# Dangerzone

## A tiny game engine / software renderer using SDL for framebuffer visualization

#### Features

1. Put Pixel

```c
void put_pixel(unsigned int x, unsigned int y, uint32_t color);
```

- Lets you color one given pixel in the framebuffer.

2. Clear Framebuffer

```c
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:

```c
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:

```c
...

// 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.