ebiten/image.go

452 lines
13 KiB
Go

// 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.
package ebiten
import (
"image"
"image/color"
"runtime"
"github.com/hajimehoshi/ebiten/internal/graphics"
"github.com/hajimehoshi/ebiten/internal/graphicsutil"
"github.com/hajimehoshi/ebiten/internal/opengl"
"github.com/hajimehoshi/ebiten/internal/shareable"
)
// emptyImage is an empty image used for filling other images with a uniform color.
//
// Do not call Fill or Clear on emptyImage or the program causes infinite recursion.
var emptyImage *Image
func init() {
emptyImage, _ = NewImage(16, 16, FilterDefault)
}
// Image represents a rectangle set of pixels.
// The pixel format is alpha-premultiplied RGBA.
// Image implements image.Image.
//
// Functions of Image never returns error as of 1.5.0-alpha, and error values are always nil.
type Image struct {
// addr holds self to check copying.
// See strings.Builder for similar examples.
addr *Image
shareableImage *shareable.Image
filter Filter
}
func (i *Image) copyCheck() {
if i.addr != i {
panic("ebiten: illegal use of non-zero Image copied by value")
}
}
// Size returns the size of the image.
func (i *Image) Size() (width, height int) {
return i.shareableImage.Size()
}
func (i *Image) isDisposed() bool {
return i.shareableImage == nil
}
// Clear resets the pixels of the image into 0.
//
// When the image is disposed, Clear does nothing.
//
// Clear always returns nil as of 1.5.0-alpha.
func (i *Image) Clear() error {
i.copyCheck()
if i.isDisposed() {
return nil
}
i.fill(0, 0, 0, 0)
return nil
}
// Fill fills the image with a solid color.
//
// When the image is disposed, Fill does nothing.
//
// Fill always returns nil as of 1.5.0-alpha.
func (i *Image) Fill(clr color.Color) error {
i.copyCheck()
if i.isDisposed() {
return nil
}
r, g, b, a := clr.RGBA()
i.fill(uint8(r>>8), uint8(g>>8), uint8(b>>8), uint8(a>>8))
return nil
}
func (i *Image) fill(r, g, b, a uint8) {
wd, hd := i.Size()
if wd*hd <= 256 {
// Prefer ReplacePixels since ReplacePixels can keep the images shared.
pix := make([]uint8, 4*wd*hd)
for i := 0; i < wd*hd; i++ {
pix[4*i] = r
pix[4*i+1] = g
pix[4*i+2] = b
pix[4*i+3] = a
}
i.ReplacePixels(pix)
return
}
ws, hs := emptyImage.Size()
sw := float64(wd) / float64(ws)
sh := float64(hd) / float64(hs)
op := &DrawImageOptions{}
op.GeoM.Scale(sw, sh)
if a > 0 {
rf := float64(r) / float64(a)
gf := float64(g) / float64(a)
bf := float64(b) / float64(a)
af := float64(a) / 0xff
op.ColorM.Translate(rf, gf, bf, af)
}
op.CompositeMode = CompositeModeCopy
op.Filter = FilterNearest
_ = i.DrawImage(emptyImage, op)
}
type geoM32 struct {
inner *GeoM
}
func (g geoM32) Elements() (a, b, c, d, tx, ty float32) {
return g.inner.elements()
}
// DrawImage draws the given image on the image i.
//
// DrawImage accepts the options. For details, see the document of DrawImageOptions.
//
// DrawImage determinines the part to draw, then DrawImage applies the geometry matrix and the color matrix.
//
// For drawing, the pixels of the argument image at the time of this call is adopted.
// Even if the argument image is mutated after this call,
// the drawing result is never affected.
//
// When the image i is disposed, DrawImage does nothing.
// When the given image img is disposed, DrawImage panics.
//
// When the given image is as same as i, DrawImage panics.
//
// DrawImage works more efficiently as batches
// when the successive calls of DrawImages satisfies the below conditions:
//
// * All render targets are same (A in A.DrawImage(B, op))
// * All render sources are same (B in A.DrawImage(B, op))
// * This is not a strong request since different images might share a same inner
// OpenGL texture in high possibility. This is not 100%, so using the same render
// source is safer.
// * All ColorM values are same
// * All CompositeMode values are same
// * All Filter values are same
//
// For more performance tips, see https://github.com/hajimehoshi/ebiten/wiki/Performance-Tips.
