path: root/src/linux.c

#include "GL/glew.h"
#include "SDL3/SDL.h"

#include "prge.h"

#include "crrn.h"
#include "crrn.c"

typedef struct {
	SDL_AudioSpec spec;
	SDL_AudioStream *stream;
} SDLSound;

typedef struct {
	SDLSound sdlsounds[MAX_SOUNDS_PLAYING];
	SDL_AudioDeviceID audio_device;
	SDL_Window *window;
	SDL_GLContext glctx;
} SDLContext;

static SDLContext sdlctx;

i32 init_sdl(prge_window_t *window)
{
	if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO)) {
		printf("error: sdl init: %s\n", SDL_GetError());
		return 0;
	}

	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
	if (window->flags & WINDOW_MULTISAMPLE)
		SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
	u32 flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE;
	sdlctx.window = SDL_CreateWindow(window->name, window->width, window->height, flags);
	if (!sdlctx.window) {
		printf("error: sdl create window: %s\n", SDL_GetError());
		return 0;
	}
	SDL_GetWindowSize(sdlctx.window, &window->width, &window->height);

	if (!(sdlctx.glctx = SDL_GL_CreateContext(sdlctx.window))) {
		printf("error: sdl create gl context: %s\n", SDL_GetError());
		return 0;
	}
	if (!SDL_GL_MakeCurrent(sdlctx.window, sdlctx.glctx)) {
		printf("error: sdl make context current: %s\n", SDL_GetError());
		return 0;
	}

	if (SDL_GL_SetSwapInterval(0))
		printf("info: vsync disabled\n");
	else 
		printf("warning: failed to disable vsync\n");

	u32 error = glewInit();
	if (error != GLEW_OK) {
		printf("error: glew: %s\n", glewGetErrorString(error));
		return 0;
	}
	if (window->flags & WINDOW_DEPTH_TEST)
		glEnable(GL_DEPTH_TEST);
	if (window->flags & WINDOW_MULTISAMPLE)
		glEnable(GL_MULTISAMPLE);

	sdlctx.audio_device = SDL_OpenAudioDevice(SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, 0);
	if (!sdlctx.audio_device) {
		printf("error: sdl: couldn't open audio device\n");
		return 0;
	}

	return 1;
}

void process_mouse_pos(input_t *input, SDL_MouseMotionEvent *event, prge_window_t window)
{
	input->mouse.pos = (v2){(f32)event->x, window.height - (f32)event->y};
	if (input->mouse.first)
		input->mouse.first = 0;
	v2 offset = {(f32)event->xrel, (f32)event->yrel};
	input->mouse.offset = v2_add(input->mouse.offset, offset);
}

void process_key(i32 down, prge_key_t *key)
{
	key->state = (down ? key_state_press : key_state_release);
}

void process_keyboard(input_t *input, SDL_KeyboardEvent *keyev)
{
	switch (keyev->scancode) {
	case SDL_SCANCODE_D:
		process_key(keyev->down, &input->move_right);
		break;
	case SDL_SCANCODE_W:
		process_key(keyev->down, &input->move_forward);
		break;
	case SDL_SCANCODE_A:
		process_key(keyev->down, &input->move_left);
		break;
	case SDL_SCANCODE_S:
		process_key(keyev->down, &input->move_backward);
		break;
	case SDL_SCANCODE_E:
		process_key(keyev->down, &input->move_up);
		break;
	case SDL_SCANCODE_Q:
		process_key(keyev->down, &input->move_down);
		break;
	case SDL_SCANCODE_SPACE:
		process_key(keyev->down, &input->jump);
		break;
	case SDL_SCANCODE_RIGHT:
		process_key(keyev->down, &input->action_right);
		break;
	case SDL_SCANCODE_UP:
		process_key(keyev->down, &input->action_up);
		break;
	case SDL_SCANCODE_LEFT:
		process_key(keyev->down, &input->action_left);
		break;
	case SDL_SCANCODE_DOWN:
		process_key(keyev->down, &input->action_down);
		break;
	case SDL_SCANCODE_ESCAPE:
		process_key(keyev->down, &input->exit);
		break;
	default:
		break;
	}
}

void process_mouse_buttons(input_t *input, SDL_MouseButtonEvent *buttonev)
{
	if (buttonev->button == SDL_BUTTON_LEFT)
		process_key(buttonev->down, &input->mouse.left);
	else if (buttonev->button == SDL_BUTTON_RIGHT)
		process_key(buttonev->down, &input->mouse.right);
}

void handle_events(prge_context_t *ctx)
{
	SDL_Event event;

	while (SDL_PollEvent(&event)) {
		switch (event.type) {
		case SDL_EVENT_KEY_DOWN:
		case SDL_EVENT_KEY_UP:
			process_keyboard(&ctx->input, &event.key);
			break;
		case SDL_EVENT_MOUSE_MOTION:
			process_mouse_pos(&ctx->input, &event.motion, ctx->window);
			break;
		case SDL_EVENT_MOUSE_BUTTON_DOWN:
		case SDL_EVENT_MOUSE_BUTTON_UP:
			process_mouse_buttons(&ctx->input, &event.button);
			break;
		case SDL_EVENT_WINDOW_RESIZED:
			ctx->window.width = event.window.data1;
			ctx->window.height = event.window.data2;
			break;
		case SDL_EVENT_QUIT:
			ctx->should_close = 1;
			break;
		default:
			break;
		}
	}
}

f32 get_elapsed_seconds(u64 current, u64 last)
{
	f32 elapsed = ((f32)current-(f32)last)/1000.0f;
	return elapsed;
}

f32 lock_framerate(u64 last, f32 target)
{
	f32 elapsed = get_elapsed_seconds(SDL_GetTicks(), last)*1000.0f;
	if (elapsed < target) {
		f32 sleep = target-elapsed;
		if (sleep > 0.0f)
			SDL_Delay(sleep);
		do {
			elapsed = get_elapsed_seconds(SDL_GetTicks(), last)*1000.0f;
		} while (elapsed < target);
	}
	f32 dt = get_elapsed_seconds(SDL_GetTicks(), last);
	return dt;
}

