sdl: event handler, handle a case where user doesn't define vtbl

4 files changed, 64 insertions, 23 deletions

diff --git a/sdl/config.lua b/sdl/config.lua
index 34a7920..0917809 100644
--- a/sdl/config.lua
+++ b/sdl/config.lua
@@ -2,8 +2,8 @@ platform =
 {
     name   = "Textured Pyramid",
     icon   = "tux.png",
-    xres   = 640,
-    yres   = 480,
+    xres   = 320,
+    yres   = 240,
     bpp    = 32,
     af     = 8,
     fovy   = 40.0,
diff --git a/sdl/event.c b/sdl/event.c
index 905a35f..a760635 100644
--- a/sdl/event.c
+++ b/sdl/event.c
@@ -2,15 +2,12 @@
  *
  * Event Handler
  *
- * notes: It would be useful to create a following function
- *        register_signal(SDL_HOLDDOWN, EVENT_ACTION_INCR, float *p, float val)
- *
- *        struct platform is still passed globally
  *
  */
 
 #include <SDL/SDL.h>
 #include <SDL/SDL_image.h>
+#include <assert.h>
 #include "client.h"
 #include "glframe.h"
 #include "platform.h"
@@ -22,17 +19,31 @@ extern int program_running;
 /* an event handler struct that contains a table with function pointers */
 static struct event_handler event_handler;
 
+/* when user inputs NULL for tbl, generic functions get stubbed */
 int event_handler_init(struct platform *plat, struct event_vtbl *tbl)
 {
-    if (!tbl || !plat)
+    if (!plat)
         return -1;
 
-    event_handler.funcs = *tbl;
     event_handler.p = plat;
 
-    /* predefined handlers that are automatically provided */
+    if (tbl)
+        event_handler.funcs = *tbl;
+    else
+    {
+        memset(&event_handler.funcs, 0, sizeof(event_handler.funcs));
+        fprintf(stdout, "event: generic event handler will be provided\n");
+    }
+
+    /* predefined generic handlers that are automatically provided */
+    if (!event_handler.funcs.keydown)
+        event_handler.funcs.keydown = &event_keydown_gen;
+
     if (!event_handler.funcs.windowresize)
-        event_handler.funcs.windowresize = window_resize;
+        event_handler.funcs.windowresize = &window_resize;
+
+    if (!event_handler.funcs.quit)
+        event_handler.funcs.quit = &event_quit_gen;
 
     return 0;
 }
@@ -44,7 +55,7 @@ void sdl_process_events(void)
     SDLKey sym;
     unsigned int *keys_held = event_handler.keys_held;
 
-    event_handler.flag = 0;
+    event_handler.key_held = 0;
 
     while (SDL_PollEvent(&event))
     {
@@ -68,13 +79,14 @@ void sdl_process_events(void)
             }
             case SDL_VIDEORESIZE:
             {
-                if (event_handler.funcs.windowresize)
-                    event_handler.funcs.windowresize(event.resize.w, event.resize.h);
+                assert(event_handler.funcs.windowresize);
+                event_handler.funcs.windowresize(event.resize.w, event.resize.h);
                 break;
             }
             case SDL_QUIT:
             {
-                program_running = 0;
+                assert(event_handler.funcs.quit);
+                event_handler.funcs.quit();
                 break;
             }
             default:
@@ -83,24 +95,46 @@ void sdl_process_events(void)
     }
 
     /* below code has to be placed here, check for keys that are being constantly held */
-    if (keys_held[SDLK_w] || keys_held[SDLK_s] || keys_held[SDLK_a] ||
-        keys_held[SDLK_d] || keys_held[SDLK_UP] || keys_held[SDLK_DOWN] ||
-        keys_held[SDLK_LEFT] || keys_held[SDLK_RIGHT] || keys_held[SDLK_n] ||
+    if (keys_held[SDLK_w]    || keys_held[SDLK_s]     || keys_held[SDLK_a]    ||
+        keys_held[SDLK_d]    || keys_held[SDLK_UP]    || keys_held[SDLK_DOWN] ||
+        keys_held[SDLK_LEFT] || keys_held[SDLK_RIGHT] || keys_held[SDLK_n]    ||
         keys_held[SDLK_m])
     {
-        event_handler.flag = !event_handler.flag;
-        event_keydown(NULL);
+        event_handler.key_held = !event_handler.key_held;
+        event_handler.funcs.keydown(NULL);
+    }
+}
+
+/* generic handler function, an exception is window_resize, it is declared
+ * in window.c */
+void event_keydown_gen(SDL_keysym *keysym)
+{
+    if (!keysym)
+        return;
+
+    switch (keysym->sym)
+    {
+        case SDLK_ESCAPE:
+            event_handler.funcs.quit();
+            break;
+        default:
+            break;
     }
 }
 
-/* here are the event handler functions */
+void event_quit_gen(void)
+{
+    program_running = 0;
+}
+
+/* here are the client event handler functions */
 void event_keydown(SDL_keysym *keysym)
 {
     const unsigned int *keys_held = event_handler.keys_held;
     struct platform *p = event_handler.p;
 
     /* a flag is toggled on if the we are interested in keys that are being held */
-    if (event_handler.flag)
+    if (event_handler.key_held)
     {
         if (keys_held[SDLK_w])
             p->c->xrot -= 5.0f;
diff --git a/sdl/event.h b/sdl/event.h
index b6a1084..30669de 100644
--- a/sdl/event.h
+++ b/sdl/event.h
@@ -8,6 +8,7 @@ struct event_vtbl
 {
     void (*keydown)(SDL_keysym *);
     void (*windowresize)(int, int);
+    void (*quit)(void);
 };
 
 struct event_handler
@@ -16,7 +17,7 @@ struct event_handler
     unsigned int keys_held[323]; /* keep track of the keys that were held */
 
     struct platform *p;          /* reference to the host platform */
-    int flag;                    /* helper flag */
+    int key_held;                /* helper flag */
 };
 
 /* function prototypes */
@@ -24,5 +25,8 @@ int event_handler_init(struct platform *, struct event_vtbl *);
 void sdl_process_events(void);
 void event_keydown(SDL_keysym *);
 
+void event_keydown_gen(SDL_keysym *);
+void event_quit_gen(void);
+
 #endif
 
diff --git a/sdl/platform.c b/sdl/platform.c
index 7c7bcdd..1fd9129 100644
--- a/sdl/platform.c
+++ b/sdl/platform.c
@@ -73,7 +73,10 @@ void platform_init(struct platform *p)
     event_tbl.keydown = event_keydown;
     ret = event_handler_init(p, &event_tbl);
     if (ret == -1)
-        fprintf(stderr, "platform: warning, failed to init event handler\n");
+    {
+        fprintf(stderr, "platform: failed to init event handler\n");
+        exit(-1);
+    }
 
     /* init client */
     p->client_init(p->c);