[client] imgui: convert help overlay to use imgui

client/CMakeLists.txt

@@ -125,6 +125,7 @@ set(SOURCES
 
 	src/overlay/fps.c
 	src/overlay/graphs.c
+	src/overlay/help.c
 )
 
 # Force cimgui to build as a static library.

client/include/app.h

@@ -138,9 +138,4 @@ void app_releaseKeybind(KeybindHandle * handle);
  */
 void app_releaseAllKeybinds(void);
 
-/**
- * Changes whether the help message is displayed or not.
- */
-void app_showHelp(bool show);
-
 #endif

client/include/overlay_utils.h

@@ -27,7 +27,10 @@
 extern "C" {
 #endif
 
+typedef struct ImVec2 ImVec2;
+
 void overlayGetImGuiRect(struct Rect * rect);
+ImVec2 * overlayGetScreenSize(void);
 void imGuiResetStyle(void);
 
 #ifdef __cplusplus

client/src/app.c

@@ -429,7 +429,6 @@ void app_handleRenderEvent(const uint64_t timeUs)
     if (g_state.escapeHelp)
     {
       g_state.escapeHelp = false;
-      app_showHelp(false);
     }
   }
   else
@@ -437,7 +436,6 @@ void app_handleRenderEvent(const uint64_t timeUs)
     if (!g_state.escapeHelp && timeUs - g_state.escapeTime > g_params.helpMenuDelayUs)
     {
       g_state.escapeHelp = true;
-      app_showHelp(true);
     }
   }
 }
@@ -562,58 +560,6 @@ void app_releaseAllKeybinds(void)
     }
 }
 
-static char * build_help_str()
-{
-  size_t size   = 50;
-  size_t offset = 0;
-  char * buffer = malloc(size);
-
-  if (!buffer)
-    return NULL;
-
-  const char * escapeName = xfree86_to_display[g_params.escapeKey];
-
-  offset += snprintf(buffer, size, "%s %-10s Toggle capture mode\n", escapeName, "");
-  if (offset >= size)
-  {
-    DEBUG_ERROR("Help string somehow overflowed. This should be impossible.");
-    return NULL;
-  }
-
-  for (int i = 0; i < KEY_MAX; ++i)
-  {
-    if (g_state.keyDescription[i])
-    {
-      const char * keyName = xfree86_to_display[i];
-      const char * desc    = g_state.keyDescription[i];
-      int needed = snprintf(buffer + offset, size - offset, "%s+%-10s %s\n", escapeName, keyName, desc);
-      if (offset + needed < size)
-        offset += needed;
-      else
-      {
-        size = size * 2 + needed;
-        void * new = realloc(buffer, size);
-        if (!new) {
-          free(buffer);
-          DEBUG_ERROR("Out of memory when constructing help text");
-          return NULL;
-        }
-        buffer = new;
-        offset += snprintf(buffer + offset, size - offset, "%s+%-10s %s\n", escapeName, keyName, desc);
-      }
-    }
-  }
-
-  return buffer;
-}
-
-void app_showHelp(bool show)
-{
-  char * help = show ? build_help_str() : NULL;
-  g_state.lgr->on_help(g_state.lgrData, help);
-  free(help);
-}
-
 GraphHandle app_registerGraph(const char * name, RingBuffer buffer)
 {
   return overlayGraph_register(name, buffer);

client/src/main.c

@@ -776,6 +776,7 @@ static int lg_run(void)
   g_state.overlays = ll_new();
   app_registerOverlay(&LGOverlayFPS   , NULL);
   app_registerOverlay(&LGOverlayGraphs, NULL);
+  app_registerOverlay(&LGOverlayHelp  , NULL);
 
