orca ui replica wip

1 files changed, 228 insertions, 0 deletions

diff --git a/fb/fb.go b/fb/fb.go
new file mode 100644
index 0000000..2c28d6d
--- /dev/null
+++ b/fb/fb.go
@@ -0,0 +1,228 @@
+package fb
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"io"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+const (
+	Width  = 800
+	Height = 480
+)
+
+type fb struct {
+	fd   int
+	data []byte
+}
+
+var _ interface {
+	io.Closer
+	draw.Image
+} = &fb{}
+
+func Open() (*fb, error) {
+	fd, err := unix.Open("/dev/fb0", unix.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	data, err := syscall.Mmap(fd, 0, Width*Height*4, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
+	if err != nil {
+		return nil, err
+	}
+	return &fb{
+		fd:   fd,
+		data: data,
+	}, nil
+}
+
+func (fb *fb) Close() error {
+	if err := syscall.Munmap(fb.data); err != nil {
+		return err
+	}
+	if err := unix.Close(fb.fd); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (fb *fb) ColorModel() color.Model { return color.RGBAModel }                 // draw.Image
+func (fb *fb) Bounds() image.Rectangle { return image.Rect(0, 0, Width, Height) } // draw.Image
+
+func (fb *fb) At(x, y int) color.Color { // draw.Image
+	if x < 0 || x >= Width || y < 0 || y >= Height {
+		return color.RGBA{}
+	}
+	off := (y*Width + x) * 4
+	bs := fb.data[off : off+4]
+	return color.RGBA{bs[2], bs[1], bs[0], bs[3]}
+}
+
+func (fb *fb) Set(x, y int, c color.Color) { // draw.Image
+	rgba := color.RGBAModel.Convert(c).(color.RGBA)
+	if x < 0 || x >= Width || y < 0 || y >= Height {
+		return
+	}
+	off := (y*Width + x) * 4
+	bs := fb.data[off : off+4]
+	bs[0] = rgba.B
+	bs[1] = rgba.G
+	bs[2] = rgba.R
+	bs[3] = rgba.A
+}
+
+// swizzle swizzles RGBA to BGRA, or vice versa
+func swizzle(bs []byte) {
+	for i := 0; i < len(bs); i += 4 {
+		bs[i], bs[i+2] = bs[i+2], bs[i]
+	}
+}
+
+func (fb *fb) ReadRGBA() *image.RGBA {
+	img := image.NewRGBA(fb.Bounds())
+	pix := img.Pix[:Width*Height*4]
+	copy(pix, fb.data)
+	swizzle(pix)
+	return img
+}
+
+func (fb *fb) WriteRGBA(img *image.RGBA) { // destructive: swizzles img's RGBA to BGRA in-place
+	if fb.Bounds() != img.Bounds() {
+		panic("img bounds mismatch")
+	}
+	pix := img.Pix[:Width*Height*4]
+	swizzle(pix)
+	copy(fb.data, pix)
+}
+
+// finfo: {
+// 	ID:[68 73 83 80 51 32 66 71 0 0 0 0 0 0 0 0]
+// 	SMemStart:437256192
+// 	SMemLen:1536000
+// 	Type:0
+// 	TypeAux:0
+// 	Visual:2
+// 	XPanStep:1
+// 	YPanStep:1
+// 	YWrapStep:1
+// 	LineLength:3200
+// 	MMIOStart:0
+// 	MMIOLen:0
+// 	Accel:0
+// 	Capabilities:0
+// 	Reserved:[0 0]
+// }
+// vinfo: {
+// 	XRes:800
+// 	YRes:480
+// 	XResVirtual:800
+// 	YResVirtual:480
+// 	XOffset:0
+// 	YOffset:0
+// 	BitsPerPixel:32
+// 	Grayscale:0
+// 	R:{Offset:16 Length:8 MSBRight:0}
+// 	G:{Offset:8 Length:8 MSBRight:0}
+// 	B:{Offset:0 Length:8 MSBRight:0}
+// 	A:{Offset:24 Length:8 MSBRight:0}
+// 	Nonstd:0
+// 	Activate:0
+// 	Height:4294967295
+// 	Width:4294967295
+// 	AccelFlags:0
+// 	Pixclock:37037
+// 	LeftMargin:40
+// 	RightMargin:60
+// 	UpperMargin:10
+// 	LowerMargin:10
+// 	HSyncLen:20
+// 	VSyncLen:10
+// 	Sync:1073741824
+// 	VMode:0
+// 	Rotate:0
+// 	Colorspace:0
+// 	Reserved:[0 0 0 0]
+// }
+
+// // include/uapi/linux/fb.h
+
+// type FBFInfo struct {
+// 	ID           [16]byte
+// 	SMemStart    uint32
+// 	SMemLen      uint32
+// 	Type         uint32
+// 	TypeAux      uint32
+// 	Visual       uint32
+// 	XPanStep     uint16
+// 	YPanStep     uint16
+// 	YWrapStep    uint16
+// 	LineLength   uint32
+// 	MMIOStart    uint32
+// 	MMIOLen      uint32
+// 	Accel        uint32
+// 	Capabilities uint16
+// 	Reserved     [2]uint16
+// }
+
+// type FBBitfield struct {
+// 	Offset   uint32
+// 	Length   uint32
+// 	MSBRight uint32
+// }
+
+// type FBVInfo struct {
+// 	XRes        uint32
+// 	YRes        uint32
+// 	XResVirtual uint32
+// 	YResVirtual uint32
+// 	XOffset     uint32
+// 	YOffset     uint32
+
+// 	BitsPerPixel uint32
+// 	Grayscale    uint32
+// 	R, G, B, A   FBBitfield
+
+// 	Nonstd uint32
+
+// 	Activate uint32
+
+// 	Height uint32
+// 	Width  uint32
+
+// 	AccelFlags uint32
+
+// 	Pixclock    uint32
+// 	LeftMargin  uint32
+// 	RightMargin uint32
+// 	UpperMargin uint32
+// 	LowerMargin uint32
+// 	HSyncLen    uint32
+// 	VSyncLen    uint32
+// 	Sync        uint32
+// 	VMode       uint32
+// 	Rotate      uint32
+// 	Colorspace  uint32
+// 	Reserved    [4]uint32
+// }
+
+// func FBGetFInfo(fd int) (finfo FBFInfo, err error) {
+// 	const FBIOGET_FSCREENINFO = 0x4602
+// 	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), FBIOGET_FSCREENINFO, uintptr(unsafe.Pointer(&finfo)))
+// 	if errno != 0 {
+// 		err = errno
+// 	}
+// 	return
+// }
+
+// func FBGetVInfo(fd int) (vinfo FBVInfo, err error) {
+// 	const FBIOGET_VSCREENINFO = 0x4600
+// 	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), FBIOGET_VSCREENINFO, uintptr(unsafe.Pointer(&vinfo)))
+// 	if errno != 0 {
+// 		err = errno
+// 	}
+// 	return
+// }