Make imgui and qtgui compile on older qt as well, opengl 3.2 required

3rdparty/qtimgui/ImGuiRenderer.cpp

@@ -39,6 +39,8 @@ QByteArray g_currentClipboardText;
 void ImGuiRenderer::initialize(WindowWrapper *window) {
     m_window.reset(window);
     initializeOpenGLFunctions();
+    g_fun = new QOpenGLFunctions_3_3_Core();
+    g_fun->initializeOpenGLFunctions();
 
     ImGui::CreateContext();
 
@@ -59,6 +61,7 @@ void ImGuiRenderer::initialize(WindowWrapper *window) {
         g_currentClipboardText = QGuiApplication::clipboard()->text().toUtf8();
         return (const char *)g_currentClipboardText.data();
     };
+    io.IniFilename = nullptr;
 
     window->installEventFilter(this);
 }
@@ -114,7 +117,7 @@ void ImGuiRenderer::renderDrawList(ImDrawData *draw_data)
     glUseProgram(g_ShaderHandle);
     glUniform1i(g_AttribLocationTex, 0);
     glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
-    glBindVertexArray(g_VaoHandle);
+    g_fun->glBindVertexArray(g_VaoHandle);
 
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
@@ -148,7 +151,7 @@ void ImGuiRenderer::renderDrawList(ImDrawData *draw_data)
     glUseProgram(last_program);
     glBindTexture(GL_TEXTURE_2D, last_texture);
     glActiveTexture(last_active_texture);
-    glBindVertexArray(last_vertex_array);
+    g_fun->glBindVertexArray(last_vertex_array);
     glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
     glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
@@ -241,8 +244,8 @@ bool ImGuiRenderer::createDeviceObjects()
     glGenBuffers(1, &g_VboHandle);
     glGenBuffers(1, &g_ElementsHandle);
 
-    glGenVertexArrays(1, &g_VaoHandle);
-    glBindVertexArray(g_VaoHandle);
+    g_fun->glGenVertexArrays(1, &g_VaoHandle);
+    g_fun->glBindVertexArray(g_VaoHandle);
     glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
     glEnableVertexAttribArray(g_AttribLocationPosition);
     glEnableVertexAttribArray(g_AttribLocationUV);
@@ -259,7 +262,7 @@ bool ImGuiRenderer::createDeviceObjects()
     // Restore modified GL state
     glBindTexture(GL_TEXTURE_2D, last_texture);
     glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
-    glBindVertexArray(last_vertex_array);
+    g_fun->glBindVertexArray(last_vertex_array);
 
     return true;
 }

3rdparty/qtimgui/ImGuiRenderer.h

@@ -1,6 +1,7 @@
 #pragma once
 
-#include <QOpenGLExtraFunctions>
+#include <QOpenGLFunctions>
+#include <QOpenGLFunctions_3_3_Core>
 #include <QObject>
 #include <QPoint>
 #include <imgui.h>
@@ -22,7 +23,7 @@ public:
     virtual QPoint mapFromGlobal(const QPoint &p) const = 0;
 };
 
-class ImGuiRenderer : public QObject, QOpenGLExtraFunctions {
+class ImGuiRenderer : public QObject, QOpenGLFunctions {
     Q_OBJECT
 public:
     void initialize(WindowWrapper *window);
@@ -53,6 +54,7 @@ private:
     int          g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
     int          g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
     unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
+    QOpenGLFunctions_3_3_Core *g_fun = nullptr;
 };
 
 }

3rdparty/qtimgui/QtImGui.cpp

@@ -21,7 +21,7 @@ public:
         return w->size();
     }
     qreal devicePixelRatio() const override {
-        return w->devicePixelRatioF();
+        return w->devicePixelRatio();
     }
     bool isActive() const override {
         return w->isActiveWindow();

gui/CMakeLists.txt

@@ -12,6 +12,12 @@ if (BUILD_PYTHON)
     
     ../3rdparty/python-console/modified/pyredirector.cc 
     ../3rdparty/python-console/modified/pyinterpreter.cc 
+    ../3rdparty/imgui/imgui_widgets.cpp
+    ../3rdparty/imgui/imgui_draw.cpp
+    ../3rdparty/imgui/imgui.cpp
+    ../3rdparty/imgui/imgui_demo.cpp
+    ../3rdparty/qtimgui/ImGuiRenderer.cpp
+    ../3rdparty/qtimgui/QtImGui.cpp    
   )
 endif()
 
@@ -27,7 +33,7 @@ set(GUI_LIBRARY_FILES_${ufamily} Qt5::Widgets Qt5::OpenGL ${OPENGL_LIBRARIES} Qt
 add_library(gui_${family} STATIC ${GUI_SOURCE_FILES} ${PYTHON_CONSOLE_SRC} ${GUI_RESOURCE_FILES})
 include(${family}/family.cmake)
 
-target_include_directories(gui_${family} PRIVATE ../${family} ${family} ../3rdparty/QtPropertyBrowser/src)
+target_include_directories(gui_${family} PRIVATE ../${family} ${family} ../3rdparty/QtPropertyBrowser/src ../3rdparty/imgui ../3rdparty/qtimgui/)
 if (BUILD_PYTHON)
   target_include_directories(gui_${family} PRIVATE ../3rdparty/python-console ../3rdparty/python-console/modified)
 endif()