144 lines
3.3 KiB
Go
144 lines
3.3 KiB
Go
package apple2
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import (
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"fmt"
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"image"
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"image/color"
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"strings"
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"time"
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)
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const (
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charWidth = 7
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charHeight = 8
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textColumns = 40
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textLines = 24
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textLinesMix = 4
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textPage1Address = uint16(0x0400)
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textPage2Address = uint16(0x0800)
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)
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func getTextCharOffset(col int, line int) uint16 {
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// See "Understanding the Apple II", page 5-10
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// http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
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section := line / 8 // Top, middle and bottom
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eigth := line % 8
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return uint16(section*40 + eigth*0x80 + col)
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}
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func getTextChar(a *Apple2, col int, line int, page int) uint8 {
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address := textPage1Address
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if page == 1 {
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address = textPage2Address
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}
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address += getTextCharOffset(col, line)
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return a.mmu.physicalMainRAM.subRange(address, address+1)[0]
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}
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func snapshotTextMode(a *Apple2, page int, mixMode bool, light color.Color) *image.RGBA {
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// Flash mode is 2Hz
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isFlashedFrame := time.Now().Nanosecond() > (1 * 1000 * 1000 * 1000 / 2)
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lineStart := 0
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if mixMode {
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lineStart = textLines - textLinesMix
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}
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width := textColumns * charWidth
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height := (textLines - lineStart) * charHeight
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size := image.Rect(0, 0, width, height)
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img := image.NewRGBA(size)
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for x := 0; x < width; x++ {
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for y := 0; y < height; y++ {
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line := y/charHeight + lineStart
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col := x / charWidth
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rowInChar := y % charHeight
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colInChar := x % charWidth
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char := getTextChar(a, col, line, page)
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topBits := char >> 6
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isInverse := topBits == 0
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isFlash := topBits == 1
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pixel := a.cg.getPixel(char, rowInChar, colInChar)
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pixel = pixel != (isInverse || (isFlash && isFlashedFrame))
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var colour color.Color
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if pixel {
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colour = light
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} else {
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colour = color.Black
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}
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img.Set(x, y, colour)
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}
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}
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return img
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}
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// DumpTextModeAnsi returns the text mode contents using ANSI escape codes
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// for reverse and flash
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func DumpTextModeAnsi(a *Apple2) string {
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content := "\n"
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content += fmt.Sprintln(strings.Repeat("#", textColumns+4))
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pageIndex := 0
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if a.io.isSoftSwitchActive(ioFlagSecondPage) {
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pageIndex = 1
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}
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isAltText := a.isApple2e && a.io.isSoftSwitchActive(ioFlagAltChar)
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for l := 0; l < textLines; l++ {
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line := ""
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for c := 0; c < textColumns; c++ {
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char := getTextChar(a, c, l, pageIndex)
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line += textMemoryByteToString(char, isAltText)
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}
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content += fmt.Sprintf("# %v #\n", line)
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}
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content += fmt.Sprintln(strings.Repeat("#", textColumns+4))
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return content
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}
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func textMemoryByteToString(value uint8, isAltCharSet bool) string {
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// See https://en.wikipedia.org/wiki/Apple_II_character_set
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// Supports the new lowercase characters in the Apple2e
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// Only ascii from 0x20 to 0x5F is visible
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topBits := value >> 6
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isInverse := topBits == 0
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isFlash := topBits == 1
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if isFlash && isAltCharSet {
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// On the Apple2e with lowercase chars there is not flash mode.
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isFlash = false
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isInverse = true
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}
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if isAltCharSet {
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value = value & 0x7F
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} else {
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value = value & 0x3F
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}
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if value < 0x20 {
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value += 0x40
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}
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if value == 0x7f {
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// DEL is full box
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value = '_'
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}
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if isFlash {
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if value == ' ' {
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// Flashing space in Apple is the full box. It can't be done with ANSI codes
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value = '_'
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}
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return fmt.Sprintf("\033[5m%v\033[0m", string(value))
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} else if isInverse {
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return fmt.Sprintf("\033[7m%v\033[0m", string(value))
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} else {
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return string(value)
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}
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}
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