framerate fix

not a permanent fix yet, casting to double feels wrong,
and the game will not try to catch up if it oversleeps

1 files changed, 38 insertions, 10 deletions

diff --git a/src/main.c b/src/main.c
index 09c5425..922ca20 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4,8 +4,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <inttypes.h>
-#include <errno.h>
+#include <errno.h> // ENOENT
+#include <math.h> // used by vk2dSleep
 
 #include "input.h"
 #include "loader.h"
@@ -14,8 +14,8 @@
 
 #include "tilemap.h"
 
-#include "incbin.h"
-#include "libplum.h"
+#include "incbin.h" // game icon
+#include "libplum.h" // decoding game icon
 
 #include "main.h"
 
@@ -273,6 +273,27 @@ void game_render_flush(SDL_Texture *framebuffer) {
 	SDL_RenderPresent(renderer);
 }
 
+// from libertea / <https://github.com/PaoloMazzon>
+double getTime(void) {
+  static double time = -1;
+  if (time == -1)
+    time = SDL_GetPerformanceCounter();
+  return (double)(SDL_GetPerformanceCounter() - time) / SDL_GetPerformanceFrequency();
+}
+
+// also from libertea / <https://github.com/PaoloMazzon>
+void vk2dSleep(double seconds) {
+    if (seconds <= 0)
+        return;
+    double start = SDL_GetPerformanceCounter();
+    double milliseconds = floor(seconds * 1000);
+    SDL_Delay(milliseconds);
+    while ((SDL_GetPerformanceCounter() - start) / (double)SDL_GetPerformanceFrequency() < seconds) {
+        volatile int i = 0;
+        (void) i;
+    }
+}
+
 int main(int const argc, char *const *const argv) {
 	save_file_name = SDL_GetPrefPath("sylvie", "game");
 	save_file_name = SDL_realloc(save_file_name, strlen(save_file_name) + strlen("save.sav") + 1);
@@ -358,12 +379,13 @@ int main(int const argc, char *const *const argv) {
 	#if defined(__EMSCRIPTEN__)
 	scale = 1;
 	#else
-	if (scale <= 0) { // this looks very wrong
+	if (scale <= 0) { // because we used atoi, the user can set scale to -1 or something
 		SDL_DisplayMode dm;
 		if (SDL_GetDesktopDisplayMode(0, &dm) != 0) {
-			SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "couldnt get desktop size", SDL_GetError(), NULL);
-			fprintf(stderr, "info: couldnt get desktop size %s\n", SDL_GetError());
+			SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_WARNING, "couldnt get desktop size", SDL_GetError(), NULL);
+			fprintf(stderr, "warn: couldnt get desktop size %s\n", SDL_GetError());
 			flags |= SDL_WINDOW_RESIZABLE;
+			scale = 3;
 		} else {
 			int x = dm.w / 2 / WINDOW_WIDTH;
 			int y = dm.h / 2 / WINDOW_HEIGHT;
@@ -375,8 +397,10 @@ int main(int const argc, char *const *const argv) {
 			if (scale == 0) {
 				scale = 1;
 			}
-			if (dm.refresh_rate != 60) {
-				SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_WARNING, "refresh rate", "this game currently only runs well on 60Hz displays", NULL);
+			if (dm.refresh_rate < 59) {
+				SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_WARNING, "refresh rate", "your monitor appears to have a refresh rate below 60Hz, the game will run slower\n"
+				"you can compile the game from source to disable vsync, unlocking the framerate\n"
+				"TODO: disabling vsync without a recompile", NULL);
 			}
 		}
 	}
@@ -494,6 +518,8 @@ void main_loop(void) {
 	int x = 0, y = 0;
 	while (1) {
 #endif
+		double const begin_time = getTime();
+
 		input_pressed = input_held;
 		SDL_Event evt;
 		while (SDL_PollEvent(&evt)) {
@@ -563,7 +589,7 @@ void main_loop(void) {
 					i = evt.tfinger.fingerId;
 					touch.positions[i].x = evt.tfinger.x;
 					touch.positions[i].y = evt.tfinger.y;
-					printf("%" PRIu64 " %" PRIu64 " %f %f\n", evt.tfinger.touchId, evt.tfinger.fingerId, evt.tfinger.x, evt.tfinger.y);
+					//printf("%" PRIu64 " %" PRIu64 " %f %f\n", evt.tfinger.touchId, evt.tfinger.fingerId, evt.tfinger.x, evt.tfinger.y);
 					reset_touch:
 					touch.input_touch = 0;
 					for (size_t i = 0; i < touch.allocated; i++) {
@@ -733,6 +759,8 @@ void main_loop(void) {
 #if defined(__EMSCRIPTEN__)
 	return;
 #else
+		double const end_time = getTime();
+		vk2dSleep(1.0/60.0 - (end_time - begin_time));
 	}
 #endif