//
// DrawImage always returns nil as of 1.5.0-alpha.
func (i *Image) DrawImage(img *Image, options *DrawImageOptions) error {
i.copyCheck()
if img.isDisposed() {
panic("ebiten: the given image to DrawImage must not be disposed")
}
if i.isDisposed() {
return nil
}
// Calculate vertices before locking because the user can do anything in
// options.ImageParts interface without deadlock (e.g. Call Image functions).
if options == nil {
options = &DrawImageOptions{}
}
parts := options.ImageParts
// Parts is deprecated. This implementations is for backward compatibility.
if parts == nil && options.Parts != nil {
parts = imageParts(options.Parts)
}
// ImageParts is deprecated. This implementations is for backward compatibility.
if parts != nil {
l := parts.Len()
for idx := 0; idx < l; idx++ {
sx0, sy0, sx1, sy1 := parts.Src(idx)
dx0, dy0, dx1, dy1 := parts.Dst(idx)
op := &DrawImageOptions{
ColorM: options.ColorM,
CompositeMode: options.CompositeMode,
}
r := image.Rect(sx0, sy0, sx1, sy1)
op.SourceRect = &r
op.GeoM.Scale(
float64(dx1-dx0)/float64(sx1-sx0),
float64(dy1-dy0)/float64(sy1-sy0))
op.GeoM.Translate(float64(dx0), float64(dy0))
op.GeoM.Concat(options.GeoM)
i.DrawImage(img, op)
}
return nil
}
w, h := img.Size()
sx0, sy0, sx1, sy1 := 0, 0, w, h
if r := options.SourceRect; r != nil {
sx0 = r.Min.X
sy0 = r.Min.Y
if sx1 > r.Max.X {
sx1 = r.Max.X
}
if sy1 > r.Max.Y {
sy1 = r.Max.Y
}
}
geom := geoM32{&options.GeoM}
if sx0 < 0 || sy0 < 0 {
dx := 0.0
dy := 0.0
if sx0 < 0 {
dx = -float64(sx0)
sx0 = 0
}
if sy0 < 0 {
dy = -float64(sy0)
sy0 = 0
}
g := &GeoM{}
g.Translate(dx, dy)
g.Concat(options.GeoM)
geom = geoM32{g}
}
mode := opengl.CompositeMode(options.CompositeMode)
filter := graphics.FilterNearest
if options.Filter != FilterDefault {
filter = graphics.Filter(options.Filter)
} else if img.filter != FilterDefault {
filter = graphics.Filter(img.filter)
}
i.shareableImage.DrawImage(img.shareableImage, sx0, sy0, sx1, sy1, geom, options.ColorM.impl, mode, filter)
return nil
}
// Bounds returns the bounds of the image.
func (i *Image) Bounds() image.Rectangle {
w, h := i.Size()
return image.Rect(0, 0, w, h)
}
// ColorModel returns the color model of the image.
func (i *Image) ColorModel() color.Model {
return color.RGBAModel
}
// At returns the color of the image at (x, y).
//
// At loads pixels from GPU to system memory if necessary, which means that At can be slow.
//
// At always returns a transparent color if the image is disposed.
//
// Note that important logic should not rely on At result since
// At might include a very slight error on some machines.
//
// At can't be called before the main loop (ebiten.Run) starts (as of version 1.4.0-alpha).
func (i *Image) At(x, y int) color.Color {
if i.isDisposed() {
return color.RGBA{}
}
clr, err := i.shareableImage.At(x, y)
if err != nil {
panic(err)
}
return clr
}
// Dispose disposes the image data. After disposing, most of image functions do nothing and returns meaningless values.
//
// Dispose is useful to save memory.
//
// When the image is disposed, Dipose does nothing.
//
// Dipose always return nil as of 1.5.0-alpha.
func (i *Image) Dispose() error {
i.copyCheck()
if i.isDisposed() {
return nil
}
i.shareableImage.Dispose()
i.shareableImage = nil
runtime.SetFinalizer(i, nil)
return nil
}
// 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).
//
// ReplacePixels may be slow (as for implementation, this calls glTexSubImage2D).
//
// When len(p) is not appropriate, ReplacePixels panics.
//
// When the image is disposed, ReplacePixels does nothing.
