From e8810495cf361a7bef7745d0fbc3b2bdd7042e42 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 14 Nov 2022 02:03:36 +0900
Subject: [PATCH] internal/graphicsdriver/opengl/gl: reland: refactoring:
 reduce opengles build tags

This is a reland of c9cff69dcba6755b024c30ad6214f0f8ced42267.

Updates #292
---
 internal/graphicsdriver/opengl/context_js.go  |  5 +++++
 .../graphicsdriver/opengl/context_notjs.go    |  4 ++++
 .../opengl/gl/default_android.go              |  4 ++++
 .../opengl/gl/default_notpurego.go            |  4 ++++
 .../opengl/gl/default_purego.go               |  4 ++++
 internal/graphicsdriver/opengl/gl/gomobile.go |  4 ++++
 .../graphicsdriver/opengl/gl/interface.go     |  1 +
 .../opengl/gl/procaddr_darwin.go              |  6 +++++-
 .../graphicsdriver/opengl/gl/procaddr_gl.go   |  2 ++
 .../graphicsdriver/opengl/gl/procaddr_gles.go |  2 ++
 .../opengl/gl/procaddr_nintendosdk.go         |  2 ++
 .../opengl/gl/procaddr_windows.go             |  1 +
 internal/graphicsdriver/opengl/graphics.go    |  7 ++++++-
 .../opengl/needsrestoring_gles.go             | 21 -------------------
 .../opengl/needsrestoring_notgles.go          | 19 -----------------
 15 files changed, 44 insertions(+), 42 deletions(-)
 delete mode 100644 internal/graphicsdriver/opengl/needsrestoring_gles.go
 delete mode 100644 internal/graphicsdriver/opengl/needsrestoring_notgles.go

diff --git a/internal/graphicsdriver/opengl/context_js.go b/internal/graphicsdriver/opengl/context_js.go
index b5f654e50..cb88ad8d8 100644
--- a/internal/graphicsdriver/opengl/context_js.go
+++ b/internal/graphicsdriver/opengl/context_js.go
@@ -608,3 +608,8 @@ func (c *context) endStencilWithEvenOddRule() {
 	c.gl.stencilOp.Invoke(gl.KEEP, gl.KEEP, gl.KEEP)
 	c.gl.colorMask.Invoke(true, true, true, true)
 }
+
+func (c *context) isES() bool {
+	// WebGL is compatible with GLES.
+	return true
+}
diff --git a/internal/graphicsdriver/opengl/context_notjs.go b/internal/graphicsdriver/opengl/context_notjs.go
index 514483345..1edd2daf2 100644
--- a/internal/graphicsdriver/opengl/context_notjs.go
+++ b/internal/graphicsdriver/opengl/context_notjs.go
@@ -477,3 +477,7 @@ func (c *context) endStencilWithEvenOddRule() {
 	c.ctx.StencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
 	c.ctx.ColorMask(true, true, true, true)
 }
+
+func (c *context) isES() bool {
+	return c.ctx.IsES()
+}
diff --git a/internal/graphicsdriver/opengl/gl/default_android.go b/internal/graphicsdriver/opengl/gl/default_android.go
index 5e6232615..5090a6ca9 100644
--- a/internal/graphicsdriver/opengl/gl/default_android.go
+++ b/internal/graphicsdriver/opengl/gl/default_android.go
@@ -41,6 +41,10 @@ func (defaultContext) Init() error {
 	return nil
 }
 
+func (defaultContext) IsES() bool {
+	return true
+}
+
 func (defaultContext) ActiveTexture(texture uint32) {
 	C.glActiveTexture(C.GLenum(texture))
 }
diff --git a/internal/graphicsdriver/opengl/gl/default_notpurego.go b/internal/graphicsdriver/opengl/gl/default_notpurego.go
index 67305030d..563e1f923 100644
--- a/internal/graphicsdriver/opengl/gl/default_notpurego.go
+++ b/internal/graphicsdriver/opengl/gl/default_notpurego.go
@@ -406,6 +406,10 @@ 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))
 }
diff --git a/internal/graphicsdriver/opengl/gl/default_purego.go b/internal/graphicsdriver/opengl/gl/default_purego.go
index 1e08bb49f..f6b02befc 100644
--- a/internal/graphicsdriver/opengl/gl/default_purego.go
+++ b/internal/graphicsdriver/opengl/gl/default_purego.go
@@ -107,6 +107,10 @@ 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))
 }
diff --git a/internal/graphicsdriver/opengl/gl/gomobile.go b/internal/graphicsdriver/opengl/gl/gomobile.go
index ce9db5d4a..45a597a2d 100644
--- a/internal/graphicsdriver/opengl/gl/gomobile.go
+++ b/internal/graphicsdriver/opengl/gl/gomobile.go
@@ -39,6 +39,10 @@ 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))
 }
diff --git a/internal/graphicsdriver/opengl/gl/interface.go b/internal/graphicsdriver/opengl/gl/interface.go
index 82ca63a7a..e5a011f07 100644
--- a/internal/graphicsdriver/opengl/gl/interface.go
+++ b/internal/graphicsdriver/opengl/gl/interface.go
@@ -20,6 +20,7 @@ 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)
diff --git a/internal/graphicsdriver/opengl/gl/procaddr_darwin.go b/internal/graphicsdriver/opengl/gl/procaddr_darwin.go
index cf88e94d5..dd9b18fff 100644
--- a/internal/graphicsdriver/opengl/gl/procaddr_darwin.go
+++ b/internal/graphicsdriver/opengl/gl/procaddr_darwin.go
@@ -18,11 +18,15 @@ import (
 	"github.com/ebitengine/purego"
 )
 
