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image.go
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image.go
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// Copyright 2016 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 restorable
import (
"errors"
"image"
"image/color"
"runtime"
"github.com/hajimehoshi/ebiten/internal/affine"
"github.com/hajimehoshi/ebiten/internal/graphics"
"github.com/hajimehoshi/ebiten/internal/math"
"github.com/hajimehoshi/ebiten/internal/opengl"
)
// MaxImageSize represents the maximum width/height of an image.
const MaxImageSize = graphics.MaxImageSize
// QuadVertexSizeInBytes returns the byte size of vertices for a quadrilateral.
func QuadVertexSizeInBytes() int {
return graphics.QuadVertexSizeInBytes()
}
// drawImageHistoryItem is an item for history of draw-image commands.
type drawImageHistoryItem struct {
image *Image
vertices []float32
colorm affine.ColorM
mode opengl.CompositeMode
}
// canMerge returns a boolean value indicating whether the drawImageHistoryItem d
// can be merged with the given conditions.
func (d *drawImageHistoryItem) canMerge(image *Image, colorm *affine.ColorM, mode opengl.CompositeMode) bool {
if d.image != image {
return false
}
if !d.colorm.Equals(colorm) {
return false
}
if d.mode != mode {
return false
}
return true
}
// Image represents an image that can be restored when GL context is lost.
type Image struct {
image *graphics.Image
filter graphics.Filter
// baseImage and baseColor are exclusive.
basePixels []byte
baseColor color.RGBA
// drawImageHistory is a set of draw-image commands.
// TODO: This should be merged with the similar command queue in package graphics (#433).
drawImageHistory []*drawImageHistoryItem
// stale indicates whether the image needs to be synced with GPU as soon as possible.
stale bool
// volatile indicates whether the image is cleared whenever a frame starts.
volatile bool
// screen indicates whether the image is used as an actual screen.
screen bool
offsetX float64
offsetY float64
}
// NewImage creates an empty image with the given size and filter.
func NewImage(width, height int, filter graphics.Filter, volatile bool) *Image {
i := &Image{
image: graphics.NewImage(width, height, filter),
filter: filter,
volatile: volatile,
}
theImages.add(i)
runtime.SetFinalizer(i, (*Image).Dispose)
return i
}
// NewImageFromImage creates an image with source image.
func NewImageFromImage(source image.Image, filter graphics.Filter) *Image {
size := source.Bounds().Size()
width, height := size.X, size.Y
rgbaImg := CopyImage(source)
w2, h2 := math.NextPowerOf2Int(width), math.NextPowerOf2Int(height)
p := make([]byte, 4*w2*h2)
for j := 0; j < height; j++ {
copy(p[j*w2*4:(j+1)*w2*4], rgbaImg.Pix[j*rgbaImg.Stride:])
}
i := &Image{
image: graphics.NewImageFromImage(rgbaImg, width, height, filter),
basePixels: p,
filter: filter,
}
theImages.add(i)
runtime.SetFinalizer(i, (*Image).Dispose)
return i
}
// NewScreenFramebufferImage creates a special image that framebuffer is one for the screen.
func NewScreenFramebufferImage(width, height int, offsetX, offsetY float64) *Image {
i := &Image{
image: graphics.NewScreenFramebufferImage(width, height, offsetX, offsetY),
volatile: true,
screen: true,
offsetX: offsetX,
offsetY: offsetY,
}
theImages.add(i)
runtime.SetFinalizer(i, (*Image).Dispose)
return i
}
// BasePixelsForTesting returns the image's basePixels for testing.
func (i *Image) BasePixelsForTesting() []byte {
return i.basePixels
}
// Size returns the image's size.
func (i *Image) Size() (int, int) {
return i.image.Size()
}
// makeStale makes the image stale.
func (i *Image) makeStale() {
i.basePixels = nil
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = true
}
// clearIfVolatile clears the image if the image is volatile.
func (i *Image) clearIfVolatile() {
if !i.volatile {
return
}
i.basePixels = nil
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
if i.image == nil {
panic("not reached")
}
i.image.Fill(0, 0, 0, 0)
}
// Fill fills the image with the given color.
func (i *Image) Fill(r, g, b, a uint8) {
theImages.makeStaleIfDependingOn(i)
i.basePixels = nil
i.baseColor = color.RGBA{r, g, b, a}
i.drawImageHistory = nil
i.stale = false
i.image.Fill(r, g, b, a)
}
// ReplacePixels replaces the image pixels with the given pixels slice.
func (i *Image) ReplacePixels(pixels []byte) {
theImages.makeStaleIfDependingOn(i)
i.image.ReplacePixels(pixels)
i.basePixels = pixels
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
}
// DrawImage draws a given image img to the image.
func (i *Image) DrawImage(img *Image, vertices []float32, colorm *affine.ColorM, mode opengl.CompositeMode) {
theImages.makeStaleIfDependingOn(i)
if img.stale || img.volatile || !IsRestoringEnabled() {
i.makeStale()
} else {
i.appendDrawImageHistory(img, vertices, colorm, mode)
}
i.image.DrawImage(img.image, vertices, colorm, mode)
}
// appendDrawImageHistory appends a draw-image history item to the image.
func (i *Image) appendDrawImageHistory(image *Image, vertices []float32, colorm *affine.ColorM, mode opengl.CompositeMode) {
if i.stale || i.volatile {
return
}
if len(i.drawImageHistory) > 0 {
last := i.drawImageHistory[len(i.drawImageHistory)-1]
if last.canMerge(image, colorm, mode) {
last.vertices = append(last.vertices, vertices...)
return
}
}
const maxDrawImageHistoryNum = 100
if len(i.drawImageHistory)+1 > maxDrawImageHistoryNum {
i.makeStale()
return
}
// All images must be resolved and not stale each after frame.
