ebiten/image.go
Hajime Hoshi 30cc36b1ba ebiten: add FinalScreenDrawer
FinalScreenDrawer is an interface for a custom screen rendering. If a
game implements FinalScreenDrawer and is passed to RunGame, its
DrawFinalScreen is called after Draw.

Also this adds `-crt` option to examples/flappy.

Closes #2046
2022-10-14 16:49:32 +09:00

1097 lines
36 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 (
"fmt"
"image"
"image/color"
"github.com/hajimehoshi/ebiten/v2/internal/affine"
"github.com/hajimehoshi/ebiten/v2/internal/atlas"
"github.com/hajimehoshi/ebiten/v2/internal/builtinshader"
"github.com/hajimehoshi/ebiten/v2/internal/graphics"
"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
"github.com/hajimehoshi/ebiten/v2/internal/ui"
)
// Image represents a rectangle set of pixels.
// The pixel format is alpha-premultiplied RGBA.
// Image implements the standard image.Image and draw.Image interfaces.
type Image struct {
// addr holds self to check copying.
// See strings.Builder for similar examples.
addr *Image
image *ui.Image
original *Image
bounds image.Rectangle
// Do not add a 'cache' member that are resolved lazily.
// This tends to forget resolving the cache easily (#2362).
}
var emptyImage *Image
func init() {
img := NewImage(3, 3)
img.Fill(color.White)
emptyImage = img.SubImage(image.Rect(1, 1, 2, 2)).(*Image)
}
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) {
s := i.Bounds().Size()
return s.X, s.Y
}
func (i *Image) isDisposed() bool {
return i.image == nil
}
func (i *Image) isSubImage() bool {
return i.original != nil
}
// Clear resets the pixels of the image into 0.
//
// When the image is disposed, Clear does nothing.
func (i *Image) Clear() {
i.Fill(color.Transparent)
}
// Fill fills the image with a solid color.
//
// When the image is disposed, Fill does nothing.
func (i *Image) Fill(clr color.Color) {
i.copyCheck()
if i.isDisposed() {
return
}
var crf, cgf, cbf, caf float32
cr, cg, cb, ca := clr.RGBA()
crf = float32(cr) / 0xffff
cgf = float32(cg) / 0xffff
cbf = float32(cb) / 0xffff
caf = float32(ca) / 0xffff
b := i.Bounds()
x, y := i.adjustPosition(b.Min.X, b.Min.Y)
i.image.Fill(crf, cgf, cbf, caf, x, y, b.Dx(), b.Dy())
}
func canSkipMipmap(geom GeoM, filter builtinshader.Filter) bool {
if filter != builtinshader.FilterLinear {
return true
}
return geom.det2x2() >= 0.999
}
// DrawImageOptions represents options for DrawImage.
type DrawImageOptions struct {
// GeoM is a geometry matrix to draw.
// The default (zero) value is identity, 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 FilterNearest.
Filter Filter
}
// adjustPosition converts the position in the *ebiten.Image coordinate to the *ui.Image coordinate.
func (i *Image) adjustPosition(x, y int) (int, int) {
if i.isSubImage() {
or := i.original.Bounds()
x -= or.Min.X
y -= or.Min.Y
return x, y
}
r := i.Bounds()
x -= r.Min.X
y -= r.Min.Y
return x, y
}
// adjustPositionF32 converts the position in the *ebiten.Image coordinate to the *ui.Image coordinate.
func (i *Image) adjustPositionF32(x, y float32) (float32, float32) {
if i.isSubImage() {
or := i.original.Bounds()
x -= float32(or.Min.X)
y -= float32(or.Min.Y)
return x, y
}
r := i.Bounds()
x -= float32(r.Min.X)
y -= float32(r.Min.Y)
return x, y
}
func (i *Image) adjustedRegion() graphicsdriver.Region {
b := i.Bounds()
x, y := i.adjustPosition(b.Min.X, b.Min.Y)
return graphicsdriver.Region{
X: float32(x),
Y: float32(y),
Width: float32(b.Dx()),
Height: float32(b.Dy()),
}
}
// DrawImage draws the given image on the image i.
//
// DrawImage accepts the options. For details, see the document of
// DrawImageOptions.
//
// 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 satisfy the below conditions:
//
// - All render targets are same (A in A.DrawImage(B, op))
// - Either all ColorM element values are same or all the ColorM have only
// diagonal ('scale') elements
// - If only (*ColorM).Scale is applied to a ColorM, the ColorM has only
// diagonal elements. The other ColorM functions might modify the other
// elements.