   // initialize metrics ringbuffers
   g_state.renderTimings = ringbuffer_new(256, sizeof(float));

client/src/overlay/help.c

@@ -0,0 +1,140 @@
+/**
+ * Looking Glass
+ * Copyright (C) 2017-2021 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "interface/overlay.h"
+#include "cimgui.h"
+#include "overlay_utils.h"
+
+#include "common/debug.h"
+
+#include "../kb.h"
+#include "../main.h"
+
+struct HelpData
+{
+  char * helpText;
+};
+
+static bool help_init(void ** udata, void * params)
+{
+  *udata = calloc(1, sizeof(struct HelpData));
+  if (!udata)
+  {
+    DEBUG_ERROR("Out of memory");
+    return false;
+  }
+  return true;
+}
+
+static void help_free(void * udata)
+{
+  free(udata);
+}
+
+static char * buildHelpText(void)
+{
+  size_t size   = 50;
+  size_t offset = 0;
+  char * buffer = malloc(size);
+
+  if (!buffer)
+    return NULL;
+
+  const char * escapeName = xfree86_to_display[g_params.escapeKey];
+
+  offset += snprintf(buffer, size, "%s %-10s Toggle capture mode\n", escapeName, "");
+  if (offset >= size)
+  {
+    DEBUG_ERROR("Help string somehow overflowed. This should be impossible.");
+    return NULL;
+  }
+
+  for (int i = 0; i < KEY_MAX; ++i)
+  {
+    if (g_state.keyDescription[i])
+    {
+      const char * keyName = xfree86_to_display[i];
+      const char * desc    = g_state.keyDescription[i];
+      int needed = snprintf(buffer + offset, size - offset, "%s+%-10s %s\n", escapeName, keyName, desc);
+      if (offset + needed < size)
+        offset += needed;
+      else
+      {
+        size = size * 2 + needed;
+        void * new = realloc(buffer, size);
+        if (!new) {
+          free(buffer);
+          DEBUG_ERROR("Out of memory when constructing help text");
+          return NULL;
+        }
+        buffer = new;
+        offset += snprintf(buffer + offset, size - offset, "%s+%-10s %s\n", escapeName, keyName, desc);
+      }
+    }
+  }
+
+  return buffer;
+}
+
+static int help_render(void * udata, bool interactive, struct Rect * windowRects,
+    int maxRects)
+{
+  struct HelpData * data = udata;
+
+  if (!g_state.escapeHelp)
+  {
+    if (data->helpText)
+    {
+      free(data->helpText);
+      data->helpText = NULL;
+    }
+    return 0;
+  }
+
+  if (!data->helpText)
+    data->helpText = buildHelpText();
+
+  ImVec2 * screen = overlayGetScreenSize();
+  igSetNextWindowBgAlpha(0.6f);
+  igSetNextWindowPos((ImVec2) { 0.0f, screen->y }, 0, (ImVec2) { 0.0f, 1.0f });
+
+  igBegin(
+    "Help",
+    NULL,
+    ImGuiWindowFlags_NoDecoration    | ImGuiWindowFlags_AlwaysAutoResize   |
+    ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoFocusOnAppearing |
+    ImGuiWindowFlags_NoNav           | ImGuiWindowFlags_NoTitleBar
+  );
+
+  igText("%s", data->helpText);
+
+  overlayGetImGuiRect(windowRects);
+  igEnd();
+
+  return 1;
+}
+
+struct LG_OverlayOps LGOverlayHelp =
+{
+  .name           = "Help",
+  .init           = help_init,
+  .free           = help_free,
+  .render         = help_render
+};

client/src/overlay_utils.c

@@ -21,6 +21,7 @@
 #include "overlay_utils.h"
 
 #include "cimgui.h"
+#include "main.h"
 
 void overlayGetImGuiRect(struct Rect * rect)
 {
@@ -35,3 +36,8 @@ void overlayGetImGuiRect(struct Rect * rect)
   rect->w = size.x;
   rect->h = size.y;
 }
+
+ImVec2 * overlayGetScreenSize(void)
+{
+  return &g_state.io->DisplaySize;
+}

client/src/overlays.h

@@ -25,6 +25,7 @@
 
 extern struct LG_OverlayOps LGOverlayFPS;
 extern struct LG_OverlayOps LGOverlayGraphs;
+extern struct LG_OverlayOps LGOverlayHelp;
 
 GraphHandle overlayGraph_register(const char * name, RingBuffer buffer);
 void overlayGraph_unregister();