ebiten/internal/atlas/image.go

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// 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 atlas
import (
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"fmt"
"image"
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"math"
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"runtime"
"sync"
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"github.com/hajimehoshi/ebiten/v2/internal/graphics"
"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
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"github.com/hajimehoshi/ebiten/v2/internal/packing"
"github.com/hajimehoshi/ebiten/v2/internal/restorable"
"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
)
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var (
minSourceSize = 0
minDestinationSize = 0
maxSize = 0
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)
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 flushDeferred() {
deferredM.Lock()
fs := deferred
deferred = nil
deferredM.Unlock()
for _, f := range fs {
f()
}
}
// baseCountToPutOnSourceBackend represents the base time duration when the image can be put onto an atlas.
// Actual time duration is increased in an exponential way for each usage as a rendering target.
const baseCountToPutOnSourceBackend = 10
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func putImagesOnSourceBackend(graphicsDriver graphicsdriver.Graphics) {
// The counter usedAsDestinationCount is updated at most once per frame (#2676).
imagesUsedAsDestination.forEach(func(i *Image) {
// This counter is not updated when the backend is created in this frame.
if !i.backendCreatedInThisFrame && i.usedAsDestinationCount < math.MaxInt {
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i.usedAsDestinationCount++
}
i.backendCreatedInThisFrame = false
})
imagesUsedAsDestination.clear()
imagesToPutOnSourceBackend.forEach(func(i *Image) {
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if i.usedAsSourceCount < math.MaxInt {
i.usedAsSourceCount++
}
if int64(i.usedAsSourceCount) >= int64(baseCountToPutOnSourceBackend*(1<<uint(min(i.usedAsDestinationCount, 31)))) {
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i.putOnSourceBackend(graphicsDriver)
i.usedAsSourceCount = 0
}
})
imagesToPutOnSourceBackend.clear()
}
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type backend struct {
// restorable is an atlas on which there might be multiple images.
restorable *restorable.Image
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// page is an atlas map. Each part is called a node.
// If page is nil, the backend's image is isolated and not on an atlas.
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page *packing.Page
// source reports whether this backend is mainly used a rendering source, but this is not 100%.
// If a non-source (destination) image is used as a source many times,
// the image's backend might be turned into a source backend to optimize draw calls.
source bool
// sourceInThisFrame reports whether this backend is used as a source in this frame.
// sourceInThisFrame is reset every frame.
sourceInThisFrame bool
}
func (b *backend) tryAlloc(width, height int) (*packing.Node, bool) {
n := b.page.Alloc(width, height)
if n == nil {
// The page can't be extended anymore. Return as failure.
return nil, false
}
b.restorable = b.restorable.Extend(b.page.Size())
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 atlases.
theBackends []*backend
imagesToPutOnSourceBackend smallImageSet
imagesUsedAsDestination smallImageSet
deferred []func()
// deferredM is a mutex for the slice operations. This must not be used for other usages.
deferredM sync.Mutex
)
func init() {
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// 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 ImageType int
const (
ImageTypeRegular ImageType = iota
ImageTypeScreen
ImageTypeVolatile
ImageTypeUnmanaged
)
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// Image is a rectangle pixel set that might be on an atlas.
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type Image struct {
width int
height int
imageType ImageType
disposed bool
backend *backend
backendCreatedInThisFrame bool
node *packing.Node
// usedAsSourceCount represents how long the image is used as a rendering source and kept not modified with
// DrawTriangles.
// In the current implementation, if an image is being modified by DrawTriangles, the image is separated from
// a restorable image on an atlas by ensureIsolatedFromSource.
//
// usedAsSourceCount is increased if the image is used as a rendering source, or set to 0 if the image is
// modified.
//
// WritePixels doesn't affect this value since WritePixels can be done on images on an atlas.
usedAsSourceCount int
// usedAsDestinationCount represents how many times an image is used as a rendering destination at DrawTriangles.
// usedAsDestinationCount affects the calculation when to put the image onto a texture atlas again.
