add qtimgui renderer library

13 files changed, 837 insertions, 0 deletions

diff --git a/3rdparty/qtimgui/.gitignore b/3rdparty/qtimgui/.gitignore
new file mode 100644
index 00000000..76b26f0d
--- /dev/null
+++ b/3rdparty/qtimgui/.gitignore
@@ -0,0 +1,44 @@
+
+# Created by https://www.gitignore.io/api/qt
+
+### Qt ###
+# C++ objects and libs
+
+*.slo
+*.lo
+*.o
+*.a
+*.la
+*.lai
+*.so
+*.dll
+*.dylib
+
+# Qt-es
+
+/.qmake.cache
+/.qmake.stash
+*.pro.user
+*.pro.user.*
+*.qbs.user
+*.qbs.user.*
+*.moc
+moc_*.cpp
+qrc_*.cpp
+ui_*.h
+Makefile*
+*build-*
+
+# QtCreator
+
+*.autosave
+
+# QtCtreator Qml
+*.qmlproject.user
+*.qmlproject.user.*
+
+# QtCtreator CMake
+CMakeLists.txt.user*
+
+
+# End of https://www.gitignore.io/api/qt
diff --git a/3rdparty/qtimgui/ImGuiRenderer.cpp b/3rdparty/qtimgui/ImGuiRenderer.cpp
new file mode 100644
index 00000000..7f19dcd1
--- /dev/null
+++ b/3rdparty/qtimgui/ImGuiRenderer.cpp
@@ -0,0 +1,381 @@
+#include "ImGuiRenderer.h"
+#include <QDateTime>
+#include <QGuiApplication>
+#include <QMouseEvent>
+#include <QClipboard>
+#include <QCursor>
+#include <QDebug>
+
+namespace QtImGui {
+
+namespace {
+
+QHash<int, ImGuiKey> keyMap = {
+    { Qt::Key_Tab, ImGuiKey_Tab },
+    { Qt::Key_Left, ImGuiKey_LeftArrow },
+    { Qt::Key_Right, ImGuiKey_RightArrow },
+    { Qt::Key_Up, ImGuiKey_UpArrow },
+    { Qt::Key_Down, ImGuiKey_DownArrow },
+    { Qt::Key_PageUp, ImGuiKey_PageUp },
+    { Qt::Key_PageDown, ImGuiKey_PageDown },
+    { Qt::Key_Home, ImGuiKey_Home },
+    { Qt::Key_End, ImGuiKey_End },
+    { Qt::Key_Delete, ImGuiKey_Delete },
+    { Qt::Key_Backspace, ImGuiKey_Backspace },
+    { Qt::Key_Enter, ImGuiKey_Enter },
+    { Qt::Key_Escape, ImGuiKey_Escape },
+    { Qt::Key_A, ImGuiKey_A },
+    { Qt::Key_C, ImGuiKey_C },
+    { Qt::Key_V, ImGuiKey_V },
+    { Qt::Key_X, ImGuiKey_X },
+    { Qt::Key_Y, ImGuiKey_Y },
+    { Qt::Key_Z, ImGuiKey_Z },
+};
+
+QByteArray g_currentClipboardText;
+
+}
+
+void ImGuiRenderer::initialize(WindowWrapper *window) {
+    m_window.reset(window);
+    initializeOpenGLFunctions();
+
+    ImGui::CreateContext();
+
+    ImGuiIO &io = ImGui::GetIO();
+    for (ImGuiKey key : keyMap.values()) {
+        io.KeyMap[key] = key;
+    }
+
+    io.RenderDrawListsFn = [](ImDrawData *drawData) {
+        instance()->renderDrawList(drawData);
+    };
+    io.SetClipboardTextFn = [](void *user_data, const char *text) {
+        Q_UNUSED(user_data);
+        QGuiApplication::clipboard()->setText(text);
+    };
+    io.GetClipboardTextFn = [](void *user_data) {
+        Q_UNUSED(user_data);
+        g_currentClipboardText = QGuiApplication::clipboard()->text().toUtf8();
+        return (const char *)g_currentClipboardText.data();
+    };
+
+    window->installEventFilter(this);
+}
+
+void ImGuiRenderer::renderDrawList(ImDrawData *draw_data)
+{
+    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+    ImGuiIO& io = ImGui::GetIO();
+    int fb_width = (int)(io.DisplaySize.x * io.DisplayFramebufferScale.x);
+    int fb_height = (int)(io.DisplaySize.y * io.DisplayFramebufferScale.y);
+    if (fb_width == 0 || fb_height == 0)
+        return;
+    draw_data->ScaleClipRects(io.DisplayFramebufferScale);
+
+    // Backup GL state
+    GLint last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, &last_active_texture);
+    glActiveTexture(GL_TEXTURE0);
+    GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
+    GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
+    GLint last_element_array_buffer; glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
+    GLint last_vertex_array; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
+    GLint last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, &last_blend_src_rgb);
+    GLint last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, &last_blend_dst_rgb);
+    GLint last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, &last_blend_src_alpha);
