From 5cfb7c9469538668f781a6e2bd4312d67205c52c Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 13 Nov 2022 14:18:20 +0900
Subject: [PATCH] internal/graphicsdriver/opengl: make context_gles.go closer
 to context_gl.go

Updates #2451
---
 internal/graphicsdriver/opengl/context_gl.go  |  4 ----
 .../graphicsdriver/opengl/context_gles.go     |  8 +++----
 internal/graphicsdriver/opengl/context_js.go  |  5 -----
 internal/graphicsdriver/opengl/graphics.go    |  2 +-
 .../opengl/needsrestoring_gles.go             | 21 +++++++++++++++++++
 .../opengl/needsrestoring_notgles.go          | 19 +++++++++++++++++
 6 files changed, 44 insertions(+), 15 deletions(-)
 create mode 100644 internal/graphicsdriver/opengl/needsrestoring_gles.go
 create mode 100644 internal/graphicsdriver/opengl/needsrestoring_notgles.go

diff --git a/internal/graphicsdriver/opengl/context_gl.go b/internal/graphicsdriver/opengl/context_gl.go
index 1a3e78989..79ddf293c 100644
--- a/internal/graphicsdriver/opengl/context_gl.go
+++ b/internal/graphicsdriver/opengl/context_gl.go
@@ -464,10 +464,6 @@ func (c *context) flush() {
 	gl.Flush()
 }
 
-func (c *context) needsRestoring() bool {
-	return false
-}
-
 func (c *context) texSubImage2D(t textureNative, args []*graphicsdriver.WritePixelsArgs) {
 	c.bindTexture(t)
 	for _, a := range args {
diff --git a/internal/graphicsdriver/opengl/context_gles.go b/internal/graphicsdriver/opengl/context_gles.go
index c2d19c372..a52350eef 100644
--- a/internal/graphicsdriver/opengl/context_gles.go
+++ b/internal/graphicsdriver/opengl/context_gles.go
@@ -194,7 +194,9 @@ func (c *context) newRenderbuffer(width, height int) (renderbufferNative, error)
 	renderbuffer := renderbufferNative(r)
 	c.bindRenderbuffer(renderbuffer)
 
-	c.ctx.RenderbufferStorage(gl.RENDERBUFFER, gl.STENCIL_INDEX8, int32(width), int32(height))
+	// GL_STENCIL_INDEX8 might not be available with OpenGL 2.1.
+	// https://www.khronos.org/opengl/wiki/Image_Format
+	c.ctx.RenderbufferStorage(gl.RENDERBUFFER, gl.DEPTH24_STENCIL8, int32(width), int32(height))
 
 	return renderbuffer, nil
 }
@@ -439,10 +441,6 @@ func (c *context) flush() {
 	c.ctx.Flush()
 }
 
-func (c *context) needsRestoring() bool {
-	return true
-}
-
 func (c *context) texSubImage2D(t textureNative, args []*graphicsdriver.WritePixelsArgs) {
 	c.bindTexture(t)
 	for _, a := range args {
diff --git a/internal/graphicsdriver/opengl/context_js.go b/internal/graphicsdriver/opengl/context_js.go
index 3079846a7..b5f654e50 100644
--- a/internal/graphicsdriver/opengl/context_js.go
+++ b/internal/graphicsdriver/opengl/context_js.go
@@ -570,11 +570,6 @@ func (c *context) flush() {
 	c.gl.flush.Invoke()
 }
 
-func (c *context) needsRestoring() bool {
-	// Though it is possible to have a logic to restore the graphics data for GPU, do not use it for performance (#1603).
-	return false
-}
-
 func (c *context) texSubImage2D(t textureNative, args []*graphicsdriver.WritePixelsArgs) {
 	c.bindTexture(t)
 	for _, a := range args {
diff --git a/internal/graphicsdriver/opengl/graphics.go b/internal/graphicsdriver/opengl/graphics.go
index 410d9df3d..607ad7ed5 100644
--- a/internal/graphicsdriver/opengl/graphics.go
+++ b/internal/graphicsdriver/opengl/graphics.go
@@ -279,7 +279,7 @@ func (g *Graphics) SetFullscreen(fullscreen bool) {
 }
 
 func (g *Graphics) NeedsRestoring() bool {
-	return g.context.needsRestoring()
+	return needsRestoring
 }
 
 func (g *Graphics) NeedsClearingScreen() bool {
diff --git a/internal/graphicsdriver/opengl/needsrestoring_gles.go b/internal/graphicsdriver/opengl/needsrestoring_gles.go
new file mode 100644
index 000000000..0d0f5523c
--- /dev/null
+++ b/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
diff --git a/internal/graphicsdriver/opengl/needsrestoring_notgles.go b/internal/graphicsdriver/opengl/needsrestoring_notgles.go
new file mode 100644
index 000000000..5399d7a61
--- /dev/null
+++ b/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