call glFlush only once

that seems to atleast get rid of the flicker
the weird issue that clears don't work is still there

src/GPU3D_OpenGL.cpp

@@ -1145,8 +1145,6 @@ void RenderSceneChunk(int y, int h)
         }
     }
 
-    glFlush();
-
     if (RenderDispCnt & 0x00A0) // fog/edge enabled
     {
         glColorMaski(0, GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
@@ -1204,8 +1202,6 @@ void RenderSceneChunk(int y, int h)
 
             glDrawArrays(GL_TRIANGLES, 0, 2*3);
         }
-
-        glFlush();
     }
 }
 

src/GPU_OpenGL.cpp

@@ -226,8 +226,6 @@ void RenderFrame()
     glBindBuffer(GL_ARRAY_BUFFER, CompVertexBufferID);
     glBindVertexArray(CompVertexArrayID);
     glDrawArrays(GL_TRIANGLES, 0, 4*3);
-
-    glFlush();
 }
 
 void BindOutputTexture()

src/frontend/qt_sdl/main.cpp

@@ -490,6 +490,14 @@ void EmuThread::run()
             // emulate
             u32 nlines = NDS::RunFrame();
 
+#ifdef OGLRENDERER_ENABLED
+            // this is hacky but this is the easiest way to call
+            // this function without dealling with a ton of
+            // macro mess
+            if (videoRenderer == 1)
+                epoxy_glFlush();
+#endif
+
 #ifdef MELONCAP
             MelonCap::Update();
 #endif // MELONCAP