+    GLint last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, &last_blend_dst_alpha);
+    GLint last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, &last_blend_equation_rgb);
+    GLint last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, &last_blend_equation_alpha);
+    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
+    GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
+    GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
+    GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
+    GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
+    GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
+
+    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
+    glEnable(GL_BLEND);
+    glBlendEquation(GL_FUNC_ADD);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glDisable(GL_CULL_FACE);
+    glDisable(GL_DEPTH_TEST);
+    glEnable(GL_SCISSOR_TEST);
+
+    // Setup viewport, orthographic projection matrix
+    glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
+    const float ortho_projection[4][4] =
+    {
+        { 2.0f/io.DisplaySize.x, 0.0f,                   0.0f, 0.0f },
+        { 0.0f,                  2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
+        { 0.0f,                  0.0f,                  -1.0f, 0.0f },
+        {-1.0f,                  1.0f,                   0.0f, 1.0f },
+    };
+    glUseProgram(g_ShaderHandle);
+    glUniform1i(g_AttribLocationTex, 0);
+    glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
+    glBindVertexArray(g_VaoHandle);
+
+    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    {
+        const ImDrawList* cmd_list = draw_data->CmdLists[n];
+        const ImDrawIdx* idx_buffer_offset = 0;
+
+        glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
+        glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
+
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
+        glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx), (const GLvoid*)cmd_list->IdxBuffer.Data, GL_STREAM_DRAW);
+
+        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
+        {
+            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
+            if (pcmd->UserCallback)
+            {
+                pcmd->UserCallback(cmd_list, pcmd);
+            }
+            else
+            {
+                glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
+                glScissor((int)pcmd->ClipRect.x, (int)(fb_height - pcmd->ClipRect.w), (int)(pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(pcmd->ClipRect.w - pcmd->ClipRect.y));
+                glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer_offset);
+            }
+            idx_buffer_offset += pcmd->ElemCount;
+        }
+    }
+
+    // Restore modified GL state
+    glUseProgram(last_program);
+    glBindTexture(GL_TEXTURE_2D, last_texture);
+    glActiveTexture(last_active_texture);
+    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);
+    glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
+    if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
+    if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
+    if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
+    if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
+    glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
+    glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
+}
+
+bool ImGuiRenderer::createFontsTexture()
+{
+    // Build texture atlas
+    ImGuiIO& io = ImGui::GetIO();
+    unsigned char* pixels;
+    int width, height;
+    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
+
+    // Upload texture to graphics system
+    GLint last_texture;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    glGenTextures(1, &g_FontTexture);
+    glBindTexture(GL_TEXTURE_2D, g_FontTexture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+    // Store our identifier