// - All CompositeMode values are same
// - All Filter values are same
//
// Even when all the above conditions are satisfied, multiple draw commands can
// be used in really rare cases. Ebitengine images usually share an internal
// automatic texture atlas, but when you consume the atlas, or you create a huge
// image, those images cannot be on the same texture atlas. In this case, draw
// commands are separated.
// Another case is when you use an offscreen as a render source. An offscreen
// doesn't share the texture atlas with high probability.
//
// For more performance tips, see https://ebitengine.org/en/documents/performancetips.html
func (i *Image) DrawImage(img *Image, options *DrawImageOptions) {
i.copyCheck()
if img.isDisposed() {
panic("ebiten: the given image to DrawImage must not be disposed")
}
if i.isDisposed() {
return
}
// 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{}
}
mode := graphicsdriver.CompositeMode(options.CompositeMode)
filter := builtinshader.Filter(options.Filter)
if offsetX, offsetY := i.adjustPosition(0, 0); offsetX != 0 || offsetY != 0 {
options.GeoM.Translate(float64(offsetX), float64(offsetY))
}
a, b, c, d, tx, ty := options.GeoM.elements32()
bounds := img.Bounds()
sx0, sy0 := img.adjustPosition(bounds.Min.X, bounds.Min.Y)
sx1, sy1 := img.adjustPosition(bounds.Max.X, bounds.Max.Y)
colorm, cr, cg, cb, ca := colorMToScale(options.ColorM.affineColorM())
vs := graphics.QuadVertices(float32(sx0), float32(sy0), float32(sx1), float32(sy1), a, b, c, d, tx, ty, cr, cg, cb, ca)
is := graphics.QuadIndices()
srcs := [graphics.ShaderImageCount]*ui.Image{img.image}
useColorM := !colorm.IsIdentity()
shader := builtinShader(filter, builtinshader.AddressUnsafe, useColorM)
var uniforms [][]float32
if useColorM {
var body [16]float32
var translation [4]float32
colorm.Elements(body[:], translation[:])
uniforms = shader.convertUniforms(map[string]interface{}{
builtinshader.UniformColorMBody: body[:],
builtinshader.UniformColorMTranslation: translation[:],
})
}
i.image.DrawTriangles(srcs, vs, is, mode, i.adjustedRegion(), graphicsdriver.Region{}, [graphics.ShaderImageCount - 1][2]float32{}, shader.shader, uniforms, false, canSkipMipmap(options.GeoM, filter))
}
// Vertex represents a vertex passed to DrawTriangles.
type Vertex struct {
// DstX and DstY represents a point on a destination image.
DstX float32
DstY float32
// SrcX and SrcY represents a point on a source image.
// Be careful that SrcX/SrcY coordinates are on the image's bounds.
// This means that a upper-left point of a sub-image might not be (0, 0).
SrcX float32
SrcY float32
// ColorR/ColorG/ColorB/ColorA represents color scaling values.
// Their interpretation depends on the concrete draw call used:
// - DrawTriangles: straight-alpha or premultiplied-alpha encoded color multiplier.
// The format is determined by ColorScaleFormat in DrawTrianglesOptions.
// If ColorA is 0, the vertex is fully transparent and color is ignored.
// If ColorA is 1, the vertex has the color (ColorR, ColorG, ColorB).
// Vertex colors are converted to premultiplied-alpha internally and
// interpolated linearly respecting alpha.
// - DrawTrianglesShader: arbitrary floating point values sent to the shader.
// These are interpolated linearly and independently from each other.
ColorR float32
ColorG float32
ColorB float32
ColorA float32
}
// Address represents a sampler address mode.
type Address int
const (
// AddressUnsafe means there is no guarantee when the texture coodinates are out of range.
AddressUnsafe Address = Address(builtinshader.AddressUnsafe)
// AddressClampToZero means that out-of-range texture coordinates return 0 (transparent).
AddressClampToZero Address = Address(builtinshader.AddressClampToZero)
// AddressRepeat means that texture coordinates wrap to the other side of the texture.
AddressRepeat Address = Address(builtinshader.AddressRepeat)
)
// FillRule is the rule whether an overlapped region is rendered with DrawTriangles(Shader).
type FillRule int
const (
// FillAll indicates all the triangles are rendered regardless of overlaps.
FillAll FillRule = iota
// EvenOdd means that triangles are rendered based on the even-odd rule.
// If and only if the number of overlappings is odd, the region is rendered.
EvenOdd
)
// ColorScaleFormat is the format of color scales in vertices.
type ColorScaleFormat int
const (
// ColorScaleFormatStraightAlpha indicates color scales in vertices are
// straight-alpha encoded color multiplier.
