imGui: Update to v1.87 and remove unnecessary headers

include/imgui_impl_vitagl.h

@@ -1,5 +1,24 @@
+// dear imgui: Renderer Backend for OpenGL2 (legacy OpenGL, fixed pipeline)
+// This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
+
 // Implemented features:
-//  [X] User texture binding. Cast 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
+// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
+// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
+// Read online: https://github.com/ocornut/imgui/tree/master/docs
+
+// **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
+// **Prefer using the code in imgui_impl_opengl3.cpp**
+// This code is mostly provided as a reference to learn how ImGui integration works, because it is shorter to read.
+// If your code is using GL3+ context or any semi modern OpenGL calls, using this is likely to make everything more
+// complicated, will require your code to reset every single OpenGL attributes to their initial state, and might
+// confuse your GPU driver.
+// The GL2 code is unable to reset attributes or even call e.g. "glUseProgram(0)" because they don't exist in that API.
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
 
 IMGUI_API bool ImGui_ImplVitaGL_Init(void);
 IMGUI_API void ImGui_ImplVitaGL_Shutdown(void);

include/imgui_vita.h

@@ -1,6 +0,0 @@
-#ifndef _IMGUI_VITA_
-
-#include "imgui.h"
-#include "imgui_impl_vitagl.h"
-
-#endif

libs/imgui

@@ -1 +1 @@
-Subproject commit 512c54bbc062c41c74f8a8bd8ff1fd6bebd1e6d0
+Subproject commit c71a50deb5ddf1ea386b91e60fa2e4a26d080074

source/gui.cpp

@@ -1,11 +1,9 @@
-#include <imgui_vita.h>
 #include <vitaGL.h>
 
 #include "config.h"
 #include "fs.h"
 #include "gui.h"
-#include "imgui.h"
-#include "imgui_internal.h"
+#include "imgui_impl_vitagl.h"
 #include "utils.h"
 #include "windows.h"
 

source/main.cpp

@@ -1,10 +1,10 @@
-#include <imgui_vita.h>
 #include <psp2/sysmodule.h>
 #include <vitaGL.h>
 
 #include "config.h"
 #include "fs.h"
 #include "gui.h"
+#include "imgui_impl_vitagl.h"
 #include "log.h"
 #include "textures.h"
 #include "utils.h"