+    io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
+
+    // Restore state
+    glBindTexture(GL_TEXTURE_2D, last_texture);
+
+    return true;
+}
+
+bool ImGuiRenderer::createDeviceObjects()
+{
+    // Backup GL state
+    GLint last_texture, last_array_buffer, last_vertex_array;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
+    glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
+
+    const GLchar *vertex_shader =
+        "#version 330\n"
+        "uniform mat4 ProjMtx;\n"
+        "in vec2 Position;\n"
+        "in vec2 UV;\n"
+        "in vec4 Color;\n"
+        "out vec2 Frag_UV;\n"
+        "out vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "	Frag_UV = UV;\n"
+        "	Frag_Color = Color;\n"
+        "	gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
+        "}\n";
+
+    const GLchar* fragment_shader =
+        "#version 330\n"
+        "uniform sampler2D Texture;\n"
+        "in vec2 Frag_UV;\n"
+        "in vec4 Frag_Color;\n"
+        "out vec4 Out_Color;\n"
+        "void main()\n"
+        "{\n"
+        "	Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
+        "}\n";
+
+    g_ShaderHandle = glCreateProgram();
+    g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
+    g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(g_VertHandle, 1, &vertex_shader, 0);
+    glShaderSource(g_FragHandle, 1, &fragment_shader, 0);
+    glCompileShader(g_VertHandle);
+    glCompileShader(g_FragHandle);
+    glAttachShader(g_ShaderHandle, g_VertHandle);
+    glAttachShader(g_ShaderHandle, g_FragHandle);
+    glLinkProgram(g_ShaderHandle);
+
+    g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
+    g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
+    g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position");
+    g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV");
+    g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
+
+    glGenBuffers(1, &g_VboHandle);
+    glGenBuffers(1, &g_ElementsHandle);
+
+    glGenVertexArrays(1, &g_VaoHandle);
+    glBindVertexArray(g_VaoHandle);
+    glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
+    glEnableVertexAttribArray(g_AttribLocationPosition);
+    glEnableVertexAttribArray(g_AttribLocationUV);
+    glEnableVertexAttribArray(g_AttribLocationColor);
+
+#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
+    glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos));
+    glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv));
+    glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col));
+#undef OFFSETOF
+
+    createFontsTexture();
+
+    // Restore modified GL state
+    glBindTexture(GL_TEXTURE_2D, last_texture);
+    glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
+    glBindVertexArray(last_vertex_array);
+
+    return true;
+}
+
+void ImGuiRenderer::newFrame()
+{
+    if (!g_FontTexture)
+        createDeviceObjects();
+
+    ImGuiIO& io = ImGui::GetIO();
+
+    // Setup display size (every frame to accommodate for window resizing)
+    io.DisplaySize = ImVec2(m_window->size().width(), m_window->size().height());
+    io.DisplayFramebufferScale = ImVec2(m_window->devicePixelRatio(), m_window->devicePixelRatio());
+
+    // Setup time step
+    double current_time =  QDateTime::currentMSecsSinceEpoch() / double(1000);
+    io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f/60.0f);
+    g_Time = current_time;
+
+    // Setup inputs
+    // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
+    if (m_window->isActive())
+    {
+        auto pos = m_window->mapFromGlobal(QCursor::pos());
+        io.MousePos = ImVec2(pos.x(), pos.y());   // Mouse position in screen coordinates (set to -1,-1 if no mouse / on another screen, etc.)
+    }
+    else
+    {
+        io.MousePos = ImVec2(-1,-1);
+    }
+
+    for (int i = 0; i < 3; i++)
+    {
+        io.MouseDown[i] = g_MousePressed[i];
+    }
+
+    io.MouseWheelH = g_MouseWheelH;
