neocturne/avr-snake
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Improve random, allow playing more than one game

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This commit is contained in:
Matthias Schiffer 2013-03-14 22:52:04 +01:00
parent 9054f9a526
commit b0dda6fda2
2 changed files with 30 additions and 12 deletions
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1
kbd.h
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@ -9,6 +9,7 @@
#define KBD_FLAG_BREAK (_BV(1)) #define KBD_FLAG_BREAK (_BV(1))
#define KBD_FLAG_EXT (_BV(2)) #define KBD_FLAG_EXT (_BV(2))
#define KBD_CODE_SPACE 0x29
#define KBD_CODE_UP 0xe075 #define KBD_CODE_UP 0xe075
#define KBD_CODE_LEFT 0xe06b #define KBD_CODE_LEFT 0xe06b
#define KBD_CODE_DOWN 0xe072 #define KBD_CODE_DOWN 0xe072

41
snake.c
View file

@ -4,6 +4,7 @@
#include <avr/io.h> #include <avr/io.h>
#include <avr/interrupt.h> #include <avr/interrupt.h>
#include <util/delay.h> #include <util/delay.h>
#include <stdbool.h>
typedef struct _point_t { typedef struct _point_t {
@ -20,6 +21,8 @@ typedef enum _dir_t {
static volatile uint8_t dir; static volatile uint8_t dir;
static volatile bool start = false;
static volatile uint16_t lfsr = 0xace1;
static point_t tail = {7, 4}; static point_t tail = {7, 4};
@ -32,7 +35,6 @@ static uint8_t history_pos = 0;
static point_t q; static point_t q;
static uint16_t rand(void) { static uint16_t rand(void) {
static uint16_t lfsr = 0xace1;
unsigned bit; unsigned bit;
/* taps: 16 14 13 11; feedback polynomial: x^16 + x^14 + x^13 + x^11 + 1 */ /* taps: 16 14 13 11; feedback polynomial: x^16 + x^14 + x^13 + x^11 + 1 */
@ -42,6 +44,10 @@ static uint16_t rand(void) {
return lfsr; return lfsr;
} }
static void rand_mix(uint16_t mix) {
lfsr ^= mix;
}
static void rand_q(void) { static void rand_q(void) {
q.x = rand() % 14; q.x = rand() % 14;
q.y = rand() % 9; q.y = rand() % 9;
@ -78,6 +84,8 @@ static uint8_t get_dir(uint8_t i) {
} }
static void reset(void) { static void reset(void) {
LedSignClear(0);
rand_q(); rand_q();
dir = EAST; dir = EAST;
@ -95,6 +103,10 @@ void kbd_handle(uint16_t code, bool make) {
return; return;
switch(code) { switch(code) {
case KBD_CODE_SPACE:
start = true;
break;
case KBD_CODE_UP: case KBD_CODE_UP:
dir = NORTH; dir = NORTH;
break; break;
@ -142,9 +154,11 @@ static bool point_used(const point_t *p, bool head) {
return false; return false;
} }
static void step(void) { static bool step(void) {
uint8_t d = dir; uint8_t d = dir;
rand_mix(d);
LedSignSet(tail.x, tail.y, 0); LedSignSet(tail.x, tail.y, 0);
int i; int i;
@ -160,9 +174,8 @@ static void step(void) {
go(&pt, d); go(&pt, d);
LedSignSet(pt.x, pt.y, 3); LedSignSet(pt.x, pt.y, 3);
if (point_used(&pt, true)) { if (point_used(&pt, true))
while(true) {} return false;
}
if (points_equal(&pt, &q)) { if (points_equal(&pt, &q)) {
rand_q(); rand_q();
@ -173,26 +186,30 @@ static void step(void) {
move(d, false); move(d, false);
} }
if (point_used(&pt, false)) { if (point_used(&pt, false))
while(true) {} return false;
}
LedSignSet(q.x, q.y, 7); LedSignSet(q.x, q.y, 7);
return true;
} }
int main() { int main() {
LedSignInit(GRAYSCALE); LedSignInit(GRAYSCALE);
kbd_init(); kbd_init();
reset();
sei(); sei();
kbd_send(KBD_CMD_RESET); kbd_send(KBD_CMD_RESET);
while(true) { while(true) {
step(); while (!start) {}
_delay_ms(100); start = false;
reset();
while (step())
_delay_ms(100);
} }
return 0; return 0;