//
// usedAsDestinationCount is never reset.
usedAsDestinationCount int
}
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// moveTo moves its content to the given image dst.
// After moveTo is called, the image i is no longer available.
//
// moveTo is similar to C++'s move semantics.
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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 as node.
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runtime.SetFinalizer(i, nil)
}
func (i *Image) isOnAtlas() bool {
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return i.node != nil
}
func (i *Image) isOnSourceBackend() bool {
if i.backend == nil {
return false
}
return i.backend.source
}
func (i *Image) resetUsedAsSourceCount() {
i.usedAsSourceCount = 0
imagesToPutOnSourceBackend.remove(i)
}
func (i *Image) paddingSize() int {
if i.imageType == ImageTypeRegular {
return 1
}
return 0
}
func (i *Image) ensureIsolatedFromSource(backends []*backend) {
i.resetUsedAsSourceCount()
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// imagesUsedAsDestination affects the counter usedAsDestination.
// The larger this counter is, the harder it is for the image to be transferred to the source backend.
imagesUsedAsDestination.add(i)
if i.backend == nil {
// `sourceInThisFrame` of `backends` should be true, so `backends` should be in `bs`.
var bs []*backend
for _, b := range theBackends {
if b.sourceInThisFrame {
bs = append(bs, b)
}
}
i.allocate(bs, false)
i.backendCreatedInThisFrame = true
return
}
if !i.isOnAtlas() {
return
}
// Check if i has the same backend as the given backends.
var needsIsolation bool
for _, b := range backends {
if i.backend == b {
needsIsolation = true
break
}
}
if !needsIsolation {
return
}
newI := NewImage(i.width, i.height, i.imageType)
// Call allocate explicitly in order to have an isolated backend from the specified backends.
// `sourceInThisFrame` of `backends` should be true, so `backends` should be in `bs`.
bs := []*backend{i.backend}
for _, b := range theBackends {
if b.sourceInThisFrame {
bs = append(bs, b)
}
}
newI.allocate(bs, false)
w, h := float32(i.width), float32(i.height)
vs := make([]float32, 4*graphics.VertexFloatCount)
graphics.QuadVertices(vs, 0, 0, w, h, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1)
is := graphics.QuadIndices()
dr := image.Rect(0, 0, i.width, i.height)
newI.drawTriangles([graphics.ShaderImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false, true)
newI.moveTo(i)
}
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func (i *Image) putOnSourceBackend(graphicsDriver graphicsdriver.Graphics) {
if i.backend == nil {
i.allocate(nil, true)
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return
}
if i.isOnSourceBackend() {
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return
}
if !i.canBePutOnAtlas() {
panic("atlas: putOnSourceBackend cannot be called on a image that cannot be on an atlas")
}
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if i.imageType != ImageTypeRegular {
panic(fmt.Sprintf("atlas: the image type must be ImageTypeRegular but %d", i.imageType))
}
newI := NewImage(i.width, i.height, ImageTypeRegular)
newI.allocate(nil, true)
w, h := float32(i.width), float32(i.height)
vs := make([]float32, 4*graphics.VertexFloatCount)
graphics.QuadVertices(vs, 0, 0, w, h, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1)
is := graphics.QuadIndices()
dr := image.Rect(0, 0, i.width, i.height)
newI.drawTriangles([graphics.ShaderImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, NearestFilterShader, nil, false, true)
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newI.moveTo(i)
i.usedAsSourceCount = 0
if !i.isOnSourceBackend() {
panic("atlas: i must be on a source backend but not")
}
}
func (i *Image) regionWithPadding() image.Rectangle {
if i.backend == nil {
panic("atlas: backend must not be nil: not allocated yet?")
}
if !i.isOnAtlas() {
return image.Rect(0, 0, i.width+i.paddingSize(), i.height+i.paddingSize())
}
return i.node.Region()
}
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// DrawTriangles draws triangles with the given image.
