add README.md

README.md

@@ -0,0 +1,74 @@
+# Dangerzone
+
+## A tiny game engine / software renderer using SDL for framebuffer visualization
+
+#### Features
+
+1. Put Pixel
+
+```
+void put_pixel(unsigned int x, unsigned int y, uint32_t color);
+```
+
+- Lets you color one given pixel in the framebuffer.
+
+2. Clear Framebuffer
+
+```
+void clear_framebuffer(uint32_t color);
+```
+
+- Lets you fill the entire framebuffer with one color.
+
+#### Usage
+
+The main function of a program that uses this engine should look something like this:
+
+```
+int main() {
+	// initialize the engine
+	if (engine_init(
+		client_poll_event,
+		client_update_framebuffer
+	)) {
+		// start the main game loop
+		engine_start();
+		// once the engine finishes, end gracefully
+		engine_stop();
+		return 0;
+	} else {
+		return 1;
+	}
+}
+```
+
+The `client_poll_event()` and `client_update_framebuffer()` are two special functions that let you poll events and update the framebuffer respectively. (Shocking, I know.) You are supposed to define them yourself and pass them as function pointers to `engine_init()`.
+
+Polling events allows you to handle mouse clicks, keyboard key presses, quitting the program and so on.
+
+Updating the framebuffer means changing color values in the respective struct and thus getting an image on the screen.
+
+An excerpt from the main game loop is below:
+
+```
+...
+
+// main game loop
+while(game_state->is_running) {
+	uint64_t start = SDL_GetPerformanceCounter();
+
+	// poll events
+	while (SDL_PollEvent(&game_state->event)) {
+		internal_state->engine_poll_events();
+	}
+
+	// call the user-defined framebuffer manipulation function
+	internal_state->engine_update_framebuffer();
+
+	...
+}
+
+...
+```
+
+If you want to modify the values for things like the window size or window name, (for now) go into `src/engine/engine.h` and change them there on the `#define` lines.

include/engine.h

@@ -8,7 +8,7 @@
 
 #define WINDOW_WIDTH 1280
 #define WINDOW_HEIGHT 720
-#define DEFAULT_WINDOW_NAME "SDL Playground"
+#define DEFAULT_WINDOW_NAME "Dangerzone"
 #define WINDOW_NAME_LENGTH 128
 #define TARGET_FRAME 1.0 / 60.0