first draft version of the mini engine

include/engine.h

@@ -0,0 +1,78 @@
+#pragma once
+
+#include <SDL3/SDL.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#define WINDOW_WIDTH 1280
+#define WINDOW_HEIGHT 720
+#define DEFAULT_WINDOW_NAME "SDL Playground"
+#define WINDOW_NAME_LENGTH 128
+#define TARGET_FRAME 1.0 / 60.0
+
+typedef struct {
+	char window_name[WINDOW_NAME_LENGTH];
+	uint16_t width, height;
+	SDL_Window *window;
+	SDL_Renderer *renderer;
+	SDL_Texture *texture;
+} engine_sdl_state_t;
+
+typedef struct {
+	/**
+	 * this function runs inside of the SDL_PollEvent loop
+	 * useful for user input, quitting the program and so on
+	 */
+	void (*engine_poll_events)(void);
+	/**
+	 * meant as the "area" for manupulating the framebuffer;
+	 * after this is executed, the contents of 
+	 * game_state->framebuffer get drawn
+	 */
+	void (*engine_update_framebuffer)(void);
+	engine_sdl_state_t *sdl_state;
+} engine_internal_state_t;
+
+typedef struct {
+	uint32_t framebuffer[WINDOW_WIDTH * WINDOW_HEIGHT];
+	SDL_Event event;
+	bool is_running;
+	uint16_t width, height;
+} game_state_t;
+
+extern engine_internal_state_t *internal_state;
+extern game_state_t *game_state;
+
+engine_sdl_state_t*
+engine_sdl_init();
+
+void 
+engine_sdl_destroy(
+	engine_sdl_state_t *state
+);
+
+bool
+engine_init(
+	void (*engine_poll_events)(void),
+	void (*engine_update_framebuffer)(void)
+);
+
+void
+engine_start();
+
+void
+engine_stop();
+
+void 
+put_pixel(
+	unsigned int x, 
+	unsigned int y, 
+	uint32_t color
+);
+
+void 
+clear_framebuffer(
+	uint32_t color
+);