[airstrike] bug in timing code

[Erik Auerswald]

Hi,

> My suggested changes can be seperated in 2 steps:
> 
> 1) The changes suggested above to make the timing code consistent (incl.
>    updating the comments) with a time base of 100ms (what seems to be
>    the intended time base at the moment, i.e. delay values would not be
>    changed, actual timing would be about 10% slower).
> 2) Changing the time base to 10ms, adjusting the comments and the
>    values.
> 
> Step 1) does not seem to be controversial, I do not insist on step 2),
> but I would prefer it this way. If no one objects I will implement step
> 1) during the weekend.

The attached patch implements step 1...

Erik
-------------- next part --------------
diff -uNrB trunk/src/core/display.c timing-step1/src/core/display.c
--- trunk/src/core/display.c	2005-08-19 22:31:15.000000000 +0200
+++ timing-step1/src/core/display.c	2005-09-02 20:47:17.000000000 +0200
@@ -5,7 +5,7 @@
 
 struct display display = 
   {
-    .frame_time = FRAMERATE,
+    .frame_time = 1000/FRAMERATE, /* duration of one frame in ms */
     .use_alpha = 1
   };
 
diff -uNrB trunk/src/engine/schedule.c timing-step1/src/engine/schedule.c
--- trunk/src/engine/schedule.c	2005-08-31 07:28:41.000000000 +0200
+++ timing-step1/src/engine/schedule.c	2005-09-02 20:54:53.000000000 +0200
@@ -93,8 +93,7 @@
 {
   if (now >= *timer)
     {
-      /* convert milliseconds to frames */
-      *timer = now + delay * FRAMERATE / 10;
+      *timer = now + delay_to_frames(delay);
       return 1;
     }
   else
diff -uNrB trunk/src/engine/schedule.h timing-step1/src/engine/schedule.h
--- trunk/src/engine/schedule.h	2005-08-19 22:31:03.000000000 +0200
+++ timing-step1/src/engine/schedule.h	2005-09-02 20:58:43.000000000 +0200
@@ -16,11 +16,16 @@
 void schedule(unsigned int delay, int priority, void (*f)(msg_t msg, void *target), msg_t msg, void *target);
 void schedule_advance(unsigned int step, int priority);
 int frame_nr(void);
+
 /* Return 1 and set the timer if more than delay passed since last time,
    else return 0 (meaning "try later"). 
-   'delay' is in milliseconds. 
+   'delay' is in 100 milliseconds. 
 */
 int rate_limit(unsigned int delay, unsigned int *timer);
-
+/* convert delay (in 100 milliseconds) to game frames */
+static INLINE unsigned int delay_to_frames(unsigned int delay)
+{
+  return (delay * FRAMERATE) / 10;
+}
 
 #endif
diff -uNrB trunk/src/engine/sprite.c timing-step1/src/engine/sprite.c
--- trunk/src/engine/sprite.c	2005-08-19 22:31:03.000000000 +0200
+++ timing-step1/src/engine/sprite.c	2005-09-02 20:58:17.000000000 +0200
@@ -63,7 +63,7 @@
 
 void sprite_alarm(unsigned int delay, sprite_t *target, msg_t msg)
 {
-  schedule(delay*FRAMERATE/10,SCHED_NORMAL,send_alarm,msg,target);
+  schedule(delay_to_frames(delay),SCHED_NORMAL,send_alarm,msg,target);
 }
 
 /* Frame checklist
diff -uNrB trunk/src/sprites/biplane.c timing-step1/src/sprites/biplane.c
--- trunk/src/sprites/biplane.c	2005-08-19 22:31:28.000000000 +0200
+++ timing-step1/src/sprites/biplane.c	2005-09-02 21:02:09.000000000 +0200
@@ -19,7 +19,7 @@
 #define FUEL_MAX_AMOUNT 1000
 #define BOMB_MAX_COUNT  12
 
-/* how often (in 10 ms) plane can do something */
+/* how often (in 100 ms) plane can do something */
 #define PLANE_SAY_DELAY 5
 #define PLANE_PUFF_DELAY 2
 
@@ -47,7 +47,7 @@
 {
   .engine_strength = 0.0,
   .turn_amount = 0.001,
-  .bomb_delay = 1200000,	/* N * 10ms */
+  .bomb_delay = 1200000,	/* N * 100ms */
   .bullet_delay = 30000000,
   .hitpoints = 0,
   .mass = 1,
@@ -62,7 +62,7 @@
 {
   .engine_strength = 0.08,
   .turn_amount = 0.05,
-  .bomb_delay = 12,	/* N * 10ms */
+  .bomb_delay = 12,	/* N * 100ms */
   .bullet_delay = 3,
   .hitpoints = 30,
   .mass = 1,
@@ -78,7 +78,7 @@
 {
   .engine_strength = 0.0,
   .turn_amount = 0.02,
-  .bomb_delay = 1200,	/* N * 10ms */
+  .bomb_delay = 1200,	/* N * 100ms */
   .bullet_delay = 3000,
   .hitpoints = 30,
   .mass = 1,
@@ -93,7 +93,7 @@
 {
   .engine_strength = 0.08,
   .turn_amount = 0.05,
-  .bomb_delay = 12,	/* N * 10ms */
+  .bomb_delay = 12,	/* N * 100ms */
   .bullet_delay = 3,
   .hitpoints = 30,
   .mass = 1,
diff -uNrB trunk/src/tests/testengine.c timing-step1/src/tests/testengine.c
--- trunk/src/tests/testengine.c	2005-08-19 22:30:42.000000000 +0200
+++ timing-step1/src/tests/testengine.c	2005-09-02 21:04:41.000000000 +0200
@@ -58,7 +58,8 @@
   if (reason) {
     ui_message(reason,400,300,ALIGN_CENTER,big_font,20); 
   }
-  for (idx = 0; idx < 2*FRAMERATE; idx++) {
+  /* wait 2s */
+  for (idx = 0; idx < (int)delay_to_frames(20); idx++) {
     /* update screen while waiting */
     draw_frame();
     game_frame();