//
// ReplacePixels always returns nil as of 1.5.0-alpha.
func (i *Image) ReplacePixels(p []byte) error {
i.copyCheck()
if i.isDisposed() {
return nil
}
i.shareableImage.ReplacePixels(p)
return nil
}
// A DrawImageOptions represents options to render an image on an image.
type DrawImageOptions struct {
// SourceRect is the region of the source image to draw.
// If SourceRect is nil, whole image is used.
//
// It is assured that texels out of the SourceRect are never used.
//
// Calling DrawImage copies the content of SourceRect pointer. This means that
// even if the SourceRect value is modified after passed to DrawImage,
// the result of DrawImage doen't change.
//
// op := &ebiten.DrawImageOptions{}
// r := image.Rect(0, 0, 100, 100)
// op.SourceRect = &r
// dst.DrawImage(src, op)
// r.Min.X = 10 // This doesn't affect the previous DrawImage.
SourceRect *image.Rectangle
// GeoM is a geometry matrix to draw.
// The default (zero) value is identify, which draws the image at (0, 0).
GeoM GeoM
// ColorM is a color matrix to draw.
// The default (zero) value is identity, which doesn't change any color.
ColorM ColorM
// CompositeMode is a composite mode to draw.
// The default (zero) value is regular alpha blending.
CompositeMode CompositeMode
// Filter is a type of texture filter.
// The default (zero) value is FilterDefault.
//
// Filter can also be specified at NewImage* functions, but
// specifying filter at DrawImageOptions is recommended (as of 1.7.0-alpha).
//
// If both Filter specified at NewImage* and DrawImageOptions are FilterDefault,
// FilterNearest is used.
// If either is FilterDefault and the other is not, the latter is used.
// Otherwise, Filter specified at DrawImageOptions is used.
Filter Filter
// Deprecated (as of 1.5.0-alpha): Use SourceRect instead.
ImageParts ImageParts
// Deprecated (as of 1.1.0-alpha): Use SourceRect instead.
Parts []ImagePart
}
// NewImage returns an empty image.
//
// If width or height is less than 1 or more than device-dependent maximum size, NewImage panics.
//
// filter argument is just for backward compatibility.
// If you are not sure, specify FilterDefault.
//
// Error returned by NewImage is always nil as of 1.5.0-alpha.
func NewImage(width, height int, filter Filter) (*Image, error) {
s := shareable.NewImage(width, height)
i := &Image{
shareableImage: s,
filter: filter,
}
i.addr = i
runtime.SetFinalizer(i, (*Image).Dispose)
return i, nil
}
// newVolatileImage returns an empty 'volatile' image.
// A volatile image is always cleared at the start of a frame.
//
// This is suitable for offscreen images that pixels are changed often.
//
// 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.
// Saving pixels is an expensive operation, and it is desirable to avoid it if possible.
//
// Note that volatile images are internal only and will never be source of drawing.
//
// If width or height is less than 1 or more than device-dependent maximum size, newVolatileImage panics.
func newVolatileImage(width, height int) *Image {
i := &Image{
shareableImage: shareable.NewVolatileImage(width, height),
}
i.addr = i
runtime.SetFinalizer(i, (*Image).Dispose)
return i
}
// NewImageFromImage creates a new image with the given image (source).
//
// If source's width or height is less than 1 or more than device-dependent maximum size, NewImageFromImage panics.
//
// filter argument is just for backward compatibility.
// If you are not sure, specify FilterDefault.
//
// Error returned by NewImageFromImage is always nil as of 1.5.0-alpha.
func NewImageFromImage(source image.Image, filter Filter) (*Image, error) {
size := source.Bounds().Size()
width, height := size.X, size.Y
s := shareable.NewImage(width, height)
i := &Image{
shareableImage: s,
filter: filter,
}
i.addr = i
runtime.SetFinalizer(i, (*Image).Dispose)
_ = i.ReplacePixels(graphicsutil.CopyImage(source))
return i, nil
}
func newImageWithScreenFramebuffer(width, height int) *Image {
i := &Image{
shareableImage: shareable.NewScreenFramebufferImage(width, height),
filter: FilterDefault,
}
i.addr = i
runtime.SetFinalizer(i, (*Image).Dispose)
return i
}
// MaxImageSize is deprecated as of 1.7.0-alpha. No replacement so far.
//
// TODO: Make this replacement (#541)
var MaxImageSize = 4096