gui.cu

#include "gui.cuh"

namespace gui {
constexpr int window_x = 512;
constexpr int window_y = 512;
constexpr char window_name[] = "mpm";
GLFWwindow *window;

void error_callback(int error, const char *description) {
  fprintf(stderr, "Error %d: %s\n", error, description);
}

void draw_dot(GLdouble x, GLdouble y, GLdouble size) {
  constexpr auto n_side = 8;
  static GLdouble sin_tab[n_side];
  static GLdouble cos_tab[n_side];

  static auto init_flag = true;
  if (init_flag) {
    GLdouble pi = 3.1415926;
    for (auto i = 0; i < n_side; i++) {
      sin_tab[i] = sin(i * pi * 2 / n_side);
      cos_tab[i] = cos(i * pi * 2 / n_side);
    }
    init_flag = false;
    (void) init_flag;
  }

  glColor3d(0.616, 0.8, 0.878);
  auto radius_x = size / window_x / 2;
  auto radius_y = size / window_y / 2;
  glBegin(GL_POLYGON);
  for (auto i = 0; i < n_side; i++) {
    glVertex2d(x + radius_x * cos_tab[i],
               y + radius_y * sin_tab[i]);
  }
  glEnd();
}

template<class T>
std::enable_if_t<std::is_same_v<T, Eigen::Vector2f> || std::is_same_v<T, Eigen::Vector2d>, std::tuple<mpm::Real, mpm::Real>>
transform(const T &a) {
  return {a[0], a[1]};
}

template<class T>
std::enable_if_t<std::is_same_v<T, Eigen::Vector3f> || std::is_same_v<T, Eigen::Vector3d>, std::tuple<mpm::Real, mpm::Real>>
transform(const T &a) {
  using mpm::Real;
  using mpm::Vector;
  Real phi = 0.49;
  Real theta = 0.56;
  Real x = a[0] - Real(0.5);
  Real y = a[1] - Real(0.5);
  Real z = a[2] - Real(0.5);
  Real c = std::cos(phi);
  Real s = std::sin(phi);
  Real C = std::cos(theta);
  Real S = std::sin(theta);
  x = x * c + z * s;
  z = z * c - x * s;
  Real u = x + Real(0.5);
  Real v = y * C + z * S + Real(0.5);
  return {u, v};
}

void init() {
  glfwSetErrorCallback(error_callback);
  if (!glfwInit()) {
    std::cerr << "glfwInit failure\n";
    exit(1);
  }
  glfwWindowHint(GLFW_SAMPLES, 8);
  window = glfwCreateWindow(window_x, window_y, window_name, nullptr,
                            nullptr);
  if (!window) {
    std::cerr << "glfwCreateWindow failure\n";
    glfwTerminate();
    exit(1);
  }
  glfwMakeContextCurrent(window);
  glfwSwapInterval(1);
  glClearColor(0.25, 0.25, 0.25, 1.0);
}

void render(const mpm::Vector *x) {
  glClear(GL_COLOR_BUFFER_BIT);
  double dot_size = 6.0;

  for (auto i = 0; i < mpm::n_particles; i++) {
    auto &p = x[i];
    auto [u, v] = transform(p);
    draw_dot(u * 2 - 1, v * 2 - 1, dot_size);
  }

  glfwSwapBuffers(window);
  glfwPollEvents();
}
}// namespace gui