Initial commit.

14 files changed, 2829 insertions, 0 deletions

diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 0000000..37533bd
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,50 @@
+# Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+src = main.c collision.c game.c input.c renderer.c
+inc = extern.h game.h input.h renderer.h screen.h version.h
+
+.ifdef GPIO
+
+src += gpio.c
+inc += gpio.h
+
+.endif
+
+obj = ${src:.c=.o}
+
+PREFIX = /usr/local
+
+CFLAGS = -O3 -march=native -pipe -flto=thin -Wall -Wno-unused-result
+LDFLAGS = -Wl,-O3 -lpthread -lSDL2 -lSDL2_ttf
+
+.ifdef SOUND
+
+LDFLAGS += -lSDL2_mixer
+
+.endif
+
+LDFLAGS += -Wl,--as-needed
+
+CFLAGS += -I/usr/local/include
+LDFLAGS += -L/usr/local/lib
+
+all: ${obj} ${inc}
+	${CC} ${LDFLAGS} -o snake ${obj}
+
+clean:
+	rm -f snake ${obj}
+
+install:
+	install -d ${PREFIX}/bin
+	install -d ${PREFIX}/share/snake
+	install snake ${PREFIX}/bin
+	install -m644 ../contrib/font.ttf ${PREFIX}/share/snake
+	install -m644 ../contrib/music.flac ${PREFIX}/share/snake
+
+deinstall:
+	rm -f ${PREFIX}/bin/snake
+	rm -rf ${PREFIX}/share/snake
+
+.PHONY: all clean install deinstall
diff --git a/src/collision.c b/src/collision.c
new file mode 100644
index 0000000..5810c84
--- /dev/null
+++ b/src/collision.c
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdbool.h>
+
+#include <SDL2/SDL.h>
+
+#include "screen.h"
+#include "renderer.h"
+
+bool
+collision(int *a, int *b)
+{
+	if (a[0] < b[0] + b[2] &&
+		a[0] + a[2] > b[0] &&
+		a[1] < b[1] + b[3] &&
+		a[1] + a[3] > b[1])
+		return 1;
+	return 0;
+}
+
+bool
+collision_block(int *a, int *b)
+{
+	return collision(
+		(int[]) {a[0], a[1], SCREEN_UNIT, SCREEN_UNIT},
+		(int[]) {b[0], b[1], SCREEN_UNIT, SCREEN_UNIT});
+}
+
+bool
+collision_bound(float x, float y, Snake_Text *message)
+{
+	if (x > message->pos.x &&
+		x < message->pos.x + message->pos.w &&
+		y > message->pos.y &&
+		y < message->pos.y + message->pos.h)
+		return 1;
+	return 0;
+}
diff --git a/src/extern.h b/src/extern.h
new file mode 100644
index 0000000..482b9ed
--- /dev/null
+++ b/src/extern.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_ttf.h>
+
+#include "renderer.h"
+#include "game.h"
+#include "input.h"
+
+bool collision(int *a, int *b);
+bool collision_block(int *a, int *b);
+bool collision_bound(float x, float y, Snake_Text *message);
+
+void draw_clear(SDL_Renderer *renderer);
+void draw_colour(SDL_Renderer *renderer, Snake_Colour colour);
+void draw_text(SDL_Renderer *renderer, TTF_Font *font,
+	int text_x, int text_y, char *text,
+	bool centre, bool select, SDL_Color fg, SDL_Color bg,
+	Snake_Text *message);
+void draw_wall(SDL_Renderer *renderer);
+void draw_snake(SDL_Renderer *renderer, Snake_Pos **snake);
+void draw_fruit(SDL_Renderer *renderer, int *fruit);
+void draw_pipe(SDL_Renderer *renderer, Snake_Pos **pipe);
+
+void game_snake_init(Snake_Pos **snake, int dx);
+void game_snake_move(Snake_Pos **snake0, Snake_Pos **snake1,
+	Snake_Input *head, bool lawi, int *legal);
+void game_snake_grow(Snake_Pos **snake);
+void game_fruit(int *fruit, Snake_Pos **snake);
+void game_snake_fall(Snake_Pos **snake, bool norm, int speed);
+void game_pipe_init(Snake_Pos **pipe);
+void game_pipe_move(Snake_Pos **pipe);
+void game_pipe_add(Snake_Pos **pipe);
+void game_pipe_del(Snake_Pos **pipe);
+void game_pipe_pos(Snake_Pos **pipe, int *state);
+void game_pipe_bound(Snake_Pos **pipe, int *pos);
+
+void input_keyboard(SDL_Keycode sym, Snake_Input *code);
+void input_controller(uint8_t button, Snake_Input *code);
+void input_gpio(int gpio, uint8_t *button);
+
+#ifdef GPIO
+
+int gpio_export(int pin);
+int gpio_unexport(int pin);
+int gpio_config(int pin, int direction, int interrupt);
+int gpio_write(int pin, int value);
+int gpio_read(int pin);
+
+#endif /* GPIO */
diff --git a/src/game.c b/src/game.c
new file mode 100644
index 0000000..1a836d0
--- /dev/null
+++ b/src/game.c
@@ -0,0 +1,317 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdbool.h>
+
+#include "extern.h"
+#include "screen.h"
+
+static bool
+_collision(int *fruit, Snake_Pos **snake)
+{
+	Snake_Pos *ptr = *snake;
+	while (ptr != NULL) {
+		if (collision_block(fruit, (int[]) {ptr->x, ptr->y}))
+			return 1;
+		ptr = ptr->next;
+	}
+	return 0;
+}
+
+static bool
+_bound(Snake_Pos **snake)
+{
+	if ((*snake)->x + SCREEN_UNIT / 2 > SCREEN_HEIGHT)
+		return 1;
+	else if ((*snake)->y + SCREEN_UNIT / 2 > SCREEN_HEIGHT)
+		return 1;
+	else if ((*snake)->x - SCREEN_UNIT / 2 < -SCREEN_UNIT)
+		return 1;
+	else if ((*snake)->y - SCREEN_UNIT / 2 < -SCREEN_UNIT)
+		return 1;
+	return 0;
+}
+
+static int
+_overlap(Snake_Pos **snake0, Snake_Pos **snake1)
+{
+	Snake_Pos *ptr0 = *snake0;
+	Snake_Pos *ptr1;
+
+	int is_overlap[2] = {0, 0};
+
+	while (ptr0->next->next != NULL) {
+		if (collision_block(
+			(int[]) {(*snake0)->x, (*snake0)->y},
+			(int[]) {ptr0->next->x, ptr0->next->y})) {
+			is_overlap[0] = 1;
+			break;
+		}
+		ptr0 = ptr0->next;
+	}
+
+	if (snake1 != NULL) {
+		ptr0 = *snake0;
+		ptr1 = *snake1;
+		while (ptr0->next->next != NULL &&
+			ptr1->next->next != NULL &&
+			(is_overlap[0] != 1 || is_overlap[1] != 2)) {
+			if (collision_block(
+				(int[]) {(*snake0)->x, (*snake0)->y},
+				(int[]) {ptr1->next->x, ptr1->next->y}))
+				is_overlap[0] = 1;
+			if (collision_block(
+				(int[]) {(*snake1)->x, (*snake1)->y},
+				(int[]) {ptr0->next->x, ptr0->next->y}))
+				is_overlap[1] = 2;
+			if (collision_block(
+				(int[]) {(*snake1)->x, (*snake1)->y},
+				(int[]) {ptr1->next->x, ptr1->next->y}))
+				is_overlap[1] = 2;
+			ptr0 = ptr0->next;
+			ptr1 = ptr1->next;
+		}
+	}
+
+	return is_overlap[0] + is_overlap[1];
+}
+
+void
+game_snake_init(Snake_Pos **snake, int dx)
+{
+	Snake_Pos *ptr;
+	while ((ptr = *snake) != NULL) {
+		*snake = (*snake)->next;
+		free(ptr);
+	}
+
+	*snake = malloc(sizeof(Snake_Pos));
+	(*snake)->next = malloc(sizeof(Snake_Pos));
+
+	(*snake)->x = (*snake)->next->x = SCREEN_HEIGHT / 2 + dx;
+	(*snake)->y = SCREEN_HEIGHT / 2;
+	(*snake)->next->y = SCREEN_HEIGHT / 2 + SCREEN_UNIT;
+	(*snake)->next->next = NULL;
+}
+
+void
+game_snake_move(Snake_Pos **snake0, Snake_Pos **snake1,
+	Snake_Input *head, bool law, int *legal)
+{
+	bool bound_snake0;
+	bool bound_snake1;
+	int overlap;
+
+	Snake_Pos *ptr0;
+	Snake_Pos *ptr1;
+
+	ptr0 = malloc(sizeof(Snake_Pos));
+	ptr0->x = (*snake0)->x;
+	ptr0->y = (*snake0)->y;
+	ptr0->next = *snake0;
+
+	switch (head[0]) {
+		case SNAKE_LEFT:
+			ptr0->x -= SCREEN_UNIT;
+			break;
+		case SNAKE_UP:
+			ptr0->y -= SCREEN_UNIT;
+			break;
+		case SNAKE_DOWN:
+			ptr0->y += SCREEN_UNIT;
+			break;
+		case SNAKE_RIGHT:
+			ptr0->x += SCREEN_UNIT;
+			break;
+		default:
+			break;
+	}
+
+	bound_snake0 = _bound(&ptr0);
+
+	if (snake1 == NULL) {
+		overlap = _overlap(&ptr0, NULL);
+
