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