//
// The vertex floats are:
//
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// 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.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool) {
backendsM.Lock()
defer backendsM.Unlock()
i.drawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, evenOdd, false)
}
func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderImageCount]image.Rectangle, shader *Shader, uniforms []uint32, evenOdd bool, keepOnAtlas bool) {
if i.disposed {
panic("atlas: the drawing target image must not be disposed (DrawTriangles)")
}
backends := make([]*backend, 0, len(srcs))
for _, src := range srcs {
if src == nil {
continue
}
if src.disposed {
panic("atlas: the drawing source image must not be disposed (DrawTriangles)")
}
if src.backend == nil {
// It is possible to spcify i.backend as a forbidden backend, but this might prevent a good allocation for a source image.
// If the backend becomes the same as i's, i's backend will be changed at ensureIsolatedFromSource.
src.allocate(nil, true)
}
backends = append(backends, src.backend)
src.backend.sourceInThisFrame = true
}
i.ensureIsolatedFromSource(backends)
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for _, src := range srcs {
// Compare i and source images after ensuring i is not on an atlas, or
// i and a source image might share the same atlas even though i != src.
if src != nil && i.backend.restorable == src.backend.restorable {
panic("atlas: Image.DrawTriangles: source must be different from the receiver")
}
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}
r := i.regionWithPadding()
// TODO: Check if dstRegion does not to violate the region.
dstRegion = dstRegion.Add(r.Min)
dx, dy := float32(r.Min.X), float32(r.Min.Y)
var oxf, oyf float32
if srcs[0] != nil {
r := srcs[0].regionWithPadding()
oxf, oyf = float32(r.Min.X), float32(r.Min.Y)
n := len(vertices)
for i := 0; i < n; i += graphics.VertexFloatCount {
vertices[i] += dx
vertices[i+1] += dy
vertices[i+2] += oxf
vertices[i+3] += oyf
}
if shader.unit() == shaderir.Texels {
sw, sh := srcs[0].backend.restorable.InternalSize()
swf, shf := float32(sw), float32(sh)
for i := 0; i < n; i += graphics.VertexFloatCount {
vertices[i+2] /= swf
vertices[i+3] /= shf
}
}
} else {
n := len(vertices)
for i := 0; i < n; i += graphics.VertexFloatCount {
vertices[i] += dx
vertices[i+1] += dy
}
}
for i, src := range srcs {
if src == nil {
continue
}
// A source region can be deliberately empty when this is not needed in order to avoid unexpected
// performance issue (#1293).
if srcRegions[i].Empty() {
continue
}
r := src.regionWithPadding()
srcRegions[i] = srcRegions[i].Add(r.Min)
}
var imgs [graphics.ShaderImageCount]*restorable.Image
for i, src := range srcs {
if src == nil {
continue
}
imgs[i] = src.backend.restorable
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}
i.backend.restorable.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader.shader, uniforms, evenOdd)
for _, src := range srcs {
if src == nil {
continue
}
if !src.isOnSourceBackend() && src.canBePutOnAtlas() {
// src might already registered, but assigning it again is not harmful.
imagesToPutOnSourceBackend.add(src)
}
}
}
// WritePixels replaces the pixels on the image.
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func (i *Image) WritePixels(pix []byte, region image.Rectangle) {
backendsM.Lock()
defer backendsM.Unlock()
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i.writePixels(pix, region)
}
func (i *Image) writePixels(pix []byte, region image.Rectangle) {
if i.disposed {
panic("atlas: the image must not be disposed at writePixels")
}
if l := 4 * region.Dx() * region.Dy(); len(pix) != l {
panic(fmt.Sprintf("atlas: len(p) must be %d but %d", l, len(pix)))
}
i.resetUsedAsSourceCount()
if i.backend == nil {
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if pix == nil {
return
}
// Allocate as a source as this image will likely be used as a source.
i.allocate(nil, true)
}
r := i.regionWithPadding()
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if !region.Eq(image.Rect(0, 0, i.width, i.height)) || i.paddingSize() == 0 {
region = region.Add(r.Min)
if pix == nil {
i.backend.restorable.WritePixels(nil, region)
return
}
// Copy pixels in the case when pix is modified before the graphics command is executed.
pix2 := graphics.NewManagedBytes(len(pix), func(bs []byte) {
copy(bs, pix)
})
i.backend.restorable.WritePixels(pix2, region)
return
}
// TODO: These loops assume that paddingSize is 1.