ColorScaleFormatStraightAlpha ColorScaleFormat = iota
// ColorScaleFormatStraightAlpha indicates color scales in vertices are
// premultiplied-alpha encoded color multiplier.
ColorScaleFormatPremultipliedAlpha
)
// DrawTrianglesOptions represents options for DrawTriangles.
type DrawTrianglesOptions struct {
// ColorM is a color matrix to draw.
// The default (zero) value is identity, which doesn't change any color.
// ColorM is applied before vertex color scale is applied.
ColorM ColorM
// ColorScaleFormat is the format of color scales in vertices.
// The default (zero) value is ColorScaleFormatStraightAlpha.
ColorScaleFormat ColorScaleFormat
// 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 FilterNearest.
Filter Filter
// Address is a sampler address mode.
// The default (zero) value is AddressUnsafe.
Address Address
// FillRule indicates the rule how an overlapped region is rendered.
//
// The rule EvenOdd is useful when you want to render a complex polygon.
// A complex polygon is a non-convex polygon like a concave polygon, a polygon with holes, or a self-intersecting polygon.
// See examples/vector for actual usages.
//
// The default (zero) value is FillAll.
FillRule FillRule
}
// MaxIndicesCount is the maximum number of indices for DrawTriangles and DrawTrianglesShader.
const MaxIndicesCount = graphics.IndicesCount
// MaxIndicesNum is the maximum number of indices for DrawTriangles and DrawTrianglesShader.
//
// Deprecated: as of v2.4. Use MaxIndicesCount instead.
const MaxIndicesNum = graphics.IndicesCount
// DrawTriangles draws triangles with the specified vertices and their indices.
//
// img is used as a source image. img cannot be nil.
// If you want to draw triangles with a solid color, use a small white image
// and adjust the color elements in the vertices. For an actual implementation,
// see the example 'vector'.
//
// Vertex contains color values, which are interpreted as straight-alpha colors.
//
// If len(indices) is not multiple of 3, DrawTriangles panics.
//
// If len(indices) is more than MaxIndicesCount, DrawTriangles panics.
//
// The rule in which DrawTriangles works effectively is same as DrawImage's.
//
// When the given image is disposed, DrawTriangles panics.
//
// When the image i is disposed, DrawTriangles does nothing.
func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, options *DrawTrianglesOptions) {
i.copyCheck()
if img != nil && img.isDisposed() {
panic("ebiten: the given image to DrawTriangles must not be disposed")
}
if i.isDisposed() {
return
}
if len(indices)%3 != 0 {
panic("ebiten: len(indices) % 3 must be 0")
}
if len(indices) > MaxIndicesCount {
panic("ebiten: len(indices) must be <= MaxIndicesCount")
}
// TODO: Check the maximum value of indices and len(vertices)?
if options == nil {
options = &DrawTrianglesOptions{}
}
mode := graphicsdriver.CompositeMode(options.CompositeMode)
address := builtinshader.Address(options.Address)
var sr graphicsdriver.Region
if address != builtinshader.AddressUnsafe {
sr = img.adjustedRegion()
}
filter := builtinshader.Filter(options.Filter)
colorm, cr, cg, cb, ca := colorMToScale(options.ColorM.affineColorM())
vs := graphics.Vertices(len(vertices))
dst := i
if options.ColorScaleFormat == ColorScaleFormatStraightAlpha {
for i, v := range vertices {
dx, dy := dst.adjustPositionF32(v.DstX, v.DstY)
vs[i*graphics.VertexFloatCount] = dx
vs[i*graphics.VertexFloatCount+1] = dy
sx, sy := img.adjustPositionF32(v.SrcX, v.SrcY)
vs[i*graphics.VertexFloatCount+2] = sx
vs[i*graphics.VertexFloatCount+3] = sy
vs[i*graphics.VertexFloatCount+4] = v.ColorR * v.ColorA * cr
vs[i*graphics.VertexFloatCount+5] = v.ColorG * v.ColorA * cg
vs[i*graphics.VertexFloatCount+6] = v.ColorB * v.ColorA * cb
vs[i*graphics.VertexFloatCount+7] = v.ColorA * ca
}
} else {
for i, v := range vertices {
dx, dy := dst.adjustPositionF32(v.DstX, v.DstY)
vs[i*graphics.VertexFloatCount] = dx
vs[i*graphics.VertexFloatCount+1] = dy
sx, sy := img.adjustPositionF32(v.SrcX, v.SrcY)
vs[i*graphics.VertexFloatCount+2] = sx
vs[i*graphics.VertexFloatCount+3] = sy
vs[i*graphics.VertexFloatCount+4] = v.ColorR * cr
vs[i*graphics.VertexFloatCount+5] = v.ColorG * cg
vs[i*graphics.VertexFloatCount+6] = v.ColorB * cb
vs[i*graphics.VertexFloatCount+7] = v.ColorA * ca
}
}
is := make([]uint16, len(indices))
copy(is, indices)
srcs := [graphics.ShaderImageCount]*ui.Image{img.image}
useColorM := !colorm.IsIdentity()
shader := builtinShader(filter, address, useColorM)
var uniforms [][]float32
if useColorM {
var body [16]float32
var translation [4]float32
colorm.Elements(body[:], translation[:])
uniforms = shader.convertUniforms(map[string]interface{}{
builtinshader.UniformColorMBody: body[:],
builtinshader.UniformColorMTranslation: translation[:],
})
}
i.image.DrawTriangles(srcs, vs, is, mode, i.adjustedRegion(), sr, [graphics.ShaderImageCount - 1][2]float32{}, shader.shader, uniforms, options.FillRule == EvenOdd, filter != builtinshader.FilterLinear)
}
// DrawTrianglesShaderOptions represents options for DrawTrianglesShader.
