Gl version detection

CMakeLists.txt

@@ -23,11 +23,12 @@ else()
   set(NANOGUI_USE_GLAD_DEFAULT OFF)
 endif()
 
-option(NANOGUI_BUILD_EXAMPLE "Build NanoGUI example application?" ON)
-option(NANOGUI_BUILD_SHARED  "Build NanoGUI as a shared library?" ON)
-option(NANOGUI_BUILD_PYTHON  "Build a Python plugin for NanoGUI?" ON)
-option(NANOGUI_USE_GLAD      "Use Glad OpenGL loader library?" ${NANOGUI_USE_GLAD_DEFAULT})
-option(NANOGUI_INSTALL       "Install NanoGUI on `make install`?" ON)
+option(NANOGUI_BUILD_EXAMPLE         "Build NanoGUI example application?" ON)
+option(NANOGUI_BUILD_SHARED          "Build NanoGUI as a shared library?" ON)
+option(NANOGUI_BUILD_PYTHON          "Build a Python plugin for NanoGUI?" ON)
+option(NANOGUI_USE_GLAD              "Use Glad OpenGL loader library?" ${NANOGUI_USE_GLAD_DEFAULT})
+option(NANOGUI_INSTALL               "Install NanoGUI on `make install`?" ON)
+option(NANOGUI_DEFAULT_GL_VERSION    "Default to GL3 compatability?"      ON)
 
 set(NANOGUI_PYTHON_VERSION "" CACHE STRING "Python version to use for compiling the Python plugin")
 
@@ -86,6 +87,11 @@ add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/ext/glfw" "ext_build/glfw")
 # XCode, but preferable for all build systems (reduces build artifacts).
 set_target_properties(glfw PROPERTIES EXCLUDE_FROM_ALL 1 EXCLUDE_FROM_DEFAULT_BUILD 1)
 
+# GL Version support: add NANOVG_GL3_IMPLEMENTATION unless disabled
+if (NANOGUI_DEFAULT_GL_VERSION)
+  list(APPEND NANOGUI_EXTRA_DEFS -DNANOVG_GL3_IMPLEMENTATION)
+endif()
+
 # Python support: add NANOGUI_PYTHON flag to all targets
 if (NANOGUI_BUILD_PYTHON)
   list(APPEND NANOGUI_EXTRA_DEFS -DNANOGUI_PYTHON)

include/nanogui/screen.h

@@ -16,6 +16,10 @@
 
 #include <nanogui/widget.h>
 
+#if defined(NANOVG_GL2_IMPLEMENTATION) || defined(NANOVG_GLES2_IMPLEMENTATION)
+#define NANOGUI_CURSOR_DISABLED
+#endif
+
 NAMESPACE_BEGIN(nanogui)
 
 /**
@@ -187,8 +191,10 @@ class NANOGUI_EXPORT Screen : public Widget {
 protected:
     GLFWwindow *mGLFWWindow;
     NVGcontext *mNVGContext;
+#if !defined(NANOGUI_CURSOR_DISABLED)
     GLFWcursor *mCursors[(int) Cursor::CursorCount];
     Cursor mCursor;
+#endif
     std::vector<Widget *> mFocusPath;
     Vector2i mFBSize;
     float mPixelRatio;

src/common.cpp

@@ -78,7 +78,9 @@ void mainloop(int refresh) {
                 std::chrono::milliseconds time(refresh);
                 while (mainloop_active) {
                     std::this_thread::sleep_for(time);
+#if !defined(NANOVG_GL2_IMPLEMENTATION) && !defined(NANOVG_GLES2_IMPLEMENTATION)
                     glfwPostEmptyEvent();
+#endif
                 }
             }
         );

src/screen.cpp

@@ -31,8 +31,6 @@
 #  include <GLFW/glfw3native.h>
 #endif
 
-/* Allow enforcing the GL2 implementation of NanoVG */
-#define NANOVG_GL3_IMPLEMENTATION
 #include <nanovg_gl.h>
 
