ebiten/internal/shareable/image.go
2020-12-31 17:52:18 +09:00

712 lines
16 KiB
Go

// Copyright 2018 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package shareable
import (
"fmt"
"runtime"
"sync"
"github.com/hajimehoshi/ebiten/v2/internal/affine"
"github.com/hajimehoshi/ebiten/v2/internal/driver"
"github.com/hajimehoshi/ebiten/v2/internal/graphics"
"github.com/hajimehoshi/ebiten/v2/internal/hooks"
"github.com/hajimehoshi/ebiten/v2/internal/packing"
"github.com/hajimehoshi/ebiten/v2/internal/restorable"
)
const (
// paddingSize represents the size of padding around an image.
// Every image or node except for a screen image has its padding.
paddingSize = 1
)
var (
minSize = 0
maxSize = 0
)
func max(a, b int) int {
if a > b {
return a
}
return b
}
func min(a, b int) int {
if a < b {
return a
}
return b
}
func init() {
hooks.AppendHookOnBeforeUpdate(func() error {
backendsM.Lock()
defer backendsM.Unlock()
resolveDeferred()
return makeImagesShared()
})
}
func resolveDeferred() {
deferredM.Lock()
fs := deferred
deferred = nil
deferredM.Unlock()
for _, f := range fs {
f()
}
}
// MaxCountForShare represents the time duration when the image can become shared.
//
// This value is exported for testing.
const MaxCountForShare = 10
// CountForStartSyncing represents the count that the image starts to sync pixels between GPU and CPU.
//
// This value is exported for testing.
const CountForStartSyncing = MaxCountForShare / 2
func makeImagesShared() error {
for i := range imagesToMakeShared {
i.nonUpdatedCount++
if i.nonUpdatedCount >= CountForStartSyncing && i.syncing == nil {
// Sync the pixel data on CPU and GPU sides explicitly in order not to block this process.
ch, err := i.backend.restorable.Sync()
if err != nil {
return err
}
i.syncing = ch
}
if i.nonUpdatedCount >= MaxCountForShare {
// TODO: Instead of waiting for the channel, use select-case and continue the loop if this
// channel is blocking. However, this might make the tests difficult.
<-i.syncing
if err := i.makeShared(); err != nil {
return err
}
i.nonUpdatedCount = 0
delete(imagesToMakeShared, i)
i.syncing = nil
}
}
return nil
}
type backend struct {
restorable *restorable.Image
// If page is nil, the backend is not shared.
page *packing.Page
}
func (b *backend) TryAlloc(width, height int) (*packing.Node, bool) {
// If the region is allocated without any extension, that's fine.
if n := b.page.Alloc(width, height); n != nil {
return n, true
}
nExtended := 1
var n *packing.Node
for {
if !b.page.Extend(nExtended) {
// The page can't be extended any more. Return as failure.
return nil, false
}
nExtended++
n = b.page.Alloc(width, height)
if n != nil {
b.page.CommitExtension()
break
}
b.page.RollbackExtension()
}
s := b.page.Size()
b.restorable = b.restorable.Extend(s, s)
if n == nil {
panic("shareable: Alloc result must not be nil at TryAlloc")
}
return n, true
}
var (
// backendsM is a mutex for critical sections of the backend and packing.Node objects.
backendsM sync.Mutex
initOnce sync.Once
// theBackends is a set of actually shared images.
theBackends = []*backend{}
imagesToMakeShared = map[*Image]struct{}{}
deferred []func()
// deferredM is a mutext for the slice operations. This must not be used for other usages.
deferredM sync.Mutex
)
func init() {
// Lock the mutex before a frame begins.
//
// In each frame, restoring images and resolving images happen respectively:
//
// [Restore -> Resolve] -> [Restore -> Resolve] -> ...
//
// Between each frame, any image operations are not permitted, or stale images would remain when restoring
// (#913).
backendsM.Lock()
}
type Image struct {
width int
height int
disposed bool
volatile bool
screen bool
backend *backend
node *packing.Node
// nonUpdatedCount represents how long the image is kept not modified with DrawTriangles.
// In the current implementation, if an image is being modified by DrawTriangles, the image is separated from
// a shared (restorable) image by ensureNotShared.
//
// nonUpdatedCount is increased every frame if the image is not modified, or set to 0 if the image is
// modified.
