ebiten: add ColorSpace and RunGameOptions.ColorSpace

This works only for macOS Metal and WebGL so far.

Closes #2871

examples/windowsize/main.go

@@ -50,6 +50,7 @@ var (
 	flagMaxWindowSize       = flag.String("maxwindowsize", "", "maximum window size (e.g., 1920x1080)")
 	flagGraphicsLibrary     = flag.String("graphicslibrary", "", "graphics library (e.g. opengl)")
 	flagRunnableOnUnfocused = flag.Bool("runnableonunfocused", true, "whether the app is runnable even on unfocused")
+	flagColorSpace          = flag.String("colorspace", "", "color space ('', 'srgb', or 'display-p3')")
 )
 
 func init() {
@@ -473,6 +474,14 @@ func main() {
 	default:
 		log.Fatalf("unexpected graphics library: %s", *flagGraphicsLibrary)
 	}
+	switch *flagColorSpace {
+	case "":
+		op.ColorSpace = ebiten.ColorSpaceDefault
+	case "srgb":
+		op.ColorSpace = ebiten.ColorSpaceSRGB
+	case "display-p3":
+		op.ColorSpace = ebiten.ColorSpaceDisplayP3
+	}
 	op.InitUnfocused = !*flagInitFocused
 	op.ScreenTransparent = *flagTransparent
 	op.X11ClassName = "Window-Size"

graphics.go

@@ -72,3 +72,17 @@ type DebugInfo struct {
 func ReadDebugInfo(d *DebugInfo) {
 	d.GraphicsLibrary = GraphicsLibrary(ui.Get().GraphicsLibrary())
 }
+
+// ColorSpace represents the color space of the screen.
+type ColorSpace int
+
+const (
+	// ColorSpaceDefault represents the default color space.
+	ColorSpaceDefault ColorSpace = iota
+
+	// ColorSpaceSRGB represents the sRGB color space (https://en.wikipedia.org/wiki/SRGB).
+	ColorSpaceSRGB
+
+	// ColorSpaceDisplayP3 represents the Display P3 color space (https://en.wikipedia.org/wiki/DCI-P3).
+	ColorSpaceDisplayP3
+)

internal/graphicsdriver/graphics.go

@@ -95,3 +95,11 @@ type Shader interface {
 }
 
 type ShaderID int
+
+type ColorSpace int
+
+const (
+	ColorSpaceDefault ColorSpace = iota
+	ColorSpaceSRGB
+	ColorSpaceDisplayP3
+)

internal/graphicsdriver/metal/ca/ca_darwin.go

@@ -29,6 +29,7 @@ import (
 	"github.com/ebitengine/purego/objc"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/cocoa"
+	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/mtl"
 )
 
@@ -51,7 +52,7 @@ type MetalLayer struct {
 // NewMetalLayer creates a new Core Animation Metal layer.
 //
 // Reference: https://developer.apple.com/documentation/quartzcore/cametallayer?language=objc.
-func NewMetalLayer() (MetalLayer, error) {
+func NewMetalLayer(colorSpace graphicsdriver.ColorSpace) (MetalLayer, error) {
 	coreGraphics, err := purego.Dlopen("/System/Library/Frameworks/CoreGraphics.framework/CoreGraphics", purego.RTLD_LAZY|purego.RTLD_GLOBAL)
 	if err != nil {
 		return MetalLayer{}, err
@@ -67,14 +68,31 @@ func NewMetalLayer() (MetalLayer, error) {
 		return MetalLayer{}, err
 	}
 
