From 5ec96d087a1184b55ef96dbc543d66918b615e5b Mon Sep 17 00:00:00 2001
From: erysdren <contact@erysdren.me>
Date: Sun, 13 Oct 2024 10:09:02 -0500
Subject: [PATCH] sdl3: speed limiter and cmdline map selection

---
 platform/sdl3/main.c | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

diff --git a/platform/sdl3/main.c b/platform/sdl3/main.c
index 0efdf3c..9dd6562 100644
--- a/platform/sdl3/main.c
+++ b/platform/sdl3/main.c
@@ -7,6 +7,8 @@
 #include "game.h"
 #include "maps.h"
 
+#define MAXFPS (60)
+
 static yeti_t yeti;
 static u16 backbuffer[YETI_FRAMEBUFFER_WIDTH * YETI_FRAMEBUFFER_HEIGHT];
 
@@ -18,6 +20,10 @@ static SDL_Surface *back = NULL;
 
 static bool focused = true;
 
+static Sint64 now = 0, then = 0;
+
+static int requested_map = 0;
+
 static void die(const char *fmt, ...)
 {
 	static char error[1024];
@@ -78,14 +84,29 @@ SDL_AppResult SDL_AppInit(void **appstate, int argc, char **argv)
 	yeti_init(&yeti, backbuffer, backbuffer, textures, palette);
 	yeti_init_lua(&yeti, YETI_GAMMA);
 	game_init(&yeti);
-	game_load_map(&yeti, &map_e1m1);
+
+	/* get requested map */
+	if (argc > 1)
+		requested_map = SDL_atoi(argv[1]);
+
+	SDL_Log("Loading map %d", requested_map);
+
+	if (requested_map >= 0)
+		game_load_map(&yeti, maps[requested_map]);
+	else
+		game_load_map(&yeti, &map_e1m1);
+
 	game_goto(&yeti.game, GAME_MODE_PLAY);
 
+	/* start counting time */
+	then = SDL_GetTicks();
+
 	return SDL_APP_CONTINUE;
 }
 
-SDL_AppResult SDL_AppIterate(void *appstate)
+void do_frame(Sint64 dt)
 {
+	static Sint64 frame_delta = 1000;
 	const bool *keys = SDL_GetKeyboardState(NULL);
 
 	yeti.keyboard.state.up = keys[SDL_SCANCODE_UP] || keys[SDL_SCANCODE_W];
@@ -98,10 +119,21 @@ SDL_AppResult SDL_AppIterate(void *appstate)
 	yeti.keyboard.state.r = keys[SDL_SCANCODE_Z];
 	yeti.keyboard.state.select = keys[SDL_SCANCODE_ESCAPE];
 
-	SDL_FillSurfaceRect(back, NULL, 0);
-	SDL_FillSurfaceRect(front, NULL, 0);
+	frame_delta += dt;
 
-	game_loop(&yeti);
+	if (frame_delta > (1000 / MAXFPS))
+	{
+		game_loop(&yeti);
+		frame_delta = 0;
+	}
+}
+
+SDL_AppResult SDL_AppIterate(void *appstate)
+{
+	/* speed limiter */
+	now = SDL_GetTicks();
+	do_frame(now - then);
+	then = now;
 
 	SDL_BlitSurface(back, NULL, front, NULL);
 	SDL_UpdateTexture(texture, NULL, front->pixels, front->pitch);