//
// ReplacePixels doesn't affect this value since ReplacePixels can be done on shared images.
nonUpdatedCount int
syncing <-chan struct{}
}
func (i *Image) moveTo(dst *Image) {
dst.dispose(false)
*dst = *i
// i is no longer available but Dispose must not be called
// since i and dst have the same values like node.
runtime.SetFinalizer(i, nil)
}
func (i *Image) isShared() bool {
return i.node != nil
}
func (i *Image) resetNonUpdatedCount() {
i.nonUpdatedCount = 0
delete(imagesToMakeShared, i)
i.syncing = nil
}
func (i *Image) ensureNotShared() {
i.resetNonUpdatedCount()
if i.backend == nil {
i.allocate(false)
return
}
if !i.isShared() {
return
}
ox, oy, w, h := i.regionWithPadding()
dx0 := float32(0)
dy0 := float32(0)
dx1 := float32(w)
dy1 := float32(h)
sx0 := float32(ox)
sy0 := float32(oy)
sx1 := float32(ox + w)
sy1 := float32(oy + h)
newImg := restorable.NewImage(w, h)
newImg.SetVolatile(i.volatile)
vs := []float32{
dx0, dy0, sx0, sy0, 1, 1, 1, 1,
dx1, dy0, sx1, sy0, 1, 1, 1, 1,
dx0, dy1, sx0, sy1, 1, 1, 1, 1,
dx1, dy1, sx1, sy1, 1, 1, 1, 1,
}
is := graphics.QuadIndices()
srcs := [graphics.ShaderImageNum]*restorable.Image{i.backend.restorable}
var offsets [graphics.ShaderImageNum - 1][2]float32
dstRegion := driver.Region{
X: paddingSize,
Y: paddingSize,
Width: float32(w - 2*paddingSize),
Height: float32(h - 2*paddingSize),
}
newImg.DrawTriangles(srcs, offsets, vs, is, nil, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressUnsafe, dstRegion, driver.Region{}, nil, nil)
i.dispose(false)
i.backend = &backend{
restorable: newImg,
}
}
func (i *Image) makeShared() error {
if i.backend == nil {
i.allocate(true)
return nil
}
if i.isShared() {
return nil
}
if !i.shareable() {
panic("shareable: makeShared cannot be called on a non-shareable image")
}
newI := NewImage(i.width, i.height)
newI.SetVolatile(i.volatile)
pixels := make([]byte, 4*i.width*i.height)
for y := 0; y < i.height; y++ {
for x := 0; x < i.width; x++ {
r, g, b, a, err := i.at(x+paddingSize, y+paddingSize)
if err != nil {
return err
}
pixels[4*(i.width*y+x)] = r
pixels[4*(i.width*y+x)+1] = g
pixels[4*(i.width*y+x)+2] = b
pixels[4*(i.width*y+x)+3] = a
}
}
newI.replacePixels(pixels)
newI.moveTo(i)
i.nonUpdatedCount = 0
i.syncing = nil
return nil
}
func (i *Image) regionWithPadding() (x, y, width, height int) {
if i.backend == nil {
panic("shareable: backend must not be nil: not allocated yet?")
}
if !i.isShared() {
return 0, 0, i.width + 2*paddingSize, i.height + 2*paddingSize
}
return i.node.Region()
}
func (i *Image) processSrc(src *Image) {
if src == nil {
return
}
if src.disposed {
panic("shareable: the drawing source image must not be disposed (DrawTriangles)")
}
if src.backend == nil {
src.allocate(true)
}
// Compare i and source images after ensuring i is not shared, or
// i and a source image might share the same texture even though i != src.
if i.backend.restorable == src.backend.restorable {
panic("shareable: Image.DrawTriangles: source must be different from the receiver")
}
}
// DrawTriangles draws triangles with the given image.
//
// The vertex floats are:
//
// 0: Destination X in pixels
// 1: Destination Y in pixels
// 2: Source X in pixels (the upper-left is (0, 0))
// 3: Source Y in pixels
// 4: Color R [0.0-1.0]
// 5: Color G
// 6: Color B
// 7: Color Y
func (i *Image) DrawTriangles(srcs [graphics.ShaderImageNum]*Image, vertices []float32, indices []uint16, colorm *affine.ColorM, mode driver.CompositeMode, filter driver.Filter, address driver.Address, dstRegion, srcRegion driver.Region, subimageOffsets [graphics.ShaderImageNum - 1][2]float32, shader *Shader, uniforms []interface{}) {
backendsM.Lock()
// Do not use defer for performance.
if i.disposed {
panic("shareable: the drawing target image must not be disposed (DrawTriangles)")
}
i.ensureNotShared()
for _, src := range srcs {
i.processSrc(src)
}
var dx, dy float32
// A screen image doesn't have its padding.