+	var colorSpaceSym uintptr
+	switch colorSpace {
+	case graphicsdriver.ColorSpaceSRGB:
+		kCGColorSpaceSRGB, err := purego.Dlsym(coreGraphics, "kCGColorSpaceSRGB")
+		if err != nil {
+			return MetalLayer{}, err
+		}
+		colorSpaceSym = kCGColorSpaceSRGB
+	default:
+		fallthrough
+	case graphicsdriver.ColorSpaceDisplayP3:
 		kCGColorSpaceDisplayP3, err := purego.Dlsym(coreGraphics, "kCGColorSpaceDisplayP3")
 		if err != nil {
 			return MetalLayer{}, err
 		}
+		colorSpaceSym = kCGColorSpaceDisplayP3
+	}
 
 	layer := objc.ID(objc.GetClass("CAMetalLayer")).Send(objc.RegisterName("new"))
+	// setColorspace: is available from iOS 13.0?
+	// https://github.com/hajimehoshi/ebiten/commit/3af351a2aa31e30affd433429c42130015b302f3
+	// TODO: Enable this on iOS as well.
 	if runtime.GOOS != "ios" {
-		colorspace, _, _ := purego.SyscallN(cgColorSpaceCreateWithName, **(**uintptr)(unsafe.Pointer(&kCGColorSpaceDisplayP3))) // Dlsym returns pointer to symbol so dereference it
+		// Dlsym returns pointer to symbol so dereference it.
+		colorspace, _, _ := purego.SyscallN(cgColorSpaceCreateWithName, **(**uintptr)(unsafe.Pointer(&colorSpaceSym)))
 		layer.Send(objc.RegisterName("setColorspace:"), colorspace)
 		purego.SyscallN(cgColorSpaceRelease, colorspace)
 	}

internal/graphicsdriver/metal/graphics_darwin.go

@@ -35,6 +35,8 @@ import (
 type Graphics struct {
 	view view
 
+	colorSpace graphicsdriver.ColorSpace
+
 	cq   mtl.CommandQueue
 	cb   mtl.CommandBuffer
 	rce  mtl.RenderCommandEncoder
@@ -90,7 +92,7 @@ func init() {
 
 // NewGraphics creates an implementation of graphicsdriver.Graphics for Metal.
 // The returned graphics value is nil iff the error is not nil.
-func NewGraphics() (graphicsdriver.Graphics, error) {
+func NewGraphics(colorSpace graphicsdriver.ColorSpace) (graphicsdriver.Graphics, error) {
 	// On old mac devices like iMac 2011, Metal is not supported (#779).
 	// TODO: Is there a better way to check whether Metal is available or not?
 	// It seems OK to call MTLCreateSystemDefaultDevice multiple times, so this should be fine.
@@ -98,12 +100,14 @@ func NewGraphics() (graphicsdriver.Graphics, error) {
 		return nil, fmt.Errorf("metal: mtl.CreateSystemDefaultDevice failed: %w", systemDefaultDeviceErr)
 	}
 
-	g := &Graphics{}
+	g := &Graphics{
+		colorSpace: colorSpace,
+	}
 
 	if runtime.GOOS != "ios" {
 		// Initializing a Metal device and a layer must be done in the main thread on macOS.
 		// Note that this assumes NewGraphics is called on the main thread on desktops.
-		if err := g.view.initialize(systemDefaultDevice); err != nil {
+		if err := g.view.initialize(systemDefaultDevice, colorSpace); err != nil {
 			return nil, err
 		}
 	}
@@ -388,7 +392,7 @@ func (g *Graphics) Initialize() error {
 
 	if runtime.GOOS == "ios" {
 		// Initializing a Metal device and a layer must be done in the render thread on iOS.
-		if err := g.view.initialize(systemDefaultDevice); err != nil {
+		if err := g.view.initialize(systemDefaultDevice, g.colorSpace); err != nil {
 			return err
 		}
 	}

internal/graphicsdriver/metal/view_darwin.go

@@ -17,6 +17,7 @@ package metal
 import (
 	"sync"
 
+	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/ca"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/mtl"
 )
@@ -58,10 +59,10 @@ func (v *view) colorPixelFormat() mtl.PixelFormat {
 	return v.ml.PixelFormat()
 }
 
-func (v *view) initialize(device mtl.Device) error {
+func (v *view) initialize(device mtl.Device, colorSpace graphicsdriver.ColorSpace) error {
 	v.device = device
 
