app,internal/window: extract native window code to separate package

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

app/gl_js.go

@@ -1,91 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package app
-
-import (
-	"errors"
-	"syscall/js"
-
-	"gioui.org/app/internal/gl"
-)
-
-type context struct {
-	ctx     js.Value
-	cnv     js.Value
-	f       *gl.Functions
-	srgbFBO *gl.SRGBFBO
-}
-
-func newContext(w *window) (*context, error) {
-	args := map[string]interface{}{
-		// Enable low latency rendering.
-		// See https://developers.google.com/web/updates/2019/05/desynchronized.
-		"desynchronized":        true,
-		"preserveDrawingBuffer": true,
-	}
-	version := 2
-	ctx := w.cnv.Call("getContext", "webgl2", args)
-	if ctx == js.Null() {
-		version = 1
-		ctx = w.cnv.Call("getContext", "webgl", args)
-	}
-	if ctx == js.Null() {
-		return nil, errors.New("app: webgl is not supported")
-	}
-	f := &gl.Functions{Ctx: ctx}
-	if err := f.Init(version); err != nil {
-		return nil, err
-	}
-	c := &context{
-		ctx: ctx,
-		cnv: w.cnv,
-		f:   f,
-	}
-	return c, nil
-}
-
-func (c *context) Functions() *gl.Functions {
-	return c.f
-}
-
-func (c *context) Release() {
-	if c.srgbFBO != nil {
-		c.srgbFBO.Release()
-		c.srgbFBO = nil
-	}
-}
-
-func (c *context) Present() error {
-	if c.srgbFBO != nil {
-		c.srgbFBO.Blit()
-	}
-	if c.srgbFBO != nil {
-		c.srgbFBO.AfterPresent()
-	}
-	if c.ctx.Call("isContextLost").Bool() {
-		return errors.New("context lost")
-	}
-	return nil
-}
-
-func (c *context) Lock() {}
-
-func (c *context) Unlock() {}
-
-func (c *context) MakeCurrent() error {
-	if c.srgbFBO == nil {
-		var err error
-		c.srgbFBO, err = gl.NewSRGBFBO(c.f)
-		if err != nil {
-			c.Release()
-			c.srgbFBO = nil
-			return err
-		}
-	}
-	w, h := c.cnv.Get("width").Int(), c.cnv.Get("height").Int()
-	if err := c.srgbFBO.Refresh(w, h); err != nil {
-		c.Release()
-		return err
-	}
-	return nil
-}