Added time to throttle updates.

1 files changed, 52 insertions, 0 deletions

diff --git a/galax.c b/galax.c
index a45e5f4..f7f58c8 100644
--- a/galax.c
+++ b/galax.c
@@ -47,6 +47,8 @@ char			*coll_data;
 
 double			si[3600],co[3600];
 
+static struct timespec	frame_start;
+
 static XFuncControl	Key(Window w, XPressRelease s, XEvent *e);
 static XFuncControl	ProcessTitle(void),ProcessIntro(void),ProcessGame(void),
 			ProcessGameOver(void),ProcessHiScore(void),
@@ -337,6 +339,8 @@ static void ClearBullets(void);
 static void ClearKeys(void);
 static void DoDebugMenu(void);
 static int Paused(int k);
+static void StartFrame(void);
+static void EndFrame(void);
 
 
 int main(int argc, char *argv[])
@@ -807,6 +811,7 @@ static XFuncControl ProcessTitle(void)
 
     ctr++;
 
+    StartFrame();
     Cls(True,xi[(ctr%800)/100],yi[(ctr%800)/100],True);
 
     Centre(20,YELLOW,"GALAXY INVADERS");
@@ -844,6 +849,7 @@ static XFuncControl ProcessTitle(void)
     DoDebugMenu();
 
     Update();
+    EndFrame();
 
     k=GetKey();
 
@@ -960,6 +966,7 @@ static XFuncControl ProcessStartLevel(void)
 {
     char s[80];
 
+    StartFrame();
     Cls(True,levdata[levelndx].sx,levdata[levelndx].sy,True);
 
     sprintf(s,"LEVEL %d",level+1);
@@ -968,6 +975,7 @@ static XFuncControl ProcessStartLevel(void)
     Centre (100,RED,levdata[levelndx].title);
 
     Update();
+    EndFrame();
 
     if (GetKey()!=NONE)
 	return(XFUNCSTOP);
@@ -994,6 +1002,7 @@ static XFuncControl ProcessGame(void)
 	if (Paused(k))
 	    return (XFUNCCONT);
 
+    StartFrame();
     Cls(True,levdata[levelndx].sx,levdata[levelndx].sy,True);
 
     if (lives)
@@ -1064,6 +1073,7 @@ static XFuncControl ProcessGame(void)
 	}
 
     Update();
+    EndFrame();
 
     if (k==QUIT)
 	{
@@ -1146,6 +1156,7 @@ static XFuncControl ProcessGameOver(void)
     static int posx=32;
     static unsigned int ctr=0;
 
+    StartFrame();
     Cls (True,0,1,True);
 
     ctr++;
@@ -1163,6 +1174,7 @@ static XFuncControl ProcessGameOver(void)
 	Centre(120,WHITE,"GAME OVER");
 
     Update();
+    EndFrame();
 
     if (GetKey()==NONE)
 	return(XFUNCCONT);
@@ -1241,6 +1253,7 @@ static XFuncControl ProcessHiScore(void)
 	first=False;
 	}
 
+    StartFrame();
     Cls (True,1,1,True);
 
     Centre(16,WHITE,"CONGRATULATIONS!");
@@ -1286,6 +1299,7 @@ static XFuncControl ProcessHiScore(void)
 	bounce--;
 
     Update();
+    EndFrame();
 
     if (len==3)
 	{
@@ -1878,3 +1892,41 @@ static void DrawAndKillAliens(void)
 	    }
 	}
 }
+
+
+static void StartFrame(void)
+{
+    clock_gettime(CLOCK_REALTIME, &frame_start);
+}
+
+
+static void EndFrame(void)
+{
+    static const long FRAME = 1000000000 / 50;
+    struct timespec now;
+    struct timespec diff;
+
+    clock_gettime(CLOCK_REALTIME, &now);
+
+    diff.tv_sec = now.tv_sec - frame_start.tv_sec;
+    diff.tv_nsec = now.tv_nsec - frame_start.tv_nsec;
+
+    if (diff.tv_sec > 0)
+    {
+    	diff.tv_sec--;
+	diff.tv_nsec += 1000000000;
+    }
+
+    if (diff.tv_nsec >= 1000000000)
+    {
+    	diff.tv_sec++;
+	diff.tv_nsec -= 1000000000;
+    }
+
+    if (diff.tv_sec == 0 && diff.tv_nsec < FRAME)
+    {
+	diff.tv_nsec = FRAME - diff.tv_nsec;
+
+	nanosleep(&diff, NULL);
+    }
+}