1package ports
2
3import (
4 "errors"
5 "fmt"
6 "image"
7 "os"
8 "time"
9)
10
11// MaxCaptureInflight bounds the capture requests admitted but not yet
12// answered, across outputs. The reply channel of the production app has
13// at least this capacity, so an output never blocks on a reply.
14const MaxCaptureInflight = 32
15
16// ErrCaptureTransient marks a capture failure that may clear on its own (the
17// renderer busy, the indicator or an exclusion not shown yet): a protocol
18// frame tries again shortly instead of failing. Test with errors.Is.
19var ErrCaptureTransient = errors.New("capture: transient")
20
21// ErrCaptureBusy: every capture slot of the renderer is leased.
22var ErrCaptureBusy = fmt.Errorf("%w: no free slot", ErrCaptureTransient)
23
24// CaptureFrame is a lease on one renderer readback slot holding a GPU
25// copy of a rendered frame. Done and Read make no Vulkan call: a worker
26// goroutine waits on Done, then reads. EndCapture returns the lease.
27type CaptureFrame interface {
28 // Done is the sync file signalled when the copy finished; nil means it
29 // had finished when BeginCapture returned. The frame owns it: it stays
30 // valid until EndCapture, and the reader must not close it.
31 Done() *os.File
32 // Read copies region (output pixels) as opaque sRGB8 BGRA rows into
33 // dst, stride bytes per row. Valid after Done signalled and before
34 // EndCapture.
35 Read(region image.Rectangle, dst []byte, stride int) error
36}
37
38// Renderer draws scenes for an output. One goroutine owns it. Frames go
39// to its own image until ExportTargets or ImportTargets gives it scanout
40// images; then each Render draws into the target chosen by UseTarget
41// (ADR 014: no CPU pass).
42type Renderer interface {
43 // SetHDR selects the HDR10 output transform (0 disables it).
44 // The DRM output calls this before ExportTargets or ImportTargets.
45 SetHDR(sdrNits float64)
46 // Render draws the scene. done is a sync file signalled when the GPU
47 // finished the frame (nil: already finished); the caller closes it.
48 Render(Scene, map[WindowID]SurfaceContent) (done *os.File, err error)
49 // ExportTargets allocates n images of the renderer's size that the
50 // display can scan out, with one of the given XRGB8888 (SDR) or
51 // XRGB2101010 (HDR) modifiers (none: any the device exports),
52 // and returns them as dmabufs; a modifier may have several memory
53 // planes (DCC metadata), each plane owning its file. singlePlane
54 // restricts the choice to one-plane modifiers.
55 // n = 0 drops the targets.
56 ExportTargets(n int, modifiers []uint64, singlePlane bool) ([]DMABuf, error)
57 // TargetModifiers lists the modifiers an image allocated outside the
58 // renderer (by the display's allocator) can have to be imported as a
59 // target: those the device renders into and imports for the XRGB8888
60 // (SDR) or XRGB2101010 (HDR) format, that the display lists (empty: any),
61 // without multi-plane ones when singlePlane. Empty when the device
62 // cannot import dmabufs.
63 TargetModifiers(display []uint64, singlePlane bool) []uint64
64 // ImportTargets makes images allocated outside the renderer its
65 // targets, replacing the previous ones (no buffers: drops them). Each
66 // is one memory object of the renderer's size and target format, with
67 // a modifier from TargetModifiers: every plane file is the same
68 // dmabuf (the planes differ by offset), and disjoint planes are
69 // refused. The caller keeps its files and must keep the memory alive
70 // while the targets are in use. An error leaves the renderer without
71 // targets.
72 ImportTargets(bufs []DMABuf) error
73 // UseTarget selects the exported image the next Render draws into.
74 UseTarget(i int)
75 // CursorBuffers allocates two linear ARGB8888 images of size×size the
76 // display can show on its cursor plane, and returns them as dmabufs.
77 CursorBuffers(size int) ([2]DMABuf, error)
78 // WriteCursor fills cursor image i with premultiplied ARGB8888 pixels
79 // (w×h, w*4 per row), cropped to the image and cleared around it.
80 WriteCursor(i int, pixels []byte, w, h int) error
81 // Pixels reads the last frame back (headless screenshots, tests). It
82 // waits for the GPU: debug only. Nil when it cannot (every capture
83 // slot leased, or the copy failed).
84 Pixels() *image.RGBA
85 // HDRPixels reads the last HDR frame's XRGB2101010 target back, each
86 // 10-bit code scaled to 16 bits (c<<6 | c>>4), A = 0xffff. It waits for
87 // the GPU: debug only. Nil when the output is SDR, the target is not
88 // readable, a slot is busy or the copy failed.
89 HDRPixels() *image.RGBA64
90 // BeginCapture submits a GPU copy of the last rendered frame into a
91 // free slot and returns without waiting. ErrCaptureBusy when every
92 // slot is leased; another error when the copy cannot be tracked (no
93 // sync file): the caller fails the request.
94 BeginCapture() (CaptureFrame, error)
95 // EndCapture returns a lease. It never waits: a slot whose copy may
96 // still run is reused only once the renderer sees it finished.
97 EndCapture(CaptureFrame)
98 // Trim frees client buffer caches left undrawn for a while and what
99 // finished frames held, without rendering. Outputs call it
100 // periodically: an idle output renders no frame to free them.
101 Trim(now time.Time) error
102 // TakeRedrawn returns the target pixels drawn since the last call
103 // (damage-limited frames count their damage only) and starts over.
104 TakeRedrawn() int
105 Close()
106}
107
108// Seat is the device broker (libseat) input devices are opened through.
109type Seat interface {
110 OpenDevice(path string) (int, error)
111 CloseDevice(fd int)
112 SwitchVT(vt int)
113}