// TODO: Is clearing edges explicitly really needed?
const paddingSize = 1
if paddingSize != i.paddingSize() {
panic(fmt.Sprintf("atlas: writePixels assumes the padding is always 1 but the actual padding was %d", i.paddingSize()))
}
pixb := graphics.NewManagedBytes(4*r.Dx()*r.Dy(), func(bs []byte) {
// Clear the edges. bs might not be zero-cleared.
rowPixels := 4 * r.Dx()
for i := 0; i < rowPixels; i++ {
bs[rowPixels*(r.Dy()-1)+i] = 0
}
for j := 1; j < r.Dy(); j++ {
bs[rowPixels*j-4] = 0
bs[rowPixels*j-3] = 0
bs[rowPixels*j-2] = 0
bs[rowPixels*j-1] = 0
}
// Copy the content.
for j := 0; j < region.Dy(); j++ {
copy(bs[4*j*r.Dx():], pix[4*j*region.Dx():4*(j+1)*region.Dx()])
}
})
i.backend.restorable.WritePixels(pixb, r)
}
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func (i *Image) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) error {
backendsM.Lock()
defer backendsM.Unlock()
// In the tests, BeginFrame might not be called often and then images might not be disposed (#2292).
// To prevent memory leaks, flush the deferred functions here.
flushDeferred()
if i.backend == nil || i.backend.restorable == nil {
for i := range pixels {
pixels[i] = 0
}
return nil
}
r := i.regionWithPadding()
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return i.backend.restorable.ReadPixels(graphicsDriver, pixels, region.Add(r.Min))
}
// 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() {
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// As MarkDisposed can be invoked from finalizers, backendsM should not be used.
deferredM.Lock()
deferred = append(deferred, func() {
i.dispose(true)
})
deferredM.Unlock()
}
func (i *Image) dispose(markDisposed bool) {
defer func() {
if markDisposed {
i.disposed = true
}
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i.backend = nil
i.node = nil
if markDisposed {
runtime.SetFinalizer(i, nil)
}
}()
i.resetUsedAsSourceCount()
if i.disposed {
return
}
if i.backend == nil {
// Not allocated yet.
return
}
if !i.isOnAtlas() {
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i.backend.restorable.Dispose()
return
}
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i.backend.page.Free(i.node)
if !i.backend.page.IsEmpty() {
// As this part can be reused, this should be cleared explicitly.
r := i.regionWithPadding()
i.backend.restorable.ClearPixels(r)
return
}
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i.backend.restorable.Dispose()
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for idx, sh := range theBackends {
if sh == i.backend {
theBackends = append(theBackends[:idx], theBackends[idx+1:]...)
return
}
}
panic("atlas: backend not found at an image being disposed")
}
func NewImage(width, height int, imageType ImageType) *Image {
// Actual allocation is done lazily, and the lock is not needed.
return &Image{
width: width,
height: height,
imageType: imageType,
}
}
func (i *Image) canBePutOnAtlas() bool {
if minSourceSize == 0 || minDestinationSize == 0 || maxSize == 0 {
panic("atlas: min*Size or maxSize must be initialized")
}
if i.imageType != ImageTypeRegular {
return false
}
return i.width+i.paddingSize() <= maxSize && i.height+i.paddingSize() <= maxSize
}
func (i *Image) allocate(forbiddenBackends []*backend, asSource bool) {
if i.backend != nil {
panic("atlas: the image is already allocated")
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}
runtime.SetFinalizer(i, (*Image).MarkDisposed)
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if i.imageType == ImageTypeScreen {
if asSource {
panic("atlas: a screen image cannot be created as a source")
}
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// A screen image doesn't have a padding.