+		if (bound_snake0 || overlap == 1)
+			*legal = 1;
+		else
+			*legal = 0;
+	} else {
+		ptr1 = malloc(sizeof(Snake_Pos));
+		ptr1->x = (*snake1)->x;
+		ptr1->y = (*snake1)->y;
+		ptr1->next = *snake1;
+
+		switch (head[1]) {
+			case SNAKE_LEFT:
+				ptr1->x -= SCREEN_UNIT;
+				break;
+			case SNAKE_UP:
+				ptr1->y -= SCREEN_UNIT;
+				break;
+			case SNAKE_DOWN:
+				ptr1->y += SCREEN_UNIT;
+				break;
+			case SNAKE_RIGHT:
+				ptr1->x += SCREEN_UNIT;
+				break;
+			default:
+				break;
+		}
+
+		bound_snake1 = _bound(&ptr1);
+		overlap = _overlap(&ptr0, &ptr1);
+
+		if ((bound_snake0 && bound_snake1) || overlap == 3)
+			*legal = 3;
+		else if (bound_snake1 || overlap == 2)
+			*legal = 2;
+		else if (bound_snake0 || overlap == 1)
+			*legal = 1;
+		else
+			*legal = 0;
+	}
+
+	if (*legal == 0 || !law) {
+		*snake0 = ptr0;
+
+		while (ptr0->next->next != NULL)
+			ptr0 = ptr0->next;
+		free(ptr0->next);
+		ptr0->next = NULL;
+
+		if (snake1 != NULL) {
+			*snake1 = ptr1;
+
+			while (ptr1->next->next != NULL)
+				ptr1 = ptr1->next;
+			free(ptr1->next);
+			ptr1->next = NULL;
+		}
+	} else {
+		free(ptr0);
+
+		if (snake1 != NULL)
+			free(ptr1);
+	}
+}
+
+void
+game_snake_grow(Snake_Pos **snake)
+{
+	Snake_Pos *ptr = *snake;
+	while (ptr->next != NULL)
+		ptr = ptr->next;
+	ptr->next = malloc(sizeof(Snake_Pos));
+	ptr->next->x = ptr->x;
+	ptr->next->y = ptr->y;
+	ptr->next->next = NULL;
+}
+
+void
+game_fruit(int *fruit, Snake_Pos **snake)
+{
+	do {
+		fruit[0] = rand() % SCREEN_SIDE * SCREEN_UNIT;
+		fruit[1] = rand() % SCREEN_SIDE * SCREEN_UNIT;
+	} while (_collision(fruit, snake));
+}
+
+void
+game_snake_fall(Snake_Pos **snake, bool norm, int speed)
+{
+	Snake_Pos *ptr = *snake;
+	while(ptr != NULL) {
+		ptr->y += norm ? speed : -speed;
+		ptr = ptr->next;
+	}
+}
+
+void
+game_pipe_init(Snake_Pos **pipe)
+{
+	Snake_Pos *ptr;
+	while ((ptr = *pipe) != NULL) {
+		*pipe = (*pipe)->next;
+		free(ptr);
+	}
+
+	*pipe = malloc(sizeof(Snake_Pos));
+	(*pipe)->x = SCREEN_HEIGHT;
+	(*pipe)->y = (rand() % (SCREEN_SIDE - PIPE_GAP) + PIPE_GAP) *
+		SCREEN_UNIT;
+	(*pipe)->next = NULL;
+}
+
+void
+game_pipe_move(Snake_Pos **pipe)
+{
+	Snake_Pos *ptr = *pipe;
+	while(ptr != NULL) {
+		ptr->x -= 1;
+		ptr = ptr->next;
+	}
+}
+
+void
+game_pipe_add(Snake_Pos **pipe)
+{
+	Snake_Pos *ptr = *pipe;
+	while(ptr->next != NULL)
+		ptr = ptr->next;
+	ptr->next = malloc(sizeof(Snake_Pos));
+	ptr->next->x = SCREEN_HEIGHT;
+	ptr->next->y = (rand() % (SCREEN_SIDE - PIPE_GAP) + PIPE_GAP) *
+		SCREEN_UNIT;
+	ptr->next->next = NULL;
+}
+
+void
+game_pipe_del(Snake_Pos **pipe)
+{
+	Snake_Pos *ptr = *pipe;
+	*pipe = (*pipe)->next;
+	free(ptr);
+}
+
+void
+game_pipe_pos(Snake_Pos **pipe, int *state)
+{
+	Snake_Pos *ptr = *pipe;
+	*state = 0;
+	*state += ptr->x + SCREEN_UNIT < 0 ? 1 : 0;
+	while(ptr->next != NULL)
+		ptr = ptr->next;
+	*state += ptr->x < SCREEN_HEIGHT - PIPE_DISTANCE * SCREEN_UNIT ? 2 : 0;
+}
+
+/*
+ * This function returns the dimension of pipes
+ * that snake is currently passing through,
+ * so that we can avoid checking all pipes for
+ * collision
+ *
+ * Array elements: x, w, y0, h0, y1, h1
+ */
+void
+game_pipe_bound(Snake_Pos **pipe, int *pos)
+{
+	Snake_Pos *ptr = *pipe;
+	while(ptr != NULL) {
+		if (ptr->x < SCREEN_HEIGHT / 2 &&
+			ptr->x + SCREEN_UNIT > SCREEN_HEIGHT / 2) {
+			pos[0] = ptr->x;
+			pos[1] = SCREEN_UNIT;
+			pos[2] = 0;
+			pos[3] = ptr->y - PIPE_GAP / 2 * SCREEN_UNIT;
+			pos[4] = ptr->y + PIPE_GAP / 2 * SCREEN_UNIT;
+			pos[5] = SCREEN_HEIGHT - ptr->y - SCREEN_UNIT;
+			return;
+		}
+		ptr = ptr->next;
+	}
+	pos[0] = 0;
+}
diff --git a/src/game.h b/src/game.h
new file mode 100644
index 0000000..a510c6c
--- /dev/null
+++ b/src/game.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define TICK_TIME_INIT	250000000
+#define TICK_TIME_DEC	10000000
+#define TICK_TIME_MIN	100000000
+
+#define PIPE_GAP	4
+#define PIPE_DISTANCE	10
+
+typedef struct _Snake_Pos {
+	int x;
+	int y;
+	struct _Snake_Pos *next;
+} Snake_Pos;
diff --git a/src/gpio.c b/src/gpio.c
new file mode 100644
index 0000000..9d4cde1
--- /dev/null
+++ b/src/gpio.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "gpio.h"
+
+#ifdef __FreeBSD__
+
+int
+gpio_config(int pin, int direction, int interrupt)
+{
+	int ret;
+	int fd = open("/dev/gpioc0", O_RDWR);
+
+	if (fd == -1) {
+		fprintf(stderr, "GPIO configuration failure\n");
+		return 1;
+	}
+
+	struct gpio_pin pin_req = {
+		.gp_pin = pin,
+		.gp_caps = interrupt,
+		.gp_flags = direction
+	};
+
+	ret = ioctl(fd, GPIOSETCONFIG, &pin_req) == 0 ? 0 : 1;
+	close(fd);
+	return ret;
+}
+
+int
+gpio_write(int pin, int value)
+{
+	int ret;
+	int fd = open("/dev/gpioc0", O_RDWR);
+
+	if (fd == -1) {
+		fprintf(stderr, "GPIO output failure\n");
+		return 1;
+	}
+
+	struct gpio_req req = {
+		.gp_pin = pin,
+		.gp_value = value
+	};
+
+	ret = ioctl(fd, GPIOSET, &req) == 0 ? 0 : 1;
+	close(fd);
+	return ret;
+}
+
+int
+gpio_read(int pin)
+{
+	int fd = open("/dev/gpioc0", O_RDWR);
+
+	if (fd == -1) {
+		fprintf(stderr, "GPIO input failure\n");
+		return 1;
+	}
+
+	struct gpio_req req = {
+		.gp_pin = pin
+	};
+
+	ioctl(fd, GPIOGET, &req);
+
+	close(fd);
+	return req.gp_value;
+}
+
+#elif __linux__
+
+int
+gpio_export(int pin)
+{
+	int export = open("/sys/class/gpio/export", O_RDWR);
+
+	if (export == -1) {
+		fprintf(stderr, "GPIO export failure\n");
+		return 1;
+	}
+
+	char buf[3];
+	int buf_size = snprintf(buf, 3, "%d", pin);
+	write(export, buf, buf_size);
+
+	close(export);
+	return 0;
+}
+
+int
+gpio_unexport(int pin)
+{
+	int unexport = open("/sys/class/gpio/unexport", O_RDWR);
+
+	if (unexport == -1) {
+		fprintf(stderr, "GPIO unexport failure\n");
+		return 1;
+	}
+
+	char buf[3];
+	int buf_size = snprintf(buf, 3, "%d", pin);
+	write(unexport, buf, buf_size);
+
+	close(unexport);
+	return 0;
+}
+
+int
+gpio_config(int pin, int direction, int interrupt)
+{
+	char path[33];
+	snprintf(path, 33, "/sys/class/gpio/gpio%d/direction", pin);
+
+	int config = open(path, O_RDWR);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO configuration failure\n");
+		return 1;
+	}
+
+	char buf[8];
+	int buf_size = snprintf(buf, 8, "%s", direction == 0 ? "in" : "out");
+	write(config, buf, buf_size);
+
+	close(config);
+
+	snprintf(path, 33, "/sys/class/gpio/gpio%d/edge", pin);
+
+	config = open(path, O_RDWR);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO configuration failure\n");
+		return 1;
+	}
+
+	buf_size = snprintf(buf, 8, "%s",
+		interrupt == 0 ? "falling" : "rising");
+	write(config, buf, buf_size);
+
+	close(config);
+	return 0;
+}
+
+int
+gpio_write(int pin, int value)
+{
+	char path[29];
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", pin);
+
+	int config = open(path, O_RDWR);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO output failure\n");