+    io.MouseWheel = g_MouseWheel;
+    g_MouseWheelH = 0;
+    g_MouseWheel = 0;
+
+    // Hide OS mouse cursor if ImGui is drawing it
+    // glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL);
+
+    // Start the frame
+    ImGui::NewFrame();
+}
+
+void ImGuiRenderer::onMousePressedChange(QMouseEvent *event)
+{
+    g_MousePressed[0] = event->buttons() & Qt::LeftButton;
+    g_MousePressed[1] = event->buttons() & Qt::RightButton;
+    g_MousePressed[2] = event->buttons() & Qt::MiddleButton;
+}
+
+void ImGuiRenderer::onWheel(QWheelEvent *event)
+{
+    // 5 lines per unit
+    g_MouseWheelH += event->pixelDelta().x() / (ImGui::GetTextLineHeight());
+    g_MouseWheel += event->pixelDelta().y() / (5.0 * ImGui::GetTextLineHeight());
+}
+
+void ImGuiRenderer::onKeyPressRelease(QKeyEvent *event)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    if (keyMap.contains(event->key())) {
+        io.KeysDown[keyMap[event->key()]] = event->type() == QEvent::KeyPress;
+    }
+
+    if (event->type() == QEvent::KeyPress) {
+        QString text = event->text();
+        if (text.size() == 1) {
+            io.AddInputCharacter(text.at(0).unicode());
+        }
+    }
+
+#ifdef Q_OS_MAC
+    io.KeyCtrl = event->modifiers() & Qt::MetaModifier;
+    io.KeyShift = event->modifiers() & Qt::ShiftModifier;
+    io.KeyAlt = event->modifiers() & Qt::AltModifier;
+    io.KeySuper = event->modifiers() & Qt::ControlModifier; // Comamnd key
+#else
+    io.KeyCtrl = event->modifiers() & Qt::ControlModifier;
+    io.KeyShift = event->modifiers() & Qt::ShiftModifier;
+    io.KeyAlt = event->modifiers() & Qt::AltModifier;
+    io.KeySuper = event->modifiers() & Qt::MetaModifier;
+#endif
+}
+
+bool ImGuiRenderer::eventFilter(QObject *watched, QEvent *event)
+{
+    switch (event->type()) {
+    case QEvent::MouseButtonPress:
+    case QEvent::MouseButtonRelease:
+        this->onMousePressedChange(static_cast<QMouseEvent *>(event));
+        break;
+    case QEvent::Wheel:
+        this->onWheel(static_cast<QWheelEvent *>(event));
+        break;
+    case QEvent::KeyPress:
+    case QEvent::KeyRelease:
+        this->onKeyPressRelease(static_cast<QKeyEvent *>(event));
+        break;
+    default:
+        break;
+    }
+    return QObject::eventFilter(watched, event);
+}
+
+ImGuiRenderer* ImGuiRenderer::instance() {
+    static ImGuiRenderer* instance = nullptr;
+    if (!instance) {
+        instance = new ImGuiRenderer();
+    }
+    return instance;
+}
+
+}
diff --git a/3rdparty/qtimgui/ImGuiRenderer.h b/3rdparty/qtimgui/ImGuiRenderer.h
new file mode 100644
index 00000000..ca69ffaa
--- /dev/null
+++ b/3rdparty/qtimgui/ImGuiRenderer.h
@@ -0,0 +1,58 @@
+#pragma once
+
+#include <QOpenGLExtraFunctions>
+#include <QObject>
+#include <QPoint>
+#include <imgui.h>
+#include <memory>
+
+class QMouseEvent;
+class QWheelEvent;
+class QKeyEvent;
+
+namespace QtImGui {
+
+class WindowWrapper {
+public:
+    virtual ~WindowWrapper() {}
+    virtual void installEventFilter(QObject *object) = 0;
+    virtual QSize size() const = 0;
+    virtual qreal devicePixelRatio() const = 0;
+    virtual bool isActive() const = 0;
+    virtual QPoint mapFromGlobal(const QPoint &p) const = 0;
+};
+
+class ImGuiRenderer : public QObject, QOpenGLExtraFunctions {
+    Q_OBJECT
+public:
+    void initialize(WindowWrapper *window);
+    void newFrame();
+
+    bool eventFilter(QObject *watched, QEvent *event);
+
+    static ImGuiRenderer *instance();
+
+private:
+    ImGuiRenderer() {}
+
+    void onMousePressedChange(QMouseEvent *event);
+    void onWheel(QWheelEvent *event);
+    void onKeyPressRelease(QKeyEvent *event);
+
+    void renderDrawList(ImDrawData *draw_data);
+    bool createFontsTexture();
+    bool createDeviceObjects();
+
+    std::unique_ptr<WindowWrapper> m_window;
+    double       g_Time = 0.0f;
+    bool         g_MousePressed[3] = { false, false, false };
+    float        g_MouseWheel;