i.backend = &backend{
restorable: restorable.NewImage(i.width, i.height, restorable.ImageTypeScreen),
}
return
}
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wp := i.width + i.paddingSize()
hp := i.height + i.paddingSize()
if !i.canBePutOnAtlas() {
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if wp > maxSize || hp > maxSize {
panic(fmt.Sprintf("atlas: the image being put on an atlas is too big: width: %d, height: %d", i.width, i.height))
}
typ := restorable.ImageTypeRegular
if i.imageType == ImageTypeVolatile {
typ = restorable.ImageTypeVolatile
}
i.backend = &backend{
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restorable: restorable.NewImage(wp, hp, typ),
source: asSource && typ == restorable.ImageTypeRegular,
}
return
}
// Check if an existing backend is available.
loop:
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for _, b := range theBackends {
if b.source != asSource {
continue
}
for _, bb := range forbiddenBackends {
if b == bb {
continue loop
}
}
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if n, ok := b.tryAlloc(wp, hp); ok {
i.backend = b
i.node = n
return
}
}
var width, height int
if asSource {
width, height = minSourceSize, minSourceSize
} else {
width, height = minDestinationSize, minDestinationSize
}
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for wp > width {
if width == maxSize {
panic(fmt.Sprintf("atlas: the image being put on an atlas is too big: width: %d, height: %d", i.width, i.height))
}
width *= 2
}
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for hp > height {
if height == maxSize {
panic(fmt.Sprintf("atlas: the image being put on an atlas is too big: width: %d, height: %d", i.width, i.height))
}
height *= 2
}
typ := restorable.ImageTypeRegular
if i.imageType == ImageTypeVolatile {
typ = restorable.ImageTypeVolatile
}
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b := &backend{
restorable: restorable.NewImage(width, height, typ),
page: packing.NewPage(width, height, maxSize),
source: asSource,
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}
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theBackends = append(theBackends, b)
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n := b.page.Alloc(wp, hp)
if n == nil {
panic("atlas: Alloc result must not be nil at allocate")
}
i.backend = b
i.node = n
}
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func (i *Image) DumpScreenshot(graphicsDriver graphicsdriver.Graphics, path string, blackbg bool) (string, error) {
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backendsM.Lock()
defer backendsM.Unlock()
return i.backend.restorable.Dump(graphicsDriver, path, blackbg, image.Rect(0, 0, i.width, i.height))
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}
func EndFrame(graphicsDriver graphicsdriver.Graphics, swapBuffersForGL func()) error {
backendsM.Lock()
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if err := restorable.EndFrame(graphicsDriver, swapBuffersForGL); err != nil {
return err
}
for _, b := range theBackends {
b.sourceInThisFrame = false
}
return nil
}
func floorPowerOf2(x int) int {
if x <= 0 {
return 0
}
p2 := 1
for p2*2 <= x {
p2 *= 2
}
return p2
}
func BeginFrame(graphicsDriver graphicsdriver.Graphics) error {
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defer backendsM.Unlock()
var err error
initOnce.Do(func() {
err = restorable.InitializeGraphicsDriverState(graphicsDriver)
if err != nil {
return
}
if len(theBackends) != 0 {
panic("atlas: all the images must be not on an atlas before the game starts")
}
// min*Size and maxSize can already be set for testings.
if minSourceSize == 0 {
minSourceSize = 1024
}
if minDestinationSize == 0 {
minDestinationSize = 16
}
if maxSize == 0 {
maxSize = floorPowerOf2(restorable.MaxImageSize(graphicsDriver))
}
})
if err != nil {
return err
}
// Restore images first before other image manipulations (#2075).
if err := restorable.RestoreIfNeeded(graphicsDriver); err != nil {
return err
}
flushDeferred()
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putImagesOnSourceBackend(graphicsDriver)
return nil
}
func DumpImages(graphicsDriver graphicsdriver.Graphics, dir string) (string, error) {
backendsM.Lock()
defer backendsM.Unlock()
return restorable.DumpImages(graphicsDriver, dir)
}