Introduced timer_delay2 as replacement for timer_delay to sleep according to given FPS rate considering calc time between frames

CHANGELOG.txt

@@ -1,5 +1,9 @@
 D1X-Rebirth Changelog
 
+20071121
+--------
+arch/sdl/key.c, arch/sdl/timer.c, include/timer.h, main/game.c, main/kconfig.c, main/kmatrix.c, main/netlist.c, main/newmenu.c, main/scores.c, main/titles.c: Introduced timer_delay2 as replacement for timer_delay to sleep according to given FPS rate considering calc time between frames
+
 20071106
 --------
 main/config.c, main/game.c, main/game.h, main/menu.c, main/newdemo.c: Correctly saving Reverse Stereo setting; Added Demo playback help keys; aligned Demo recording to 20 frames per second to save lots of hard drive space

arch/sdl/key.c

@@ -511,10 +511,7 @@ int key_inkey()
 		key = key_data.keybuffer[key_data.keyhead];
 		key_data.keyhead = add_one(key_data.keyhead);
 	}
-//added 9/3/98 by Matt Mueller to free cpu time instead of hogging during menus and such
-	else timer_delay(1);
-//end addition - Matt Mueller
-	     
+
         return key;
 }
 

arch/sdl/timer.c

@@ -32,3 +32,23 @@ void timer_delay(fix seconds)
 {
 	SDL_Delay(f2i(fixmul(seconds, i2f(1000))));
 }
+
+// Replacement for timer_delay which considers calc time the program needs between frames (not reentrant)
+void timer_delay2(int fps)
+{
+	static u_int32_t last_render_time=0;
+
+	if (last_render_time > SDL_GetTicks()) // Fallback for SDL_GetTicks() wraparound
+		last_render_time = 0;
+	else
+	{
+		int FrameDelay = (1000/fps) // ms to pause between frames for desired FPS rate
+				 - (SDL_GetTicks()-last_render_time)/(F1_0/1000) // Substract the time the game needs to do it's operations
+				 - 10; // Substract 10ms inaccuracy due to OS scheduling
+
+		if (FrameDelay > 0)
+			SDL_Delay(FrameDelay);
+	
+		last_render_time = SDL_GetTicks();
+	}
+}

include/timer.h

@@ -69,6 +69,7 @@ extern fix timer_get_approx_seconds();
 //NOT_USED extern unsigned int timer_get_millisecondsX();	// Assume interrupts disabled
 
 void timer_delay(fix seconds);
+void timer_delay2(int fps);
 
 //==========================================================================
 // Use to access the BIOS ticker... ie...   i = TICKER

main/game.c

@@ -774,22 +774,10 @@ void calc_frame_time()
 
 	// sleep for one frame to free CPU cycles if GameArg.SysUseNiceFPS is active.
 	if (GameArg.SysUseNiceFPS)
-	{
-		// Timer which sleeps for the time between frames but substracts 10ms timer inaccuracy.
-		// CPU usage not optimized, but more reliable to get desired FPS and smooth gameplay.
-		// Should probably replaced by a better solution.
-		int FrameDelay = (1000/GameArg.SysMaxFPS)	// ms to pause between frames for desired FPS rate
-				 - FrameTime/(F1_0/1000)	// Substract the time the game needs to do it's operations
-				 - 10;				// Substract 10ms inaccuracy due to OS scheduling
-
-		if (FrameDelay > 0)
-			SDL_Delay(FrameDelay);
-	}
+		timer_delay2(GameArg.SysMaxFPS);
 
 	while (FrameTime < f1_0 / GameArg.SysMaxFPS)
 	{
-// 		if (GameArg.SysUseNiceFPS)
-// 			timer_delay(f1_0 / GameArg.SysMaxFPS - FrameTime);
 		timer_value = timer_get_fixed_seconds();
 		FrameTime = timer_value - last_timer_value;
 	}
@@ -1499,7 +1487,7 @@ int do_game_pause()
 
 	while (Game_paused) 
 	{
-		timer_delay(1);
+		timer_delay2(20);
 #ifdef OGL
 		show_boxed_message(msg);
 #endif

main/kconfig.c

@@ -677,7 +677,7 @@ void kconfig_sub(kc_item * items,int nitems, char * title)
 
 	while(1)
 	{
-		timer_delay(400);
+		timer_delay2(20);
 
 #ifdef OGL
 		gr_flip();

main/kmatrix.c

@@ -312,7 +312,7 @@ void kmatrix_view(int network)
 	done = 0;
 
 	while(!done)	{
-		timer_delay(400);
+		timer_delay2(20);
 		kmatrix_redraw();
 
 		for (i=0; i<4; i++ )	

main/netlist.c

@@ -236,7 +236,7 @@ void show_game_rules(netgame_info game)
 	done = 0;
 
 	while(!done)	{
-		timer_delay(400);
+		timer_delay2(20);
 		gr_set_current_canvas(NULL);
 #ifdef OGL
 		gr_flip();

main/newmenu.c

@@ -838,7 +838,7 @@ int newmenu_do3_real( char * title, char * subtitle, int nitems, newmenu_item *
 #endif
 
 	while(!done)	{
-		timer_delay(400);
+		timer_delay2(20);
 #ifdef OGL
 		gr_flip();
 
@@ -1631,7 +1631,7 @@ ReadFileNames:
 #endif
 
 	while(!done)	{
-		timer_delay(400);
+		timer_delay2(20);
 		ocitem = citem;
 		ofirst_item = first_item;
                 gr_update();
@@ -2038,7 +2038,7 @@ int newmenu_listbox1( char * title, int nitems, char * items[], int allow_abort_
 #endif
 
 	while(!done)	{
-		timer_delay(400);
+		timer_delay2(20);
 #ifdef OGL
 		gr_flip();
 		nm_draw_background1(NULL);

main/scores.c

@@ -372,7 +372,7 @@ ReshowScores:
 	looper = 0;
 
 	while(!done)	{
-		timer_delay(400);
+		timer_delay2(20);
 		gr_set_current_canvas(NULL);
 #ifdef OGL
 		gr_flip();

main/titles.c

@@ -126,7 +126,7 @@ int show_title_screen( char * filename, int allow_keys )
 			gr_free_bitmap_data (&title_bm);
 			break;
 		}
-		timer_delay(400);
+		timer_delay2(20);
         }
 
 	gr_free_bitmap_data (&title_bm);
@@ -753,7 +753,7 @@ int show_briefing(int screen_num, char *message)
 					}
 					while (timer_get_fixed_seconds() < start_time + KEY_DELAY_DEFAULT/2)
 						;
-					timer_delay(400);
+					timer_delay2(20);
 #ifdef OGL
 					gr_flip();
 					show_fullscr(&briefing_bm);
@@ -876,7 +876,7 @@ int show_briefing(int screen_num, char *message)
 				}
 				while (timer_get_approx_seconds() < start_time + KEY_DELAY_DEFAULT/2)
 					;
-				timer_delay(400);
+				timer_delay2(20);
 #ifdef OGL
 				gr_flip();
 				show_fullscr(&briefing_bm);