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8cc6fa82fd
As restoring from context lost doesn't happen on browsers, isContextLost doesn't have to be called.
83 lines
2.1 KiB
Go
83 lines
2.1 KiB
Go
// Copyright 2022 The Ebitengine Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package opengl
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import (
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"fmt"
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"os"
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"strings"
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"syscall/js"
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"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
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"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/opengl/gl"
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)
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// NewGraphics creates an implementation of graphicsdriver.Graphics for OpenGL.
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// The returned graphics value is nil iff the error is not nil.
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func NewGraphics(canvas js.Value) (graphicsdriver.Graphics, error) {
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var glContext js.Value
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attr := js.Global().Get("Object").New()
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attr.Set("alpha", true)
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attr.Set("premultipliedAlpha", true)
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attr.Set("stencil", true)
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var webGL2 bool
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if webGL2MightBeAvailable() {
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glContext = canvas.Call("getContext", "webgl2", attr)
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}
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if glContext.Truthy() {
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webGL2 = true
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} else {
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// Even though WebGL2RenderingContext exists, getting a webgl2 context might fail (#1738).
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glContext = canvas.Call("getContext", "webgl", attr)
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if !glContext.Truthy() {
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glContext = canvas.Call("getContext", "experimental-webgl", attr)
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}
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}
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if !glContext.Truthy() {
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return nil, fmt.Errorf("opengl: getContext failed")
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}
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ctx, err := gl.NewDefaultContext(glContext)
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if err != nil {
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return nil, err
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}
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g := &Graphics{}
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g.context.canvas = canvas
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g.context.ctx = ctx
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g.context.webGL2 = webGL2
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if !webGL2 {
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glContext.Call("getExtension", "OES_standard_derivatives")
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}
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return g, nil
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}
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func webGL2MightBeAvailable() bool {
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env := os.Getenv("EBITENGINE_OPENGL")
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for _, t := range strings.Split(env, ",") {
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switch strings.TrimSpace(t) {
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case "webgl1":
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return false
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}
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}
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return js.Global().Get("WebGL2RenderingContext").Truthy()
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}
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