A simple library that wraps godrm as draw.Image
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

146 lines
3.2 KiB

package imagedrm
import (
"fmt"
"github.com/kytart/godrm/pkg/drm"
"github.com/kytart/godrm/pkg/mode"
"launchpad.net/gommap"
"os"
)
type Framebuffer struct {
*mode.FB
id uint32
data []byte
}
type Image struct {
file *os.File
modeset *mode.SimpleModeset
displays []*Display
}
type Display struct {
mode *mode.Modeset
fb *Framebuffer
savedCrtc *mode.Crtc
}
func NewImage(card int) (*Image, error) {
file, err := drm.OpenCard(card)
if err != nil {
return nil, fmt.Errorf("open drm card: %w", err)
}
if !drm.HasDumbBuffer(file) {
return nil, fmt.Errorf("drm device does not support dumb buffers")
}
modeset, err := mode.NewSimpleModeset(file)
if err != nil {
return nil, fmt.Errorf("create modeset: %w", err)
}
image := &Image{
file: file,
modeset: modeset,
}
for _, mod := range modeset.Modesets {
display, err := image.setupDisplay(mod)
if err != nil {
image.Close()
return nil, fmt.Errorf("setup display: %w", err)
}
image.displays = append(image.displays, display)
}
return image, nil
}
func (i *Image) Close() error {
for _, display := range i.displays {
err := i.destroyFramebuffer(display)
if err != nil {
fmt.Println(err)
}
}
return i.file.Close()
}
func (i *Image) createFramebuffer(dev *mode.Modeset) (*Framebuffer, error) {
fb, err := mode.CreateFB(i.file, dev.Width, dev.Height, 32)
if err != nil {
return nil, fmt.Errorf("create framebuffer: %w", err)
}
fbID, err := mode.AddFB(i.file, dev.Width, dev.Height, 24, 32, fb.Pitch, fb.Handle)
if err != nil {
return nil, fmt.Errorf("create dumb buffer: %w", err)
}
offset, err := mode.MapDumb(i.file, fb.Handle)
if err != nil {
return nil, fmt.Errorf("map dumb: %w", err)
}
mmap, err := gommap.MapAt(0, i.file.Fd(), int64(offset), int64(fb.Size), gommap.PROT_READ|gommap.PROT_WRITE, gommap.MAP_SHARED)
if err != nil {
return nil, fmt.Errorf("mmap framebuffer: %w", err)
}
for i := uint64(0); i < fb.Size; i++ {
mmap[i] = 0
}
return &Framebuffer{
FB: fb,
id: fbID,
data: mmap,
}, nil
}
func (i *Image) destroyFramebuffer(display *Display) error {
err := gommap.MMap(display.fb.data).UnsafeUnmap()
if err != nil {
return fmt.Errorf("munmap memory: %w", err)
}
err = mode.RmFB(i.file, display.fb.id)
if err != nil {
return fmt.Errorf("remove frame buffer: %w", err)
}
err = mode.DestroyDumb(i.file, display.fb.Handle)
if err != nil {
return fmt.Errorf("destroy dumb buffer: %w", err)
}
return i.modeset.SetCrtc(display.mode, display.savedCrtc)
}
func (i *Image) setupDisplay(mod mode.Modeset) (*Display, error) {
framebuf, err := i.createFramebuffer(&mod)
if err != nil {
return nil, fmt.Errorf("create framebuffer: %w", err)
}
// save current CRTC of this display to restore at exit
savedCrtc, err := mode.GetCrtc(i.file, mod.Crtc)
if err != nil {
return nil, fmt.Errorf("get CRTC for connector %d: %w", mod.Conn, err)
}
// change the display
err = mode.SetCrtc(i.file, mod.Crtc, framebuf.id, 0, 0, &mod.Conn, 1, &mod.Mode)
if err != nil {
return nil, fmt.Errorf("set CRTC for connector %d: %w", mod.Conn, err)
}
return &Display{
mode: &mod,
fb: framebuf,
savedCrtc: savedCrtc,
}, nil
}