+		return 1;
+	}
+
+	char buf[2];
+	int buf_size = snprintf(buf, 2, "%d", value);
+	write(config, buf, buf_size);
+
+	close(config);
+	return 0;
+}
+
+int
+gpio_read(int pin)
+{
+	char path[29];
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", pin);
+
+	int config = open(path, O_RDONLY);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO input failure\n");
+		return 1;
+	}
+
+	char buf[2];
+	read(config, buf, 2);
+
+	close(config);
+	return atoi(buf);
+}
+
+#endif /* __FreeBSD__ */
diff --git a/src/gpio.h b/src/gpio.h
new file mode 100644
index 0000000..0b6b75d
--- /dev/null
+++ b/src/gpio.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define GPIO_LOW	0x00
+#define GPIO_HIGH	0x01
+
+#ifdef __FreeBSD__
+
+#include <stdint.h>
+
+#include <sys/gpio.h>
+
+#define GPIO_IN		GPIO_PIN_INPUT
+#define GPIO_OUT	GPIO_PIN_OUTPUT
+#define GPIO_INT	GPIO_INTR_EDGE_FALLING
+
+#elif __linux__
+
+#define GPIO_IN		0x00
+#define GPIO_OUT	0x01
+/*
+ * 0: falling
+ * 1: rising
+ */
+#define GPIO_INT	0
+
+#endif /* __FreeBSD__ */
+
+/* Raspberry Pi 3 */
+#define GPIO_PIN_IN0	4	/* 7: DPAD_LEFT */
+#define GPIO_PIN_IN1	14	/* 8: DPAD_UP */
+#define GPIO_PIN_IN2	15	/* 10: DPAD_DOWN */
+#define GPIO_PIN_IN3	17	/* 11: DPAD_RIGHT */
+
+#define GPIO_PIN_IN4	18	/* 12: BACK */
+#define GPIO_PIN_IN5	27	/* 13: GUIDE */
+#define GPIO_PIN_IN6	22	/* 15: START */
+
+#define GPIO_PIN_IN7	23	/* 16: A */
+#define GPIO_PIN_IN8	24	/* 18: B */
+#define GPIO_PIN_IN9	10	/* 19: X */
+#define GPIO_PIN_IN10	9	/* 21: Y */
+
+#define GPIO_PIN_IN11	25	/* 22: LEFTSHOULDER */
+#define GPIO_PIN_IN12	11	/* 23: RIGHTSHOULDER */
+
+#define GPIO_PIN_IN13	8	/* 24: LEFTSTICK */
+#define GPIO_PIN_IN14	7	/* 26: RIGHTSTICK */
+
+/* Second controller */
+#define GPIO_PIN_IN15	0	/* 27: DPAD_LEFT */
+#define GPIO_PIN_IN16	1	/* 28: DPAD_UP */
+#define GPIO_PIN_IN17	5	/* 29: DPAD_DOWN */
+#define GPIO_PIN_IN18	6	/* 31: DPAD_RIGHT */
+
+/* Unused */
+#define GPIO_PIN_IN19	12	/* 32: NULL */
+#define GPIO_PIN_IN20	13	/* 33: NULL */
+#define GPIO_PIN_IN21	19	/* 35: NULL */
+#define GPIO_PIN_IN22	16	/* 36: NULL */
+#define GPIO_PIN_IN23	26	/* 37: NULL */
+#define GPIO_PIN_IN24	20	/* 38: NULL */
+#define GPIO_PIN_IN25	21	/* 40: NULL */
diff --git a/src/input.c b/src/input.c
new file mode 100644
index 0000000..46ba24a
--- /dev/null
+++ b/src/input.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <SDL2/SDL.h>
+
+#include "input.h"
+
+void
+input_keyboard(SDL_Keycode sym, Snake_Input *code)
+{
+	switch (sym) {
+		case SDLK_LEFT:
+			*code = SNAKE_LEFT;
+			break;
+		case SDLK_UP:
+			*code = SNAKE_UP;
+			break;
+		case SDLK_DOWN:
+			*code = SNAKE_DOWN;
+			break;
+		case SDLK_RIGHT:
+			*code = SNAKE_RIGHT;
+			break;
+		case SDLK_SPACE:
+			*code = SNAKE_JUMP;
+			break;
+		case SDLK_RETURN:
+			*code = SNAKE_SELECT;
+			break;
+		case SDLK_ESCAPE:
+			*code = SNAKE_PAUSE;
+			break;
+		case SDLK_r:
+			*code = SNAKE_RESET;
+			break;
+		case SDLK_g:
+			*code = SNAKE_GOD;
+			break;
+		case SDLK_h:
+			*code = SNAKE_GROW;
+			break;
+		case SDLK_t:
+			*code = SNAKE_TELEPORT;
+			break;
+		case SDLK_m:
+			*code = SNAKE_MUSIC;
+			break;
+		case SDLK_COMMA:
+			*code = SNAKE_TICK_DECREASE;
+			break;
+		case SDLK_PERIOD:
+			*code = SNAKE_TICK_INCREASE;
+			break;
+		case SDLK_s:
+			*code = SNAKE_LEFT;
+			break;
+		case SDLK_e:
+			*code = SNAKE_UP;
+			break;
+		case SDLK_d:
+			*code = SNAKE_DOWN;
+			break;
+		case SDLK_f:
+			*code = SNAKE_RIGHT;
+			break;
+		default:
+			*code = SNAKE_EMPTY;
+			break;
+	}
+}
+
+void
+input_controller(uint8_t button, Snake_Input *code)
+{
+	switch (button) {
+		case SDL_CONTROLLER_BUTTON_DPAD_LEFT:
+			*code = SNAKE_LEFT;
+			break;
+		case SDL_CONTROLLER_BUTTON_DPAD_UP:
+			*code = SNAKE_UP;
+			break;
+		case SDL_CONTROLLER_BUTTON_DPAD_DOWN:
+			*code = SNAKE_DOWN;
+			break;
+		case SDL_CONTROLLER_BUTTON_DPAD_RIGHT:
+			*code = SNAKE_RIGHT;
+			break;
+		case SDL_CONTROLLER_BUTTON_START:
+			*code = SNAKE_SELECT;
+			break;
+		case SDL_CONTROLLER_BUTTON_BACK:
+			*code = SNAKE_PAUSE;
+			break;
+		case SDL_CONTROLLER_BUTTON_GUIDE:
+			*code = SNAKE_GOD;
+			break;
+		case SDL_CONTROLLER_BUTTON_A:
+			*code = SNAKE_JUMP;
+			break;
+		case SDL_CONTROLLER_BUTTON_B:
+			break;
+		case SDL_CONTROLLER_BUTTON_X:
+			*code = SNAKE_RESET;
+			break;
+		case SDL_CONTROLLER_BUTTON_Y:
+			*code = SNAKE_MUSIC;
+			break;
+		case SDL_CONTROLLER_BUTTON_LEFTSTICK:
+			*code = SNAKE_TELEPORT;
+			break;
+		case SDL_CONTROLLER_BUTTON_RIGHTSTICK:
+			*code = SNAKE_GROW;
+			break;
+		case SDL_CONTROLLER_BUTTON_LEFTSHOULDER:
+			*code = SNAKE_TICK_DECREASE;
+			break;
+		case SDL_CONTROLLER_BUTTON_RIGHTSHOULDER:
+			*code = SNAKE_TICK_INCREASE;
+			break;
+		default:
+			*code = SNAKE_EMPTY;
+			break;
+	}
+}
+
+#ifdef GPIO
+
+void
+input_gpio(int gpio, uint8_t *button)
+{
+	switch (gpio) {
+		case 0:
+			*button = SDL_CONTROLLER_BUTTON_DPAD_LEFT;
+			break;
+		case 1:
+			*button = SDL_CONTROLLER_BUTTON_DPAD_UP;
+			break;
+		case 2:
+			*button = SDL_CONTROLLER_BUTTON_DPAD_DOWN;
+			break;
+		case 3:
+			*button = SDL_CONTROLLER_BUTTON_DPAD_RIGHT;
+			break;
+		case 4:
+			*button = SDL_CONTROLLER_BUTTON_BACK;
+			break;
+		case 5:
+			*button = SDL_CONTROLLER_BUTTON_GUIDE;
+			break;
+		case 6:
+			*button = SDL_CONTROLLER_BUTTON_START;
+			break;
+		case 7:
+			*button = SDL_CONTROLLER_BUTTON_A;
+			break;
+		case 8:
+			*button = SDL_CONTROLLER_BUTTON_B;
+			break;
+		case 9:
+			*button = SDL_CONTROLLER_BUTTON_X;
+			break;
+		case 10:
+			*button = SDL_CONTROLLER_BUTTON_Y;
+			break;
+		case 11:
+			*button = SDL_CONTROLLER_BUTTON_LEFTSHOULDER;
+			break;
+		case 12:
+			*button = SDL_CONTROLLER_BUTTON_RIGHTSHOULDER;
+			break;
+		case 13:
+			*button = SDL_CONTROLLER_BUTTON_LEFTSTICK;
+			break;
+		case 14:
+			*button = SDL_CONTROLLER_BUTTON_RIGHTSTICK;
+			break;
+		default:
+			*button = SDL_CONTROLLER_BUTTON_INVALID;
+			break;
+	}
+}
+
+#endif /* GPIO */
diff --git a/src/input.h b/src/input.h
new file mode 100644
index 0000000..0446474
--- /dev/null
+++ b/src/input.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+typedef enum {
+	SNAKE_EMPTY,
+	SNAKE_LEFT,
+	SNAKE_UP,
+	SNAKE_DOWN,
+	SNAKE_RIGHT,
+	SNAKE_JUMP,
+	SNAKE_SELECT,
+	SNAKE_PAUSE,
+	SNAKE_RESET,
+	SNAKE_GOD,
+	SNAKE_GROW,
+	SNAKE_TELEPORT,
+	SNAKE_MUSIC,
+	SNAKE_TICK_DECREASE,
+	SNAKE_TICK_INCREASE
+} Snake_Input;
+
+typedef enum {
+	SNAKE_KEYBOARD,
+	SNAKE_TOUCHSCREEN,
+	SNAKE_CONTROLLER
+} Snake_Device;
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..48b8fc8
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,1542 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <pthread.h>
+#include <unistd.h>
+
+#ifdef __linux__
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <poll.h>
