initial commit

3 files changed, 189 insertions, 0 deletions

diff --git a/src/c.zig b/src/c.zig
new file mode 100644
index 0000000..eeea35f
--- /dev/null
+++ b/src/c.zig
@@ -0,0 +1,5 @@
+pub usingnamespace @cImport({
+    @cDefine("CIMGUI_DEFINE_ENUMS_AND_STRUCTS", "1");
+    @cInclude("cimgui.h");
+    @cInclude("GLFW/glfw3.h");
+});
diff --git a/src/glfw_impl.zig b/src/glfw_impl.zig
new file mode 100644
index 0000000..7ef2f63
--- /dev/null
+++ b/src/glfw_impl.zig
@@ -0,0 +1,107 @@
+const c = @import("c.zig");
+const builtin = @import("builtin");
+pub const ClientApi = enum {
+    Unknown,
+    OpenGL,
+    Vulkan,
+};
+
+// Data
+var g_Window: ?*c.GLFWwindow = null;
+var g_ClientApi: ClientApi = .Unknown;
+var g_Time: f32 = 0.0;
+var g_MouseJustPressed = [5]bool;
+var g_MouseCursors = [_]?*c.GLFWcursor{null} ** @enumToInt(c.ImGuiMouseCursor_COUNT);
+var g_WantUpdateMonitors = true;
+
+// Chain GLFW callbacks for main viewport:
+// our callbacks will call the user's previously installed callbacks, if any.
+var g_PrevUserCallbackMousebutton: ?*c.GLFWmousebuttonfun = null;
+var g_PrevUserCallbackScroll: ?*c.GLFWscrollfun = null;
+var g_PrevUserCallbackKey: ?*c.GLFWkeyfun = null;
+var g_PrevUserCallbackChar: ?*c.GLFWcharfun = null;
+
+pub fn Init(window: *c.GLFWwindow, install_callbacks: bool, client_api: ClientApi) void {
+  g_Window = window;
+  g_Time = 0.0;
+
+  // Setup back-end capabilities flags
+  const io = c.igGetIO();
+  io.*.BackendFlags |= @enumToInt(c.ImGuiBackendFlags_HasMouseCursors); // We can honor GetMouseCursor() values (optional)
+  io.*.BackendFlags |= @enumToInt(c.ImGuiBackendFlags_HasSetMousePos); // We can honor io.WantSetMousePos requests (optional, rarely used)
+  io.*.BackendFlags |= @enumToInt(c.ImGuiBackendFlags_PlatformHasViewports); // We can create multi-viewports on the Platform side (optional)
+  if (false and c.GLFW_HAS_GLFW_HOVERED and builtin.os == builtin.Os.windows) {
+    io.*.BackendFlags |= @enumToInt(ImGuiBackendFlags_HasMouseHoveredViewport); // We can set io.MouseHoveredViewport correctly (optional, not easy)
+  }
+  io.*.BackendPlatformName = c"imgui_impl_glfw";
+
+  // Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array.
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Tab)] = c.GLFW_KEY_TAB;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_LeftArrow)] = c.GLFW_KEY_LEFT;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_RightArrow)] = c.GLFW_KEY_RIGHT;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_UpArrow)] = c.GLFW_KEY_UP;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_DownArrow)] = c.GLFW_KEY_DOWN;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_PageUp)] = c.GLFW_KEY_PAGE_UP;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_PageDown)] = c.GLFW_KEY_PAGE_DOWN;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Home)] = c.GLFW_KEY_HOME;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_End)] = c.GLFW_KEY_END;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Insert)] = c.GLFW_KEY_INSERT;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Delete)] = c.GLFW_KEY_DELETE;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Backspace)] = c.GLFW_KEY_BACKSPACE;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Space)] = c.GLFW_KEY_SPACE;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Enter)] = c.GLFW_KEY_ENTER;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Escape)] = c.GLFW_KEY_ESCAPE;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_KeyPadEnter)] = c.GLFW_KEY_KP_ENTER;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_A)] = c.GLFW_KEY_A;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_C)] = c.GLFW_KEY_C;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_V)] = c.GLFW_KEY_V;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_X)] = c.GLFW_KEY_X;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Y)] = c.GLFW_KEY_Y;
+  io.*.KeyMap[@enumToInt(c.ImGuiKey_Z)] = c.GLFW_KEY_Z;
+
+  // io.SetClipboardTextFn = ImGui_ImplGlfw_SetClipboardText;
+  // io.GetClipboardTextFn = ImGui_ImplGlfw_GetClipboardText;
+  // io.ClipboardUserData = g_Window;
+
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_Arrow)] = c.glfwCreateStandardCursor(c.GLFW_ARROW_CURSOR);
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_TextInput)] = c.glfwCreateStandardCursor(c.GLFW_IBEAM_CURSOR);
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_ResizeAll)] = c.glfwCreateStandardCursor(c.GLFW_ARROW_CURSOR); // FIXME: GLFW doesn't have this.
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_ResizeNS)] = c.glfwCreateStandardCursor(c.GLFW_VRESIZE_CURSOR);
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_ResizeEW)] = c.glfwCreateStandardCursor(c.GLFW_HRESIZE_CURSOR);
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_ResizeNESW)] = c.glfwCreateStandardCursor(c.GLFW_ARROW_CURSOR); // FIXME: GLFW doesn't have this.
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_ResizeNWSE)] = c.glfwCreateStandardCursor(c.GLFW_ARROW_CURSOR); // FIXME: GLFW doesn't have this.
