game: render at 60FPS and animate player accordingly

The input handling is not yet properly working.

1 files changed, 73 insertions, 30 deletions

diff --git a/game.c b/game.c
index a77234c..54e0581 100644
--- a/game.c
+++ b/game.c
@@ -2,19 +2,34 @@
 #define PLAYER_IS_DEAD 2
 #define PLAYER_HAS_WON 3
 
+#include <time.h>
+#include <unistd.h>
 
 
+void update_player_animation(struct level_struct *cur_level_state) {
+	// Cycle through the player's faces
+	cur_level_state->player_face++;
+	if (cur_level_state->player_face == 4) {
+		cur_level_state->player_face = 0;
+	}
+}
+
 // player_action moves the player
 // It returns one of the three PLAYER_ define values ( top of this file )
 int player_action( signed int xdiff, signed int ydiff, struct level_struct *currentlevel )
 {
-	// Find the tile the player moved into/onto using the player's current position
+	// no movent so we just update the animation
+	if (xdiff == 0 && ydiff == 0) {
+		update_player_animation(currentlevel);
+		return PLAYER_IS_OK;
+	}
+
+	// Find the tile the player moved into/onto using the player's
+	// current position
 	int newx = currentlevel->px + xdiff;
 	int newy = currentlevel->py + ydiff;
 	
-	// Cycle through the player's faces
-	currentlevel->player_face++;
-	if ( currentlevel->player_face == 4 ) currentlevel->player_face = 0;
+	update_player_animation(currentlevel);
 	
 	// Check to make sure these directions are not solid ( ie walls )
 	// and also to see if they are interactive ( ie buttons )
@@ -77,23 +92,46 @@ int player_action( signed int xdiff, signed int ydiff, struct level_struct *curr
 
 int play_level(SDL_Renderer* renderer, struct level_struct *currentlevel)
 {
+	struct timespec last_render;
+	last_render.tv_sec = 0;
+	last_render.tv_nsec = 0;
+
 	// Loop until the user completes the level
 	int player_status = PLAYER_IS_OK;
 
-	while ( player_status == PLAYER_IS_OK )
-	{
-		SDL_Event userinput;
-		
-		// WaitEvent is like PollEvent, but instead we pause the program's
-		// execution until we get input
-		SDL_WaitEvent( &userinput );
-		render(renderer, currentlevel);
+	while ( player_status == PLAYER_IS_OK ) {
+	  struct timespec start, end;
+		clock_gettime(CLOCK_MONOTONIC_RAW, &start);
+
+		double since_last = (start.tv_sec - last_render.tv_sec) * 1000000 + (double)(start.tv_nsec - last_render.tv_nsec) / 1000;
+		double ms_since_last = (double)since_last/(double)1000;
+		printf("ms since last %f\n", ms_since_last);
+		if (last_render.tv_nsec == 0 || ms_since_last >= 16.5) {
+			printf("fps: %f\n", 1000 / ms_since_last);
+		  render(renderer, currentlevel);
+		} else {
+			float sleep_ms = 16.5 - ms_since_last;
+			printf("not yet. Sleep for %f ms\n", sleep_ms);
+			if (sleep_ms > 0) {
+				usleep(sleep_ms * 1000);
+			}
+			continue;
+		}
+
+		clock_gettime(CLOCK_MONOTONIC_RAW, &end);
+
+		uint64_t delta_us = (end.tv_sec - start.tv_sec) * 1000000 + (end.tv_nsec - start.tv_nsec) / 1000;
+		double ms = (double)delta_us/(double)1000;
+		printf("time taken %f\n", ms);
+
+		last_render = end;
 		
+		SDL_Event userinput;
+		int got_event = SDL_PollEvent(&userinput);
+
 		// Player movement
 		signed int y, x;
-		
-		if ( userinput.type == SDL_KEYDOWN )
-		{
+		if ( userinput.type == SDL_KEYDOWN ) {
 			switch ( userinput.key.keysym.sym )
 			{
 				case SDLK_UP:
@@ -133,23 +171,28 @@ int play_level(SDL_Renderer* renderer, struct level_struct *currentlevel)
 					y = 0;
 					break;
 			}
-			
-			// Now move the player
-			player_status = player_action( x, y, currentlevel );
-			
-			// Move all of the echidnas
-			run_all_echidnaAI_onestep( currentlevel );
+		}
 
-			// And make sure we open/close red doors if any
-			// of them are stepping on red levers
-			check_echidna_on_switches( currentlevel );
-			
-			// Check to see if the player has run into an echidna
-			if ( check_echidna_proximity( currentlevel ) == 1 ) player_status = PLAYER_IS_DEAD;
-			
-			// Show a losing screen if applicable
-			if (player_status == PLAYER_IS_DEAD) render_a_losingscreen(renderer, currentlevel);
+		// Now update the player state
+		player_status = player_action(x, y, currentlevel);
+
+		// there was no event so there is nothing else to do
+		if (!got_event) {
+			continue;
 		}
+
+		// Move all of the echidnas
+		run_all_echidnaAI_onestep( currentlevel );
+
+		// And make sure we open/close red doors if any
+		// of them are stepping on red levers
+		check_echidna_on_switches( currentlevel );
+
+		// Check to see if the player has run into an echidna
+		if ( check_echidna_proximity( currentlevel ) == 1 ) player_status = PLAYER_IS_DEAD;
+
+		// Show a losing screen if applicable
+		if (player_status == PLAYER_IS_DEAD) render_a_losingscreen(renderer, currentlevel);
 	}
 	
 	// The code running play_level needs to know if too advance