Added comments

examples/directx9_example/main.cpp

@@ -20,7 +20,10 @@ struct CUSTOMVERTEX
 };
 #define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE|D3DFVF_TEX1)
 
-// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer)
+// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
+// If text or lines are blurry when integrating ImGui in your engine:
+// - try adjusting ImGui::GetIO().PixelCenterOffset to 0.0f or 0.5f
+// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
 static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
 {
     size_t total_vtx_count = 0;

examples/opengl_example/main.cpp

@@ -11,14 +11,17 @@
 static GLFWwindow* window;
 static GLuint fontTex;
 
-// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer)
+// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
-// We are using the fixed pipeline. 
+// If text or lines are blurry when integrating ImGui in your engine:
-// A faster way would be to collate all vertices from all cmd_lists into a single vertex buffer
+// - try adjusting ImGui::GetIO().PixelCenterOffset to 0.0f or 0.5f
+// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
 static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
 {
     if (cmd_lists_count == 0)
         return;
 
+    // We are using the OpenGL fixed pipeline to make the example code simpler to read!
+    // A probable faster way to render would be to collate all vertices from all cmd_lists into a single vertex buffer.
     // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

imgui.cpp

@@ -53,7 +53,7 @@
    - every frame: 
       1/ in your mainloop or right after you got your keyboard/mouse info, call ImGui::GetIO() and fill the 'Input' data, then call ImGui::NewFrame().
       2/ use any ImGui function you want between NewFrame() and Render()
-      3/ ImGui::Render() to render all the accumulated command-lists. it will cack your RenderDrawListFn handler set in the IO structure.
+      3/ ImGui::Render() to render all the accumulated command-lists. it will call your RenderDrawListFn handler that you set in the IO structure.
    - all rendering information are stored into command-lists until ImGui::Render() is called.
    - effectively it means you can create widgets at any time in your code, regardless of "update" vs "render" considerations.
    - a typical application skeleton may be:
@@ -87,6 +87,10 @@
             // swap video buffer, etc.
         }
 
+ - if text or lines are blurry when integrating ImGui in your engine:
+   - try adjusting ImGui::GetIO().PixelCenterOffset to 0.0f or 0.5f
+   - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
+
  - some widgets carry state and requires an unique ID to do so.
    - unique ID are typically derived from a string label, an indice or a pointer.
    - use PushID/PopID to easily create scopes and avoid ID conflicts. A Window is also an implicit scope.