#include "stb_vorbis.c"

i32 load_vorbis(arena_t *arena, sound_t *sounds, const char *filename)
{
	sound_t sound;
	sound.name = filename;

	i32 i = find_sound(sounds, sound.name);
	if (i != -1) {
		printf("info: \"%s\" already loaded\n", sound.name);
		return i;
	}

	/* TODO(pryazha): Custom loader with arenas (or provide allocator to stb) */
	i16 *output;
	i32 samples = stb_vorbis_decode_filename(filename, &sound.channels,
		&sound.freq, &output);
	if (samples == -1) {
		printf("error: \"%s\" failed to open\n", filename);
		return -1;
	}

	sound.bps = sizeof(i16);
	sound.size = sound.channels*samples*sound.bps;
	sound.data = push_arena(arena, sound.size);
	prb_memmove(sound.data, output, sound.size);
	free(output);

	i = load_sound(sounds, sound);
	if (i == -1) {
		pop_arena(arena, sound.size);
		return i;
	}

	printf("info: \"%s\" loaded successfully\n", filename);

	return i;
}

void play_sound(sound_t *sounds, sound_queue_t *queue, sound_queue_node_t *nodes, i32 id)
{
	if ((id == -1) && (id >= MAX_SOUNDS_LOADED)) {
		printf("error: invalid sound id = %d\n", id);
		return;
	}

	if (!sounds[id].data) {
		printf("error: sound with id = %d doesn't exist\n", id);
		return;
	}

	sound_t *sound = sounds+id;

	if (!enqueue_sound(queue, nodes, sound)) {
		printf("error: failed to enqueue the sound \"%s\"\n", sound->name);
		return;
	}

	printf("info: queue content:\n");
	for (sound_queue_node_t *node = queue->first; node; node = node->next) {
		printf("%s%s", node->sound->name, (node->next ? " -> " : "\n"));
	}
}

SDLSound *get_empty_sdl_sound()
{
	for (i32 i = 0; i < MAX_SOUNDS_PLAYING; i++) {
		SDLSound *sdlsound = sdlctx.sdlsounds+i;
		if (!sdlsound->stream)
			return sdlsound;
		if (SDL_GetAudioStreamAvailable(sdlsound->stream) == 0)
			return sdlsound;
	}
	return 0;
}

void update_sdl_sounds(sound_queue_t *queue)
{
	SDLSound *sdlsound;
	sound_t *sound;
	SDL_AudioSpec spec;

	while ((sdlsound = get_empty_sdl_sound()) && (sound = dequeue_sound(queue))) {
		switch (sound->bps) {
		case 2:
			spec.format = SDL_AUDIO_S16;
			break;
		default:
			printf("error: sound: \"%s\". Unsupported audio format\n", sound->name);
			return;
		}
		spec.channels = sound->channels;
		spec.freq = sound->freq;

		if (sdlsound->stream) {
			if (!prb_memeq(&sdlsound->spec, &spec, sizeof(SDL_AudioSpec))) {
				sdlsound->spec = spec;
				SDL_SetAudioStreamFormat(sdlsound->stream, &sdlsound->spec, 0);
			}
		} else {
			sdlsound->spec = spec;
			sdlsound->stream = SDL_CreateAudioStream(&sdlsound->spec, 0);
			if (!sdlsound->stream) {
				printf("error: sailed to create audio stream\n");
				return;
			}
			if (!SDL_BindAudioStream(sdlctx.audio_device, sdlsound->stream)) {
				SDL_DestroyAudioStream(sdlsound->stream);
				printf("error: failed to bind audio stream to device\n");
				return;
			}
		}
		printf("info: playing: \"%s\"\n", sound->name);
		SDL_PutAudioStreamData(sdlsound->stream, sound->data, sound->size);
	}
}

i32 main(void)
{
	// engine init
	prge_context_t prgectx = init_prge();
	u32 flags = WINDOW_DEPTH_TEST | WINDOW_MULTISAMPLE;
	prgectx.window = (prge_window_t){800, 600, "prge example", flags};

	f32 fps = 60.0f;
	f32 mspf = 1000.0f/fps;

	// sdl and opengl init
	if (!init_sdl(&prgectx.window))
		return 1;

	// game init
	game_context_t gctx = {0};
	init(&prgectx, &gctx);

	u64 last = SDL_GetTicks();
	while (!prgectx.should_close) {
		SDL_SetWindowRelativeMouseMode(sdlctx.window, prgectx.input.mouse.capture);

		handle_events(&prgectx);

		prgectx.input.dt = lock_framerate(last, mspf);
		last = SDL_GetTicks();

		pop_arena(&prgectx.frame_arena, prgectx.frame_arena.used);

		glViewport(0, 0, prgectx.window.width, prgectx.window.height);
		update_and_render(&prgectx, &gctx);
		update_sdl_sounds(&prgectx.sound_queue);
		update_input(&prgectx.input);

		SDL_GL_SwapWindow(sdlctx.window);
	}

	return 0;
}