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Mathias Gredal
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Implement a backend for BGFX
1 parent bad0588 commit 17a8a3b

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‎imgui-app/build.gradle‎

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@@ -18,11 +18,13 @@ dependencies {
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api 'org.lwjgl:lwjgl'
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api 'org.lwjgl:lwjgl-glfw'
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api 'org.lwjgl:lwjgl-opengl'
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api 'org.lwjgl:lwjgl-bgfx'
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['natives-linux', 'natives-windows', 'natives-macos'].each {
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api "org.lwjgl:lwjgl::$it"
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api "org.lwjgl:lwjgl-glfw::$it"
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api "org.lwjgl:lwjgl-opengl::$it"
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api "org.lwjgl:lwjgl-bgfx::$it"
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}
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api project(':imgui-binding')

‎imgui-app/src/main/java/imgui/app/BGFXWindow.java‎

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package imgui.app;
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import imgui.ImGui;
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import imgui.bgfx.ImGuiImplBGFX;
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import imgui.flag.ImGuiConfigFlags;
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import imgui.glfw.ImGuiImplGlfw;
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import org.lwjgl.BufferUtils;
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import org.lwjgl.bgfx.BGFXInit;
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import org.lwjgl.glfw.GLFW;
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import org.lwjgl.glfw.*;
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import org.lwjgl.system.MemoryStack;
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import org.lwjgl.system.MemoryUtil;
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import org.lwjgl.system.Platform;
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import java.nio.IntBuffer;
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import java.util.Objects;
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import static org.lwjgl.bgfx.BGFX.*;
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import static org.lwjgl.glfw.GLFW.*;
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import static org.lwjgl.system.Configuration.GLFW_LIBRARY_NAME;
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import static org.lwjgl.system.MemoryStack.stackPush;
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public abstract class BGFXWindow {
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private final ImGuiImplBGFX imGuiBGFX = new ImGuiImplBGFX();
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private final ImGuiImplGlfw imGuiGlfw = new ImGuiImplGlfw();
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/**
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* Pointer to the native GLFW window.
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*/
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protected long handle;
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/**
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* Background color of the window.
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*/
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protected final Color colorBg = new Color(.5f, .5f, .5f, 1);
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/**
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* Method to initialize application.
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*
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* @param config configuration object with basic window information
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*/
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protected void init(final Configuration config) {
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initWindow(config);
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initImGui(config);
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imGuiGlfw.init(handle, true);
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imGuiBGFX.init();
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}
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/**
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* Method to dispose all used application resources and destroy its window.
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*/
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protected void dispose() {
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imGuiBGFX.dispose();
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imGuiGlfw.dispose();
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disposeImGui();
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disposeWindow();
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}
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/**
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* Method to create and initialize GLFW window.
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*
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* @param config configuration object with basic window information
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*/
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protected void initWindow(final Configuration config) {
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if (Platform.get() == Platform.MACOSX) {
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GLFW_LIBRARY_NAME.set("glfw_async");
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}
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GLFWErrorCallback.createPrint(System.err).set();
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if (!GLFW.glfwInit()) {
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throw new IllegalStateException("Unable to initialize GLFW");
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}
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glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
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handle = glfwCreateWindow(config.getWidth(), config.getHeight(), config.getTitle(), MemoryUtil.NULL, MemoryUtil.NULL);
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if (handle == MemoryUtil.NULL) {
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throw new RuntimeException("Failed to create the GLFW window");
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}
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try (MemoryStack stack = stackPush()) {
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final IntBuffer pWidth = stack.mallocInt(1); // int*
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final IntBuffer pHeight = stack.mallocInt(1); // int*
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GLFW.glfwGetWindowSize(handle, pWidth, pHeight);
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final GLFWVidMode vidmode = Objects.requireNonNull(GLFW.glfwGetVideoMode(GLFW.glfwGetPrimaryMonitor()));
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GLFW.glfwSetWindowPos(handle, (vidmode.width() - pWidth.get(0)) / 2, (vidmode.height() - pHeight.get(0)) / 2);
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}
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try (MemoryStack stack = stackPush()) {
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BGFXInit init = BGFXInit.malloc(stack);
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bgfx_init_ctor(init);
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init.resolution(it -> it
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.width(config.getWidth())
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.height(config.getHeight())
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.reset(BGFX_RESET_VSYNC));
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switch (Platform.get()) {
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case LINUX:
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init.platformData()
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.ndt(GLFWNativeX11.glfwGetX11Display())
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.nwh(GLFWNativeX11.glfwGetX11Window(handle));
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break;
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case MACOSX:
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init.platformData()
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.nwh(GLFWNativeCocoa.glfwGetCocoaWindow(handle));
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break;
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case WINDOWS:
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init.platformData()
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.nwh(GLFWNativeWin32.glfwGetWin32Window(handle));
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break;
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}
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if (!bgfx_init(init)) {
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throw new RuntimeException("Error initializing bgfx renderer");
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}
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}
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if (config.isFullScreen()) {
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GLFW.glfwMaximizeWindow(handle);
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} else {
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GLFW.glfwShowWindow(handle);
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}
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clearBuffer();
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renderBuffer();
