ebiten/image.go

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// Copyright 2014 Hajime Hoshi
//
// 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.
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package ebiten
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import (
"image"
"image/color"
"runtime"
"sync"
"github.com/hajimehoshi/ebiten/internal/opengl"
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)
func glContext() *opengl.Context {
// This is called from finalizers even when the context or the program is not set.
g, ok := theGraphicsContext.Load().(*graphicsContext)
if !ok {
return nil
}
if g == nil {
return nil
}
return g.GLContext()
}
type images struct {
images map[*imageImpl]struct{}
m sync.Mutex
lastChecked *imageImpl
}
var theImagesForRestoring = images{
images: map[*imageImpl]struct{}{},
}
func (i *images) add(img *imageImpl) (*Image, error) {
i.m.Lock()
defer i.m.Unlock()
i.images[img] = struct{}{}
eimg := &Image{img}
runtime.SetFinalizer(eimg, theImagesForRestoring.remove)
return eimg, nil
}
func (i *images) remove(img *Image) {
if err := img.Dispose(); err != nil {
panic(err)
}
i.m.Lock()
defer i.m.Unlock()
delete(i.images, img.impl)
runtime.SetFinalizer(img, nil)
}
func (i *images) resolveStalePixels(context *opengl.Context) error {
i.m.Lock()
defer i.m.Unlock()
i.lastChecked = nil
for img := range i.images {
if err := img.resolveStalePixels(context); err != nil {
return err
}
}
return nil
}
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func (i *images) resetPixelsIfDependingOn(target *Image, context *opengl.Context) error {
i.m.Lock()
defer i.m.Unlock()
if i.lastChecked == target.impl {
return nil
}
i.lastChecked = target.impl
for img := range i.images {
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if err := img.resetPixelsIfDependingOn(target.impl, context); err != nil {
return err
}
}
return nil
}
func (i *images) restore(context *opengl.Context) error {
i.m.Lock()
defer i.m.Unlock()
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// Dispose all images first because framebuffer/texture numbers can be reused.
// If framebuffers/textures are not disposed here, a newly created framebuffer/texture
// number can be a same number as existing one.
for img := range i.images {
if img.isDisposed() {
continue
}
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if err := img.restorable.DisposeOnlyImage(); err != nil {
return err
}
}
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imagesWithoutDependency := []*imageImpl{}
imagesWithDependency := []*imageImpl{}
for img := range i.images {
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if img.hasDependency() {
imagesWithDependency = append(imagesWithDependency, img)
} else {
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imagesWithoutDependency = append(imagesWithoutDependency, img)
}
}
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// Images depending on other images should be processed first.
for _, img := range imagesWithoutDependency {
if err := img.restore(context); err != nil {
return err
}
}
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for _, img := range imagesWithDependency {
if err := img.restore(context); err != nil {
return err
}
}
return nil
}
func (i *images) clearVolatileImages() error {
i.m.Lock()
defer i.m.Unlock()
for img := range i.images {
if err := img.clearIfVolatile(); err != nil {
return err
}
}
return nil
}
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// Image represents an image.
// The pixel format is alpha-premultiplied.
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// Image implements image.Image.
type Image struct {
impl *imageImpl
}
// Size returns the size of the image.
//
// This function is concurrent-safe.
func (i *Image) Size() (width, height int) {
return i.impl.restorable.Size()
}
// Clear resets the pixels of the image into 0.
//
// This function is concurrent-safe.
func (i *Image) Clear() error {
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if err := theImagesForRestoring.resetPixelsIfDependingOn(i, glContext()); err != nil {
return err
}
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return i.impl.Fill(color.Transparent)
}
// Fill fills the image with a solid color.
//
// This function is concurrent-safe.
func (i *Image) Fill(clr color.Color) error {
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if err := theImagesForRestoring.resetPixelsIfDependingOn(i, glContext()); err != nil {
return err
}
return i.impl.Fill(clr)
}
// DrawImage draws the given image on the receiver image.
//
// This method accepts the options.
// The parts of the given image at the parts of the destination.
// After determining parts to draw, this applies the geometry matrix and the color matrix.
//
// Here are the default values:
// ImageParts: (0, 0) - (source width, source height) to (0, 0) - (source width, source height)
// (i.e. the whole source image)
// GeoM: Identity matrix
// ColorM: Identity matrix (that changes no colors)
// CompositeMode: CompositeModeSourceOver (regular alpha blending)
//
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// Note that this function returns immediately and actual drawing is done lazily.