+    float        g_MouseWheelH;
+    GLuint       g_FontTexture = 0;
+    int          g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
+    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;
+};
+
+}
diff --git a/3rdparty/qtimgui/LICENSE b/3rdparty/qtimgui/LICENSE
new file mode 100644
index 00000000..7c7077fc
--- /dev/null
+++ b/3rdparty/qtimgui/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 Ryohei Ikegami
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/3rdparty/qtimgui/QtImGui.cpp b/3rdparty/qtimgui/QtImGui.cpp
new file mode 100644
index 00000000..97205389
--- /dev/null
+++ b/3rdparty/qtimgui/QtImGui.cpp
@@ -0,0 +1,78 @@
+#include "QtImGui.h"
+#include "ImGuiRenderer.h"
+#include <QWindow>
+#ifdef QT_WIDGETS_LIB
+#include <QWidget>
+#endif
+
+namespace QtImGui {
+
+#ifdef QT_WIDGETS_LIB
+
+namespace {
+
+class QWidgetWindowWrapper : public WindowWrapper {
+public:
+    QWidgetWindowWrapper(QWidget *w) : w(w) {}
+    void installEventFilter(QObject *object) override {
+        return w->installEventFilter(object);
+    }
+    QSize size() const override {
+        return w->size();
+    }
+    qreal devicePixelRatio() const override {
+        return w->devicePixelRatioF();
+    }
+    bool isActive() const override {
+        return w->isActiveWindow();
+    }
+    QPoint mapFromGlobal(const QPoint &p) const override {
+        return w->mapFromGlobal(p);
+    }
+private:
+    QWidget *w;
+};
+
+}
+
+void initialize(QWidget *window) {
+    ImGuiRenderer::instance()->initialize(new QWidgetWindowWrapper(window));
+}
+
+#endif
+
+namespace {
+
+class QWindowWindowWrapper : public WindowWrapper {
+public:
+    QWindowWindowWrapper(QWindow *w) : w(w) {}
+    void installEventFilter(QObject *object) override {
+        return w->installEventFilter(object);
+    }
+    QSize size() const override {
+        return w->size();
+    }
+    qreal devicePixelRatio() const override {
+        return w->devicePixelRatio();
+    }
+    bool isActive() const override {
+        return w->isActive();
+    }
+    QPoint mapFromGlobal(const QPoint &p) const override {
+        return w->mapFromGlobal(p);
+    }
+private:
+    QWindow *w;
+};
+
+}
+
+void initialize(QWindow *window) {
+    ImGuiRenderer::instance()->initialize(new QWindowWindowWrapper(window));
+}
+
+void newFrame() {
+    ImGuiRenderer::instance()->newFrame();
+}
+
+}
diff --git a/3rdparty/qtimgui/QtImGui.h b/3rdparty/qtimgui/QtImGui.h
new file mode 100644
index 00000000..337e67c0
--- /dev/null
+++ b/3rdparty/qtimgui/QtImGui.h
@@ -0,0 +1,15 @@
+#pragma once
+
+class QWidget;
+class QWindow;
+
+namespace QtImGui {
+
+#ifdef QT_WIDGETS_LIB
+void initialize(QWidget *window);
+#endif
+
+void initialize(QWindow *window);
+void newFrame();
+
+}
diff --git a/3rdparty/qtimgui/README.md b/3rdparty/qtimgui/README.md
new file mode 100644
index 00000000..16a46f55
--- /dev/null
+++ b/3rdparty/qtimgui/README.md
@@ -0,0 +1,38 @@
+# QtImGui
+
+Qt (QOpenGLWidget / QOpenGLWindow) backend for [ImGui](https://github.com/ocornut/imgui)
+
+It enables ImGui to run in QOpenGLWidget / QOpenGLWindow.
+
+[![https://gyazo.com/eb68699c96b9147cca3d5ea9fadfc263](https://i.gyazo.com/eb68699c96b9147cca3d5ea9fadfc263.gif)](https://gyazo.com/eb68699c96b9147cca3d5ea9fadfc263)
+
+## How to use
+
+* Add QtImGui sources and headers to your project
+    * If you are using git submodule, run `git submodule update --init --recursive` to ensure that the inner submodule is initialized as well.
+* Add `include(path/to/qtimgui.pri)` to youre `.pro` file
+* Subclass `QOpenGLWindow` or `QOpenGLWidget` and:
+
+```cpp
+class DemoWindow : public QOpenGLWindow
+{
+protected:
+    void initializeGL() override
+    {
+        QtImGui::initialize(this);
+    }
+    void paintGL() override
+    {
+        // you can do custom GL rendering as well in paintGL
+
+        QtImGui::newFrame();
+
+        ImGui::Text("Hello");
+        // more widgets...