-	ml, err := ca.NewMetalLayer()
+	ml, err := ca.NewMetalLayer(colorSpace)
 	if err != nil {
 		return err
 	}

internal/graphicsdriver/opengl/graphics_js.go

@@ -27,7 +27,7 @@ type graphicsPlatform struct {
 
 // NewGraphics creates an implementation of graphicsdriver.Graphics for OpenGL.
 // The returned graphics value is nil iff the error is not nil.
-func NewGraphics(canvas js.Value) (graphicsdriver.Graphics, error) {
+func NewGraphics(canvas js.Value, colorSpace graphicsdriver.ColorSpace) (graphicsdriver.Graphics, error) {
 	var glContext js.Value
 
 	attr := js.Global().Get("Object").New()
@@ -41,6 +41,13 @@ func NewGraphics(canvas js.Value) (graphicsdriver.Graphics, error) {
 		return nil, fmt.Errorf("opengl: getContext for webgl2 failed")
 	}
 
+	switch colorSpace {
+	case graphicsdriver.ColorSpaceSRGB:
+		glContext.Set("drawingBufferColorSpace", "srgb")
+	case graphicsdriver.ColorSpaceDisplayP3:
+		glContext.Set("drawingBufferColorSpace", "display-p3")
+	}
+
 	ctx, err := gl.NewDefaultContext(glContext)
 	if err != nil {
 		return nil, err

internal/ui/ui.go

@@ -23,6 +23,7 @@ import (
 	_ "github.com/ebitengine/hideconsole"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/atlas"
+	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/mipmap"
 	"github.com/hajimehoshi/ebiten/v2/internal/thread"
 )
@@ -177,6 +178,7 @@ type RunOptions struct {
 	SkipTaskbar       bool
 	SingleThread      bool
 	DisableHiDPI      bool
+	ColorSpace        graphicsdriver.ColorSpace
 	X11ClassName      string
 	X11InstanceName   string
 }

internal/ui/ui_android.go

@@ -95,6 +95,7 @@ import (
 )
 
 type graphicsDriverCreatorImpl struct {
+	colorSpace graphicsdriver.ColorSpace
 }
 
 func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, GraphicsLibrary, error) {

internal/ui/ui_darwin.go

@@ -167,6 +167,7 @@ func (u *UserInterface) initializePlatform() error {
 
 type graphicsDriverCreatorImpl struct {
 	transparent bool
+	colorSpace  graphicsdriver.ColorSpace
 }
 
 func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, GraphicsLibrary, error) {
@@ -189,8 +190,8 @@ func (*graphicsDriverCreatorImpl) newDirectX() (graphicsdriver.Graphics, error)
 	return nil, errors.New("ui: DirectX is not supported in this environment")
 }
 
-func (*graphicsDriverCreatorImpl) newMetal() (graphicsdriver.Graphics, error) {
+func (g *graphicsDriverCreatorImpl) newMetal() (graphicsdriver.Graphics, error) {
-	return metal.NewGraphics()
+	return metal.NewGraphics(g.colorSpace)
 }
 
 func (*graphicsDriverCreatorImpl) newPlayStation5() (graphicsdriver.Graphics, error) {

internal/ui/ui_glfw.go

@@ -1089,6 +1089,7 @@ func (u *UserInterface) initOnMainThread(options *RunOptions) error {
 
 	g, lib, err := newGraphicsDriver(&graphicsDriverCreatorImpl{
 		transparent: options.ScreenTransparent,
+		colorSpace:  options.ColorSpace,
 	}, options.GraphicsLibrary)
 	if err != nil {
 		return err

internal/ui/ui_ios.go

@@ -34,6 +34,7 @@ import (
 )
 
 type graphicsDriverCreatorImpl struct {
+	colorSpace graphicsdriver.ColorSpace
 }
 
 func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, GraphicsLibrary, error) {
@@ -57,7 +58,7 @@ func (*graphicsDriverCreatorImpl) newDirectX() (graphicsdriver.Graphics, error)
 }
 
