name_desc.md

Variable Name Descriptions

Within Diablo the same variable name may be used within different contexts. The intention of this document is to provide a brief description of what each variable name represent based on its context.

Screen Coordinates

The pixels of the screen are accessed through a Screen structure, with 64 byte padding on the left, 64 on the right, 160 on the top and 16 on the bottom side of the screen, respectively.

• x: x-coordinate from top left corner of screen.
• y: y-coordinate from top left corner of screen.
• screen_x: x-coordinate+64 from top left corner of screen.
• screen_y: y-coordinate+160 from top left corner of screen.
• width: width in number of pixels.
• height: height in number of pixels.

0 <= x < 640
0 <= y < 480

0 <= screen_x < 768
0 <= screen_y < 656

x = screen_x-64
y = screen_y-160

  0
0 +-----------------------------------------------+ 768-1
  |      0                                        |
  |    0 +--------------------------------+ 640-1 |
  |      |                                |       |
  |      |                                |       |
  |      |                                |       |
  |      |                                |       |
  |      |                                |       |
  |      |                                |       |
  |      +--------------------------------+       |
  |     480-1                                     |
  +-----------------------------------------------+
 656-1

Map Coordinates

Primarily, there are two kinds of maps.

112x112 maps where each cell has the in game width of a dungeon piece (64 pixels).

40x40 maps where each cell has the in game width of a tile tile (128 pixels).

• x: x-coordinate on a 112x112 map.
• y: y-coordinate on a 112x112 map.
• w: width in dungeon pieces on a 112x112 map.
• h: height in dungeon pieces on a 112x112 map.

0 <= x < 112
0 <= y < 112

                  (x=0, y=0)
                      _
                     / \
                    /   \
               y   /     \   x
                  /       \
                 /         \
(x=0, y=112-1)  |           |  (x=112-1, y=0)
                 \         /
                  \       /
                   \     /
                    \   /
                     \_/
              (x=112-1, y=112-1)

• tx: x-coordinate on a 40x40 map.
• ty: y-coordinate on a 40x40 map.
• tw: width in tiles on a 40x40 map.
• th: height in tiles on a 40x40 map.

                  (tx=0, ty=0)
                       _
                      / \
                     /   \
               ty   /     \   tx
                   /       \
                  /         \
(tx=0, ty=40-1)  |           |  (tx=40-1, ty=0)
                  \         /
                   \       /
                    \     /
                     \   /
                      \_/
               (tx=40-1, ty=40-1)

Specifically for dungeon generation, there are additional kinds of maps.

80x80 maps represent tile ID maps of twice the size, repeating each tile of the original 40x40 map in blocks of 2x2.

• dx: x-coordinate on a 80x80 map.
• dy: y-coordinate on a 80x80 map.
• dw: width in tiles on a 80x80 map.
• dh: height in tiles on a 80x80 map.

0 <= dx < 80
0 <= dy < 80

                  (dx=0, dy=0)
                       _
                      / \
                     /   \
               dy   /     \   dx
                   /       \
                  /         \
(dx=0, dy=80-1)  |           |  (dx=80-1, dy=0)
                  \         /
                   \       /
                    \     /
                     \   /
                      \_/
               (dx=80-1, dy=80-1)