From 18d3d911952525410b86f5bf1df3e47c58af6855 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 12 Oct 2024 23:43:06 +0900
Subject: [PATCH] internal/glfw: reduce TLS usages at refreshContextAttribs

---
 internal/glfw/context_unix.c     | 18 ++++++++----------
 internal/glfw/context_windows.go | 17 +++--------------
 2 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/internal/glfw/context_unix.c b/internal/glfw/context_unix.c
index ee6dc2574..f56275404 100644
--- a/internal/glfw/context_unix.c
+++ b/internal/glfw/context_unix.c
@@ -326,7 +326,6 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
                                     const _GLFWctxconfig* ctxconfig)
 {
     int i;
-    _GLFWwindow* previous;
     const char* version;
     const char* prefixes[] =
     {
@@ -339,10 +338,9 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
     window->context.source = ctxconfig->source;
     window->context.client = GLFW_OPENGL_API;
 
-    previous = _glfwPlatformGetTls(&_glfw.contextSlot);
+    // In Ebitengine, only one window is created.
+    // Always assume that the current context is not set.
     glfwMakeContextCurrent((GLFWwindow*) window);
-    if (_glfwPlatformGetTls(&_glfw.contextSlot) != window)
-        return GLFW_FALSE;
 
     window->context.GetIntegerv = (PFNGLGETINTEGERVPROC)
         window->context.getProcAddress("glGetIntegerv");
@@ -351,7 +349,7 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
     if (!window->context.GetIntegerv || !window->context.GetString)
     {
         _glfwInputError(GLFW_PLATFORM_ERROR, "Entry point retrieval is broken");
-        glfwMakeContextCurrent((GLFWwindow*) previous);
+        glfwMakeContextCurrent(NULL);
         return GLFW_FALSE;
     }
 
@@ -369,7 +367,7 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
                             "OpenGL ES version string retrieval is broken");
         }
 
-        glfwMakeContextCurrent((GLFWwindow*) previous);
+        glfwMakeContextCurrent(NULL);
         return GLFW_FALSE;
     }
 
@@ -401,7 +399,7 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
                             "No version found in OpenGL ES version string");
         }
 
-        glfwMakeContextCurrent((GLFWwindow*) previous);
+        glfwMakeContextCurrent(NULL);
         return GLFW_FALSE;
     }
 
@@ -431,7 +429,7 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
                             window->context.major, window->context.minor);
         }
 
-        glfwMakeContextCurrent((GLFWwindow*) previous);
+        glfwMakeContextCurrent(NULL);
         return GLFW_FALSE;
     }
 
@@ -447,7 +445,7 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
         {
             _glfwInputError(GLFW_PLATFORM_ERROR,
                             "Entry point retrieval is broken");
-            glfwMakeContextCurrent((GLFWwindow*) previous);
+            glfwMakeContextCurrent(NULL);
             return GLFW_FALSE;
         }
     }
@@ -556,7 +554,7 @@ GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
             window->context.swapBuffers(window);
     }
 
-    glfwMakeContextCurrent((GLFWwindow*) previous);
+    glfwMakeContextCurrent(NULL);
     return GLFW_TRUE;
 }
 
diff --git a/internal/glfw/context_windows.go b/internal/glfw/context_windows.go
index 836c9cbd1..3ee361daf 100644
--- a/internal/glfw/context_windows.go
+++ b/internal/glfw/context_windows.go
@@ -252,13 +252,10 @@ func (w *Window) refreshContextAttribs(ctxconfig *ctxconfig) (ferr error) {
 	w.context.source = ctxconfig.source
 	w.context.client = OpenGLAPI
 
-	p1, err := _glfw.contextSlot.get()
-	if err != nil {
-		return err
-	}
-	previous := (*Window)(unsafe.Pointer(p1))
+	// In Ebitengine, only one window is created.
+	// Always assume that the current context is not set.
 	defer func() {
-		err := previous.MakeContextCurrent()
+		err := (*Window)(nil).MakeContextCurrent()
 		if ferr == nil {
 			ferr = err
 		}
@@ -267,14 +264,6 @@ func (w *Window) refreshContextAttribs(ctxconfig *ctxconfig) (ferr error) {
 		return err
 	}
 
-	p2, err := _glfw.contextSlot.get()
-	if err != nil {
-		return err
-	}
-	if (*Window)(unsafe.Pointer(p2)) != w {
-		return nil
-	}
-
 	getIntegerv := w.context.getProcAddress("glGetIntegerv")
 	getString := w.context.getProcAddress("glGetString")
 	if getIntegerv == 0 || getString == 0 {