+
+        ImGui::Render();
+    }
+};
+```
+
+See [QOpenGLWidget example](demo-widget/demo-widget.cpp) and [QOpenGLWindow example](/demo-window/demo-window.cpp) for details.
diff --git a/3rdparty/qtimgui/demo-widget/demo-widget.cpp b/3rdparty/qtimgui/demo-widget/demo-widget.cpp
new file mode 100644
index 00000000..f0c44bef
--- /dev/null
+++ b/3rdparty/qtimgui/demo-widget/demo-widget.cpp
@@ -0,0 +1,85 @@
+#include <QtImGui.h>
+#include <imgui.h>
+#include <QApplication>
+#include <QTimer>
+#include <QSurfaceFormat>
+#include <QOpenGLWidget>
+#include <QOpenGLExtraFunctions>
+
+class DemoWindow : public QOpenGLWidget, private QOpenGLExtraFunctions
+{
+protected:
+    void initializeGL() override
+    {
+        initializeOpenGLFunctions();
+        QtImGui::initialize(this);
+    }
+    void paintGL() override
+    {
+        QtImGui::newFrame();
+
+        // 1. Show a simple window
+        // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
+        {
+            static float f = 0.0f;
+            ImGui::Text("Hello, world!");
+            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
+            ImGui::ColorEdit3("clear color", (float*)&clear_color);
+            if (ImGui::Button("Test Window")) show_test_window ^= 1;
+            if (ImGui::Button("Another Window")) show_another_window ^= 1;
+            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
+        }
+
+        // 2. Show another simple window, this time using an explicit Begin/End pair
+        if (show_another_window)
+        {
+            ImGui::SetNextWindowSize(ImVec2(200,100), ImGuiSetCond_FirstUseEver);
+            ImGui::Begin("Another Window", &show_another_window);
+            ImGui::Text("Hello");
+            ImGui::End();
+        }
+
+        // 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow()
+        if (show_test_window)
+        {
+            ImGui::SetNextWindowPos(ImVec2(650, 20), ImGuiSetCond_FirstUseEver);
+            ImGui::ShowTestWindow();
+        }
+
+        // Do render before ImGui UI is rendered
+        glViewport(0, 0, width(), height());
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        ImGui::Render();
+    }
+
+private:
+    bool show_test_window = true;
+    bool show_another_window = false;
+    ImVec4 clear_color = ImColor(114, 144, 154);
+};
+
+int main(int argc, char *argv[])
+{
+    // Use OpenGL 3 Core Profile
+    QSurfaceFormat glFormat;
+    glFormat.setVersion(3, 3);
+    glFormat.setProfile(QSurfaceFormat::CoreProfile);
+    QSurfaceFormat::setDefaultFormat(glFormat);
+
+    QApplication a(argc, argv);
+
+    // Show window
+    DemoWindow w;
+    w.setWindowTitle("QtImGui widget example");
+    w.resize(1280, 720);
+    w.show();
+
+    // Update at 60 fps
+    QTimer timer;
+    QObject::connect(&timer, SIGNAL(timeout()), &w, SLOT(update()));
+    timer.start(16);
+
+    return a.exec();
+}
diff --git a/3rdparty/qtimgui/demo-widget/demo-widget.pro b/3rdparty/qtimgui/demo-widget/demo-widget.pro
new file mode 100644
index 00000000..d3492da9
--- /dev/null
+++ b/3rdparty/qtimgui/demo-widget/demo-widget.pro
@@ -0,0 +1,8 @@
+QT       += core gui widgets
+TARGET = demo-widget
+TEMPLATE = app
+
+include(../qtimgui.pri)
+
+SOURCES += \
+    demo-widget.cpp
diff --git a/3rdparty/qtimgui/demo-window/demo-window.cpp b/3rdparty/qtimgui/demo-window/demo-window.cpp
new file mode 100644
index 00000000..b86c5c85
--- /dev/null
+++ b/3rdparty/qtimgui/demo-window/demo-window.cpp
@@ -0,0 +1,85 @@
+#include <QtImGui.h>