 NAMESPACE_BEGIN(nanogui)
@@ -43,6 +41,33 @@ std::map<GLFWwindow *, Screen *> __nanogui_screens;
 static bool gladInitialized = false;
 #endif
 
+inline NVGcontext* nvgCreateContext(int flags) {
+#if defined(NANOVG_GL2_IMPLEMENTATION)
+  return nvgCreateGL2(flags);
+#elif defined(NANOVG_GL3_IMPLEMENTATION)
+  return nvgCreateGL3(flags);
+#elif defined(NANOVG_GLES2_IMPLEMENTATION)
+  return nvgCreateGLES2(flags);
+#elif defined(NANOVG_GLES3_IMPLEMENTATION)
+  return nvgCreateGLES3(flags);
+#else
+#error No NANOVG_GL*_IMPLEMENTATION macro defined
+#endif
+}
+inline void nvgDeleteContext(NVGcontext* ctx) {
+#if defined(NANOVG_GL2_IMPLEMENTATION)
+  nvgDeleteGL2(ctx);
+#elif defined(NANOVG_GL3_IMPLEMENTATION)
+  nvgDeleteGL3(ctx);
+#elif defined(NANOVG_GLES2_IMPLEMENTATION)
+  nvgDeleteGLES2(ctx);
+#elif defined(NANOVG_GLES3_IMPLEMENTATION)
+  nvgDeleteGLES3(ctx);
+#else
+#error No NANOVG_GL*_IMPLEMENTATION macro defined
+#endif
+}
+
 /* Calculate pixel ratio for hi-dpi devices. */
 static float get_pixel_ratio(GLFWwindow *window) {
 #if defined(_WIN32)
@@ -118,19 +143,29 @@ static float get_pixel_ratio(GLFWwindow *window) {
 
 Screen::Screen()
     : Widget(nullptr), mGLFWWindow(nullptr), mNVGContext(nullptr),
-      mCursor(Cursor::Arrow), mBackground(0.3f, 0.3f, 0.32f, 1.f),
+#if !defined(NANOGUI_CURSOR_DISABLED)
+      mCursor(Cursor::Arrow),
+#endif
+      mBackground(0.3f, 0.3f, 0.32f, 1.f),
       mShutdownGLFWOnDestruct(false), mFullscreen(false) {
+#if !defined(NANOGUI_CURSOR_DISABLED)
     memset(mCursors, 0, sizeof(GLFWcursor *) * (int) Cursor::CursorCount);
+#endif
 }
 
 Screen::Screen(const Vector2i &size, const std::string &caption, bool resizable,
                bool fullscreen, int colorBits, int alphaBits, int depthBits,
                int stencilBits, int nSamples,
                unsigned int glMajor, unsigned int glMinor)
     : Widget(nullptr), mGLFWWindow(nullptr), mNVGContext(nullptr),
-      mCursor(Cursor::Arrow), mBackground(0.3f, 0.3f, 0.32f, 1.f), mCaption(caption),
+#if !defined(NANOGUI_CURSOR_DISABLED)
+      mCursor(Cursor::Arrow),
+#endif
+      mBackground(0.3f, 0.3f, 0.32f, 1.f), mCaption(caption),
       mShutdownGLFWOnDestruct(false), mFullscreen(fullscreen) {
+#if !defined(NANOGUI_CURSOR_DISABLED)
     memset(mCursors, 0, sizeof(GLFWcursor *) * (int) Cursor::CursorCount);
+#endif
 
     /* Request a forward compatible OpenGL glMajor.glMinor core profile context.
        Default value is an OpenGL 3.3 core profile context. */
@@ -240,6 +275,7 @@ Screen::Screen(const Vector2i &size, const std::string &caption, bool resizable,
         }
     );
 
