VGA Tests
---

To aid in the development of PCjs VGA support, I've started adding some VGA tests to the project.  For now, the
only "tests" are samples taken directly from [Michael Abrash's Graphics Programming Black Book](https://github.com/jeffpar/abrash-black-book).

Abrash's book is available on many sites, but I'm partial to the Markdown version that [James Gregory](https://github.com/jagregory)
has made available on GitHub, because (a) it's a brilliant way to share the text, and (b) it apparently has Abrash's blessing, so
I feel more comfortable forking it, using it, and resharing it.

The main reasons for my [fork](https://github.com/jeffpar/abrash-black-book): to make the book's
images display properly on GitHub, and to extract and add assorted source code listings as I need them.  Since that
project's [/src](https://github.com/jeffpar/abrash-black-book/tree/master/src) folder contains just the book's text,
I've added a [/code](https://github.com/jeffpar/abrash-black-book/tree/master/code) folder for the source code listings.
The name of each source code file matches the name displayed in the text (eg, [L23-1.ASM](L23-1.ASM) is Listing 23.1
from [Chapter 23](https://github.com/jeffpar/abrash-black-book/blob/master/src/chapter-23.md)).

I assume something similar was done on the CD-ROM that accompanied the Black Book, but since I don't have the original
book or its CD-ROM, I'm extracting the source code directly from the Markdown text, and then "tabifying" it with 8-column
tab stops.

Development of PCjs VGA support has just begun (June 2015), so don't expect *anything* here to to run properly yet.

---

List of VGA Samples from [Michael Abrash's Graphics Programming Black Book](https://github.com/jeffpar/abrash-black-book):

 * [Chapter 23](https://github.com/jeffpar/abrash-black-book/blob/master/src/chapter-23.md)
	 * [L23-1.ASM](https://github.com/jeffpar/abrash-black-book/blob/master/code/L23-1.ASM) 

---

Also, I've updated the PCjs [Library](/disks/pc/library.xml) disk collection to include the following disk image:

	<disk path="/tests/pc/vga/">VGA Tests (Black Book)</disk>

But wait, you say, that *path* refers to a directory, not a disk image.  And that's true; normally the *path* for a disk
entry will refer to either an IMG file *or* a JSON-encoded IMG file.  However, if the *path* ends with a slash, then it's
assumed to be a directory, and so PCjs will ask the server to enumerate the contents of that directory and send back a
JSON-encoded disk image containing all the files in that directory (including any subdirectories).

Since the contents of this directory will probably be in flux for a while, I've opted for this approach.  Once
things settle down, I'll generate a JSON-encoded disk image containing a snapshot of this directory.

I've updated a [Compaq DeskPro 386 Machine](/devices/pc/machine/compaq/deskpro386/vga/2048kb/) to use the
[Library](/disks/pc/library.xml) disk collection and automatically load the above disk:

	<fdc ref="/disks/pc/library.xml"
	     width="340px"
	     automount='{A: {name: "PC-DOS 3.00 (Disk 1)",
	                     path: "/disks/pc/dos/ibm/3.00/PCDOS300-DISK1.json"},
	                 B: {name: "VGA Tests (Black Book)",
	                     path: "/tests/pc/vga/"}
	     }' />