 func (g *graphicsDriverCreatorImpl) newMetal() (graphicsdriver.Graphics, error) {
-	return metal.NewGraphics()
+	return metal.NewGraphics(g.colorSpace)
 }
 
 func (*graphicsDriverCreatorImpl) newPlayStation5() (graphicsdriver.Graphics, error) {

internal/ui/ui_js.go

@@ -30,6 +30,7 @@ import (
 
 type graphicsDriverCreatorImpl struct {
 	canvas     js.Value
+	colorSpace graphicsdriver.ColorSpace
 }
 
 func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, GraphicsLibrary, error) {
@@ -38,7 +39,7 @@ func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, Graphics
 }
 
 func (g *graphicsDriverCreatorImpl) newOpenGL() (graphicsdriver.Graphics, error) {
-	return opengl.NewGraphics(g.canvas)
+	return opengl.NewGraphics(g.canvas, g.colorSpace)
 }
 
 func (*graphicsDriverCreatorImpl) newDirectX() (graphicsdriver.Graphics, error) {
@@ -772,6 +773,7 @@ func (u *UserInterface) initOnMainThread(options *RunOptions) error {
 
 	g, lib, err := newGraphicsDriver(&graphicsDriverCreatorImpl{
 		canvas:     canvas,
+		colorSpace: options.ColorSpace,
 	}, options.GraphicsLibrary)
 	if err != nil {
 		return err

internal/ui/ui_linbsd.go

@@ -36,6 +36,7 @@ func (u *UserInterface) initializePlatform() error {
 
 type graphicsDriverCreatorImpl struct {
 	transparent bool
+	colorSpace  graphicsdriver.ColorSpace
 }
 
 func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, GraphicsLibrary, error) {

internal/ui/ui_mobile.go

@@ -143,7 +143,9 @@ func (u *UserInterface) runMobile(game Game, options *RunOptions) (err error) {
 
 	u.context = newContext(game)
 
-	g, lib, err := newGraphicsDriver(&graphicsDriverCreatorImpl{}, options.GraphicsLibrary)
+	g, lib, err := newGraphicsDriver(&graphicsDriverCreatorImpl{
+		colorSpace: options.ColorSpace,
+	}, options.GraphicsLibrary)
 	if err != nil {
 		return err
 	}

internal/ui/ui_windows.go

@@ -36,6 +36,7 @@ func (u *UserInterface) initializePlatform() error {
 
 type graphicsDriverCreatorImpl struct {
 	transparent bool
+	colorSpace  graphicsdriver.ColorSpace
 }
 
 func (g *graphicsDriverCreatorImpl) newAuto() (graphicsdriver.Graphics, GraphicsLibrary, error) {

run.go

@@ -22,6 +22,7 @@ import (
 	"sync/atomic"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/clock"
+	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/ui"
 )
 
@@ -283,6 +284,14 @@ type RunGameOptions struct {
 	// The default (zero) value is false, which means that HiDPI is enabled.
 	DisableHiDPI bool
 
+	// ColorSpace indicates the color space of the screen.
+	//
+	// ColorSpace is available only with some graphics libraries (macOS Metal and WebGL so far).
+	// Otherwise, ColorSpace is ignored.
+	//
+	// The default (zero) value is ColorSpaceDefault, which means that color space depends on the environment.
+	ColorSpace ColorSpace
+
 	// X11DisplayName is a class name in the ICCCM WM_CLASS window property.
 	X11ClassName string
 
@@ -713,6 +722,7 @@ func toUIRunOptions(options *RunGameOptions) *ui.RunOptions {
 		SkipTaskbar:       options.SkipTaskbar,
 		SingleThread:      options.SingleThread,
 		DisableHiDPI:      options.DisableHiDPI,
+		ColorSpace:        graphicsdriver.ColorSpace(options.ColorSpace),
 		X11ClassName:      options.X11ClassName,
 		X11InstanceName:   options.X11InstanceName,
 	}