A Character (Char) is the basic unit of all VIP generated bitmapped graphics on the VB. It is used by both Objects and Background Maps, as well as being used by Worlds themselves in certain situations. Chars have the following characteristics:
| Width | Eight (8) pixels |
| Height | Eight (8) pixels |
| Bits per Pixel | Two (2) |
| Colors | Three (3) red shades chosen from a possible four (4)
(See: Brightness and Palettes and Transparency) |
| Transparency | One (1) bit; color 0 is always transparent |
| Size (bytes) | Sixteen (16) |
| Total available | 2,048 |
For efficiency in the VIP, the 2,048 (0×800) Chars in Char RAM are arranged into four segments in the VB's address space. However, for more efficient access by software, Char RAM is also mirrored into the range: 0×00078000 - 0x0007FFFF. To compute the address of Char "N" the formula is:
CharN = N * 16 + 0×00078000.
Character RAM Layout
| Address Range | Chars |
0×00006000 - 0x00007FFF | 0 - 511 (0×000 - 0x1FF) |
0x0000E000 - 0x0000FFFF | 512 - 1023 (0×200 - 0x3FF) |
0×00016000 - 0x00017FFF | 1024 - 1535 (0×400 - 0x5FF) |
0x0001E000 - 0x0001FFFF | 1536 - 2047 (0×600 - 0x7FF) |
| |
0×00078000 - 0x0007FFFF | 0 - 2047 (0×000 - 0x7FF) |
Character Layout
Discussion