odin_imgui_example

gistfile1.txt

package main

import "core:log"
import "core:runtime"
import gl   "vendor:OpenGL"
// import glfw "shared:odin-glfw"
import "vendor:glfw"

DESIRED_GL_MAJOR_VERSION :: 4;
DESIRED_GL_MINOR_VERSION :: 5;

import imgui  "../odin-imgui";
import imgl   "../odin-imgui/impl/opengl";
import imglfw "../odin-imgui/impl/glfw";

main :: proc() {
    // Make sure we can set up GLFW
    if !bool(glfw.Init()) {
        desc, err := glfw.GetError();
        log.error("GLFW init failed:", err, desc);
        return;
    }
    defer glfw.Terminate();

    glfw.WindowHint(glfw.CONTEXT_VERSION_MAJOR, DESIRED_GL_MAJOR_VERSION);
    glfw.WindowHint(glfw.CONTEXT_VERSION_MINOR, DESIRED_GL_MINOR_VERSION);
    glfw.WindowHint(glfw.OPENGL_PROFILE, glfw.OPENGL_CORE_PROFILE);
    glfw.WindowHint(glfw.DOUBLEBUFFER, 1);
    glfw.WindowHint(glfw.DEPTH_BITS, 24);
    glfw.WindowHint(glfw.STENCIL_BITS, 8);

    window := glfw.CreateWindow(1280, 720, "GitBuilding UI", nil, nil);
    defer glfw.DestroyWindow(window);

    glfw.SetErrorCallback(error_callback);
    // glfw.set_key_callback(window, key_callback);

    glfw.MakeContextCurrent(window);
    glfw.SwapInterval(1);

    gl.load_up_to(DESIRED_GL_MAJOR_VERSION, DESIRED_GL_MINOR_VERSION, proc(p: rawptr, name: cstring) { (cast(^rawptr)p)^ = glfw.GetProcAddress(name) });
    gl.ClearColor(0.25, 0.25, 0.25, 1);

    // This line throws the following error
    // /usr/bin/ld: /home/jwright/Downloads/gbui/gbui.o: in function `imgui_impl_opengl.ImGui_ImplOpenGL3_InitPlatformInterface':
    // odin_package:(.text+0x17934): undefined reference to `igGetPlatformIO'
    // clang: error: linker command failed with exit code 1 (use -v to see invocation)
    imgui_state := init_imgui_state(window);
    // io := imgui.get_io();

    for !glfw.WindowShouldClose(window) {
        /*gl.Viewport(0, 0, i32(io.display_size.x), i32(io.display_size.y));
        gl.Scissor(0, 0, i32(io.display_size.x), i32(io.display_size.y));
        gl.Clear(gl.COLOR_BUFFER_BIT);
        imgl.imgui_render(imgui.get_draw_data(), imgui_state.opengl_state);*/

        glfw.SwapBuffers(window);
        glfw.PollEvents();
    }
}

get_logger :: proc() -> log.Logger {
    logger_opts := log.Options {
        .Level,
        .Line,
        .Procedure,
    };
    return log.create_console_logger(opt = logger_opts);
}

error_callback :: proc "c" (error: i32, description: cstring) {
    context = runtime.default_context();
    context.logger = get_logger();
    log.error("GLFW error:", error, description);
}

Imgui_State :: struct {
    opengl_state: imgl.OpenGL_State,
}

init_imgui_state :: proc(window: glfw.WindowHandle) -> Imgui_State {
    res := Imgui_State{};

    imgui.create_context();
    imgui.style_colors_dark();

    imglfw.setup_state(window, true);

    imgl.setup_state(&res.opengl_state);

    return res;
}

imgui_new_frame :: proc() {
    imglfw.update_display_size();
    imglfw.update_mouse();
    imglfw.update_dt();
}