Backends: OpenGL3: Shallow tweak of compile-time extensions detection.

Detect polygon mode using same method as others (not define/symbol).
IMGUI_IMPL_OPENGL_MAY_HAVE_EXTENSIONS -> IMGUI_IMPL_OPENGL_HAS_EXTENSIONS

backends/imgui_impl_glfw.cpp

@@ -114,7 +114,7 @@ enum GlfwClientApi
 {
     GlfwClientApi_Unknown,
     GlfwClientApi_OpenGL,
-    GlfwClientApi_Vulkan
+    GlfwClientApi_Vulkan,
 };
 
 struct ImGui_ImplGlfw_Data
@@ -674,11 +674,9 @@ static void ImGui_ImplGlfw_UpdateMouseData()
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
     ImGuiIO& io = ImGui::GetIO();
 
-
     // (those braces are here to reduce diff with multi-viewports support in 'docking' branch)
     {
         GLFWwindow* window = bd->Window;
-
 #ifdef __EMSCRIPTEN__
         const bool is_window_focused = true;
 #else

backends/imgui_impl_opengl3.cpp

@@ -176,22 +176,13 @@
 #define GL_VERTEX_ARRAY_BINDING GL_VERTEX_ARRAY_BINDING_OES
 #endif
 
-// Desktop GL 2.0+ has glPolygonMode() which GL ES and WebGL don't have.
-#ifdef GL_POLYGON_MODE
-#define IMGUI_IMPL_HAS_POLYGON_MODE
-#endif
-
-// Desktop GL 3.2+ has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
-#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_2)
-#define IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
-#endif
-
-// Desktop GL 3.3+ and GL ES 3.0+ have glBindSampler()
-#if !defined(IMGUI_IMPL_OPENGL_ES2) && (defined(IMGUI_IMPL_OPENGL_ES3) || defined(GL_VERSION_3_3))
-#define IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
+// Desktop GL 2.0+ has extension and glPolygonMode() which GL ES and WebGL don't have..
+#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3)
+#define IMGUI_IMPL_OPENGL_HAS_EXTENSIONS        // has glGetIntegerv(GL_NUM_EXTENSIONS)
+#define IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE      // has glPolygonMode()
 #endif
 
-// Desktop GL and GL ES 3.0+ have glBindBuffer() with GL_PIXEL_UNPACK_BUFFER target.
+// Desktop GL 2.1+ and GL ES 3.0+ have glBindBuffer() with GL_PIXEL_UNPACK_BUFFER target.
 #if !defined(IMGUI_IMPL_OPENGL_ES2)
 #define IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_BUFFER_PIXEL_UNPACK
 #endif
@@ -201,9 +192,14 @@
 #define IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
 #endif
 
-// Desktop GL use extension detection
-#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3)
-#define IMGUI_IMPL_OPENGL_MAY_HAVE_EXTENSIONS
+// Desktop GL 3.2+ has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
+#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_2)
+#define IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
+#endif
+
+// Desktop GL 3.3+ and GL ES 3.0+ have glBindSampler()
+#if !defined(IMGUI_IMPL_OPENGL_ES2) && (defined(IMGUI_IMPL_OPENGL_ES3) || defined(GL_VERSION_3_3))
+#define IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
 #endif
 
 // [Debugging]
@@ -364,7 +360,7 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 
     // Detect extensions we support
     bd->HasClipOrigin = (bd->GlVersion >= 450);
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_EXTENSIONS
+#ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
     GLint num_extensions = 0;
     glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
     for (GLint i = 0; i < num_extensions; i++)
@@ -416,7 +412,7 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
     if (bd->GlVersion >= 310)
         glDisable(GL_PRIMITIVE_RESTART);
 #endif
-#ifdef IMGUI_IMPL_HAS_POLYGON_MODE
+#ifdef IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 #endif
 
@@ -505,7 +501,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
     GLuint last_vertex_array_object; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, (GLint*)&last_vertex_array_object);
 #endif
-#ifdef IMGUI_IMPL_HAS_POLYGON_MODE
+#ifdef IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
     GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
 #endif
     GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
@@ -644,7 +640,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     if (bd->GlVersion >= 310) { if (last_enable_primitive_restart) glEnable(GL_PRIMITIVE_RESTART); else glDisable(GL_PRIMITIVE_RESTART); }
 #endif
 
-#ifdef IMGUI_IMPL_HAS_POLYGON_MODE
+#ifdef IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
     // Desktop OpenGL 3.0 and OpenGL 3.1 had separate polygon draw modes for front-facing and back-facing faces of polygons
     if (bd->GlVersion <= 310 || bd->GlProfileIsCompat)
     {
@@ -655,7 +651,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     {
         glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]);
     }
-#endif // IMGUI_IMPL_HAS_POLYGON_MODE
+#endif // IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
 
     glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
     glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);