type DrawTrianglesShaderOptions struct {
// CompositeMode is a composite mode to draw.
// The default (zero) value is regular alpha blending.
CompositeMode CompositeMode
// Uniforms is a set of uniform variables for the shader.
// The keys are the names of the uniform variables.
// The values must be float or []float.
// If the uniform variable type is an array, a vector or a matrix,
// you have to specify linearly flattened values as a slice.
// For example, if the uniform variable type is [4]vec4, the number of the slice values will be 16.
Uniforms map[string]interface{}
// Images is a set of the source images.
// All the images' sizes must be the same.
Images [4]*Image
// FillRule indicates the rule how an overlapped region is rendered.
//
// The rule EvenOdd is useful when you want to render a complex polygon.
// A complex polygon is a non-convex polygon like a concave polygon, a polygon with holes, or a self-intersecting polygon.
// See examples/vector for actual usages.
//
// The default (zero) value is FillAll.
FillRule FillRule
}
func init() {
var op DrawTrianglesShaderOptions
if got, want := len(op.Images), graphics.ShaderImageCount; got != want {
panic(fmt.Sprintf("ebiten: len((DrawTrianglesShaderOptions{}).Images) must be %d but %d", want, got))
}
}
// DrawTrianglesShader draws triangles with the specified vertices and their indices with the specified shader.
//
// Vertex contains color values, which can be interpreted for any purpose by the shader.
//
// For the details about the shader, see https://ebitengine.org/en/documents/shader.html.
//
// If len(indices) is not multiple of 3, DrawTrianglesShader panics.
//
// If len(indices) is more than MaxIndicesCount, DrawTrianglesShader panics.
//
// When a specified image is non-nil and is disposed, DrawTrianglesShader panics.
//
// When the image i is disposed, DrawTrianglesShader does nothing.
func (i *Image) DrawTrianglesShader(vertices []Vertex, indices []uint16, shader *Shader, options *DrawTrianglesShaderOptions) {
i.copyCheck()
if i.isDisposed() {
return
}
if len(indices)%3 != 0 {
panic("ebiten: len(indices) % 3 must be 0")
}
if len(indices) > MaxIndicesCount {
panic("ebiten: len(indices) must be <= MaxIndicesCount")
}
// TODO: Check the maximum value of indices and len(vertices)?
