Added some rudimentary UI related stuff: ui.png with the first 32x32 section being a hotbar item; uiDraw(), which draws hotbar_count(value to be controlled by amount of items w/ slots the player has (e.g., belt, slotted glove, etc.)) amount of hotbar item images at partial translucency. Also added hitting 'i' to switch to/draw the inventoryContext - at the moment, it does nothing more than cause an SDL_Rect to be drawn and switch to inventoryContext (which does nothing in itself).

context.c

@@ -88,6 +88,10 @@ void walkContext(int key_press) {
       current_context = &lookContext;
       interfacePrint("Look where?");
       break;
+    case 'i':
+      current_context = &inventoryContext;
+      interfacePrint("You check out your sack.");
+      break;
   }
 }
 
@@ -149,3 +153,13 @@ void activateContext(int key_press) {
   }
   current_context = &walkContext;
 }
+
+void inventoryContext(int key_press) {
+  switch (key_press) {
+    case KEY_ESC:
+    case 'q':
+      interfacePrint("That's enough of that...");
+      current_context = &walkContext;
+      break;
+  }
+}

context.h

@@ -20,4 +20,5 @@ void consoleContext(int key_press);
 void walkContext(int key_press);
 void lookContext(int key_press);
 void activateContext(int key_press);
+void inventoryContext(int key_press);
 #endif

interface/sdl.c

@@ -225,11 +225,11 @@ int interfaceInit() {
   if (interfaceVideoSet())
     return ERROR;
   // FIXME: this should be handled differently, but we need to set the window width/height to the surface's reported width/height, as some window managers will resize the SDL window.
+  SDL_Delay(100);
   video_width = (SDL_GetVideoSurface())->w;
   video_height = (SDL_GetVideoSurface())->h;
   if (interfaceVideoSet())
     return ERROR;
-
   SDL_WM_SetCaption(NAME, NULL);
 
   consoleAddCommand("quit", interfaceQuit);
@@ -240,6 +240,7 @@ int interfaceInit() {
   /* tile specific stuff */
   /* load our surfaces from memory */
   font_spritesheet = IMG_Load_RW(SDL_RWFromMem(&font_images, font_images_length), 1);
+  ui_spritesheet = IMG_Load_RW(SDL_RWFromMem(&ui_images, ui_images_length), 1);
   player_spritesheet = IMG_Load_RW(SDL_RWFromMem(&player_images, player_images_length), 1);
   npc_spritesheet = IMG_Load_RW(SDL_RWFromMem(&npc_images, npc_images_length), 1);
   wall_spritesheet = IMG_Load_RW(SDL_RWFromMem(&wall_images, wall_images_length), 1);
@@ -328,6 +329,22 @@ void cameraDraw() {
   interfaceDrawString(test, screen->w-strlen(test)*g_tile_width, 0);
 }
 
+void uiDraw() {
+  int hotbar_count = 4;
+  // TODO: move the next line to a uiSetAlpha function (so user can customize).
+  // TODO: create a Surface in interfaceInit() and simply blit that here.
+  SDL_SetAlpha(ui_spritesheet, SDL_SRCALPHA, 200);
+  SDL_Rect hotbar_item_rect = { 0, 0, 32, 32 };
+  int hotbar_width = hotbar_count*32;
+  int hotbar_height = 32;
+  int i = 0;
+  while (i < hotbar_count) {
+    SDL_Rect hotbar_target_rect = {(screen->w/2 - hotbar_width/2)+i*32, screen->h-hotbar_height, (screen->w/2 - hotbar_width/2)+32+i*32, screen->h};
+    SDL_BlitSurface(ui_spritesheet, &hotbar_item_rect, screen, &hotbar_target_rect);
+    i++;
+  }
+}
+
 int interfaceLoop() {
   while (SDL_WaitEvent(&event)) {
     switch(event.type) {
@@ -398,12 +415,24 @@ void interfaceDraw() {
   // TODO: instead of redrawing whole screen, redraw last positions of tiles
   //SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 0, 0, 0));
   cameraDraw(); // draw our current view
+  uiDraw();
   if (current_context == &consoleContext) {
     interfaceDrawConsole();
+  } else if (current_context == &inventoryContext) {
+    interfaceDrawInventory();
   }
   SDL_Flip(screen); // redraw!
 }
 
+void interfaceDrawInventory() {
+  SDL_Surface *new_surface = SDL_CreateRGBSurface(screen->flags, (screen->w/6), screen->h/2, screen->format->BitsPerPixel, screen->format->Rmask, screen->format->Gmask, screen->format->Bmask, screen->format->Amask);
+  SDL_Rect render_area = { screen->w-(screen->w/6), screen->h/8, screen->w/6, screen->h/2 };
+  SDL_FillRect(new_surface, NULL, SDL_MapRGB(new_surface->format, 196, 164, 64));
+  SDL_SetAlpha(new_surface, SDL_SRCALPHA, 128);
+  SDL_BlitSurface(new_surface, NULL, screen, &render_area);
+  SDL_FreeSurface(new_surface);
+}
+
 void interfaceDrawConsole() {
   int line;
   struct ConsoleEntry *entry;

interface/sdl.h

@@ -14,6 +14,7 @@
 
   SDL_Surface* screen;
   SDL_Surface* font_spritesheet;
+  SDL_Surface* ui_spritesheet;
   SDL_Surface* player_spritesheet;
   SDL_Surface* npc_spritesheet;
   SDL_Surface* shadow_spritesheet;
@@ -38,6 +39,8 @@ float g_tile_height;
 
 void interfaceSetScale(float scale_x, float scale_y);
 
+void uiDraw();
+
 void interfaceDrawString(const char *string, int start_x, int start_y);
 void interfaceDrawChar(char ch, int start_x, int start_y);
 

pack_tiles.c

@@ -31,6 +31,7 @@ int main(int argc, char **argv) {
   fprintf(tiles_h, "#define TILE_WIDTH 16\n#define TILE_HEIGHT 32\n");
 
   convert("tiles/font.png", "font_images");
+  convert("tiles/ui.png", "ui_images");
   convert("tiles/players.png", "player_images");
   convert("tiles/npcs.png", "npc_images");
   convert("tiles/walls.png", "wall_images");

tiles/tiles.h

@@ -6,6 +6,9 @@
 extern unsigned char font_images[];
 extern unsigned int font_images_length;
 
+extern unsigned char ui_images[];
+extern unsigned int ui_images_length;
+
 extern unsigned char player_images[];
 extern unsigned int player_images_length;