SpriteGrabber

Utility to help sprite-grabbing process

Disclaimer

Please understand that grabbing pictures or graphics elements from another software by any means (included this application) in some circumstances may be recognized as an unlawful act.

Forewords

The refactoring of an old game is an endless and somewhat difficult job, one of the most tiring a frustrating part of this work is IMHO the recovery of original graphics elements.

This application is a tool meant to give some relief to those fouls that boldly get into this specific and dangerous task.

Please NOTE that this application is still a work in progress and it's long to be complete.

Side note

There are other utilities like this one and probably better ones. MAME itself has a special feature that allows to dump game pallette usually bound to F4 key.

Usage

This application need a graphic source where to pick the elements to grab. At this stage these sources can be:

• MNG bundle file(s);
• AVI file(s).

Both these kind of sources are produced from emulators such as MAME. If you are using MAME you need to run it from the console with -mngwrite or -aviwrite command line options. Snapping into MNG files can be achieved also with Shift+F12 key combination. If you're going to use the second format take into account that AVI files recorded from MAME are pretty uncompressed: this means that it will consume an huge amount of disk space (usually 1Gb per minute of recording).

Despites the widespread idea that MAME should be able to save animated GIF (Shift+F12) I haven't found a recent release of MAME capable of doing so. I added support for this kind of files but you will probably never have a chance to use it.

Once launched the application shows the main form where you can recognize four main items:

• Frames bundles textbox;
• Frame picturebox (x2);
• Messages listview.

Sited below the two frames picturebox there are a number of widgets (buttons, textboxes, up-down controls) to adjust, report and run the workflow actions.

The Frame bundles texbox simply report the filename of the last selected graphic source. To select a graphic source you need to push onto the button on the right of the textbox and select a suitable file from your archives (or drag & drop the same file over the textbox). Once the file has been selected the application will investigate it collecting the total frames number and loading the first two frames to place them in Frames pictureboxes.

Each frame picturebox is used to depict the frame selected by the user acting on up-down controls placed under the picturebox itself. The button placed between the two up-down control is used to exchange the frames into the pictureboxes (and frames indexes accordingly). Those frames are used by the application to summon the sprite during the grabbing process, as a general hint you should try to select two frames with the most common background and the sprite meant to be collected in two different and not overlapping positions.

Messages listview is a simple log of actions and results/errors occurred during the application run. The list itself can be cleared / saved acting on its context menu.

Frames textbox (placed on the left below the picturebox) reports the total number of frames available in the graphic source.

BG Color textbox (placed on the right below the picturebox) reports the currently selected background color. Background color is gathered automatically by the application when one of the frames change nevertheless the user can change the background color just by clicking onto the desired color on depicted frames. Please note that selecting the background color it's not mandatory but it will optimize the grabbing extraction process.

Capture button is the trigger of the main function of the application. Pushing this button will open a new window where selected frames are compared to check for differences (to be precise the left one is compared against the right one). The result of comparision is shown in the picturebox placed in center of the window, this can be assumed as the source of the sprite. Between two frames of a same time sequence the common portion (the part that's NOT changing) is probably the background and thus can be removed. The remaining elements are either sprites or portion of background changing between frames (portions of background hidden by the sprite itself, portion of background sliding in or out of the scene due to scrolling etc). Some portions of such remainder can be removed adjusting Offset up-down controls placed under the frame picturebox (please note that both offsets value can be either positive or negative). If you have initially selected two good frames and applied the correct offset the sprite is hopefully clear and isolated. Now you can select it by mouse (just click and drag the cursor until the yellow rectangle include the sprite) you don't need to be extremely precise in this selection since an optimization algorithm is run just after you release the mouse button and the smallest rectangle including the sprite will be drawn for you. Once the sprite has been selected you have three choices:

1. trash everything clicking on Close button;
2. store your sprite for later use clicking on Collect;
3. immediately save the selected sprite with Save button.

If you press Save you're asked for a location where to save the sprite file (please note that it will be saved as a PNG image to preserve the transparent background) but it won't store this into yout sprite collection, after saving the window will close. Collect will store the selected sprite in your global collection (but it won't save it anywere) the window will NOT close allowing you to hunt for another sprite. Close will obviously close the window without saving or storing the selected sprite (if any).

The checkbox Swap frames allows to reverse the order of checking (i.e. the right image is compared against the left one). This often allows to collect another sprite without need to get back to the main window.

Once back on the main window you'll probably want to repeat the process (with different frames) to collect more and more sprites.

The amount of sprites collected on your hunting/grabbing session is reported on the right of the Sprites button.

After you repeated the process of grabbing some times you can look/manage your sprites collection by clicking the button Sprites. There (on the new window) you'll find sprites depicted by their miniatures enlisted on the left. Clicking on a sprite will display it in all it's glory on the right panel. If you wish to investigate details you can zoom in by using the zoom-bar on the right of the panel istelf. Once you're satisfied of the sprite collection you can click on Save button and select the folder where the sprite collection will be saved (as a bundle of PNG images), you can do partial saving by selecting which sprite(s) to save on the left list prior to press Save button. From this window you can also remove sprites from the collection or clear the entire collection by clicking on the appropiate context menu item of the list. The textbox near Save button must be filled with the basename for sprite's files.

Guidelines to properly collect game frames

Besides which emulator you will use and which format you'll be going to use for the graphic source the success of the grabbing will mostly depend on the correct collection of frames before the grabbing job actually start. These are some rules I'm using to setup a good graphic source as a base for sprite grabbing:

• Select levels or portion of levels where the background is uniform and not changing/moving;
• Move sprite (or trigger it to move or wait for it to move) on a uniform background;
• Try to collect frames where the sprite is placed in NON-overlapping positions;
• If the game has different scrolling directions try to record a sequence where the direction is uniform.

Build

Just download/clone the project with github and then open it in Microsoft Visual Studio.

MNG File handling

I'm using the SprinterMNG library from Sprinter Publishing to handle .mng pictures bundles.

Copyright notices

Visual Studio (C) 2017 Microsoft Corporation.

SprinterMNG Copyright © Sprinter Publishing 2009.

MAME Copyright (C) 1997-2019 MAMEDev and contributors.

TODO

• Drag & drop support;
• Handle .gif (animated ones) as graphics source format;
• Handle .zip pictures bundle as graphics source format;
• Equalize sprite format before saving collection;
• Better layout;
• Preview sprite collection animation;
• Change order in sprites collection;
• Sprite editor;
• Create sprite-sheet;
• Add installer;
• Localization;
• More smartness in sprite grabbing procedure.

References

MAME:

1. https://www.mamedev.org/
2. https://docs.mamedev.org/commandline/commandline-all.html
3. https://strategywiki.org/wiki/MAME/Special_Keys#F4

Microsoft Video Studio:

• https://visualstudio.microsoft.com/