+
+#endif /* __linux__ */
+
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_ttf.h>
+
+#ifdef SOUND
+
+#include <SDL2/SDL_mixer.h>
+
+#endif /* SOUND */
+
+#include "version.h"
+#include "extern.h"
+#include "screen.h"
+
+#ifdef GPIO
+
+#include "gpio.h"
+
+#endif /* GPIO */
+
+static pthread_mutex_t mutex;
+static pthread_cond_t cond;
+
+static SDL_Renderer *renderer;
+static TTF_Font *font_20;
+static TTF_Font *font_24;
+
+/*
+ * Default to keyboard,
+ * GPIO inputs are mapped to controller keys
+ */
+static Snake_Device device = SNAKE_KEYBOARD;
+static int selection = 0;
+
+static Snake_Text text_title;
+static Snake_Text text_help_top;
+static Snake_Text text_help_0;
+static Snake_Text text_help_1;
+static Snake_Text text_help_2;
+static Snake_Text text_help_3;
+static Snake_Text text_help_4;
+static Snake_Text text_help_5;
+static Snake_Text text_help_6;
+static Snake_Text text_help_7;
+
+static Snake_Text text_score;
+
+static Snake_Text text_prompt_start;
+static Snake_Text text_prompt_resume;
+
+static Snake_Text text_prompt_0;
+static Snake_Text text_prompt_1;
+static Snake_Text text_prompt_2;
+
+static bool start = 1;
+static bool end = 0;
+static bool begin = 0;
+
+static bool god = 0;
+static bool reset = 0;
+static bool wait = 0;
+static bool multiplayer = 0;
+static bool flappy = 0;
+
+static struct timespec delay = {
+	.tv_sec = 0,
+	.tv_nsec = TICK_TIME_INIT
+};
+
+static int score;
+static int result;
+static int distance;
+static int speed;
+
+static Snake_Input input = SNAKE_EMPTY;
+static Snake_Input head[2][2];
+
+static Snake_Pos *snake0 = NULL;
+static Snake_Pos *snake1 = NULL;
+
+static int fruit[2];
+
+static Snake_Pos *gap = NULL;
+
+static void*
+handler_rendering(void *args)
+{
+	const SDL_Color fg = {
+		COLOUR_FOREGROUND_R,
+		COLOUR_FOREGROUND_G,
+		COLOUR_FOREGROUND_B
+	};
+	const SDL_Color bg = {
+		COLOUR_BACKGROUND_R,
+		COLOUR_BACKGROUND_G,
+		COLOUR_BACKGROUND_B
+	};
+	const SDL_Color bg_s = {
+		COLOUR_BACKGROUND_SHADE_R,
+		COLOUR_BACKGROUND_SHADE_G,
+		COLOUR_BACKGROUND_SHADE_B
+	};
+
+	char result_str[23];
+	char score_str[11];
+
+	Snake_Text text_result;
+
+	Snake_Text text_welcome;
+	Snake_Text text_clear;
+	Snake_Text text_gameover;
+	Snake_Text text_pause;
+
+	while (!end) {
+		draw_clear(renderer);
+		draw_colour(renderer, SNAKE_FOREGROUND);
+
+		draw_wall(renderer);
+
+		draw_text(renderer,
+			font_20,
+			SCREEN_HEIGHT + 4 * SCREEN_UNIT_X,
+			SCREEN_UNIT_Y,
+			"Snake",
+			1,
+			0,
+			fg,
+			bg,
+			&text_title);
+		draw_text(renderer,
+			font_20,
+			SCREEN_HEIGHT + 4 * SCREEN_UNIT_X,
+			2 * SCREEN_UNIT_Y,
+			"Help",
+			1,
+			0,
+			fg,
+			bg,
+			&text_help_top);
+		if (god)
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				2.5 * SCREEN_UNIT_Y,
+				"0. Don't forget to cheat",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_0);
+		if (device == SNAKE_KEYBOARD) {
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				3 * SCREEN_UNIT_Y,
+				"1. Classic: use arrow keys to move",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_1);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				3.5 * SCREEN_UNIT_Y,
+				"2. Multiplayer: use s, e, d, f keys",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_2);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				4 * SCREEN_UNIT_Y,
+				"3. Flappy: SPACE key to jump",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_3);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				4.5 * SCREEN_UNIT_Y,
+				"4. ESCAPE key to pause",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_4);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				5 * SCREEN_UNIT_Y,
+				"5. r key to reset",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_5);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				5.5 * SCREEN_UNIT_Y,
+				"6. m key to toggle music",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_6);
+		} else if (device == SNAKE_TOUCHSCREEN) {
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				3 * SCREEN_UNIT_Y,
+				"1. Classic: swipe to move",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_1);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				3.5 * SCREEN_UNIT_Y,
+				"2. Multiplayer: use different side",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_2);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				4 * SCREEN_UNIT_Y,
+				"3. Flappy: tap to jump",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_3);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				4.5 * SCREEN_UNIT_Y,
+				"4. Tap here to pause",
+				0,
+				1,
+				fg,
+				bg,
+				&text_help_4);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				5 * SCREEN_UNIT_Y,
+				"5. Tap here to reset",
+				0,
+				1,
+				fg,
+				bg,
+				&text_help_5);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				5.5 * SCREEN_UNIT_Y,
+				"6. Tap here to toggle music",
+				0,
+				1,
+				fg,
+				bg,
+				&text_help_6);
+		} else if (device == SNAKE_CONTROLLER) {
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				3 * SCREEN_UNIT_Y,
+				"1. Classic: use D-pad to move",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_1);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				3.5 * SCREEN_UNIT_Y,
+				"2. Multiplayer: second controller",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_2);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				4 * SCREEN_UNIT_Y,
+				"3. Flappy: Press A to jump",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_3);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				4.5 * SCREEN_UNIT_Y,
+				"4. Press BACK to pause",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_4);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				5 * SCREEN_UNIT_Y,
+				"5. Press X to reset",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_5);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+				5.5 * SCREEN_UNIT_Y,
+				"6. Press Y to toggle music",
+				0,
+				0,
+				fg,
+				bg,
+				&text_help_6);
+		}
+		draw_text(renderer,
+			font_20,
+			SCREEN_HEIGHT + SCREEN_UNIT_X / 4,
+			6 * SCREEN_UNIT_Y,
+			"7. Have fun",
+			0,
+			0,
+			fg,
+			bg,
+			&text_help_7);
+
+		snprintf(score_str, 11, "Score: %d", score);
+
+		draw_text(renderer,
+			font_20,
+			SCREEN_HEIGHT + 4 * SCREEN_UNIT_X,
+			7 * SCREEN_UNIT_Y,
+			score_str,
+			1,
+			0,
+			fg,
+			bg,
+			&text_score);
+
+		draw_snake(renderer, &snake0);
+
+		if (flappy) {
+			draw_pipe(renderer, &gap);
+		} else if (multiplayer)
+			draw_snake(renderer, &snake1);
+		else if (!start)
+			draw_fruit(renderer, fruit);
+
+		if (start || reset) {
+			if (multiplayer) {
+				if (result == 3)
+					snprintf(result_str, 23, "Draw");
+				else if (result > 0)
+					snprintf(result_str, 23,
+						"%s is the winner",
+						result == 1 ?
