package apple2 import ( "errors" "fmt" ) /* See: https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Companies/Apple/Documentation/Apple%20Technical%20Information%20Library/a2til041.txt */ // CharacterGenerator represents the ROM wth the characters bitmaps type CharacterGenerator struct { data []uint8 columnMap charColumnMap page int } type charColumnMap func(column int) int func charGenColumnsMap2Plus(column int) int { return 6 - column } func charGenColumnsMap2e(column int) int { return column } const ( charGenPageSize = 2048 ) // NewCharacterGenerator instantiates a new Character Generator with the rom on the file given func newCharacterGenerator(filename string, order charColumnMap) (*CharacterGenerator, error) { var cg CharacterGenerator err := cg.load(filename) if err != nil { return nil, err } cg.columnMap = order return &cg, nil } func (cg *CharacterGenerator) load(filename string) error { bytes, err := loadResource(filename) if err != nil { return err } size := len(bytes) if size < charGenPageSize { return errors.New("Character ROM size not supported") } cg.data = bytes return nil } func (cg *CharacterGenerator) setPage(page int) { // Some clones had a switch to change codepage with extra characters pages := len(cg.data) / charGenPageSize cg.page = page % pages } func (cg *CharacterGenerator) nextPage() { cg.setPage(cg.page + 1) } func (cg *CharacterGenerator) getPixel(char uint8, row int, column int) bool { bits := cg.data[int(char)*8+row+cg.page*charGenPageSize] bit := cg.columnMap(column) value := bits >> uint(bit) & 1 return value == 1 } func (cg *CharacterGenerator) dumpCharRaw(char int) { base := int(char) * 8 fmt.Printf("Char: %v\n---------\n", char) for i := 0; i < 8; i++ { fmt.Print("|") b := cg.data[base+i] for j := 0; j < 8; j++ { if (b>>uint(j))&1 == 1 { fmt.Print("#") } else { fmt.Print(" ") } } fmt.Println("|") } fmt.Println("---------") } func (cg *CharacterGenerator) dumpChar(char uint8) { fmt.Printf("Char: %v\n---------\n", char) for row := 0; row < 8; row++ { fmt.Print("|") for col := 0; col < 7; col++ { if cg.getPixel(char, row, col) { fmt.Print("#") } else { fmt.Print(" ") } } fmt.Println("|") } fmt.Println("---------") } // Dump to sdtout all the character maps func (cg *CharacterGenerator) Dump() { pages := len(cg.data) / charGenPageSize for p := 0; p < pages; p++ { cg.setPage(p) for i := 0; i < 256; i++ { cg.dumpChar(uint8(i)) //cg.dumpCharRaw(int(i)) } } }