//
// This function is concurrent-safe.
func (i *Image) DrawImage(image *Image, options *DrawImageOptions) error {
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if err := theImagesForRestoring.resetPixelsIfDependingOn(i, glContext()); err != nil {
return err
}
return i.impl.DrawImage(image, options)
}
// Bounds returns the bounds of the image.
//
// This function is concurrent-safe.
func (i *Image) Bounds() image.Rectangle {
w, h := i.impl.restorable.Size()
return image.Rect(0, 0, w, h)
}
// ColorModel returns the color model of the image.
//
// This function is concurrent-safe.
func (i *Image) ColorModel() color.Model {
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return color.RGBAModel
}
// At returns the color of the image at (x, y).
//
// This method loads pixels from VRAM to system memory if necessary.
//
// This method can't be called before the main loop (ebiten.Run) starts (as of version 1.4.0-alpha).
//
// This function is concurrent-safe.
func (i *Image) At(x, y int) color.Color {
return i.impl.At(x, y, glContext())
}
// Dispose disposes the image data. After disposing, the image becomes invalid.
// This is useful to save memory.
//
// The behavior of any functions for a disposed image is undefined.
//
// This function is concurrent-safe.
func (i *Image) Dispose() error {
if i.impl.isDisposed() {
return nil
}
if err := theImagesForRestoring.resetPixelsIfDependingOn(i, glContext()); err != nil {
return err
}
return i.impl.Dispose()
}
// ReplacePixels replaces the pixels of the image with p.
//
// The given p must represent RGBA pre-multiplied alpha values. len(p) must equal to 4 * (image width) * (image height).
//
// This function may be slow (as for implementation, this calls glTexSubImage2D).
//
// This function is concurrent-safe.
func (i *Image) ReplacePixels(p []uint8) error {
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if err := theImagesForRestoring.resetPixelsIfDependingOn(i, glContext()); err != nil {
return err
}
return i.impl.ReplacePixels(p)
}
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// A DrawImageOptions represents options to render an image on an image.
type DrawImageOptions struct {
ImageParts ImageParts
GeoM GeoM
ColorM ColorM
CompositeMode CompositeMode
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// Deprecated (as of 1.1.0-alpha): Use ImageParts instead.
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Parts []ImagePart
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}
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// NewImage returns an empty image.
//
// NewImage generates a new texture and a new framebuffer.
//
// This function is concurrent-safe.
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func NewImage(width, height int, filter Filter) (*Image, error) {
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img, err := newImageImpl(width, height, filter, false)
if err != nil {
return nil, err
}
if err := img.Fill(color.Transparent); err != nil {
return nil, err
}
eimg, err := theImagesForRestoring.add(img)
if err != nil {
return nil, err
}
return eimg, nil
}
// newVolatileImage returns an empty 'volatile' image.
// A volatile image is always cleared at the start of a frame.
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//
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// This is suitable for offscreen images that pixels are changed often.
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//
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// Pixels in regular non-volatile images are saved at each end of a frame if the image
// is changed, and restored automatically from the saved pixels on GL context lost.
// On the other hand, pixels in volatile images are not saved.
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// Saving pixels is an expensive operation, and it is desirable to avoid it if possible.
//
// This function is concurrent-safe.
func newVolatileImage(width, height int, filter Filter) (*Image, error) {
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img, err := newImageImpl(width, height, filter, true)
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if err != nil {
return nil, err
}
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if err := img.Fill(color.Transparent); err != nil {
return nil, err
}
eimg, err := theImagesForRestoring.add(img)
if err != nil {
return nil, err
}
return eimg, nil
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}
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// NewImageFromImage creates a new image with the given image (source).
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//
// NewImageFromImage generates a new texture and a new framebuffer.
//
// This function is concurrent-safe.
func NewImageFromImage(source image.Image, filter Filter) (*Image, error) {
img, err := newImageImplFromImage(source, filter)
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if err != nil {
return nil, err
}
eimg, err := theImagesForRestoring.add(img)
if err != nil {
return nil, err
}
return eimg, nil
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}
func newImageWithScreenFramebuffer(width, height int) (*Image, error) {
img, err := newScreenImageImpl(width, height)
if err != nil {
return nil, err
}
eimg, err := theImagesForRestoring.add(img)
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if err != nil {
return nil, err
}
return eimg, nil
}