+						"Player 2" : "Player 1");
+				else
+					snprintf(result_str, 23, "Reset");
+				text_result.cache = 0;
+
+				draw_text(renderer,
+					font_24,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 -
+					0.75 * SCREEN_UNIT_Y,
+					result_str,
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_result);
+			}
+			if (start)
+				draw_text(renderer,
+					font_24,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2,
+					"Welcome",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_welcome);
+			else if (!flappy && !multiplayer &&
+				score == SCREEN_BLOCK / 2)
+				draw_text(renderer,
+					font_24,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2,
+					"Why don't you have legs?",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_clear);
+			else
+				draw_text(renderer,
+					font_24,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2,
+					"Game over!",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_gameover);
+			if (device == SNAKE_KEYBOARD)
+				draw_text(renderer,
+					font_20,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 +
+					0.75 * SCREEN_UNIT_Y,
+					"Press RETURN key for selection",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_prompt_start);
+			else if (device == SNAKE_TOUCHSCREEN)
+				draw_text(renderer,
+					font_20,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 +
+					0.75 * SCREEN_UNIT_Y,
+					"Tap the option to select",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_prompt_start);
+			else if (device == SNAKE_CONTROLLER)
+				draw_text(renderer,
+					font_20,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 +
+					0.75 * SCREEN_UNIT_Y,
+					"Press START to select",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_prompt_start);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT / 2,
+				SCREEN_HEIGHT / 2 + 1.5 * SCREEN_UNIT_Y,
+				"Classic",
+				1,
+				device == SNAKE_TOUCHSCREEN ||
+				selection == 0 ? 1 : 0,
+				fg,
+				bg_s,
+				&text_prompt_0);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT / 2,
+				SCREEN_HEIGHT / 2 + 2.25 * SCREEN_UNIT_Y,
+				"Multiplayer",
+				1,
+				device == SNAKE_TOUCHSCREEN ||
+				selection == 1 ? 1 : 0,
+				fg,
+				bg_s,
+				&text_prompt_1);
+			draw_text(renderer,
+				font_20,
+				SCREEN_HEIGHT / 2,
+				SCREEN_HEIGHT / 2 + 3 * SCREEN_UNIT_Y,
+				"Flappy",
+				1,
+				device == SNAKE_TOUCHSCREEN ||
+				selection == 2 ? 1 : 0,
+				fg,
+				bg_s,
+				&text_prompt_2);
+		} else if (wait) {
+			draw_text(renderer,
+				font_24,
+				SCREEN_HEIGHT / 2,
+				SCREEN_HEIGHT / 2,
+				"Paused",
+				1,
+				0,
+				fg,
+				bg_s,
+				&text_pause);
+			if (device == SNAKE_KEYBOARD)
+				draw_text(renderer,
+					font_20,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 +
+					0.75 * SCREEN_UNIT_Y,
+					"Press ESCAPE key to resume",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_prompt_resume);
+			else if (device == SNAKE_TOUCHSCREEN)
+				draw_text(renderer,
+					font_20,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 +
+					0.75 * SCREEN_UNIT_Y,
+					"Tap here to resume",
+					1,
+					1,
+					fg,
+					bg_s,
+					&text_prompt_resume);
+			else if (device == SNAKE_CONTROLLER)
+				draw_text(renderer,
+					font_20,
+					SCREEN_HEIGHT / 2,
+					SCREEN_HEIGHT / 2 +
+					0.75 * SCREEN_UNIT_Y,
+					"Press START to resume",
+					1,
+					0,
+					fg,
+					bg_s,
+					&text_prompt_resume);
+		}
+
+		SDL_RenderPresent(renderer);
+	}
+	return 0;
+}
+
+static void*
+handler_logic(void *args)
+{
+	struct timespec clock_start;
+	struct timespec clock_end;
+	double clock_pass = 0;
+	int pipe_dim[6];
+	int pipe_pos = 0;
+
+	clock_gettime(CLOCK_MONOTONIC, &clock_start);
+
+	for (;;) {
+		pthread_mutex_lock(&mutex);
+		while (start || reset || wait) {
+			if (!wait) {
+				clock_pass = 0;
+				pipe_pos = 0;
+			}
+			pthread_cond_wait(&cond, &mutex);
+			clock_gettime(CLOCK_MONOTONIC, &clock_start);
+		}
+		pthread_mutex_unlock(&mutex);
+
+		if (end)
+			return 0;
+
+		if (flappy) {
+			pthread_mutex_lock(&mutex);
+			while (!begin)
+				pthread_cond_wait(&cond, &mutex);
+			pthread_mutex_unlock(&mutex);
+
+			game_pipe_bound(&gap, pipe_dim);
+
+			if (pipe_pos - SCREEN_UNIT > pipe_dim[0]) {
+				score++;
+				text_score.cache = 0;
+			}
+			pipe_pos = pipe_dim[0];
+
+			if (!god && (collision(
+				(int[]) {snake0->next->x, snake0->next->y,
+				2 * SCREEN_UNIT, SCREEN_UNIT},
+				(int[]) {pipe_dim[0], pipe_dim[2],
+				pipe_dim[1], pipe_dim[3]}) ||
+				collision(
+				(int[]) {snake0->next->x, snake0->next->y,
+				2 * SCREEN_UNIT, SCREEN_UNIT},
+				(int[]) {pipe_dim[0], pipe_dim[4],
+				pipe_dim[1], pipe_dim[5]}) ||
+				snake0->y < 0 ||
+				snake0->y + SCREEN_UNIT > SCREEN_HEIGHT)) {
+				pthread_mutex_lock(&mutex);
+				reset = 1;
+				pthread_mutex_unlock(&mutex);
+			} else {
+				game_pipe_move(&gap);
+
+				game_pipe_pos(&gap, &result);
+				if (result == 3) {
+					game_pipe_del(&gap);
+					game_pipe_add(&gap);
+				} else if (result == 2) {
+					game_pipe_add(&gap);
+				} else if (result == 1) {
+					game_pipe_del(&gap);
+				}
+			}
+		} else if (!multiplayer) {
+			game_snake_move(&snake0, NULL,
+				head[0], !god, &result);
+
+			if (result == 0 || god) {
+				head[1][0] = head[0][0];
+
+				if (collision_block(fruit,
+					(int[]) {snake0->x, snake0->y})) {
+					score++;
+					text_score.cache = 0;
+					game_snake_grow(&snake0);
+
+					if (score == SCREEN_BLOCK / 2) {
+						pthread_mutex_lock(&mutex);
+						reset = 1;
+						pthread_mutex_unlock(&mutex);
+					}
+
+					game_fruit(fruit, &snake0);
+
+					if (delay.tv_nsec - TICK_TIME_DEC >=
+						TICK_TIME_MIN)
+						delay.tv_nsec -= TICK_TIME_DEC;
+				}
+			} else {
+				pthread_mutex_lock(&mutex);
+				reset = 1;
+				pthread_mutex_unlock(&mutex);
+			}
+		} else {
+			game_snake_move(&snake0, &snake1,
+				head[0], !god, &result);
+
+			if (result == 0 || god) {
+				head[1][0] = head[0][0];
+				head[1][1] = head[0][1];
+
+				clock_gettime(CLOCK_MONOTONIC, &clock_end);
+				clock_pass += (clock_end.tv_sec -
+					clock_start.tv_sec) +
+					(clock_end.tv_nsec -
+					clock_start.tv_nsec) * 0.000000001;
+				clock_gettime(CLOCK_MONOTONIC, &clock_start);
+
+				score = clock_pass;
+				text_score.cache = 0;
+				game_snake_grow(&snake0);
+				game_snake_grow(&snake1);
+			} else {
+				pthread_mutex_lock(&mutex);
+				reset = 1;
+				pthread_mutex_unlock(&mutex);
+			}
+		}
+
+		nanosleep(&delay, NULL);
+	}
+}
+
+static void*
+handler_gravity(void *args)
+{
+	const struct timespec delay = {
+		.tv_sec = 0,
+		.tv_nsec = 1000000000 / SCREEN_UNIT
+	};
+
+	for (;;) {
+		pthread_mutex_lock(&mutex);
+		while (!flappy || !begin || start || reset || wait)
+			pthread_cond_wait(&cond, &mutex);
+		pthread_mutex_unlock(&mutex);
+
+		if (end)
+			return 0;
+
+		if (distance > 0) {
+			game_snake_fall(&snake0, 0,
+				distance > speed ? speed : distance);
+			speed++;
+
+			pthread_mutex_lock(&mutex);
+			distance -= distance > speed ? speed : distance;
+			if (distance == 0)
+				speed = 1;
+			pthread_mutex_unlock(&mutex);
+		} else {
+			game_snake_fall(&snake0, 1, speed);
+			speed++;
+		}
+
+		nanosleep(&delay, NULL);
+	}
+}
+
+#ifdef GPIO
+
+#ifdef __FreeBSD__
+
+static void*
+handler_gpio(void *args)
+{
+	const struct timespec delay = {
+		.tv_sec = 0,
+		.tv_nsec = 50000000
+	};
+
+	SDL_Event event;
+	event.type = SDL_CONTROLLERBUTTONUP;
+
+	while (!end) {
+		if (gpio_read(GPIO_PIN_IN0) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_LEFT;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN1) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_UP;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN2) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_DOWN;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN3) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_RIGHT;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN4) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_BACK;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN5) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_GUIDE;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN6) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_START;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN7) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_A;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN8) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_B;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN9) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_X;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN10) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_Y;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN11) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_LEFTSHOULDER;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN12) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_RIGHTSHOULDER;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN13) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_LEFTSTICK;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN14) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_RIGHTSTICK;