+#include <imgui.h>
+#include <QGuiApplication>
+#include <QTimer>
+#include <QSurfaceFormat>
+#include <QOpenGLWindow>
+#include <QOpenGLExtraFunctions>
+
+class DemoWindow : public QOpenGLWindow, private QOpenGLExtraFunctions
+{
+protected:
+    void initializeGL() override
+    {
+        initializeOpenGLFunctions();
+        QtImGui::initialize(this);
+    }
+    void paintGL() override
+    {
+        QtImGui::newFrame();
+
+        // 1. Show a simple window
+        // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
+        {
+            static float f = 0.0f;
+            ImGui::Text("Hello, world!");
+            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
+            ImGui::ColorEdit3("clear color", (float*)&clear_color);
+            if (ImGui::Button("Test Window")) show_test_window ^= 1;
+            if (ImGui::Button("Another Window")) show_another_window ^= 1;
+            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
+        }
+
+        // 2. Show another simple window, this time using an explicit Begin/End pair
+        if (show_another_window)
+        {
+            ImGui::SetNextWindowSize(ImVec2(200,100), ImGuiSetCond_FirstUseEver);
+            ImGui::Begin("Another Window", &show_another_window);
+            ImGui::Text("Hello");
+            ImGui::End();
+        }
+
+        // 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow()
+        if (show_test_window)
+        {
+            ImGui::SetNextWindowPos(ImVec2(650, 20), ImGuiSetCond_FirstUseEver);
+            ImGui::ShowTestWindow();
+        }
+
+        // Do render before ImGui UI is rendered
+        glViewport(0, 0, width(), height());
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        ImGui::Render();
+    }
+
+private:
+    bool show_test_window = true;
+    bool show_another_window = false;
+    ImVec4 clear_color = ImColor(114, 144, 154);
+};
+
+int main(int argc, char *argv[])
+{
+    // Use OpenGL 3 Core Profile
+    QSurfaceFormat glFormat;
+    glFormat.setVersion(3, 3);
+    glFormat.setProfile(QSurfaceFormat::CoreProfile);
+    QSurfaceFormat::setDefaultFormat(glFormat);
+
+    QGuiApplication a(argc, argv);
+
+    // Show window
+    DemoWindow w;
+    w.setTitle("QtImGui window example");
+    w.resize(1280, 720);
+    w.show();
+
+    // Update at 60 fps
+    QTimer timer;
+    QObject::connect(&timer, SIGNAL(timeout()), &w, SLOT(update()));
+    timer.start(16);
+
+    return a.exec();
+}
diff --git a/3rdparty/qtimgui/demo-window/demo-window.pro b/3rdparty/qtimgui/demo-window/demo-window.pro
new file mode 100644
index 00000000..92032c4a
--- /dev/null
+++ b/3rdparty/qtimgui/demo-window/demo-window.pro
@@ -0,0 +1,8 @@
+QT       += core gui
+TARGET = demo-window
+TEMPLATE = app
+
+include(../qtimgui.pri)
+
+SOURCES += \
+    demo-window.cpp
diff --git a/3rdparty/qtimgui/qtimgui.pri b/3rdparty/qtimgui/qtimgui.pri
new file mode 100644
index 00000000..21ac0813
--- /dev/null
+++ b/3rdparty/qtimgui/qtimgui.pri
@@ -0,0 +1,13 @@
+
+SOURCES += \
+    $$PWD/imgui/imgui_draw.cpp \
+    $$PWD/imgui/imgui.cpp \
+    $$PWD/imgui/imgui_demo.cpp \
+    $$PWD/ImGuiRenderer.cpp \
+    $$PWD/QtImGui.cpp
+
+INCLUDEPATH += $$PWD/imgui $$PWD
+
+HEADERS += \
+    $$PWD/ImGuiRenderer.h \
+    $$PWD/QtImGui.h
diff --git a/3rdparty/qtimgui/qtimgui.pro b/3rdparty/qtimgui/qtimgui.pro
new file mode 100644
index 00000000..0f1791fc
--- /dev/null
+++ b/3rdparty/qtimgui/qtimgui.pro
@@ -0,0 +1,3 @@
+TEMPLATE = subdirs
+
+SUBDIRS += demo-widget demo-window