if !i.screen {
dx = paddingSize
dy = paddingSize
}
dstRegion.X += dx
dstRegion.Y += dx
var oxf, oyf float32
if srcs[0] != nil {
ox, oy, _, _ := srcs[0].regionWithPadding()
ox += paddingSize
oy += paddingSize
oxf, oyf = float32(ox), float32(oy)
n := len(vertices) / graphics.VertexFloatNum
for i := 0; i < n; i++ {
vertices[i*graphics.VertexFloatNum+0] += dx
vertices[i*graphics.VertexFloatNum+1] += dy
vertices[i*graphics.VertexFloatNum+2] += oxf
vertices[i*graphics.VertexFloatNum+3] += oyf
}
// srcRegion can be delibarately empty when this is not needed in order to avoid unexpected
// performance issue (#1293).
if srcRegion.Width != 0 && srcRegion.Height != 0 {
srcRegion.X += oxf
srcRegion.Y += oyf
}
} else {
n := len(vertices) / graphics.VertexFloatNum
for i := 0; i < n; i++ {
vertices[i*graphics.VertexFloatNum+0] += dx
vertices[i*graphics.VertexFloatNum+1] += dy
}
}
var offsets [graphics.ShaderImageNum - 1][2]float32
var s *restorable.Shader
var imgs [graphics.ShaderImageNum]*restorable.Image
if shader == nil {
// Fast path for rendering without a shader (#1355).
imgs[0] = srcs[0].backend.restorable
} else {
for i, subimageOffset := range subimageOffsets {
src := srcs[i+1]
if src == nil {
continue
}
ox, oy, _, _ := src.regionWithPadding()
offsets[i][0] = float32(ox) + paddingSize - oxf + subimageOffset[0]
offsets[i][1] = float32(oy) + paddingSize - oyf + subimageOffset[1]
}
s = shader.shader
for i, src := range srcs {
if src == nil {
continue
}
imgs[i] = src.backend.restorable
}
}
i.backend.restorable.DrawTriangles(imgs, offsets, vertices, indices, colorm, mode, filter, address, dstRegion, srcRegion, s, uniforms)
for _, src := range srcs {
if src == nil {
continue
}
if !src.isShared() && src.shareable() {
// src might already registered, but assiging it again is not harmful.
imagesToMakeShared[src] = struct{}{}
}
}
backendsM.Unlock()
}
func (i *Image) ReplacePixels(pix []byte) {
backendsM.Lock()
defer backendsM.Unlock()
i.replacePixels(pix)
}
func (i *Image) replacePixels(pix []byte) {
if i.disposed {
panic("shareable: the image must not be disposed at replacePixels")
}
i.resetNonUpdatedCount()
if i.backend == nil {
if pix == nil {
return
}
i.allocate(true)
}
x, y, w, h := i.regionWithPadding()
if pix == nil {
i.backend.restorable.ReplacePixels(nil, x, y, w, h)
return
}
ow, oh := w-2*paddingSize, h-2*paddingSize
if l := 4 * ow * oh; len(pix) != l {
panic(fmt.Sprintf("shareable: len(p) must be %d but %d", l, len(pix)))
}
// Add a padding around the image.
pixb := make([]byte, 4*w*h)
for j := 0; j < oh; j++ {
copy(pixb[4*((j+paddingSize)*w+paddingSize):], pix[4*j*ow:4*(j+1)*ow])
}
i.backend.restorable.ReplacePixels(pixb, x, y, w, h)
}
func (img *Image) Pixels(x, y, width, height int) ([]byte, error) {
backendsM.Lock()
defer backendsM.Unlock()
x += paddingSize
y += paddingSize
bs := make([]byte, 4*width*height)
idx := 0
for j := y; j < y+height; j++ {
for i := x; i < x+width; i++ {
r, g, b, a, err := img.at(i, j)
if err != nil {
return nil, err
}
bs[4*idx] = r
bs[4*idx+1] = g
bs[4*idx+2] = b
bs[4*idx+3] = a
idx++
}
}
return bs, nil
}
func (i *Image) at(x, y int) (byte, byte, byte, byte, error) {
if i.backend == nil {
return 0, 0, 0, 0, nil
}
ox, oy, w, h := i.regionWithPadding()
if x < 0 || y < 0 || x >= w || y >= h {
return 0, 0, 0, 0, nil
}
return i.backend.restorable.At(x+ox, y+oy)
}
// MarkDisposed marks the image as disposed. The actual operation is deferred.
