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Support for half pixel shifts on hgr mono

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This commit is contained in:
Ivan Izaguirre 2019-05-02 12:21:07 +02:00
parent 90250cdf3e
commit ba6faa0203
2 changed files with 45 additions and 5 deletions
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47
apple2/screen.go
View File

@ -9,6 +9,13 @@ import (
"time"
)
/*
References:
- "Understanding the Apple II", http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
- "Apple II Reference Manual"
- "More Colors for your Apple", https://archive.org/details/byte-magazine-1979-06/page/n61
*/
// Snapshot the currently visible screen
func Snapshot(a *Apple2) *image.RGBA {
isTextMode := a.io.isSoftSwitchActive(ioFlagText)
@ -25,7 +32,8 @@ func Snapshot(a *Apple2) *image.RGBA {
} else {
if isHiResMode {
//return snapshotHiResModeReferenceMono(a, pageIndex)
return snapshotHiResModeReferenceColor(a, pageIndex)
return linesSeparatedFilter(snapshotHiResModeMonoShift(a, pageIndex))
//return snapshotHiResModeReferenceColor(a, pageIndex)
//return snapshotHiResModeReferenceColorSolid(a, pageIndex)
} else {
// Lo res mode not supported
@ -85,7 +93,7 @@ const (
func getTextCharOffset(col int, line int) uint16 {
// See "Understand the Apple II", page 5-10
// See "Understanding the Apple II", page 5-10
// http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
section := line / 8 // Top, middle and bottom
eigth := line % 8
@ -142,7 +150,7 @@ func snapshotTextMode(a *Apple2, page int) *image.RGBA {
func getGraphLineOffset(line int) uint16 {
// See "Understand the Apple II", page 5-14
// See "Understanding the Apple II", page 5-14
// http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
section := line >> 6 // Top, middle and bottom
outerEigth := (line >> 3) & 0x07
@ -161,7 +169,6 @@ func getGraphLine(a *Apple2, line int, page int) []uint8 {
lo := uint8(address)
memPage := a.mmu.internalPage(hi)
//fmt.Printf("line: %v, lo: %x\n", line, lo)
return memPage[lo : lo+40]
}
@ -189,6 +196,38 @@ func snapshotHiResModeReferenceMono(a *Apple2, page int) *image.RGBA {
return img
}
func snapshotHiResModeMonoShift(a *Apple2, page int) *image.RGBA {
// As described in "Undertanding the Apple II", with half pixel shifts
size := image.Rect(0, 0, 2*graphWidth, graphHeight)
img := image.NewRGBA(size)
for y := 0; y < graphHeight; y++ {
bytes := getGraphLine(a, y, page)
x := 0
previousColour := color.Black
for _, b := range bytes {
shifted := b>>7 != 1
for j := uint(0); j < 7; j++ {
bit := (b >> j) & 1
colour := color.Black
if bit == 1 {
colour = color.White
}
if shifted {
img.Set(x, y, previousColour)
} else {
img.Set(x, y, colour)
}
img.Set(x+1, y, colour)
previousColour = colour
x += 2
}
}
}
return img
}
func snapshotHiResModeReferenceColor(a *Apple2, page int) *image.RGBA {
// As defined on "Apple II Reference Manual", page 19
size := image.Rect(0, 0, graphWidth, graphHeight)

3
apple2sdl/run.go
View File

@ -45,7 +45,8 @@ func SDLRun(a *apple2.Apple2) {
img := apple2.Snapshot(a)
if img != nil {
surface, err := sdl.CreateRGBSurfaceFrom(unsafe.Pointer(&img.Pix[0]),
int32(img.Bounds().Dx()), int32(img.Bounds().Dy()), 32, 40*7*4,
int32(img.Bounds().Dx()), int32(img.Bounds().Dy()),
32, 4*img.Bounds().Dx(),
0x0000ff, 0x0000ff00, 0x00ff0000, 0xff000000)
// Valid for little endian. Should we reverse for big endian?
// 0xff000000, 0x00ff0000, 0x0000ff00, 0x000000ff)