if options == nil {
options = &DrawTrianglesShaderOptions{}
}
mode := graphicsdriver.CompositeMode(options.CompositeMode)
vs := graphics.Vertices(len(vertices))
dst := i
src := options.Images[0]
for i, v := range vertices {
dx, dy := dst.adjustPositionF32(v.DstX, v.DstY)
vs[i*graphics.VertexFloatCount] = dx
vs[i*graphics.VertexFloatCount+1] = dy
sx, sy := v.SrcX, v.SrcY
if src != nil {
sx, sy = src.adjustPositionF32(sx, sy)
}
vs[i*graphics.VertexFloatCount+2] = sx
vs[i*graphics.VertexFloatCount+3] = sy
vs[i*graphics.VertexFloatCount+4] = v.ColorR
vs[i*graphics.VertexFloatCount+5] = v.ColorG
vs[i*graphics.VertexFloatCount+6] = v.ColorB
vs[i*graphics.VertexFloatCount+7] = v.ColorA
}
is := make([]uint16, len(indices))
copy(is, indices)
var imgs [graphics.ShaderImageCount]*ui.Image
var imgw, imgh int
for i, img := range options.Images {
if img == nil {
continue
}
if img.isDisposed() {
panic("ebiten: the given image to DrawTrianglesShader must not be disposed")
}
if i == 0 {
imgw, imgh = img.Size()
} else {
// TODO: Check imgw > 0 && imgh > 0
if w, h := img.Size(); imgw != w || imgh != h {
panic("ebiten: all the source images must be the same size with the rectangle")
}
}
imgs[i] = img.image
}
var sx, sy int
var sr graphicsdriver.Region
if img := options.Images[0]; img != nil {
b := img.Bounds()
sx, sy = img.adjustPosition(b.Min.X, b.Min.Y)
sr = img.adjustedRegion()
}
var offsets [graphics.ShaderImageCount - 1][2]float32
for i, img := range options.Images[1:] {
if img == nil {
continue
}
b := img.Bounds()
x, y := img.adjustPosition(b.Min.X, b.Min.Y)
// (sx, sy) is the upper-left position of the first image.
// Calculate the distance between the current image's upper-left position and the first one's.
offsets[i][0] = float32(x - sx)
offsets[i][1] = float32(y - sy)
}
i.image.DrawTriangles(imgs, vs, is, mode, i.adjustedRegion(), sr, offsets, shader.shader, shader.convertUniforms(options.Uniforms), options.FillRule == EvenOdd, true)
}
// DrawRectShaderOptions represents options for DrawRectShader.
type DrawRectShaderOptions struct {
// GeoM is a geometry matrix to draw.
// The default (zero) value is identity, which draws the rectangle at (0, 0).
GeoM GeoM
// ColorScale is a scale of color.
// This scaling values are passed to the `color vec4` argument of the Fragment function in a Kage program.
// The default (zero) value is identity, which is (1, 1, 1, 1).
ColorScale ColorScale
// CompositeMode is a composite mode to draw.
// The default (zero) value is regular alpha blending.
CompositeMode CompositeMode
// Uniforms is a set of uniform variables for the shader.
// The keys are the names of the uniform variables.
// The values must be float or []float.
// If the uniform variable type is an array, a vector or a matrix,
// you have to specify linearly flattened values as a slice.
// For example, if the uniform variable type is [4]vec4, the number of the slice values will be 16.
Uniforms map[string]interface{}
// Images is a set of the source images.
// All the images' sizes must be the same.
Images [4]*Image
}
func init() {
var op DrawRectShaderOptions
if got, want := len(op.Images), graphics.ShaderImageCount; got != want {
panic(fmt.Sprintf("ebiten: len((DrawRectShaderOptions{}).Images) must be %d but %d", want, got))
}
}
// DrawRectShader draws a rectangle with the specified width and height with the specified shader.
//
// For the details about the shader, see https://ebitengine.org/en/documents/shader.html.
//
// When one of the specified image is non-nil and is disposed, DrawRectShader panics.
//
// When the image i is disposed, DrawRectShader does nothing.
func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawRectShaderOptions) {
i.copyCheck()
if i.isDisposed() {
return
}
if options == nil {
options = &DrawRectShaderOptions{}
}
mode := graphicsdriver.CompositeMode(options.CompositeMode)
var imgs [graphics.ShaderImageCount]*ui.Image
for i, img := range options.Images {
if img == nil {
continue
}
if img.isDisposed() {
panic("ebiten: the given image to DrawRectShader must not be disposed")
}
if w, h := img.Size(); width != w || height != h {
panic("ebiten: all the source images must be the same size with the rectangle")
}
imgs[i] = img.image
}
var sx, sy int
var sr graphicsdriver.Region
if img := options.Images[0]; img != nil {
b := img.Bounds()
sx, sy = img.adjustPosition(b.Min.X, b.Min.Y)
sr = img.adjustedRegion()
}
if offsetX, offsetY := i.adjustPosition(0, 0); offsetX != 0 || offsetY != 0 {
options.GeoM.Translate(float64(offsetX), float64(offsetY))
}
a, b, c, d, tx, ty := options.GeoM.elements32()
cr, cg, cb, ca := options.ColorScale.elements()
vs := graphics.QuadVertices(float32(sx), float32(sy), float32(sx+width), float32(sy+height), a, b, c, d, tx, ty, cr, cg, cb, ca)
is := graphics.QuadIndices()
var offsets [graphics.ShaderImageCount - 1][2]float32
for i, img := range options.Images[1:] {
if img == nil {
continue
}
b := img.Bounds()
x, y := img.adjustPosition(b.Min.X, b.Min.Y)
// (sx, sy) is the upper-left position of the first image.