+			event.cbutton.which = 0;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN15) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_LEFT;
+			event.cbutton.which = 1;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN16) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_UP;
+			event.cbutton.which = 1;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN17) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_DOWN;
+			event.cbutton.which = 1;
+			SDL_PushEvent(&event);
+		} else if (gpio_read(GPIO_PIN_IN18) == 0) {
+			event.cbutton.button =
+				SDL_CONTROLLER_BUTTON_DPAD_RIGHT;
+			event.cbutton.which = 1;
+			SDL_PushEvent(&event);
+		}
+
+		nanosleep(&delay, NULL);
+	}
+	return 0;
+}
+
+#elif __linux__
+
+static void*
+handler_gpio(void *args)
+{
+	struct pollfd pfd[19];
+	char path[29];
+
+	for (int i = 0; i < 19; i++)
+		pfd[i].events = POLLPRI | POLLERR;
+
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN0);
+	pfd[0].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN1);
+	pfd[1].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN2);
+	pfd[2].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN3);
+	pfd[3].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN4);
+	pfd[4].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN5);
+	pfd[5].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN6);
+	pfd[6].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN7);
+	pfd[7].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN8);
+	pfd[8].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN9);
+	pfd[9].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN10);
+	pfd[10].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN11);
+	pfd[11].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN12);
+	pfd[12].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN13);
+	pfd[13].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN14);
+	pfd[14].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN15);
+	pfd[15].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN16);
+	pfd[16].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN17);
+	pfd[17].fd = open(path, O_RDONLY);
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", GPIO_PIN_IN18);
+	pfd[18].fd = open(path, O_RDONLY);
+
+	SDL_Event event;
+	event.type = SDL_CONTROLLERBUTTONUP;
+
+	char val[2];
+
+	while (!end) {
+		poll(pfd, 19, -1);
+
+		for (int i = 0; i < 19; i++) {
+			if (pfd[i].revents & (POLLPRI | POLLERR)) {
+				pfd[i].revents &= ~(POLLPRI | POLLERR);
+				read(pfd[i].fd, val, 2);
+				lseek(pfd[i].fd, 0, SEEK_SET);
+
+				if (atoi(val) != 0)
+					continue;
+
+				input_gpio(i % 15, &event.cbutton.button);
+
+				if (i < 15)
+					event.cbutton.which = 0;
+				else
+					event.cbutton.which = 1;
+
+				SDL_PushEvent(&event);
+				break;
+			}
+		}
+	}
+	return 0;
+}
+
+#endif /* __FreeBSD__ */
+
+#endif /* GPIO */
+
+int
+main(void)
+{
+	printf("Snake " VERSION "." RELEASE "." PATCH EXTRA "\n"
+		"Copyright (c) 2019-2020, yzrh <yzrh@noema.org>\n");
+
+	if (SDL_Init(SDL_INIT_VIDEO |
+		SDL_INIT_AUDIO |
+		SDL_INIT_GAMECONTROLLER) != 0) {
+		fprintf(stderr, "SDL initialisation failure: %s\n",
+			SDL_GetError());
+		return 1;
+	}
+
+	SDL_Window *window = SDL_CreateWindow(
+		"Snake " VERSION "." RELEASE "." PATCH EXTRA,
+		SDL_WINDOWPOS_UNDEFINED,
+		SDL_WINDOWPOS_UNDEFINED,
+		SCREEN_WIDTH,
+		SCREEN_HEIGHT,
+		SDL_WINDOW_OPENGL);
+
+	if (window == NULL) {
+		fprintf(stderr, "Window creation failure: %s\n",
+			SDL_GetError());
+		return 1;
+	}
+
+	renderer = SDL_CreateRenderer(
+		window,
+		-1,
+		SDL_RENDERER_ACCELERATED |
+		SDL_RENDERER_PRESENTVSYNC);
+
+	if (renderer == NULL) {
+		fprintf(stderr, "Renderer creation failure: %s\n",
+			SDL_GetError());
+		return 1;
+	}
+
+	if (TTF_Init() != 0) {
+		fprintf(stderr, "TTF initialisation failure: %s\n",
+			TTF_GetError());
+		return 1;
+	}
+
+	font_20 = TTF_OpenFont("../contrib/font.ttf", 20);
+	font_24 = TTF_OpenFont("../contrib/font.ttf", 24);
+
+	if (font_20 == NULL) {
+		font_20 = TTF_OpenFont("/usr/local/share/snake/font.ttf", 20);
+		font_24 = TTF_OpenFont("/usr/local/share/snake/font.ttf", 24);
+	}
+
+	if (font_20 == NULL) {
+		font_20 = TTF_OpenFont("/usr/share/snake/font.ttf", 20);
+		font_24 = TTF_OpenFont("/usr/share/snake/font.ttf", 24);
+	}
+
+	if (font_20 == NULL) {
+		fprintf(stderr, "%s\n", TTF_GetError());
+		return 1;
+	}
+
+#ifdef SOUND
+
+	if ((Mix_Init(MIX_INIT_FLAC) & MIX_INIT_FLAC) != MIX_INIT_FLAC)
+		fprintf(stderr, "Mixer initialisation failure: %s\n",
+			Mix_GetError());
+
+	if (Mix_OpenAudio(48000, AUDIO_S16SYS, 2, 4096) == -1)
+		fprintf(stderr, "%s\n", Mix_GetError());
+
+	Mix_Music *music = Mix_LoadMUS("../contrib/music.flac");
+
+	if (music == NULL)
+		music = Mix_LoadMUS("/usr/local/share/snake/music.flac");
+
+	if (music == NULL)
+		music = Mix_LoadMUS("/usr/share/snake/music.flac");
+
+	if (music == NULL)
+		fprintf(stderr, "%s\n", Mix_GetError());
+
+	if (Mix_PlayMusic(music, -1) == -1)
+		fprintf(stderr, "Audio playback failure: %s\n",
+			Mix_GetError());
+
+#endif /* SOUND */
+
+#ifdef GPIO
+
+#ifdef __linux__
+
+	gpio_export(GPIO_PIN_IN0);
+	gpio_export(GPIO_PIN_IN1);
+	gpio_export(GPIO_PIN_IN2);
+	gpio_export(GPIO_PIN_IN3);
+	gpio_export(GPIO_PIN_IN4);
+	gpio_export(GPIO_PIN_IN5);
+	gpio_export(GPIO_PIN_IN6);
+	gpio_export(GPIO_PIN_IN7);
+	gpio_export(GPIO_PIN_IN8);
+	gpio_export(GPIO_PIN_IN9);
+	gpio_export(GPIO_PIN_IN10);
+	gpio_export(GPIO_PIN_IN11);
+	gpio_export(GPIO_PIN_IN12);
+	gpio_export(GPIO_PIN_IN13);
+	gpio_export(GPIO_PIN_IN14);
+	gpio_export(GPIO_PIN_IN15);
+	gpio_export(GPIO_PIN_IN16);
+	gpio_export(GPIO_PIN_IN17);
+	gpio_export(GPIO_PIN_IN18);
+
+	/* Wait for sysfs directory to show up */
+	sleep(1);
+
+#endif /* __linux__ */
+
+	gpio_config(GPIO_PIN_IN0, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN1, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN2, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN3, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN4, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN5, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN6, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN7, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN8, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN9, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN10, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN11, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN12, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN13, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN14, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN15, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN16, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN17, GPIO_IN, GPIO_INT);
+	gpio_config(GPIO_PIN_IN18, GPIO_IN, GPIO_INT);
+
+#endif /* GPIO */
+
+	int seed;
+	int random = open("/dev/random", O_RDONLY);
+	if (read(random, &seed, sizeof(int)) > 0)
+		srand(seed);
+	close(random);
+
+	SDL_JoystickID player = 0;
+	SDL_Event event;
+
+	pthread_mutex_init(&mutex, NULL);
+	pthread_cond_init(&cond, NULL);
+	pthread_t th_renderer;
+	pthread_t th_logic;
+	pthread_t th_gravity;
+
+	#ifdef GPIO
+
+	pthread_t th_gpio;
+
+	#endif /* GPIO */
+
+	pthread_create(&th_renderer, NULL, handler_rendering, NULL);
+	pthread_create(&th_logic, NULL, handler_logic, NULL);
+	pthread_create(&th_gravity, NULL, handler_gravity, NULL);
+
+	#ifdef GPIO
+
+	pthread_create(&th_gpio, NULL, handler_gpio, NULL);
+
+	#endif /* GPIO */
+
+	while (SDL_WaitEvent(&event)) {
+		if (event.type == SDL_QUIT)
+			break;
+
+		switch (event.type) {
+			case SDL_KEYUP:
+				if (device != SNAKE_KEYBOARD) {
+					device = SNAKE_KEYBOARD;
+					text_help_1.cache = 0;