// MarkDisposed can be called from finalizers.
//
// A function from finalizer must not be blocked, but disposing operation can be blocked.
// Defer this operation until it becomes safe. (#913)
func (i *Image) MarkDisposed() {
deferredM.Lock()
deferred = append(deferred, func() {
i.dispose(true)
})
deferredM.Unlock()
}
func (i *Image) dispose(markDisposed bool) {
defer func() {
if markDisposed {
i.disposed = true
}
i.backend = nil
i.node = nil
if markDisposed {
runtime.SetFinalizer(i, nil)
}
}()
i.resetNonUpdatedCount()
if i.disposed {
return
}
if i.backend == nil {
// Not allocated yet.
return
}
if !i.isShared() {
i.backend.restorable.Dispose()
return
}
i.backend.page.Free(i.node)
if !i.backend.page.IsEmpty() {
// As this part can be reused, this should be cleared explicitly.
i.backend.restorable.ClearPixels(i.regionWithPadding())
return
}
i.backend.restorable.Dispose()
index := -1
for idx, sh := range theBackends {
if sh == i.backend {
index = idx
break
}
}
if index == -1 {
panic("shareable: backend not found at an image being disposed")
}
theBackends = append(theBackends[:index], theBackends[index+1:]...)
}
func NewImage(width, height int) *Image {
// Actual allocation is done lazily, and the lock is not needed.
return &Image{
width: width,
height: height,
}
}
func (i *Image) SetVolatile(volatile bool) {
i.volatile = volatile
if i.backend == nil {
return
}
if i.volatile {
i.ensureNotShared()
}
i.backend.restorable.SetVolatile(i.volatile)
}
func (i *Image) shareable() bool {
if minSize == 0 || maxSize == 0 {
panic("shareable: minSize or maxSize must be initialized")
}
if i.volatile {
return false
}
if i.screen {
return false
}
return i.width+2*paddingSize <= maxSize && i.height+2*paddingSize <= maxSize
}
func (i *Image) allocate(shareable bool) {
if i.backend != nil {
panic("shareable: the image is already allocated")
}
runtime.SetFinalizer(i, (*Image).MarkDisposed)
if i.screen {
// A screen image doesn't have a padding.
i.backend = &backend{
restorable: restorable.NewScreenFramebufferImage(i.width, i.height),
}
return
}
if !shareable || !i.shareable() {
i.backend = &backend{
restorable: restorable.NewImage(i.width+2*paddingSize, i.height+2*paddingSize),
}
i.backend.restorable.SetVolatile(i.volatile)
return
}
for _, b := range theBackends {
if n, ok := b.TryAlloc(i.width+2*paddingSize, i.height+2*paddingSize); ok {
i.backend = b
i.node = n
return
}
}
size := minSize
for i.width+2*paddingSize > size || i.height+2*paddingSize > size {
if size == maxSize {
panic(fmt.Sprintf("shareable: the image being shared is too big: width: %d, height: %d", i.width, i.height))
}
size *= 2
}
b := &backend{
restorable: restorable.NewImage(size, size),
page: packing.NewPage(size, maxSize),
}
b.restorable.SetVolatile(i.volatile)
theBackends = append(theBackends, b)
n := b.page.Alloc(i.width+2*paddingSize, i.height+2*paddingSize)
if n == nil {
panic("shareable: Alloc result must not be nil at allocate")
}
i.backend = b
i.node = n
}
func (i *Image) Dump(path string, blackbg bool) error {
backendsM.Lock()
defer backendsM.Unlock()
return i.backend.restorable.Dump(path, blackbg)
}
func NewScreenFramebufferImage(width, height int) *Image {
// Actual allocation is done lazily.
i := &Image{
width: width,
height: height,
screen: true,
}
return i
}
func EndFrame() error {
backendsM.Lock()
return restorable.ResolveStaleImages()
}
func BeginFrame() error {
defer backendsM.Unlock()
var err error
initOnce.Do(func() {
err = restorable.InitializeGraphicsDriverState()
if err != nil {
return
}
if len(theBackends) != 0 {
panic("shareable: all the images must be not-shared before the game starts")
}
minSize = 1024
// The maximum size is 8192 no matter what the available sizes are (#1453).
maxSize = min(max(minSize, restorable.MaxImageSize()), 8192)
})
if err != nil {
return err
}
return restorable.RestoreIfNeeded()
}
func DumpImages(dir string) error {
backendsM.Lock()
defer backendsM.Unlock()
return restorable.DumpImages(dir)
}