app/internal/window: add needVSync() to eglDriver interface

This enables calling eglSwapInterval with an interval value of 0 or 1
on a per driver basis.

Signed-off-by: Denis Bernard <db047h@gmail.com>

app/internal/window/egl.go

@@ -28,6 +28,7 @@ type eglDriver interface {
 	eglDisplay() _EGLNativeDisplayType
 	eglWindow(visID int) (_EGLNativeWindowType, int, int, error)
 	eglDestroy()
+	needVSync() bool
 }
 
 type eglContext struct {
@@ -156,6 +157,14 @@ func (c *context) MakeCurrent() error {
 		c.eglWin = nilEGLNativeWindowType
 		return err
 	}
+	// eglSwapInterval 1 leads to erratic frame rates and unnecessary blocking.
+	// We rely on platform specific frame rate limiting instead, except on Windows
+	// and X11 where eglSwapInterval is all there is.
+	if c.driver.needVSync() {
+		eglSwapInterval(c.eglCtx.disp, 1)
+	} else {
+		eglSwapInterval(c.eglCtx.disp, 0)
+	}
 	if c.eglCtx.srgb {
 		return nil
 	}
@@ -269,13 +278,5 @@ func createSurfaceAndMakeCurrent(eglCtx *eglContext, win _EGLNativeWindowType) (
 		eglDestroySurface(eglCtx.disp, eglSurf)
 		return nilEGLSurface, fmt.Errorf("eglMakeCurrent error 0x%x", eglGetError())
 	}
-	// eglSwapInterval 1 leads to erratic frame rates and unnecessary blocking.
-	// We rely on platform specific frame rate limiting instead, except on Windows
-	// where eglSwapInterval is all there is.
-	if runtime.GOOS != "windows" {
-		eglSwapInterval(eglCtx.disp, 0)
-	} else {
-		eglSwapInterval(eglCtx.disp, 1)
-	}
 	return eglSurf, nil
 }

app/internal/window/egl_android.go

@@ -18,3 +18,5 @@ func (w *window) eglWindow(visID int) (_EGLNativeWindowType, int, int, error) {
 	win, width, height := w.nativeWindow(visID)
 	return _EGLNativeWindowType(win), width, height, nil
 }
+
+func (w *window) needVSync() bool { return false }

app/internal/window/egl_wayland.go

@@ -62,3 +62,5 @@ func (w *window) eglWindow(visID int) (_EGLNativeWindowType, int, int, error) {
 	C.wl_egl_window_resize(eglWin, C.int(width), C.int(height), 0, 0)
 	return _EGLNativeWindowType(uintptr(unsafe.Pointer(eglWin))), width, height, nil
 }
+
+func (w *window) needVSync() bool { return false }

app/internal/window/egl_windows.go

@@ -158,3 +158,5 @@ func (w *window) eglWindow(visID int) (_EGLNativeWindowType, int, int, error) {
 func (w *window) NewContext() (gl.Context, error) {
 	return newContext(w)
 }
+
+func (w *window) needVSync() bool { return true }