graphicsdriver/metal: Bug fix: Sync textures before replacing a region

Updates #1213

internal/graphicsdriver/metal/graphics.go

@@ -440,7 +440,7 @@ func (g *Graphics) NewImage(width, height int) (driver.Image, error) {
 		Width:       graphics.InternalImageSize(width),
 		Height:      graphics.InternalImageSize(height),
 		StorageMode: storageMode,
-		Usage:       textureUsage,
+		Usage:       mtl.TextureUsageShaderRead | mtl.TextureUsageRenderTarget,
 	}
 	var t mtl.Texture
 	g.t.Call(func() error {
@@ -873,6 +873,10 @@ func (i *Image) ReplacePixels(args []*driver.ReplacePixelsArgs) {
 	if g.drawCalled {
 		g.flush(true, false)
 		g.drawCalled = false
+
+		// When mtl.TextureUsageRenderTarget is specified, synchronizing the texture memory before replacing
+		// a region seems necessary (#1213).
+		i.syncTexture()
 	}
 
 	g.t.Call(func() error {

internal/graphicsdriver/metal/view_ios.go

@@ -58,8 +58,6 @@ func (v *view) update() {
 }
 
 const (
-	textureUsage = mtl.TextureUsageShaderRead | mtl.TextureUsageRenderTarget
-
 	storageMode         = mtl.StorageModeShared
 	resourceStorageMode = mtl.ResourceStorageModeShared
 )

internal/graphicsdriver/metal/view_macos.go

@@ -46,9 +46,6 @@ func (v *view) update() {
 }
 
 const (
-	// MTLTextureUsageRenderTarget might cause a problematic render result. Not sure the reason.
-	textureUsage = mtl.TextureUsageShaderRead
-
 	storageMode         = mtl.StorageModeManaged
 	resourceStorageMode = mtl.ResourceStorageModeManaged
 )