[OpenGL] Keep glClipControl local to imgui_impl_opengl3.cpp

src/gl/gl.h

@@ -18,8 +18,6 @@ void* glXGetProcAddressARB(const unsigned char*);
 
 unsigned int eglSwapBuffers( void*, void* );
 
-void glClipControl(int origin, int depth);
-
 #ifdef __cplusplus
 }
 #endif

src/gl/imgui_impl_opengl3.cpp

@@ -74,8 +74,8 @@
 #define GL_ZERO_TO_ONE                    0x935F
 #define GL_CLIP_DEPTH_MODE                0x935D
 
-#include "loaders/loader_gl.h"
-extern gl_loader gl;
+void* get_glx_proc_address(const char* name);
+void (*glClipControl)(int origin, int depth);
 
 // 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)
@@ -96,6 +96,8 @@ static unsigned int g_VboHandle = 0, g_ElementsHandle = 0;
 // Functions
 bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 {
+    glClipControl = reinterpret_cast<decltype(glClipControl)> (get_glx_proc_address("glClipControl"));
+
     // Query for GL version
 #if !defined(IMGUI_IMPL_OPENGL_ES2)
 
@@ -245,8 +247,8 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     GLenum last_clip_depth_mode = 0; glGetIntegerv(GL_CLIP_DEPTH_MODE, (GLint*)&last_clip_depth_mode);
     if (last_clip_origin == GL_UPPER_LEFT) {
         clip_origin_lower_left = false;
-        if (gl.glClipControl)
-            gl.glClipControl(GL_LOWER_LEFT, GL_ZERO_TO_ONE);
+        if (glClipControl)
+            glClipControl(GL_LOWER_LEFT, GL_ZERO_TO_ONE);
     }
 #endif
 
@@ -343,8 +345,8 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
 
 #if defined(GL_CLIP_ORIGIN) && !defined(__APPLE__)
-    if (!clip_origin_lower_left && gl.glClipControl)
-        gl.glClipControl(last_clip_origin, last_clip_depth_mode);
+    if (!clip_origin_lower_left && glClipControl)
+        glClipControl(last_clip_origin, last_clip_depth_mode);
 #endif
 }
 

src/gl/inject.cpp

@@ -25,7 +25,7 @@
 EXPORT_C_(void *) glXGetProcAddress(const unsigned char* procName);
 EXPORT_C_(void *) glXGetProcAddressARB(const unsigned char* procName);
 
-gl_loader gl;
+static gl_loader gl;
 
 struct state {
     ImGuiContext *imgui_ctx = nullptr;

src/loaders/loader_gl.cpp

@@ -83,10 +83,6 @@ bool gl_loader::Load(bool egl_only) {
     return false;
   }
 
-  glClipControl =
-      reinterpret_cast<decltype(this->glClipControl)>(
-          glXGetProcAddress((const unsigned char *)"glClipControl"));
-
   loaded_ = true;
   return true;
 }

src/loaders/loader_gl.h

@@ -23,8 +23,6 @@ class gl_loader {
   decltype(&::glXGetSwapIntervalMESA) glXGetSwapIntervalMESA;
   decltype(&::glXMakeCurrent) glXMakeCurrent;
 
-  decltype(&::glClipControl) glClipControl;
-
   decltype(&::eglSwapBuffers) eglSwapBuffers;
 
  private: