app/internal/window: move context refresh to window

Instead of calling from the low level context into the window
for its surface and dimensions, add a Context.MakeCurrent method
that does it directly.

The result is simpler and clearer logic. For example, synchronization
is obviously no longer needed. It wasn't necessary before, but the
reason was unclear.

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

app/internal/window/egl_wayland.go

@@ -6,7 +6,6 @@ package window
 
 import (
 	"errors"
-	"sync"
 	"unsafe"
 
 	"gioui.org/app/internal/egl"
@@ -22,52 +21,50 @@ import (
 */
 import "C"
 
-var eglWindows struct {
-	mu      sync.Mutex
-	windows map[*C.struct_wl_surface]*C.struct_wl_egl_window
-}
-
-func (w *window) EGLDestroy() {
-	surf, _, _ := w.surface()
-	if surf == nil {
-		return
-	}
-	eglWindows.mu.Lock()
-	defer eglWindows.mu.Unlock()
-	if eglWin, ok := eglWindows.windows[surf]; ok {
-		C.wl_egl_window_destroy(eglWin)
-		delete(eglWindows.windows, surf)
-	}
-}
-
-func (w *window) EGLDisplay() egl.NativeDisplayType {
-	return egl.NativeDisplayType(unsafe.Pointer(w.display()))
-}
-
-func (w *window) EGLWindow(visID int) (egl.NativeWindowType, int, int, error) {
-	surf, width, height := w.surface()
-	if surf == nil {
-		return 0, 0, 0, errors.New("wayland: no surface")
-	}
-	eglWindows.mu.Lock()
-	defer eglWindows.mu.Unlock()
-	eglWin, ok := eglWindows.windows[surf]
-	if !ok {
-		if eglWindows.windows == nil {
-			eglWindows.windows = make(map[*C.struct_wl_surface]*C.struct_wl_egl_window)
-		}
-		eglWin = C.wl_egl_window_create(surf, C.int(width), C.int(height))
-		if eglWin == nil {
-			return 0, 0, 0, errors.New("wayland: wl_egl_window_create failed")
-		}
-		eglWindows.windows[surf] = eglWin
-	}
-	C.wl_egl_window_resize(eglWin, C.int(width), C.int(height), 0, 0)
-	return egl.NativeWindowType(uintptr(unsafe.Pointer(eglWin))), width, height, nil
+type context struct {
+	win *window
+	*egl.Context
+	eglWin *C.struct_wl_egl_window
 }
 
 func (w *window) NewContext() (gl.Context, error) {
-	return egl.NewContext(w)
+	disp := egl.NativeDisplayType(unsafe.Pointer(w.display()))
+	ctx, err := egl.NewContext(disp)
+	if err != nil {
+		return nil, err
+	}
+	return &context{Context: ctx, win: w}, nil
 }
 
-func (w *window) NeedVSync() bool { return false }
+func (c *context) Release() {
+	if c.Context != nil {
+		c.Context.Release()
+		c.Context = nil
+	}
+	if c.eglWin != nil {
+		C.wl_egl_window_destroy(c.eglWin)
+		c.eglWin = nil
+	}
+}
+
+func (c *context) MakeCurrent() error {
+	c.Context.ReleaseSurface()
+	if c.eglWin != nil {
+		C.wl_egl_window_destroy(c.eglWin)
+		c.eglWin = nil
+	}
+	surf, width, height := c.win.surface()
+	if surf == nil {
+		return errors.New("wayland: no surface")
+	}
+	eglWin := C.wl_egl_window_create(surf, C.int(width), C.int(height))
+	if eglWin == nil {
+		return errors.New("wayland: wl_egl_window_create failed")
+	}
+	c.eglWin = eglWin
+	eglSurf := egl.NativeWindowType(uintptr(unsafe.Pointer(eglWin)))
+	if err := c.Context.CreateSurface(eglSurf, width, height); err != nil {
+		return err
+	}
+	return c.Context.MakeCurrent()
+}