+  g_MouseCursors[@enumToInt(c.ImGuiMouseCursor_Hand)] = c.glfwCreateStandardCursor(c.GLFW_HAND_CURSOR);
+
+  // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
+  g_PrevUserCallbackMousebutton = null;
+  g_PrevUserCallbackScroll = null;
+  g_PrevUserCallbackKey = null;
+  g_PrevUserCallbackChar = null;
+  if (install_callbacks and false) {
+    // g_PrevUserCallbackMousebutton = glfwSetMouseButtonCallback(window, ImGui_ImplGlfw_MouseButtonCallback);
+    // g_PrevUserCallbackScroll = glfwSetScrollCallback(window, ImGui_ImplGlfw_ScrollCallback);
+    // g_PrevUserCallbackKey = glfwSetKeyCallback(window, ImGui_ImplGlfw_KeyCallback);
+    // g_PrevUserCallbackChar = glfwSetCharCallback(window, ImGui_ImplGlfw_CharCallback);
+  }
+
+  // Our mouse update function expect PlatformHandle to be filled for the main viewport
+  const main_viewport = c.igGetMainViewport();
+  main_viewport.*.PlatformHandle = g_Window;
+  if (builtin.os == builtin.Os.windows) {
+    main_viewport.*.PlatformHandleRaw = c.glfwGetWin32Window(g_Window);
+  }
+
+  // if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable != 0)
+  //    ImGui_ImplGlfw_InitPlatformInterface();
+
+  g_ClientApi = client_api;
+}
+
+pub fn Shutdown() void {
+  // ImGui_ImplGlfw_ShutdownPlatformInterface();
+  for (g_MouseCursors) |*cursor| {
+    c.glfwDestroyCursor(cursor.*);
+    cursor.* = null;
+  }
+  g_ClientApi = .Unknown;
+}
diff --git a/src/main.zig b/src/main.zig
new file mode 100644
index 0000000..42fa152
--- /dev/null
+++ b/src/main.zig
@@ -0,0 +1,77 @@
+const c = @import("c.zig");
+const std = @import("std");
+const panic = std.debug.panic;
+const glfw_impl = @import("glfw_impl.zig");
+
+extern fn errorCallback(err: c_int, description: [*c]const u8) void {
+      panic("Error: {}\n", description);
+}
+
+var window: *c.GLFWwindow = undefined;
+
+pub fn main() void {
+  _ = c.glfwSetErrorCallback(errorCallback);
+
+  if (c.glfwInit() == c.GL_FALSE) {
+      panic("GLFW init failure\n");
+  }
+  defer c.glfwTerminate();
+
+  c.glfwWindowHint(c.GLFW_CONTEXT_VERSION_MAJOR, 3);
+  c.glfwWindowHint(c.GLFW_CONTEXT_VERSION_MINOR, 2);
+  c.glfwWindowHint(c.GLFW_OPENGL_FORWARD_COMPAT, c.GL_TRUE);
+  c.glfwWindowHint(c.GLFW_OPENGL_PROFILE, c.GLFW_OPENGL_CORE_PROFILE);
+
+  // c.glfwWindowHint(c.GLFW_OPENGL_DEBUG_CONTEXT, debug_gl.is_on);
+  // c.glfwWindowHint(c.GLFW_DEPTH_BITS, 0);
+  // c.glfwWindowHint(c.GLFW_STENCIL_BITS, 8);
+  c.glfwWindowHint(c.GLFW_RESIZABLE, c.GL_TRUE);
+
+  const window_width = 640;
+  const window_height = 480;
+  window = c.glfwCreateWindow(window_width, window_height, c"ImGUI Test", null, null) orelse {
+      panic("unable to create window\n");
+  };
+  defer c.glfwDestroyWindow(window);
+
+  c.glfwMakeContextCurrent(window);
+  c.glfwSwapInterval(1);
+
+  const context = c.igCreateContext(null);
+  defer c.igDestroyContext(context);
+
+  const io = c.igGetIO();
+  io.*.ConfigFlags |= @enumToInt(c.ImGuiConfigFlags_NavEnableKeyboard);
+  io.*.ConfigFlags |= @enumToInt(c.ImGuiConfigFlags_DockingEnable);
+  io.*.ConfigFlags |= @enumToInt(c.ImGuiConfigFlags_ViewportsEnable);
+
+  const style = c.igGetStyle();
+  c.igStyleColorsDark(style);
+
+  if (io.*.ConfigFlags & @enumToInt(c.ImGuiConfigFlags_ViewportsEnable) != 0) {
+    style.*.WindowRounding = 0.0;
+    style.*.Colors[@enumToInt(c.ImGuiCol_WindowBg)].w = 1.0;
+  }
+
+  glfw_impl.Init(window, true, glfw_impl.ClientApi.OpenGL);
+  // ImGui_InitForOpenGL(window, true);
+  // ImGui_ImplOpenGL3_Init(glsl_version);
+
+  const start_time = c.glfwGetTime();
+  var prev_time = start_time;
+
+  while (c.glfwWindowShouldClose(window) == c.GL_FALSE) {
+    // c.glClear(c.GL_COLOR_BUFFER_BIT | c.GL_DEPTH_BUFFER_BIT | c.GL_STENCIL_BUFFER_BIT);
+
+    const now_time = c.glfwGetTime();
+    const elapsed = now_time - prev_time;
+    prev_time = now_time;
+
+    // nextFrame(t, elapsed);
+
+    // draw(t, @This());
+    c.glfwSwapBuffers(window);
+
+    c.glfwPollEvents();
+  }
+}