app,app/internal/wm: release OpenGL context after use

Otherwise, making a context current on another thread may result in
an EGL_BAD_ACCESS error.

Fixes gio#248

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/internal/wm/d3d11_windows.go

@@ -117,6 +117,8 @@ func (c *d3d11Context) MakeCurrent() error {
 	return nil
 }
 
+func (c *d3d11Context) ReleaseCurrent() {}
+
 func (c *d3d11Context) Lock() {}
 
 func (c *d3d11Context) Unlock() {}

app/internal/wm/gl_ios.go

@@ -139,6 +139,10 @@ func (c *context) MakeCurrent() error {
 	return nil
 }
 
+func (c *context) ReleaseCurrent() {
+	C.gio_makeCurrent(0)
+}
+
 func (w *window) NewContext() (Context, error) {
 	return newContext(w)
 }

app/internal/wm/gl_js.go

@@ -62,6 +62,8 @@ func (c *context) MakeCurrent() error {
 	return nil
 }
 
+func (c *context) ReleaseCurrent() {}
+
 func (w *window) NewContext() (Context, error) {
 	return newContext(w)
 }

app/internal/wm/gl_macos.go

@@ -90,6 +90,10 @@ func (c *context) MakeCurrent() error {
 	return nil
 }
 
+func (c *context) ReleaseCurrent() {
+	C.gio_clearCurrentContext()
+}
+
 func (w *window) NewContext() (Context, error) {
 	return newContext(w)
 }

app/internal/wm/window.go

@@ -70,6 +70,7 @@ type Context interface {
 	API() gpu.API
 	Present() error
 	MakeCurrent() error
+	ReleaseCurrent()
 	Refresh() error
 	Release()
 	Lock()

app/loop.go

@@ -69,6 +69,7 @@ func (l *renderLoop) renderLoop(ctx wm.Context) error {
 			initErr <- err
 			return
 		}
+		defer ctx.ReleaseCurrent()
 		g, err := gpu.New(ctx.API())
 		if err != nil {
 			initErr <- err