does anybody know whether there is a touchscreen (or tablet) emulated that works with DOS/Windows 3.1?

The emulated touchscreen used in most of the Megatouch games works with DOS; if you watch carefully booting up the new XL ones you'll see config.sys installing a "touchscreen mouse emulator driver" from the ROM disk.

Cool. It will be interesting to investigate whether this could offer better support for certain kinds of applications than is possible through just int33h.

So I'm still not sure on the best way to approach this regarding the overlays that are required to cover the tablet for each game.

Ideally the overlays should be part of the romset for each game but am not seeing how this would currently be possible. Would using SVG_SCREEN be an option here or is that specifically for the handhelds that require control over the segments to be illuminated?

The obvious way is to use artwork and bundle all overlays into artwork for the device, then the user would have to manually select the view required for each game.

Can I even use artwork with a device?

In no particular order:
- artworks are at the driver level only, because historically they're supposed to layout the whole machine. SVG_SCREEN magics around that by not being an artwork but being a screen instead. You can use an artwork in addition to svg_screen to say put an image of the physical handheld around the LCD/VFD. Artworks aren't currently designed to embed other artworks, only primitive elements which include screens, so a hierarchical device-based structure is not supported at this point
- artworks are not in svg because svg is missing support for functionality we have in artworks and which I don't necessarily understand: clickability, inclusion of screens, aspect ratio management, probably other things. Plus our svg rendered doesn't do images yet.
- artworks are not in the romset to make it easy to change/override them. svg_screens are harder to change, especially with the rom size effect which cuts larger files.
- in practice, svg_screen has been accepted even given previous because it makes the games playable for a lot more people, and because I did it and those who would bitch are afraid of me :-)

Yeah, I eventually realised artwork is only discovered at the driver level, so abandoned that approach.

So I pursued the usage of SVG_SCREEN and converted an overlay to SVG using Inkscape.

Using SVG_SCREEN seems to seriously kill performance, any idea why? The SVG is 14MB but would likely be reduced with an expert converting it.

Is this approach a viable solution to emulating the tablet, or am I wasting my time?