Revert "internal/graphicsdriver/opengl/gl: refactoring"

This reverts commit c9cff69dcb.

Reason: compmile error for browsers

internal/graphicsdriver/opengl/gl/default_android.go

@@ -41,10 +41,6 @@ func (defaultContext) Init() error {
 	return nil
 }
 
-func (defaultContext) IsES() bool {
-	return true
-}
-
 func (defaultContext) ActiveTexture(texture uint32) {
 	C.glActiveTexture(C.GLenum(texture))
 }

internal/graphicsdriver/opengl/gl/default_notpurego.go

@@ -406,10 +406,6 @@ func boolToInt(b bool) int {
 	return 0
 }
 
-func (c *defaultContext) IsES() bool {
-	return isES
-}
-
 func (c *defaultContext) ActiveTexture(texture uint32) {
 	C.glowActiveTexture(c.gpActiveTexture, (C.GLenum)(texture))
 }

internal/graphicsdriver/opengl/gl/default_purego.go

@@ -107,10 +107,6 @@ func boolToInt(b bool) int {
 	return 0
 }
 
-func (c *defaultContext) IsES() bool {
-	return isES
-}
-
 func (c *defaultContext) ActiveTexture(texture uint32) {
 	purego.SyscallN(c.gpActiveTexture, uintptr(texture))
 }

internal/graphicsdriver/opengl/gl/gomobile.go

@@ -39,10 +39,6 @@ func (g *gomobileContext) Init() error {
 	return nil
 }
 
-func (g *gomobileContext) IsES() bool {
-	return true
-}
-
 func (g *gomobileContext) ActiveTexture(texture uint32) {
 	g.ctx.ActiveTexture(gl.Enum(texture))
 }

internal/graphicsdriver/opengl/gl/interface.go

@@ -20,7 +20,6 @@ package gl
 // See https://pkg.go.dev/golang.org/x/mobile/gl#Context
 type Context interface {
 	Init() error
-	IsES() bool
 
 	ActiveTexture(texture uint32)
 	AttachShader(program uint32, shader uint32)

internal/graphicsdriver/opengl/gl/procaddr_darwin.go

@@ -18,15 +18,11 @@ import (
 	"github.com/ebitengine/purego"
 )
 
-var (
-	opengl uintptr
-	isES   bool
-)
+var opengl uintptr
 
 func init() {
 	opengl = purego.Dlopen("/System/Library/Frameworks/OpenGLES.framework/Versions/Current/OpenGLES", purego.RTLD_GLOBAL)
 	if opengl != 0 {
-		isES = true
 		return
 	}
 	opengl = purego.Dlopen("/System/Library/Frameworks/OpenGL.framework/Versions/Current/OpenGL", purego.RTLD_GLOBAL)

internal/graphicsdriver/opengl/gl/procaddr_gl.go

@@ -28,8 +28,6 @@ import "C"
 
 import "unsafe"
 
-var isES = false
-
 func getProcAddress(namea string) unsafe.Pointer {
 	cname := C.CString(namea)
 	defer C.free(unsafe.Pointer(cname))

internal/graphicsdriver/opengl/gl/procaddr_gles.go

@@ -35,8 +35,6 @@ import (
 	"unsafe"
 )
 
-var isES = true
-
 func getProcAddress(namea string) unsafe.Pointer {
 	const ext = "EXT"
 	if strings.HasSuffix(namea, ext) {

internal/graphicsdriver/opengl/gl/procaddr_nintendosdk.go

@@ -28,8 +28,6 @@ import "C"
 
 import "unsafe"
 
-var isES = false
-
 func getProcAddress(namea string) unsafe.Pointer {
 	cname := C.CString(namea)
 	defer C.free(unsafe.Pointer(cname))

internal/graphicsdriver/opengl/gl/procaddr_windows.go

@@ -24,7 +24,6 @@ import (
 var (
 	opengl32              = windows.NewLazySystemDLL("opengl32")
 	procWglGetProcAddress = opengl32.NewProc("wglGetProcAddress")
-	isES                  = false
 )
 
 func getProcAddress(namea string) uintptr {

internal/graphicsdriver/opengl/graphics.go

@@ -16,7 +16,6 @@ package opengl
 
 import (
 	"fmt"
-	"runtime"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
@@ -266,11 +265,7 @@ func (g *Graphics) SetFullscreen(fullscreen bool) {
 }
 
 func (g *Graphics) NeedsRestoring() bool {
-	// Though it is possible to have a logic to restore the graphics data for GPU, do not use it for performance (#1603).
-	if runtime.GOOS == "js" {
-		return false
-	}
-	return g.context.ctx.IsES()
+	return needsRestoring
 }
 
 func (g *Graphics) NeedsClearingScreen() bool {

internal/graphicsdriver/opengl/needsrestoring_gles.go

@@ -0,0 +1,21 @@
+// Copyright 2022 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !android && !ios && !opengles
+
+package opengl
+
+// Though it is possible to have a logic to restore the graphics data for GPU, do not use it for performance (#1603).
+
+const needsRestoring = false

internal/graphicsdriver/opengl/needsrestoring_notgles.go

@@ -0,0 +1,19 @@
+// Copyright 2022 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build android || ios || opengles
+
+package opengl
+
+const needsRestoring = true