-var opengl uintptr
+var (
+	opengl uintptr
+	isES   bool
+)
 
 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)
diff --git a/internal/graphicsdriver/opengl/gl/procaddr_gl.go b/internal/graphicsdriver/opengl/gl/procaddr_gl.go
index 36edc228f..fe341ee59 100644
--- a/internal/graphicsdriver/opengl/gl/procaddr_gl.go
+++ b/internal/graphicsdriver/opengl/gl/procaddr_gl.go
@@ -28,6 +28,8 @@ import "C"
 
 import "unsafe"
 
+var isES = false
+
 func getProcAddress(namea string) unsafe.Pointer {
 	cname := C.CString(namea)
 	defer C.free(unsafe.Pointer(cname))
diff --git a/internal/graphicsdriver/opengl/gl/procaddr_gles.go b/internal/graphicsdriver/opengl/gl/procaddr_gles.go
index 8a0dec9e6..79ca45434 100644
--- a/internal/graphicsdriver/opengl/gl/procaddr_gles.go
+++ b/internal/graphicsdriver/opengl/gl/procaddr_gles.go
@@ -35,6 +35,8 @@ import (
 	"unsafe"
 )
 
+var isES = true
+
 func getProcAddress(namea string) unsafe.Pointer {
 	const ext = "EXT"
 	if strings.HasSuffix(namea, ext) {
diff --git a/internal/graphicsdriver/opengl/gl/procaddr_nintendosdk.go b/internal/graphicsdriver/opengl/gl/procaddr_nintendosdk.go
index 84babbded..cb2c26786 100644
--- a/internal/graphicsdriver/opengl/gl/procaddr_nintendosdk.go
+++ b/internal/graphicsdriver/opengl/gl/procaddr_nintendosdk.go
@@ -28,6 +28,8 @@ import "C"
 
 import "unsafe"
 
+var isES = false
+
 func getProcAddress(namea string) unsafe.Pointer {
 	cname := C.CString(namea)
 	defer C.free(unsafe.Pointer(cname))
diff --git a/internal/graphicsdriver/opengl/gl/procaddr_windows.go b/internal/graphicsdriver/opengl/gl/procaddr_windows.go
index e0a946d5b..68bc9b9d9 100644
--- a/internal/graphicsdriver/opengl/gl/procaddr_windows.go
+++ b/internal/graphicsdriver/opengl/gl/procaddr_windows.go
@@ -24,6 +24,7 @@ import (
 var (
 	opengl32              = windows.NewLazySystemDLL("opengl32")
 	procWglGetProcAddress = opengl32.NewProc("wglGetProcAddress")
+	isES                  = false
 )
 
 func getProcAddress(namea string) uintptr {
diff --git a/internal/graphicsdriver/opengl/graphics.go b/internal/graphicsdriver/opengl/graphics.go
index e9dddb310..3496103cf 100644
--- a/internal/graphicsdriver/opengl/graphics.go
+++ b/internal/graphicsdriver/opengl/graphics.go
@@ -16,6 +16,7 @@ package opengl
 
 import (
 	"fmt"
+	"runtime"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
@@ -265,7 +266,11 @@ func (g *Graphics) SetFullscreen(fullscreen bool) {
 }
 
 func (g *Graphics) NeedsRestoring() bool {
-	return needsRestoring
+	// 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.isES()
 }
 
 func (g *Graphics) NeedsClearingScreen() bool {
diff --git a/internal/graphicsdriver/opengl/needsrestoring_gles.go b/internal/graphicsdriver/opengl/needsrestoring_gles.go
deleted file mode 100644
index 0d0f5523c..000000000
--- a/internal/graphicsdriver/opengl/needsrestoring_gles.go
+++ /dev/null
@@ -1,21 +0,0 @@
-// 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
diff --git a/internal/graphicsdriver/opengl/needsrestoring_notgles.go b/internal/graphicsdriver/opengl/needsrestoring_notgles.go
deleted file mode 100644
index 5399d7a61..000000000
--- a/internal/graphicsdriver/opengl/needsrestoring_notgles.go
+++ /dev/null
@@ -1,19 +0,0 @@
-// 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