rntviewer/src/rntviewer.cpp

#include <ROOT/RNTupleReader.hxx>
#include <ROOT/RNTuple.hxx>
#include <TFile.h>

#include <cstdio>
#include <cstdint>
#include <chrono>

#include <sys/mman.h>
#include <unistd.h>

#ifdef DEBUG
#include <sanitizer/asan_interface.h>
#endif

#include <imgui/imgui.h>
#include <imgui/backends/imgui_impl_glfw.h>
#include <imgui/backends/imgui_impl_opengl3.h>
#include <imgui_club/imgui_memory_editor.h>

#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>

#include "types.h"
#include "defer.hpp"
#include "mem.h"
#include "app_state.h"

namespace chr = std::chrono;

#include "mem.cpp"
#include "render.cpp"
#include "mainloop.cpp"

using namespace ROOT::Experimental;

internal
size_t file_size(FILE *f)
{
  fseek(f, 0, SEEK_END);
  size_t res = ftell(f);
  fseek(f, 0, SEEK_SET);
  return res;  
}

internal 
b8 init_imgui(GLFWwindow* window) {
	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	ImGuiIO& io = ImGui::GetIO(); (void) io;
	io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;

	ImGui::StyleColorsDark();

	ImGui_ImplGlfw_InitForOpenGL(window, true);
	ImGui_ImplOpenGL3_Init("#version 460");

	return true;
}

internal 
void glfw_error_callback(i32 error, const char *description) {
	fprintf(stderr, "GLFW error %d: %s\n", error, description);
}

internal 
GLFWwindow* init_glfw(i32 desired_win_width, i32 desired_win_height)
{
	glfwSetErrorCallback(glfw_error_callback);
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_DOUBLEBUFFER, GLFW_TRUE);
	glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
	glfwWindowHint(GLFW_DECORATED, GLFW_TRUE);
	glfwWindowHint(GLFW_DEPTH_BITS, 32);
#if defined(HARU_SLOW)
	glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, true);
#endif

	GLFWwindow *window = glfwCreateWindow(
			desired_win_width, desired_win_height,
			"RNTuple Viewer",
			nullptr,
			nullptr
			);

	glfwMakeContextCurrent(window);
	//glfwSetFramebufferSizeCallback(window, resize_keep_ratio);

	return window;
}

int main(int argc, char **argv)
{
  if (argc < 3) {
    fprintf(stderr, "Usage: %s <ntuple_name> <ntuple_file.root>\n", argv[0]);
    return 1;
  }

  // Collect arguments
  const char *ntpl_name = argv[1];
  const char *fname = argv[2];

  // Allocate program memory
  Arena *arena = arena_alloc();
  if (!arena) {
    fprintf(stderr, "Failed to allocate memory\n");
    return 1;
  }
  defer { arena_release(arena); };

  // Init imgui and GLFW
  GLFWwindow *window = init_glfw(800, 600);
  if (!window) {
    fprintf(stderr, "Failed to init GLFW\n");
    return 1;
  }
  defer { glfwTerminate(); };
  
  if (!init_imgui(window)) {
    fprintf(stderr, "Failed to init Imgui\n");
    return 1;
  }

  // Open and map the file
  FILE *file = fopen(fname, "rb");
  defer { fclose(file); };

  const int fd = fileno(file);
  const size_t fsize = file_size(file);
  void *fmem = mmap(0, fsize, PROT_READ, MAP_SHARED_VALIDATE, fd, 0);
  if (!fmem) {
    fprintf(stderr, "Failed to open file %s\n", fname);
    return 1;
  }
  defer { munmap(fmem, fsize); };

  // Open the TFile
  TFile *tfile = TFile::Open(fname, "READ");
  if (!tfile) {
    fprintf(stderr, "Failed to open TFile.\n");
    return 1;
  }
  defer { delete tfile; };

  // Get the RNTuple information
  const RNTuple *anchor = tfile->Get<RNTuple>(ntpl_name);
  if (!anchor) {
    fprintf(stderr, "RNTuple '%s' not found in %s.\n", ntpl_name, fname);
    return 1;
  }

  // Start main loop
  App_State app {};
  app.inspected_file = (u8*)fmem;
  app.inspected_file_size = fsize;
  
  run_main_loop(window, arena, app);

  return 0;
}