// Calculate the distance between the current image's upper-left position and the first one's.
offsets[i][0] = float32(x - sx)
offsets[i][1] = float32(y - sy)
}
i.image.DrawTriangles(imgs, vs, is, mode, i.adjustedRegion(), sr, offsets, shader.shader, shader.convertUniforms(options.Uniforms), false, true)
}
// SubImage returns an image representing the portion of the image p visible through r.
// The returned value shares pixels with the original image.
//
// The returned value is always *ebiten.Image.
//
// If the image is disposed, SubImage returns nil.
//
// A sub-image returned by SubImage can be used as a rendering source and a rendering destination.
// If a sub-image is used as a rendering source, the image is used as if it is a small image.
// If a sub-image is used as a rendering destination, the region being rendered is clipped.
//
// Successive uses of multiple various regions as rendering destination might not be efficient,
// even though all the underlying images are the same.
// It's because such renderings cannot be unified into one internal draw command.
func (i *Image) SubImage(r image.Rectangle) image.Image {
i.copyCheck()
if i.isDisposed() {
return nil
}
r = r.Intersect(i.Bounds())
// Need to check Empty explicitly. See the standard image package implementations.
if r.Empty() {
r = image.ZR
}
// Keep the original image's reference not to dispose that by GC.
var orig = i
if i.isSubImage() {
orig = i.original
}
img := &Image{
image: i.image,
bounds: r,
original: orig,
}
img.addr = img
return img
}
// Bounds returns the bounds of the image.
//
// Bounds implements the standard image.Image's Bounds.
func (i *Image) Bounds() image.Rectangle {
if i.isDisposed() {
panic("ebiten: the image is already disposed")
}
return i.bounds
}
// ColorModel returns the color model of the image.
//
// ColorModel implements the standard image.Image's ColorModel.
func (i *Image) ColorModel() color.Model {
return color.RGBAModel
}
// ReadPixels reads the image's pixels from the image.
//
// The given pixels represent RGBA pre-multiplied alpha values.
//
// ReadPixels loads pixels from GPU to system memory if necessary, which means that ReadPixels can be slow.
//
// ReadPixels always sets a transparent color if the image is disposed.
//
// len(pixels) must be 4 * (bounds width) * (bounds height).
// If len(pixels) is not correct, ReadPixels panics.
//
// ReadPixels also works on a sub-image.
//
// Note that an important logic should not rely on values returned by ReadPixels, since
// the returned values can include very slight differences between some machines.
//
// ReadPixels can't be called outside the main loop (ebiten.Run's updating function) starts.
func (i *Image) ReadPixels(pixels []byte) {
b := i.Bounds()
if got, want := len(pixels), 4*b.Dx()*b.Dy(); got != want {
panic(fmt.Sprintf("ebiten: len(pixels) must be %d but %d at ReadPixels", want, got))
}
if i.isDisposed() {
for i := range pixels {
pixels[i] = 0
}
return
}
x, y := i.adjustPosition(b.Min.X, b.Min.Y)
i.image.ReadPixels(pixels, x, y, b.Dx(), b.Dy())
}
// At returns the color of the image at (x, y).
//
// At implements the standard image.Image's At.
//
// 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 an important logic should not rely on values returned by At, since
// the returned values can include very slight differences between some machines.
//
// At can't be called outside the main loop (ebiten.Run's updating function) starts.
func (i *Image) At(x, y int) color.Color {
r, g, b, a := i.at(x, y)
return color.RGBA{r, g, b, a}
}
// RGBA64At implements the standard image.RGBA64Image's RGBA64At.
//
// RGBA64At loads pixels from GPU to system memory if necessary, which means
// that RGBA64At can be slow.
//
// RGBA64At always returns a transparent color if the image is disposed.
//
// Note that an important logic should not rely on values returned by RGBA64At,
// since the returned values can include very slight differences between some machines.
//
// RGBA64At can't be called outside the main loop (ebiten.Run's updating function) starts.
func (i *Image) RGBA64At(x, y int) color.RGBA64 {
r, g, b, a := i.at(x, y)
return color.RGBA64{uint16(r) * 0x101, uint16(g) * 0x101, uint16(b) * 0x101, uint16(a) * 0x101}
}
func (i *Image) at(x, y int) (r, g, b, a byte) {
if i.isDisposed() {
return 0, 0, 0, 0
}
if !image.Pt(x, y).In(i.Bounds()) {
return 0, 0, 0, 0
}
x, y = i.adjustPosition(x, y)
var pix [4]byte
i.image.ReadPixels(pix[:], x, y, 1, 1)
return pix[0], pix[1], pix[2], pix[3]
}
// Set sets the color at (x, y).
