internal/cocoa: bring back NSInvocation for CopyFromTexture (#3136)

This is a partial revert of c3ea539 but keeps the change for removal of NSInvocation in SetScissorRect, GetBytes,
and ReplaceRegion.

Closes #3135

internal/cocoa/api_cocoa_darwin.go

@@ -21,10 +21,14 @@ import (
 )
 
 var (
+	class_NSInvocation      = objc.GetClass("NSInvocation")
+	class_NSMethodSignature = objc.GetClass("NSMethodSignature")
 	class_NSAutoreleasePool = objc.GetClass("NSAutoreleasePool")
 	class_NSString          = objc.GetClass("NSString")
 	class_NSProcessInfo     = objc.GetClass("NSProcessInfo")
 	class_NSColor           = objc.GetClass("NSColor")
+	class_NSWindow          = objc.GetClass("NSWindow")
+	class_NSView            = objc.GetClass("NSView")
 	class_NSScreen          = objc.GetClass("NSScreen")
 )
 
@@ -32,6 +36,15 @@ var (
 	sel_alloc                              = objc.RegisterName("alloc")
 	sel_new                                = objc.RegisterName("new")
 	sel_release                            = objc.RegisterName("release")
+	sel_invocationWithMethodSignature      = objc.RegisterName("invocationWithMethodSignature:")
+	sel_setSelector                        = objc.RegisterName("setSelector:")
+	sel_setTarget                          = objc.RegisterName("setTarget:")
+	sel_setArgumentAtIndex                 = objc.RegisterName("setArgument:atIndex:")
+	sel_getReturnValue                     = objc.RegisterName("getReturnValue:")
+	sel_invoke                             = objc.RegisterName("invoke")
+	sel_invokeWithTarget                   = objc.RegisterName("invokeWithTarget:")
+	sel_instanceMethodSignatureForSelector = objc.RegisterName("instanceMethodSignatureForSelector:")
+	sel_signatureWithObjCTypes             = objc.RegisterName("signatureWithObjCTypes:")
 	sel_initWithUTF8String                 = objc.RegisterName("initWithUTF8String:")
 	sel_UTF8String                         = objc.RegisterName("UTF8String")
 	sel_length                             = objc.RegisterName("length")
@@ -163,6 +176,52 @@ func (v NSView) SetWantsLayer(wantsLayer bool) {
 	v.Send(sel_setWantsLayer, wantsLayer)
 }
 
+// NSInvocation is being used to call functions that can't be called directly with purego.SyscallN.
+// See the downsides of that function for what it cannot do.
+type NSInvocation struct {
+	objc.ID
+}
+
+func NSInvocation_invocationWithMethodSignature(sig NSMethodSignature) NSInvocation {
+	return NSInvocation{objc.ID(class_NSInvocation).Send(sel_invocationWithMethodSignature, sig.ID)}
+}
+
+func (i NSInvocation) SetSelector(cmd objc.SEL) {
+	i.Send(sel_setSelector, cmd)
+}
+
+func (i NSInvocation) SetTarget(target objc.ID) {
+	i.Send(sel_setTarget, target)
+}
+
+func (i NSInvocation) SetArgumentAtIndex(arg unsafe.Pointer, idx int) {
+	i.Send(sel_setArgumentAtIndex, arg, idx)
+}
+
+func (i NSInvocation) GetReturnValue(ret unsafe.Pointer) {
+	i.Send(sel_getReturnValue, ret)
+}
+
+func (i NSInvocation) Invoke() {
+	i.Send(sel_invoke)
+}
+
+func (i NSInvocation) InvokeWithTarget(target objc.ID) {
+	i.Send(sel_invokeWithTarget, target)
+}
+
+type NSMethodSignature struct {
+	objc.ID
+}
+
+// NSMethodSignature_signatureWithObjCTypes takes a string that represents the type signature of a method.
+// It follows the encoding specified in the Apple Docs.
+//
+// [Apple Docs]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html#//apple_ref/doc/uid/TP40008048-CH100
+func NSMethodSignature_signatureWithObjCTypes(types string) NSMethodSignature {
+	return NSMethodSignature{objc.ID(class_NSMethodSignature).Send(sel_signatureWithObjCTypes, types)}
+}
+
 type NSAutoreleasePool struct {
 	objc.ID
 }

internal/graphicsdriver/metal/mtl/mtl_darwin.go

@@ -1003,10 +1003,20 @@ func (bce BlitCommandEncoder) SynchronizeTexture(texture Texture, slice int, lev
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlblitcommandencoder/1400754-copyfromtexture?language=objc.
 func (bce BlitCommandEncoder) CopyFromTexture(sourceTexture Texture, sourceSlice int, sourceLevel int, sourceOrigin Origin, sourceSize Size, destinationTexture Texture, destinationSlice int, destinationLevel int, destinationOrigin Origin) {
-	sel := sel_copyFromTexture_sourceSlice_sourceLevel_sourceOrigin_sourceSize_toTexture_destinationSlice_destinationLevel_destinationOrigin
+	// copyFromTexture requires so many arguments that Send doesn't work (#3135).
-	bce.commandEncoder.Send(sel,
+	inv := cocoa.NSInvocation_invocationWithMethodSignature(cocoa.NSMethodSignature_signatureWithObjCTypes("v@:@QQ{MTLOrigin=qqq}{MTLSize=qqq}@QQ{MTLOrigin=qqq}"))
-		sourceTexture.texture, sourceSlice, sourceLevel, sourceOrigin, sourceSize,
+	inv.SetTarget(bce.commandEncoder)
-		destinationTexture.texture, destinationSlice, destinationLevel, destinationOrigin)
+	inv.SetSelector(sel_copyFromTexture_sourceSlice_sourceLevel_sourceOrigin_sourceSize_toTexture_destinationSlice_destinationLevel_destinationOrigin)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&sourceTexture), 2)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&sourceSlice), 3)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&sourceLevel), 4)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&sourceOrigin), 5)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&sourceSize), 6)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&destinationTexture), 7)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&destinationSlice), 8)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&destinationLevel), 9)
+	inv.SetArgumentAtIndex(unsafe.Pointer(&destinationOrigin), 10)
+	inv.Invoke()
 }
 
 // Library is a collection of compiled graphics or compute functions.