From 40561a65374e167644024070fe0cbd6d97b7e769 Mon Sep 17 00:00:00 2001
From: xamidev <121681048+xamidev@users.noreply.github.com>
Date: Thu, 12 Sep 2024 17:54:30 +0200
Subject: [PATCH] Add: snake game! (basics)

---
 src/drivers/framebuffer.c |   6 +-
 src/drivers/kb.c          |  16 ++++
 src/drivers/kb.h          |   2 +
 src/kernel/shell.c        |   1 +
 src/libc/stdio.c          |  19 +++++
 src/libc/stdio.h          |   4 +-
 src/programs/misc.c       |   2 +-
 src/programs/programs.h   |   1 +
 src/programs/snake.c      | 161 ++++++++++++++++++++++++++++++++++++++
 9 files changed, 206 insertions(+), 6 deletions(-)
 create mode 100644 src/programs/snake.c

diff --git a/src/drivers/framebuffer.c b/src/drivers/framebuffer.c
index 9b4b231..0767638 100644
--- a/src/drivers/framebuffer.c
+++ b/src/drivers/framebuffer.c
@@ -12,10 +12,8 @@ extern char* framebuffer;
 
 void putpixel(uint32_t* fb, int pitch, int bpp, int x, int y, uint32_t color)
 {
-	if (bpp == 32) {
-		uint32_t* pixel_addr = (uint32_t*)((uint8_t*)fb + y * pitch + x *(bpp / 8));
-		*pixel_addr = color;
-	}
+	uint32_t* pixel_addr = (uint32_t*)((uint8_t*)fb + y * pitch + x *(bpp / 8));
+	*pixel_addr = color;
 }
 
 void draw_char(unsigned short int c, int cx, int cy, uint32_t fg, uint32_t bg)
diff --git a/src/drivers/kb.c b/src/drivers/kb.c
index f4c556c..b45e5f1 100644
--- a/src/drivers/kb.c
+++ b/src/drivers/kb.c
@@ -140,3 +140,19 @@ char keyboard_getchar()
 	keyboard_buffer_start = (keyboard_buffer_start+1) % KEYBOARD_BUFFER_SIZE;
 	return c;
 }
+
+int keyboard_has_input()
+{
+	return keyboard_buffer_start != keyboard_buffer_end;
+}
+
+char keyboard_getchar_non_blocking()
+{
+	if (keyboard_has_input())
+	{
+		char c = keyboard_buffer[keyboard_buffer_start];
+		keyboard_buffer_start = (keyboard_buffer_start+1)%KEYBOARD_BUFFER_SIZE;
+		return c;
+	}
+	return 0;
+}
diff --git a/src/drivers/kb.h b/src/drivers/kb.h
index d40730f..ceff888 100644
--- a/src/drivers/kb.h
+++ b/src/drivers/kb.h
@@ -14,5 +14,7 @@
 #define RIGHT_SHIFT_RELEASED    0xB6
 
 char keyboard_getchar();
+int keyboard_has_input();
+char keyboard_getchar_non_blocking();
 
 #endif
diff --git a/src/kernel/shell.c b/src/kernel/shell.c
index 4635483..10ec05e 100644
--- a/src/kernel/shell.c
+++ b/src/kernel/shell.c
@@ -145,6 +145,7 @@ void shell_install()
   register_command("bmp", program_bmp);
   register_command("lspci", program_lspci);
   register_command("naval", program_navalbattle);
+  register_command("snake", program_snake);
 
   for (;;)
   {
diff --git a/src/libc/stdio.c b/src/libc/stdio.c
index 220b8ea..d332202 100644
--- a/src/libc/stdio.c
+++ b/src/libc/stdio.c
@@ -39,6 +39,25 @@ void draw_cursor(uint32_t color)
 	}
 }
 
+void draw_pixel(int x, int y, uint32_t color) //high level wrapper for putpixel
+{
+	putpixel(framebuffer, scanline, 32, x, y, color);
+}
+
+void draw_square(int x, int y, uint32_t color, int size)
+{
+	int startx = x*size;
+	int starty = y*size;
+
+	for (int i=0; i<size; i++)
+	{
+		for (int j=0; j<size; j++)
+		{
+			draw_pixel(startx+i, starty+j, color);
+		}
+	}
+}
+
 void erase_cursor()
 {
 	draw_cursor(black);
diff --git a/src/libc/stdio.h b/src/libc/stdio.h
index 0da0a59..d18c3b0 100644
--- a/src/libc/stdio.h
+++ b/src/libc/stdio.h
@@ -22,8 +22,10 @@
 
 void draw_cursor(uint32_t color);
 void erase_cursor();
-
 void move_cursor(int x, int y);
+
+void draw_pixel(int x, int y, uint32_t color);
+void draw_square(int x, int y, uint32_t color, int size);
 void putchar(unsigned short int c, int x, int y, uint32_t fg, uint32_t bg);
 void puts(const char* str);
 void clear(void);
diff --git a/src/programs/misc.c b/src/programs/misc.c
index 3a4ecca..c8f364d 100644
--- a/src/programs/misc.c
+++ b/src/programs/misc.c
@@ -74,7 +74,7 @@ void program_uptime()
 
 void program_help()
 {
-	printf("help\tpanic\twords\tprimes\trainbow\tclear\nmath\tbf\t   uptime   echo\t  sysinfo\tconway\nrot13   morse\tcowsay   time\t  read\t   reboot\npi\t  ls\t   cat\t  bmp\t   lspci\t  naval\n");
+	printf("help\tpanic\twords\tprimes\trainbow\tclear\nmath\tbf\t   uptime   echo\t  sysinfo\tconway\nrot13   morse\tcowsay   time\t  read\t   reboot\npi\t  ls\t   cat\t  bmp\t   lspci\t  naval\nsnake\n");
 }
 