//
// Set implements the standard draw.Image's Set.
//
// Set loads pixels from GPU to system memory if necessary, which means that Set can be slow.
//
// In the current implementation, successive calls of Set invokes loading pixels at most once, so this is efficient.
//
// If the image is disposed, Set does nothing.
func (i *Image) Set(x, y int, clr color.Color) {
i.copyCheck()
if i.isDisposed() {
return
}
if !image.Pt(x, y).In(i.Bounds()) {
return
}
if i.isSubImage() {
i = i.original
}
dx, dy := i.adjustPosition(x, y)
cr, cg, cb, ca := clr.RGBA()
i.image.WritePixels([]byte{byte(cr / 0x101), byte(cg / 0x101), byte(cb / 0x101), byte(ca / 0x101)}, dx, dy, 1, 1)
}
// Dispose disposes the image data.
// After disposing, most of image functions do nothing and returns meaningless values.
//
// Calling Dispose is not mandatory. GC automatically collects internal resources that no objects refer to.
// However, calling Dispose explicitly is helpful if memory usage matters.
//
// If the image is a sub-image, Dispose does nothing.
//
// When the image is disposed, Dipose does nothing.
func (i *Image) Dispose() {
i.copyCheck()
if i.isDisposed() {
return
}
if i.isSubImage() {
return
}
i.image.MarkDisposed()
i.image = nil
}
// WritePixels replaces the pixels of the image.
//
// The given pixels are treated as RGBA pre-multiplied alpha values.
//
// len(pix) must be 4 * (bounds width) * (bounds height).
// If len(pix) is not correct, WritePixels panics.
//
// WritePixels also works on a sub-image.
//
// When the image is disposed, WritePixels does nothing.
func (i *Image) WritePixels(pixels []byte) {
i.copyCheck()
if i.isDisposed() {
return
}
r := i.Bounds()
x, y := i.adjustPosition(r.Min.X, r.Min.Y)
// Do not need to copy pixels here.
// * In internal/mipmap, pixels are copied when necessary.
// * In internal/atlas, pixels are copied to make its paddings.
i.image.WritePixels(pixels, x, y, r.Dx(), r.Dy())
}
// ReplacePixels replaces the pixels of the image.
//
// Deprecated: as of v2.4. Use WritePixels instead.
func (i *Image) ReplacePixels(pixels []byte) {
i.WritePixels(pixels)
}
// NewImage returns an empty image.
//
// If width or height is less than 1 or more than device-dependent maximum size, NewImage panics.
//
// NewImage should be called only when necessary.
// For example, you should avoid to call NewImage every Update or Draw call.
// Reusing the same image by Clear is much more efficient than creating a new image.
//
// NewImage panics if RunGame already finishes.
func NewImage(width, height int) *Image {
return newImage(image.Rect(0, 0, width, height), atlas.ImageTypeRegular)
}
// NewImageOptions represents options for NewImage.
type NewImageOptions struct {
// Unmanaged represents whether the image is unmanaged or not.
// The default (zero) value is false, that means the image is managed.
//
// An unmanaged image is never on an internal automatic texture atlas.
// A regular image is a part of an internal texture atlas, and locating them is done automatically in Ebitengine.
// Unmanaged is useful when you want finer controls over the image for performance and memory reasons.
Unmanaged bool
}
// NewImageWithOptions returns an empty image with the given bounds and the options.
//
// If width or height is less than 1 or more than device-dependent maximum size, NewImageWithOptions panics.
//
// The rendering origin position is (0, 0) of the given bounds.
// If DrawImage is called on a new image created by NewImageOptions,
// for example, the center of scaling and rotating is (0, 0), that might not be a upper-left position.
//
// If options is nil, the default setting is used.
//
// NewImageWithOptions should be called only when necessary.
// For example, you should avoid to call NewImageWithOptions every Update or Draw call.
// Reusing the same image by Clear is much more efficient than creating a new image.
