izapple2/screenText.go
2020-10-03 23:38:26 +02:00

227 lines
5.8 KiB
Go

package izapple2
import (
"fmt"
"image"
"image/color"
"strings"
"time"
)
const (
charWidth = 7
charHeight = 8
textColumns = 40
textLines = 24
textPage1Address = uint16(0x0400)
textPage2Address = uint16(0x0800)
textPageSize = uint16(0x0400)
)
func snapshotText40Mode(a *Apple2, isSecondPage bool, light color.Color) *image.RGBA {
text := getTextFromMemory(a.mmu.getVideoRAM(false), isSecondPage)
return renderTextMode(a, text, nil /*colorMap*/, light)
}
func snapshotText80Mode(a *Apple2, isSecondPage bool, light color.Color) *image.RGBA {
text := getText80FromMemory(a, isSecondPage)
return renderTextMode(a, text, nil /*colorMap*/, light)
}
func snapshotText40RGBMode(a *Apple2, isSecondPage bool) *image.RGBA {
text := getTextFromMemory(a.mmu.getVideoRAM(false), isSecondPage)
colorMap := getTextFromMemory(a.mmu.getVideoRAM(true), isSecondPage)
return renderTextMode(a, text, colorMap, nil)
}
func snapshotText40RGBModeColors(a *Apple2, isSecondPage bool) *image.RGBA {
colorMap := getTextFromMemory(a.mmu.getVideoRAM(true), isSecondPage)
return renderTextMode(a, nil /*text*/, colorMap, nil)
}
func getTextCharOffset(col int, line int) uint16 {
// See "Understanding the Apple II", page 5-10
// http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
section := line / 8 // Top, middle and bottom
eighth := line % 8
return uint16(section*40 + eighth*0x80 + col)
}
func getText80FromMemory(a *Apple2, isSecondPage bool) []uint8 {
text40Columns := getTextFromMemory(a.mmu.getVideoRAM(false), isSecondPage)
text40ColumnsAlt := getTextFromMemory(a.mmu.getVideoRAM(true), isSecondPage)
// Merge the two 40 cols to return 80 cols
text80Columns := make([]uint8, 2*len(text40Columns))
for i := 0; i < len(text40Columns); i++ {
text80Columns[2*i] = text40ColumnsAlt[i]
text80Columns[2*i+1] = text40Columns[i]
}
return text80Columns
}
func getTextFromMemory(mem *memoryRange, isSecondPage bool) []uint8 {
addressStart := textPage1Address
if isSecondPage {
addressStart = textPage2Address
}
addressEnd := addressStart + textPageSize
data := mem.subRange(addressStart, addressEnd)
text := make([]uint8, textLines*textColumns)
for l := 0; l < textLines; l++ {
for c := 0; c < textColumns; c++ {
char := data[getTextCharOffset(c, l)]
text[textColumns*l+c] = char
}
}
return text
}
func getRGBTextColor(pixel bool, colorKey uint8) color.Color {
if pixel {
colorKey >>= 4
}
colorKey &= 0x0f
return ntscColorMap[colorKey]
}
func renderTextMode(a *Apple2, text []uint8, colorMap []uint8, light color.Color) *image.RGBA {
// Flash mode is 2Hz (host time)
isFlashedFrame := time.Now().Nanosecond() > (1 * 1000 * 1000 * 1000 / 2)
isAltText := a.io.isSoftSwitchActive(ioFlagAltChar)
columns := len(text) / textLines
if text == nil {
columns = textColumns
}
width := columns * charWidth
height := textLines * charHeight
size := image.Rect(0, 0, width, height)
img := image.NewRGBA(size)
for x := 0; x < width; x++ {
for y := 0; y < height; y++ {
line := y / charHeight
col := x / charWidth
rowInChar := y % charHeight
colInChar := x % charWidth
charIndex := line*columns + col
var char uint8
if text != nil {
char = text[charIndex]
} else {
char = 79 + 128 // Debug screen filed with O
}
var pixel bool
if a.isApple2e {
vid6 := (char & 0x40) != 0
vid7 := (char & 0x80) != 0
char := char & 0x3f
if vid6 && (vid7 || isAltText) {
char += 0x40
}
if vid7 || (vid6 && isFlashedFrame && !isAltText) {
char += 0x80
}
pixel = !a.cg.getPixel(char, rowInChar, colInChar)
} else {
pixel = a.cg.getPixel(char, rowInChar, colInChar)
topBits := char >> 6
isInverse := topBits == 0
isFlash := topBits == 1
pixel = pixel != (isInverse || (isFlash && isFlashedFrame))
}
var colour color.Color
if colorMap != nil {
colour = getRGBTextColor(pixel, colorMap[charIndex])
} else if pixel {
colour = light
} else {
colour = color.Black
}
img.Set(x, y, colour)
}
}
return img
}
// DumpTextModeAnsi returns the text mode contents using ANSI escape codes
// for reverse and flash
func DumpTextModeAnsi(a *Apple2) string {
is80Columns := a.io.isSoftSwitchActive(ioFlag80Col)
isSecondPage := a.io.isSoftSwitchActive(ioFlagSecondPage) && !a.mmu.store80Active
isAltText := a.isApple2e && a.io.isSoftSwitchActive(ioFlagAltChar)
var text []uint8
if is80Columns {
text = getText80FromMemory(a, isSecondPage)
} else {
text = getTextFromMemory(a.mmu.getVideoRAM(false), isSecondPage)
}
columns := len(text) / textLines
content := "\n"
content += fmt.Sprintln(strings.Repeat("#", columns+4))
for l := 0; l < textLines; l++ {
line := ""
for c := 0; c < columns; c++ {
char := text[l*columns+c]
line += textMemoryByteToString(char, isAltText)
}
content += fmt.Sprintf("# %v #\n", line)
}
content += fmt.Sprintln(strings.Repeat("#", columns+4))
return content
}
func textMemoryByteToString(value uint8, isAltCharSet bool) string {
// See https://en.wikipedia.org/wiki/Apple_II_character_set
// Supports the new lowercase characters in the Apple2e
// Only ascii from 0x20 to 0x5F is visible
topBits := value >> 6
isInverse := topBits == 0
isFlash := topBits == 1
if isFlash && isAltCharSet {
// On the Apple2e with lowercase chars there is not flash mode.
isFlash = false
isInverse = true
}
if isAltCharSet {
value = value & 0x7F
} else {
value = value & 0x3F
}
if value < 0x20 {
value += 0x40
}
if value == 0x7f {
// DEL is full box
value = '_'
}
if isFlash {
if value == ' ' {
// Flashing space in Apple is the full box. It can't be done with ANSI codes
value = '_'
}
return fmt.Sprintf("\033[5m%v\033[0m", string(value))
} else if isInverse {
return fmt.Sprintf("\033[7m%v\033[0m", string(value))
} else {
return string(value)
}
}