Added more inline documentation to ex_bitmap_flip

Author: Daniel Johnson

examples/ex_bitmap_flip.c

@@ -6,6 +6,7 @@
 
 #include "common.c"
 
+/* Fire the update every 10 milliseconds. */
 #define INTERVAL 0.01
 
 
@@ -15,7 +16,7 @@ float bmp_dx = 96;
 float bmp_dy = 96;
 int bmp_flag = 0;
 
-
+/* Updates the bitmap velocity, orientation and position. */
 static void update(ALLEGRO_BITMAP *bmp)
 {
    ALLEGRO_BITMAP *target = al_get_target_bitmap();
@@ -67,29 +68,43 @@ int main(int argc, char **argv)
    bool done = false;
    bool redraw = true;
 
+   /* Silence unused arguments warnings. */
    (void)argc;
    (void)argv;
 
    if (!al_init()) {
       abort_example("Failed to init Allegro.\n");
    }
 
+   /* Initialize the image addon. Requires the allegro_image addon
+    * library.
+    */
    if (!al_init_image_addon()) {
       abort_example("Failed to init IIO addon.\n");
    }
 
+   /* Initialize the image font. Requires the allegro_font addon
+    * library.
+    */
    al_init_font_addon();
-   init_platform_specific();
+   init_platform_specific(); /* Helper functions from common.c. */
 
+   /* Create a new display that we can render the image to. */
    display = al_create_display(640, 480);
    if (!display) {
       abort_example("Error creating display.\n");
    }
 
+   /* Allegro requires installing drivers for all input devices before
+    * they can be used.
+    */
    if (!al_install_keyboard()) {
       abort_example("Error installing keyboard.\n");
    }
 
+   /* Loads a font from disk. This will use al_load_bitmap_font if you
+    * pass the name of a known bitmap format, or else al_load_ttf_font.
+    */
    font = al_load_font("data/fixed_font.tga", 0, 0);
    if (!font) {
       abort_example("Error loading data/fixed_font.tga\n");
@@ -117,13 +132,17 @@ int main(int argc, char **argv)
 
    al_start_timer(timer);
 
+   /* Default premultiplied aplha blending. */
    al_set_blender(ALLEGRO_ADD, ALLEGRO_ONE, ALLEGRO_INVERSE_ALPHA);
 
+   /* Primary 'game' loop. */
    while (!done) {
       ALLEGRO_EVENT event;
 
+      /* If the timer has since been fired and the queue is empty, draw.*/
       if (redraw && al_is_event_queue_empty(queue)) {
          update(bmp);
+         /* Clear so we don't get trippy artifacts left after zoom. */
          al_clear_to_color(al_map_rgb_f(0, 0, 0));
          al_draw_tinted_bitmap(bmp, al_map_rgba_f(1, 1, 1, 0.5),
             bmp_x, bmp_y, bmp_flag);
@@ -138,6 +157,9 @@ int main(int argc, char **argv)
             if (event.keyboard.keycode == ALLEGRO_KEY_ESCAPE)
                done = true;
             else if (event.keyboard.keycode == ALLEGRO_KEY_SPACE) {
+               /* Spacebar toggles whether render from a memory bitmap
+                * or display bitamp.
+                */
                if (bmp == mem_bmp) {
                   bmp = disp_bmp;
                   text = "Display bitmap (space to change)";