// So we don't have to care if image is stale or not here.
item := &drawImageHistoryItem{
image: image,
vertices: vertices,
colorm: *colorm,
mode: mode,
}
i.drawImageHistory = append(i.drawImageHistory, item)
}
// At returns a color value at (x, y).
//
// Note that this must not be called until context is available.
func (i *Image) At(x, y int) (color.RGBA, error) {
w, h := i.image.Size()
w2, h2 := math.NextPowerOf2Int(w), math.NextPowerOf2Int(h)
if x < 0 || y < 0 || w2 <= x || h2 <= y {
return color.RGBA{}, nil
}
if i.basePixels == nil || i.drawImageHistory != nil || i.stale {
if err := i.readPixelsFromGPU(i.image); err != nil {
return color.RGBA{}, err
}
}
idx := 4*x + 4*y*w2
r, g, b, a := i.basePixels[idx], i.basePixels[idx+1], i.basePixels[idx+2], i.basePixels[idx+3]
return color.RGBA{r, g, b, a}, nil
}
// makeStaleIfDependingOn makes the image stale if the image depends on target.
func (i *Image) makeStaleIfDependingOn(target *Image) {
if i.stale {
return
}
if i.dependsOn(target) {
i.makeStale()
}
}
// readPixelsFromGPU reads the pixels from GPU and resolves the image's 'stale' state.
func (i *Image) readPixelsFromGPU(image *graphics.Image) error {
var err error
i.basePixels, err = image.Pixels()
if err != nil {
return err
}
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
return nil
}
// resolveStale resolves the image's 'stale' state.
func (i *Image) resolveStale() error {
if !IsRestoringEnabled() {
return nil
}
if i.volatile {
return nil
}
if !i.stale {
return nil
}
return i.readPixelsFromGPU(i.image)
}
// dependsOn returns a boolean value indicating whether the image depends on target.
func (i *Image) dependsOn(target *Image) bool {
for _, c := range i.drawImageHistory {
if c.image == target {
return true
}
}
return false
}
// dependingImages returns all images that is depended by the image.
func (i *Image) dependingImages() map[*Image]struct{} {
r := map[*Image]struct{}{}
for _, c := range i.drawImageHistory {
r[c.image] = struct{}{}
}
return r
}
// hasDependency returns a boolean value indicating whether the image depends on another image.
func (i *Image) hasDependency() bool {
if i.stale {
return false
}
return len(i.drawImageHistory) > 0
}
// Restore restores *graphics.Image from the pixels using its state.
func (i *Image) restore() error {
w, h := i.image.Size()
if i.screen {
// The screen image should also be recreated because framebuffer might
// be changed.
i.image = graphics.NewScreenFramebufferImage(w, h, i.offsetX, i.offsetY)
i.basePixels = nil
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
return nil
}
if i.volatile {
i.image = graphics.NewImage(w, h, i.filter)
i.basePixels = nil
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
return nil
}
if i.stale {
// TODO: panic here?
return errors.New("restorable: pixels must not be stale when restoring")
}
w2, h2 := math.NextPowerOf2Int(w), math.NextPowerOf2Int(h)
img := image.NewRGBA(image.Rect(0, 0, w2, h2))
if i.basePixels != nil {
for j := 0; j < h; j++ {
copy(img.Pix[j*img.Stride:], i.basePixels[j*w2*4:(j+1)*w2*4])
}
}
gimg := graphics.NewImageFromImage(img, w, h, i.filter)
if i.baseColor != (color.RGBA{}) {
if i.basePixels != nil {
panic("not reached")
}
gimg.Fill(i.baseColor.R, i.baseColor.G, i.baseColor.B, i.baseColor.A)
}
for _, c := range i.drawImageHistory {
// All dependencies must be already resolved.
if c.image.hasDependency() {
panic("not reached")
}
gimg.DrawImage(c.image.image, c.vertices, &c.colorm, c.mode)
}
i.image = gimg
var err error
i.basePixels, err = gimg.Pixels()
if err != nil {
return err
}
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
return nil
}
// Dispose disposes the image.
//
// After disposing, calling the function of the image causes unexpected results.
func (i *Image) Dispose() {
theImages.makeStaleIfDependingOn(i)
i.image.Dispose()
i.image = nil
i.basePixels = nil
i.baseColor = color.RGBA{}
i.drawImageHistory = nil
i.stale = false
theImages.remove(i)
runtime.SetFinalizer(i, nil)
}
// IsInvalidated returns a boolean value indicating whether the image is invalidated.
//
// If an image is invalidated, GL context is lost and all the images should be restored asap.
func (i *Image) IsInvalidated() (bool, error) {
// FlushCommands is required because c.offscreen.impl might not have an actual texture.
if err := graphics.FlushCommands(); err != nil {
return false, err
}
if !IsRestoringEnabled() {
return false, nil
}
return i.image.IsInvalidated(), nil
}