+					text_help_2.cache = 0;
+					text_help_3.cache = 0;
+					text_help_4.cache = 0;
+					text_help_5.cache = 0;
+					text_help_6.cache = 0;
+					text_prompt_start.cache = 0;
+					text_prompt_resume.cache = 0;
+				}
+				input_keyboard(event.key.keysym.sym, &input);
+				if (multiplayer &&
+					(event.key.keysym.sym ==
+					SDLK_s ||
+					event.key.keysym.sym ==
+					SDLK_e ||
+					event.key.keysym.sym ==
+					SDLK_d ||
+					event.key.keysym.sym ==
+					SDLK_f))
+					player = 1;
+				else
+					player = 0;
+				break;
+			case SDL_FINGERUP:
+				if (device != SNAKE_TOUCHSCREEN) {
+					device = SNAKE_TOUCHSCREEN;
+					text_help_1.cache = 0;
+					text_help_2.cache = 0;
+					text_help_3.cache = 0;
+					text_help_4.cache = 0;
+					text_help_5.cache = 0;
+					text_help_6.cache = 0;
+					text_prompt_start.cache = 0;
+					text_prompt_resume.cache = 0;
+				}
+				if (start || reset || wait) {
+					if (collision_bound(
+						event.tfinger.x,
+						event.tfinger.y,
+						&text_help_5)) {
+						input = SNAKE_RESET;
+					} else if (collision_bound(
+						event.tfinger.x,
+						event.tfinger.y,
+						&text_help_6)) {
+						input = SNAKE_MUSIC;
+					} else if (wait) {
+						if (collision_bound(
+							event.tfinger.x,
+							event.tfinger.y,
+							&text_prompt_resume))
+							input = SNAKE_PAUSE;
+					} else {
+						if (collision_bound(
+							event.tfinger.x,
+							event.tfinger.y,
+							&text_prompt_0)) {
+							selection = 0;
+							input = SNAKE_SELECT;
+						} else if (collision_bound(
+							event.tfinger.x,
+							event.tfinger.y,
+							&text_prompt_1)) {
+							selection = 1;
+							input = SNAKE_SELECT;
+						} else if (collision_bound(
+							event.tfinger.x,
+							event.tfinger.y,
+							&text_prompt_2)) {
+							selection = 2;
+							input = SNAKE_SELECT;
+						}
+					}
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_help_4)) {
+					input = SNAKE_PAUSE;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_help_5)) {
+					input = SNAKE_RESET;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_help_6)) {
+					input = SNAKE_MUSIC;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_help_top)) {
+					input = SNAKE_GOD;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_score)) {
+					input = SNAKE_GROW;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_title)) {
+					input = SNAKE_TELEPORT;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_help_1)) {
+					input = SNAKE_TICK_DECREASE;
+				} else if (collision_bound(
+					event.tfinger.x,
+					event.tfinger.y,
+					&text_help_7)) {
+					input = SNAKE_TICK_INCREASE;
+				} else if (flappy) {
+					input = SNAKE_JUMP;
+				} else {
+					input = SNAKE_EMPTY;
+				}
+				break;
+			case SDL_FINGERMOTION:
+				if (device != SNAKE_TOUCHSCREEN) {
+					device = SNAKE_TOUCHSCREEN;
+					text_help_1.cache = 0;
+					text_help_2.cache = 0;
+					text_help_3.cache = 0;
+					text_help_4.cache = 0;
+					text_help_5.cache = 0;
+					text_help_6.cache = 0;
+					text_prompt_start.cache = 0;
+					text_prompt_resume.cache = 0;
+				}
+				if ((event.tfinger.dx *
+					event.tfinger.dx) >
+					(event.tfinger.dy *
+					event.tfinger.dy)) {
+					if (event.tfinger.dx > 1)
+						input = SNAKE_RIGHT;
+					else if (event.tfinger.dx < -1)
+						input = SNAKE_LEFT;
+				} else {
+					if (event.tfinger.dy > 1)
+						input = SNAKE_DOWN;
+					else if (event.tfinger.dy < -1)
+						input = SNAKE_UP;
+				}
+				if (multiplayer &&
+					event.tfinger.x > SCREEN_HEIGHT / 2)
+					player = 1;
+				else
+					player = 0;
+				break;
+			case SDL_CONTROLLERBUTTONUP:
+				if (device != SNAKE_CONTROLLER) {
+					device = SNAKE_CONTROLLER;
+					text_help_1.cache = 0;
+					text_help_2.cache = 0;
+					text_help_3.cache = 0;
+					text_help_4.cache = 0;
+					text_help_5.cache = 0;
+					text_help_6.cache = 0;
+					text_prompt_start.cache = 0;
+					text_prompt_resume.cache = 0;
+				}
+				input_controller(event.cbutton.button, &input);
+				player = event.cbutton.which;
+				break;
+			default:
+				break;
+		}
+
+		if (!start && !reset && !wait) {
+			switch (input) {
+				case SNAKE_LEFT:
+					if (head[1][player] != SNAKE_RIGHT)
+						head[0][player] = SNAKE_LEFT;
+					break;
+				case SNAKE_UP:
+					if (head[1][player] != SNAKE_DOWN)
+						head[0][player] = SNAKE_UP;
+					break;
+				case SNAKE_DOWN:
+					if (head[1][player] != SNAKE_UP)
+						head[0][player] = SNAKE_DOWN;
+					break;
+				case SNAKE_RIGHT:
+					if (head[1][player] != SNAKE_LEFT)
+						head[0][player] = SNAKE_RIGHT;
+					break;
+				case SNAKE_JUMP:
+					if (!begin) {
+						pthread_mutex_lock(&mutex);
+						begin = 1;
+						pthread_cond_broadcast(&cond);
+						pthread_mutex_unlock(&mutex);
+					}
+					if (flappy) {
+						pthread_mutex_lock(&mutex);
+						distance += PIPE_GAP / 2 *
+							SCREEN_UNIT;
+						if (distance == 0)
+							speed = 1;
+						pthread_mutex_unlock(&mutex);
+					}
+					break;
+				case SNAKE_RESET:
+					pthread_mutex_lock(&mutex);
+					reset = 1;
+					pthread_mutex_unlock(&mutex);
+					break;
+				case SNAKE_GOD:
+					god = 1;
+					break;
+				case SNAKE_GROW:
+					if (god && !flappy && !multiplayer)
+						game_snake_grow(&snake0);
+					break;
+				case SNAKE_TELEPORT:
+					if (god) {
+						snake0->x = snake0->y =
+							SCREEN_HEIGHT / 2;
+						if (flappy) {
+							snake0->next->x =
+								SCREEN_HEIGHT /
+								2 - SCREEN_UNIT;
+							snake0->next->y =
+								SCREEN_HEIGHT /
+								2;
+						}
+					}
+					break;
+				case SNAKE_MUSIC:
+#ifdef SOUND
+					if (Mix_PausedMusic())
+						Mix_ResumeMusic();
+					else
+						Mix_PauseMusic();
+#endif /* SOUND */
+					break;
+				case SNAKE_TICK_DECREASE:
+					if (god && !flappy && delay.tv_nsec -
+						TICK_TIME_DEC >= TICK_TIME_MIN)
+						delay.tv_nsec -= TICK_TIME_DEC;
+					break;
+				case SNAKE_TICK_INCREASE:
+					if (god && !flappy)
+						delay.tv_nsec += TICK_TIME_DEC;
+					break;
+				case SNAKE_PAUSE:
+					wait = 1;
+					break;
+				default:
+					break;
+			}
+		} else {
+			switch (input) {
+				case SNAKE_RESET:
+					wait = 0;
+
+					pthread_mutex_lock(&mutex);
+					reset = 1;
+					pthread_mutex_unlock(&mutex);
+					break;
+				case SNAKE_MUSIC:
+#ifdef SOUND
+					if (Mix_PausedMusic())
+						Mix_ResumeMusic();
+					else
+						Mix_PauseMusic();
+#endif /* SOUND */
+					break;
+				case SNAKE_SELECT:
+					if (wait)
+						break;
+
+					if (selection == 0) {
+						flappy = 0;
+						multiplayer = 0;
+					} else if (selection == 1) {
+						flappy = 0;
+						multiplayer = 1;
+					} else if (selection == 2) {
+						multiplayer = 0;
+						flappy = 1;
+					}
+
+					delay.tv_nsec = TICK_TIME_INIT;
+
+					god = 0;
+
+					head[0][0] = head[0][1] =
+						SNAKE_UP;
+					head[1][0] = head[1][1] =
+						SNAKE_EMPTY;
+
+					score = 0;
+					text_score.cache = 0;
+
+					if (flappy) {
+						delay.tv_nsec = TICK_TIME_INIT /
+							SCREEN_UNIT;
+
+						game_snake_init(&snake0, 0);
+
+						snake0->next->x =
+							SCREEN_HEIGHT / 2 -
+							SCREEN_UNIT;
+						snake0->next->y =
+							SCREEN_HEIGHT / 2;
+
+						game_pipe_init(&gap);
+
+						pthread_mutex_lock(&mutex);
+						begin = 0;
+						distance = 0;
+						speed = 1;
+						pthread_mutex_unlock(&mutex);
+					} else if (!multiplayer) {
+						game_snake_init(
+							&snake0, 0);
+						game_fruit(
+							fruit,
+							&snake0);
+					} else {
+						game_snake_init(
+							&snake0,
+							-4 *
+							SCREEN_UNIT);
+						game_snake_init(
+							&snake1,
+							4 *
+							SCREEN_UNIT);
+					}
+					start = 0;
+
+					pthread_mutex_lock(&mutex);
+					reset = 0;
+					pthread_cond_broadcast(&cond);
+					pthread_mutex_unlock(&mutex);
+					break;
+				case SNAKE_PAUSE:
+					wait = 0;
+
+					pthread_mutex_lock(&mutex);
+					pthread_cond_broadcast(&cond);
+					pthread_mutex_unlock(&mutex);
+					break;
+				case SNAKE_UP:
+					if ((start || reset) &&
+						selection - 1 >= 0)
+						selection--;
+					break;
+				case SNAKE_DOWN:
+					if ((start || reset) &&
+						selection + 1 <= 2)
+						selection++;
+					break;
+				default:
+					break;
+			}
+		}
+		input = SNAKE_EMPTY;
+	}
+
+	start = 0;
+	end = 1;
+
+	wait = 0;
+	flappy = 1;
+
+	pthread_mutex_lock(&mutex);
+	reset = 0;
+	pthread_cond_broadcast(&cond);
+	pthread_mutex_unlock(&mutex);
+
+	#ifdef GPIO
+