+#if !defined(NANOVG_GL2_IMPLEMENTATION) && !defined(NANOVG_GLES2_IMPLEMENTATION)
     glfwSetDropCallback(mGLFWWindow,
         [](GLFWwindow *w, int count, const char **filenames) {
             auto it = __nanogui_screens.find(w);
@@ -251,6 +287,7 @@ Screen::Screen(const Vector2i &size, const std::string &caption, bool resizable,
             s->dropCallbackEvent(count, filenames);
         }
     );
+#endif
 
     glfwSetScrollCallback(mGLFWWindow,
         [](GLFWwindow *w, double x, double y) {
@@ -335,7 +372,7 @@ void Screen::initialize(GLFWwindow *window, bool shutdownGLFWOnDestruct) {
     flags |= NVG_DEBUG;
 #endif
 
-    mNVGContext = nvgCreateGL3(flags);
+    mNVGContext = nvgCreateContext(flags);
     if (mNVGContext == nullptr)
         throw std::runtime_error("Could not initialize NanoVG!");
 
@@ -348,8 +385,10 @@ void Screen::initialize(GLFWwindow *window, bool shutdownGLFWOnDestruct) {
     mProcessEvents = true;
     __nanogui_screens[mGLFWWindow] = this;
 
+#if !defined(NANOGUI_CURSOR_DISABLED)
     for (int i=0; i < (int) Cursor::CursorCount; ++i)
         mCursors[i] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR + i);
+#endif
 
     /// Fixes retina display-related font rendering issue (#185)
     nvgBeginFrame(mNVGContext, mSize[0], mSize[1], mPixelRatio);
@@ -358,12 +397,14 @@ void Screen::initialize(GLFWwindow *window, bool shutdownGLFWOnDestruct) {
 
 Screen::~Screen() {
     __nanogui_screens.erase(mGLFWWindow);
+#if !defined(NANOGUI_CURSOR_DISABLED)
     for (int i=0; i < (int) Cursor::CursorCount; ++i) {
         if (mCursors[i])
             glfwDestroyCursor(mCursors[i]);
     }
+#endif
     if (mNVGContext)
-        nvgDeleteGL3(mNVGContext);
+        nvgDeleteContext(mNVGContext);
     if (mGLFWWindow && mShutdownGLFWOnDestruct)
         glfwDestroyWindow(mGLFWWindow);
 }
@@ -425,7 +466,9 @@ void Screen::drawWidgets() {
 #endif
 
     glViewport(0, 0, mFBSize[0], mFBSize[1]);
+#if !defined(NANOVG_GL2_IMPLEMENTATION) && !defined(NANOVG_GLES2_IMPLEMENTATION)
     glBindSampler(0, 0);
+#endif
     nvgBeginFrame(mNVGContext, mSize[0], mSize[1], mPixelRatio);
 
     draw(mNVGContext);
@@ -521,11 +564,13 @@ bool Screen::cursorPosCallbackEvent(double x, double y) {
         p -= Vector2i(1, 2);
 
         if (!mDragActive) {
+#if !defined(NANOGUI_CURSOR_DISABLED)
             Widget *widget = findWidget(p);
             if (widget != nullptr && widget->cursor() != mCursor) {
                 mCursor = widget->cursor();
                 glfwSetCursor(mGLFWWindow, mCursors[(int) mCursor]);
             }
+#endif
         } else {
             ret = mDragWidget->mouseDragEvent(
                 p - mDragWidget->parent()->absolutePosition(), p - mMousePos,
@@ -569,10 +614,12 @@ bool Screen::mouseButtonCallbackEvent(int button, int action, int modifiers) {
                 mMousePos - mDragWidget->parent()->absolutePosition(), button,
                 false, mModifiers);
 
+#if !defined(NANOGUI_CURSOR_DISABLED)
         if (dropWidget != nullptr && dropWidget->cursor() != mCursor) {
             mCursor = dropWidget->cursor();
             glfwSetCursor(mGLFWWindow, mCursors[(int) mCursor]);
         }
+#endif
 
         if (action == GLFW_PRESS && (button == GLFW_MOUSE_BUTTON_1 || button == GLFW_MOUSE_BUTTON_2)) {
             mDragWidget = findWidget(mMousePos);