//
// NewImageWithOptions panics if RunGame already finishes.
func NewImageWithOptions(bounds image.Rectangle, options *NewImageOptions) *Image {
imageType := atlas.ImageTypeRegular
if options != nil && options.Unmanaged {
imageType = atlas.ImageTypeUnmanaged
}
return newImage(bounds, imageType)
}
func newImage(bounds image.Rectangle, imageType atlas.ImageType) *Image {
if isRunGameEnded() {
panic(fmt.Sprintf("ebiten: NewImage cannot be called after RunGame finishes"))
}
width, height := bounds.Dx(), bounds.Dy()
if width <= 0 {
panic(fmt.Sprintf("ebiten: width at NewImage must be positive but %d", width))
}
if height <= 0 {
panic(fmt.Sprintf("ebiten: height at NewImage must be positive but %d", height))
}
i := &Image{
image: ui.NewImage(width, height, imageType),
bounds: bounds,
}
i.addr = i
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.
//
// NewImageFromImage should be called only when necessary.
// For example, you should avoid to call NewImageFromImage every Update or Draw call.
// Reusing the same image by Clear and WritePixels is much more efficient than creating a new image.
//
// NewImageFromImage panics if RunGame already finishes.
//
// The returned image's upper-left position is always (0, 0). The source's bounds are not respected.
func NewImageFromImage(source image.Image) *Image {
return NewImageFromImageWithOptions(source, nil)
}
// NewImageFromImageOptions represents options for NewImageFromImage.
type NewImageFromImageOptions struct {
// Unmanaged represents whether the image is unmanaged or not.
// The default (zero) value is false, that means the image is managed.
//
// An unmanaged image is never on an internal automatic texture atlas.
// A regular image is a part of an internal texture atlas, and locating them is done automatically in Ebitengine.
// Unmanaged is useful when you want finer controls over the image for performance and memory reasons.
Unmanaged bool
// PreserveBounds represents whether the new image's bounds are the same as the given image.
// The default (zero) value is false, that means the new image's upper-left position is adjusted to (0, 0).
PreserveBounds bool
}
// NewImageFromImageWithOptions creates a new image with the given image (source) with the given options.
//
// If source's width or height is less than 1 or more than device-dependent maximum size, NewImageFromImageWithOptions panics.
//
// If options is nil, the default setting is used.
//
// NewImageFromImageWithOptions should be called only when necessary.
// For example, you should avoid to call NewImageFromImageWithOptions every Update or Draw call.
// Reusing the same image by Clear and WritePixels is much more efficient than creating a new image.
//
// NewImageFromImageWithOptions panics if RunGame already finishes.
func NewImageFromImageWithOptions(source image.Image, options *NewImageFromImageOptions) *Image {
if options == nil {
options = &NewImageFromImageOptions{}
}
var r image.Rectangle
if options.PreserveBounds {
r = source.Bounds()
} else {
size := source.Bounds().Size()
r = image.Rect(0, 0, size.X, size.Y)
}
i := NewImageWithOptions(r, &NewImageOptions{
Unmanaged: options.Unmanaged,
})
// If the given image is an Ebitengine image, use DrawImage instead of reading pixels from the source.
// This works even before the game loop runs.
if source, ok := source.(*Image); ok {
op := &DrawImageOptions{}
if options.PreserveBounds {
b := source.Bounds()
op.GeoM.Translate(float64(b.Min.X), float64(b.Min.Y))
}
i.DrawImage(source, op)
return i
}
i.WritePixels(imageToBytes(source))
return i
}
// colorMToScale returns a new color matrix and color sclaes that equal to the given matrix in terms of the effect.
//
// If the given matrix is merely a scaling matrix, colorMToScale returns
// an identity matrix and its scaling factors in premultiplied-alpha format.
// This is useful to optimize the rendering speed by avoiding the use of the
// color matrix and instead multiplying all vertex colors by the scale.
func colorMToScale(colorm affine.ColorM) (newColorM affine.ColorM, r, g, b, a float32) {
if colorm.IsIdentity() {
return colorm, 1, 1, 1, 1
}
if !colorm.ScaleOnly() {
return colorm, 1, 1, 1, 1
}
r = colorm.At(0, 0)
g = colorm.At(1, 1)
b = colorm.At(2, 2)
a = colorm.At(3, 3)
// Color matrices work on non-premultiplied colors.
// This color matrix can only make colors darker or equal,
// and thus can never invoke color clamping.
// Thus the simpler vertex color scale based shader can be used.
//
// Negative color values can become positive and out-of-range
// after applying to vertex colors below, which can make the min() in the shader kick in.
//
// Alpha values smaller than 0, combined with negative vertex colors,
// can also make the min() kick in, so that shall be ruled out too.
if r < 0 || g < 0 || b < 0 || a < 0 || r > 1 || g > 1 || b > 1 {
return colorm, 1, 1, 1, 1
}
return affine.ColorMIdentity{}, r * a, g * a, b * a, a
}
// private implements FinalScreen.
func (*Image) private() {
}