 // Panic
diff --git a/src/programs/programs.h b/src/programs/programs.h
index fca21de..097900f 100644
--- a/src/programs/programs.h
+++ b/src/programs/programs.h
@@ -43,5 +43,6 @@ void program_lspci();
 // Games
 void program_navalbattle();
 void program_conway();
+void program_snake();
 
 #endif
diff --git a/src/programs/snake.c b/src/programs/snake.c
new file mode 100644
index 0000000..fcdd584
--- /dev/null
+++ b/src/programs/snake.c
@@ -0,0 +1,161 @@
+// Snake game
+// Author: xamidev
+// Licensed under the Unlicense. See the repo below.
+// https://github.com/xamidev/blankos
+
+#include "../kernel/system.h"
+#include "../libc/stdio.h"
+#include "../drivers/framebuffer.h"
+#include "../drivers/kb.h"
+#include "../libc/string.h"
+#include "../libc/crypto.h"
+
+#define WIDTH        25
+#define HEIGHT 	     25
+#define PIXEL_SIZE   20
+
+// to add:
+// score
+// sound
+
+typedef struct
+{
+	int x;
+	int y;
+} SnakeSegment;
+
+typedef struct
+{
+	SnakeSegment segments[100];
+	int length;
+	int dx;
+	int dy;
+} Snake;
+
+typedef struct
+{
+	int x;
+	int y;
+} Food;
+
+Snake snake;
+Food food;
+
+int is_snake(int x, int y);
+
+void init_game()
+{
+	snake.length = 1;
+	snake.segments[0].x = WIDTH/2;
+	snake.segments[0].y = HEIGHT/2;
+	snake.dx = 1;
+	snake.dy = 0;
+
+	food.x = rand() % (WIDTH-1);
+	food.y = rand() % (HEIGHT-1);
+}
+
+void draw_board()
+{
+	erase_cursor();
+	for (int y=0; y<=HEIGHT; y++)
+	{
+		for (int x=0; x<=WIDTH; x++)
+		{
+			if (x == 0 || x == WIDTH || y == 0 || y == HEIGHT)
+			{
+				draw_square(x, y, white, PIXEL_SIZE);
+			}
+			else if (is_snake(x, y)) {
+				draw_square(x, y, green, PIXEL_SIZE);
+			} else if(x == food.x && y == food.y) {
+				draw_square(x, y, red, PIXEL_SIZE);
+			} else {
+				draw_square(x, y, black, PIXEL_SIZE);
+			}
+		}
+	}
+}
+
+int is_snake(int x, int y)
+{
+	for (int i=0; i<snake.length; i++)
+	{
+		if (snake.segments[i].x == x && snake.segments[i].y == y)
+		{
+			return 1;
+		}
+	}
+	return 0;
+}
+
+void move_snake()
+{
+	for (int i=snake.length-1; i>0; i--)
+	{
+		snake.segments[i] = snake.segments[i-1];
+	}
+
+	snake.segments[0].x += snake.dx;
+	snake.segments[0].y += snake.dy;
+
+	if (snake.segments[0].x < 0) snake.segments[0].x = WIDTH-1;
+	if (snake.segments[0].x >= WIDTH) snake.segments[0].x = 0;
+	if (snake.segments[0].y < 0) snake.segments[0].y = HEIGHT-1;
+	if (snake.segments[0].y >= HEIGHT) snake.segments[0].y = 0;
+
+	if (snake.segments[0].x == food.x && snake.segments[0].y == food.y)
+	{
+		snake.length++;
+		food.x = rand() % (WIDTH-1);
+		food.y = rand() % (HEIGHT-1);
+	}
+}
+
+void handle_input(char key)
+{	
+	if (key == 'w' && snake.dy == 0) {
+		snake.dx = 0;
+		snake.dy = -1;
+	} else if (key == 's' && snake.dy == 0) {
+		snake.dx = 0;
+		snake.dy = 1;
+	} else if (key == 'a' && snake.dx == 0) {
+		snake.dx = -1;
+		snake.dy = 0;
+	} else if (key == 'd' && snake.dx == 0) {
+		snake.dx = 1;
+		snake.dy = 0;
+	} else if (key =='q') {
+		clear();
+		shell_install();
+	} 
+}
+
+void program_snake(int argc, char* argv[])
+{
+	int game_speed;
+	if (argc < 2)
+	{
+		game_speed = 4;
+	} else {
+		game_speed = atoi(argv[1]);
+	}
+
+	clear();
+	init_game();
+
+	for(;;)
+	{
+		char key = keyboard_getchar_non_blocking();
+
+		if (key)
+		{
+			handle_input(key);
+		}
+
+		move_snake();
+		draw_board();
+		delay(game_speed);
+	}
+}