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GLFW.glfwSetWindowSizeCallback(handle, new GLFWWindowSizeCallback() {
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@Override
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public void invoke(final long window, final int width, final int height) {
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runFrame();
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}
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});
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}
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/**
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* Method to initialize Dear ImGui context. Could be overridden to do custom Dear ImGui setup before application start.
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*
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* @param config configuration object with basic window information
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*/
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protected void initImGui(final Configuration config) {
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ImGui.createContext();
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}
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/**
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* Method called every frame, before calling {@link #process()} method.
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*/
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protected void preProcess() {
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}
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/**
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* Method called every frame, after calling {@link #process()} method.
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*/
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protected void postProcess() {
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}
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/**
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* Main application loop.
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*/
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protected void run() {
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while (!GLFW.glfwWindowShouldClose(handle)) {
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runFrame();
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}
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}
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/**
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* Method used to run the next frame.
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*/
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protected void runFrame() {
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startFrame();
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preProcess();
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process();
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postProcess();
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endFrame();
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}
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/**
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* Method to be overridden by user to provide main application logic.
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*/
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public abstract void process();
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/**
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* Method used to clear the OpenGL buffer.
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*/
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private void clearBuffer() {
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int color = Math.round(colorBg.getRed() * 255);
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color = (color << 8) + Math.round(colorBg.getGreen() * 255);
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color = (color << 8) + Math.round(colorBg.getBlue() * 255);
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color = (color << 8) + Math.round(colorBg.getAlpha() * 255);
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bgfx_set_view_clear(0, BGFX_CLEAR_COLOR | BGFX_CLEAR_DEPTH, color, 1.0f, 0);
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IntBuffer w = BufferUtils.createIntBuffer(1);
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IntBuffer h = BufferUtils.createIntBuffer(1);
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glfwGetWindowSize(getHandle(), w, h);
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int width = w.get(0);
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int height = h.get(0);
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bgfx_set_view_rect(0, 0, 0, width, height);
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}
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/**
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* Method called at the beginning of the main cycle.
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* It clears OpenGL buffer and starts an ImGui frame.
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*/
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protected void startFrame() {
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clearBuffer();
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imGuiGlfw.newFrame();
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ImGui.newFrame();
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}
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/**
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* Method called in the end of the main cycle.
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* It renders ImGui and swaps GLFW buffers to show an updated frame.
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*/
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protected void endFrame() {
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ImGui.render();
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imGuiBGFX.renderDrawData(ImGui.getDrawData());
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if (ImGui.getIO().hasConfigFlags(ImGuiConfigFlags.ViewportsEnable)) {
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final long backupWindowPtr = GLFW.glfwGetCurrentContext();
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ImGui.updatePlatformWindows();
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ImGui.renderPlatformWindowsDefault();
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GLFW.glfwMakeContextCurrent(backupWindowPtr);
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}
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renderBuffer();
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}
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/**
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* Method to render the OpenGL buffer and poll window events.
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*/
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private void renderBuffer() {
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bgfx_frame(false);
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GLFW.glfwPollEvents();
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}
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/**
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* Method to destroy Dear ImGui context.
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*/
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protected void disposeImGui() {
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ImGui.destroyContext();
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}
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/**
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* Method to destroy GLFW window.
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*/
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protected void disposeWindow() {
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bgfx_shutdown();
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Callbacks.glfwFreeCallbacks(handle);
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GLFW.glfwDestroyWindow(handle);
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GLFW.glfwTerminate();
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Objects.requireNonNull(GLFW.glfwSetErrorCallback(null)).free();
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}
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/**
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* @return pointer to the native GLFW window
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*/
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public final long getHandle() {
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return handle;
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}
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/**
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* @return {@link Color} instance, which represents background color for the window
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*/
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public final Color getColorBg() {
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return colorBg;
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}
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}

‎imgui-lwjgl3/build.gradle‎

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@@ -17,6 +17,7 @@ dependencies {
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implementation 'org.lwjgl:lwjgl'
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implementation 'org.lwjgl:lwjgl-glfw'
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implementation 'org.lwjgl:lwjgl-opengl'
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implementation 'org.lwjgl:lwjgl-bgfx'
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implementation project(':imgui-binding')
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}

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