+	pthread_join(th_gpio, NULL);
+
+	#endif /* GPIO */
+
+	pthread_join(th_gravity, NULL);
+	pthread_join(th_logic, NULL);
+	pthread_join(th_renderer, NULL);
+	pthread_cond_destroy(&cond);
+	pthread_mutex_destroy(&mutex);
+
+#ifdef GPIO
+
+#ifdef __linux__
+
+	gpio_unexport(GPIO_PIN_IN0);
+	gpio_unexport(GPIO_PIN_IN1);
+	gpio_unexport(GPIO_PIN_IN2);
+	gpio_unexport(GPIO_PIN_IN3);
+	gpio_unexport(GPIO_PIN_IN4);
+	gpio_unexport(GPIO_PIN_IN5);
+	gpio_unexport(GPIO_PIN_IN6);
+	gpio_unexport(GPIO_PIN_IN7);
+	gpio_unexport(GPIO_PIN_IN8);
+	gpio_unexport(GPIO_PIN_IN9);
+	gpio_unexport(GPIO_PIN_IN10);
+	gpio_unexport(GPIO_PIN_IN11);
+	gpio_unexport(GPIO_PIN_IN12);
+	gpio_unexport(GPIO_PIN_IN13);
+	gpio_unexport(GPIO_PIN_IN14);
+	gpio_unexport(GPIO_PIN_IN15);
+	gpio_unexport(GPIO_PIN_IN16);
+	gpio_unexport(GPIO_PIN_IN17);
+	gpio_unexport(GPIO_PIN_IN18);
+
+#endif /* __linux__ */
+
+#endif /* GPIO */
+
+#ifdef SOUND
+	Mix_Quit();
+#endif /* SOUND */
+
+	TTF_Quit();
+	SDL_DestroyRenderer(renderer);
+	SDL_DestroyWindow(window);
+	SDL_Quit();
+}
diff --git a/src/renderer.c b/src/renderer.c
new file mode 100644
index 0000000..c742e18
--- /dev/null
+++ b/src/renderer.c
@@ -0,0 +1,244 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdbool.h>
+
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_ttf.h>
+
+#include "renderer.h"
+#include "screen.h"
+#include "game.h"
+
+void
+draw_clear(SDL_Renderer *renderer)
+{
+	SDL_SetRenderDrawColor(renderer,
+		COLOUR_BACKGROUND_R,
+		COLOUR_BACKGROUND_G,
+		COLOUR_BACKGROUND_B,
+		255);
+	SDL_RenderClear(renderer);
+}
+
+void
+draw_colour(SDL_Renderer *renderer, Snake_Colour colour)
+{
+	int r;
+	int g;
+	int b;
+
+	switch (colour) {
+		case SNAKE_FOREGROUND:
+			r = COLOUR_FOREGROUND_R;
+			g = COLOUR_FOREGROUND_G;
+			b = COLOUR_FOREGROUND_B;
+			break;
+		case SNAKE_BACKGROUND:
+			r = COLOUR_BACKGROUND_R;
+			g = COLOUR_BACKGROUND_G;
+			b = COLOUR_BACKGROUND_B;
+			break;
+		case SNAKE_BACKGROUND_SHADE:
+			r = COLOUR_BACKGROUND_SHADE_R;
+			g = COLOUR_BACKGROUND_SHADE_G;
+			b = COLOUR_BACKGROUND_SHADE_B;
+			break;
+		case SNAKE_RED:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		case SNAKE_GREEN:
+			r = COLOUR_GREEN_R;
+			g = COLOUR_GREEN_G;
+			b = COLOUR_GREEN_B;
+			break;
+		case SNAKE_BLUE:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		case SNAKE_YELLOW:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		case SNAKE_MAGENTA:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		case SNAKE_CYAN:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		case SNAKE_WHITE:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		case SNAKE_BLACK:
+			r = COLOUR_RED_R;
+			g = COLOUR_RED_G;
+			b = COLOUR_RED_B;
+			break;
+		default:
+			break;
+	}
+
+	SDL_SetRenderDrawColor(renderer,
+		r,
+		g,
+		b,
+		255);
+}
+
+void
+draw_text(SDL_Renderer *renderer, TTF_Font *font,
+	int text_x, int text_y, char *text,
+	bool centre, bool select, SDL_Color fg, SDL_Color bg,
+	Snake_Text *message)
+{
+	if (!message->cache) {
+		if (message->texture != NULL)
+			SDL_DestroyTexture(message->texture);
+
+		SDL_Surface *surface =
+			TTF_RenderUTF8_Shaded(font, text, fg, bg);
+		message->texture =
+			SDL_CreateTextureFromSurface(renderer, surface);
+		SDL_FreeSurface(surface);
+
+		message->pos.x = text_x;
+		message->pos.y = text_y;
+		TTF_SizeText(font, text, &message->pos.w, &message->pos.h);
+		if (centre)
+			message->pos.x -= message->pos.w / 2;
+		message->pos.y -= message->pos.h;
+
+		message->cache = 1;
+	}
+
+	SDL_RenderCopy(renderer, message->texture, NULL, &message->pos);
+
+	if (select) {
+		SDL_SetRenderDrawColor(renderer,
+			COLOUR_FOREGROUND_R,
+			COLOUR_FOREGROUND_G,
+			COLOUR_FOREGROUND_B,
+			255);
+		SDL_RenderDrawLine(renderer,
+			message->pos.x, message->pos.y,
+			message->pos.x, message->pos.y + message->pos.h);
+		SDL_RenderDrawLine(renderer,
+			message->pos.x, message->pos.y,
+			message->pos.x + message->pos.w, message->pos.y);
+		SDL_RenderDrawLine(renderer,
+			message->pos.x, message->pos.y + message->pos.h,
+			message->pos.x + message->pos.w,
+				message->pos.y + message->pos.h);
+		SDL_RenderDrawLine(renderer,
+			message->pos.x + message->pos.w, message->pos.y,
+			message->pos.x + message->pos.w,
+				message->pos.y + message->pos.h);
+	}
+}
+
+void
+draw_wall(SDL_Renderer *renderer)
+{
+	SDL_RenderDrawLine(renderer,
+		0, 0,
+		0, SCREEN_HEIGHT);
+	SDL_RenderDrawLine(renderer,
+		0, 0,
+		SCREEN_HEIGHT, 0);
+	SDL_RenderDrawLine(renderer,
+		0, SCREEN_HEIGHT - 1,
+		SCREEN_HEIGHT, SCREEN_HEIGHT - 1);
+	SDL_RenderDrawLine(renderer,
+		SCREEN_HEIGHT, 0,
+		SCREEN_HEIGHT, SCREEN_HEIGHT);
+}
+
+void
+draw_snake(SDL_Renderer *renderer, Snake_Pos **snake)
+{
+	Snake_Pos *ptr = *snake;
+
+	SDL_Rect pos;
+	while (ptr != NULL) {
+		pos.x = ptr->x;
+		pos.y = ptr->y;
+		pos.w = SCREEN_UNIT;
+		pos.h = SCREEN_UNIT;
+		SDL_RenderFillRect(renderer, &pos);
+		ptr = ptr->next;
+	}
+}
+
+void
+draw_fruit(SDL_Renderer *renderer, int *fruit)
+{
+	int rx = fruit[0] + SCREEN_UNIT / 2;
+	int ry = fruit[1] + SCREEN_UNIT / 2;
+
+	/* Midpoint circle algorithm */
+	int x = SCREEN_UNIT / 2;
+	int y = 0;
+	int dx = 1;
+	int dy = 1;
+	int err = dx - ((SCREEN_UNIT / 2) << 1);
+	while (x >= y) {
+		SDL_RenderDrawLine(renderer,
+			rx - y, ry + x,
+			rx + y, ry + x);
+		SDL_RenderDrawLine(renderer,
+			rx - x, ry + y,
+			rx + x, ry + y);
+		SDL_RenderDrawLine(renderer,
+			rx - x, ry - y,
+			rx + x, ry - y);
+		SDL_RenderDrawLine(renderer,
+			rx - y, ry - x,
+			rx + y, ry - x);
+
+		if (err <= 0) {
+			y++;
+			err += dy;
+			dy += 2;
+		}
+
+		if (err > 0) {
+			x--;
+			dx += 2;
+			err += dx - ((SCREEN_UNIT / 2) << 1);
+		}
+	}
+}
+
+void
+draw_pipe(SDL_Renderer *renderer, Snake_Pos **pipe)
+{
+	Snake_Pos *ptr = *pipe;
+
+	SDL_Rect pos;
+	while (ptr != NULL) {
+		pos.x = ptr->x;
+		pos.y = 0;
+		pos.w = SCREEN_UNIT;
+		if (ptr->x + SCREEN_UNIT > SCREEN_HEIGHT)
+			pos.w -= ptr->x + SCREEN_UNIT - SCREEN_HEIGHT;
+		pos.h = ptr->y - PIPE_GAP / 2 * SCREEN_UNIT;
+		SDL_RenderFillRect(renderer, &pos);
+		pos.y = ptr->y + PIPE_GAP / 2 * SCREEN_UNIT;
+		pos.h = SCREEN_HEIGHT - ptr->y - SCREEN_UNIT;
+		SDL_RenderFillRect(renderer, &pos);
+		ptr = ptr->next;
+	}
+}
diff --git a/src/renderer.h b/src/renderer.h
new file mode 100644
index 0000000..b6de4d8
--- /dev/null
+++ b/src/renderer.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+typedef struct {
+	SDL_Texture *texture;
+	SDL_Rect pos;
+	bool cache;
+} Snake_Text;
+
+typedef enum {
+	SNAKE_FOREGROUND,
+	SNAKE_BACKGROUND,
+	SNAKE_BACKGROUND_SHADE,
+	SNAKE_RED,
+	SNAKE_GREEN,
+	SNAKE_BLUE,
+	SNAKE_YELLOW,
+	SNAKE_MAGENTA,
+	SNAKE_CYAN,
+	SNAKE_WHITE,
+	SNAKE_BLACK
+} Snake_Colour;
diff --git a/src/screen.h b/src/screen.h
new file mode 100644
index 0000000..158cdaa
--- /dev/null
+++ b/src/screen.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define SCREEN_WIDTH	800
+#define SCREEN_HEIGHT	480
+#define SCREEN_UNIT	20
+
+#define COLOUR_FOREGROUND_R		51
+#define COLOUR_FOREGROUND_G		255
+#define COLOUR_FOREGROUND_B		51
+#define COLOUR_BACKGROUND_R		40
+#define COLOUR_BACKGROUND_G		40
+#define COLOUR_BACKGROUND_B		40
+#define COLOUR_BACKGROUND_SHADE_R	80
+#define COLOUR_BACKGROUND_SHADE_G	80
+#define COLOUR_BACKGROUND_SHADE_B	80
+
+#define COLOUR_RED_R			255
+#define COLOUR_RED_G			0
+#define COLOUR_RED_B			0
+#define COLOUR_GREEN_R			0
+#define COLOUR_GREEN_G			255
+#define COLOUR_GREEN_B			0
+#define COLOUR_BLUE_R			0
+#define COLOUR_BLUE_G			0
+#define COLOUR_BLUE_B			255
+
+#define COLOUR_YELLOW_R			255
+#define COLOUR_YELLOW_G			255
+#define COLOUR_YELLOW_B			0
+#define COLOUR_MAGENTA_R		255
+#define COLOUR_MAGENTA_G		0
+#define COLOUR_MAGENTA_B		255
+#define COLOUR_CYAN_R			0
+#define COLOUR_CYAN_G			255
+#define COLOUR_CYAN_B			255
+
+#define COLOUR_WHITE_R			255
+#define COLOUR_WHITE_G			255
+#define COLOUR_WHITE_B			255
+
+#define COLOUR_BLACK_R			0
+#define COLOUR_BLACK_G			0
+#define COLOUR_BLACK_B			0
+
+#define SCREEN_UNIT_X ((SCREEN_WIDTH - SCREEN_HEIGHT) / 8)
+#define SCREEN_UNIT_Y (SCREEN_HEIGHT / 8)
+#define SCREEN_SIDE (SCREEN_HEIGHT / SCREEN_UNIT - 1)
+#define SCREEN_BLOCK (SCREEN_SIDE * SCREEN_SIDE)
diff --git a/src/version.h b/src/version.h
new file mode 100644
index 0000000..4cdcebb
--- /dev/null
+++ b/src/version.h
@@ -0,0 +1,10 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define VERSION	"0"
+#define RELEASE	"6"
+#define PATCH	"2"
+#define EXTRA	"_3"