working snake basis, todo animation and gameplay

project/main.c

@@ -106,7 +106,10 @@ int main(void)
 	mode_life_init();
 	mode_snake_init();
 
-	mode_audio_start();
+	app_mode = MODE_SNAKE;
+	mode_snake_start();
+
+	//mode_audio_start();
 
 	ms_time_t last;
 	while (1) {

project/main.h

@@ -15,4 +15,8 @@
 #define STR_HELPER(x) #x
 #define STR(x) STR_HELPER(x)
 
+// screen size
+#define SCREEN_W 16
+#define SCREEN_H 16
+
 #endif // MAIN_H

project/mode_audio.c

@@ -34,7 +34,7 @@ static void boot_animation(void)
 	dmtx_clear(dmtx);
 
 	// Boot animation (for FFT)
-	for (int i = 0; i < 16; i++) {
+	for (int i = 0; i < SCREEN_W; i++) {
 		dmtx_set(dmtx, i, 0, 1);
 		dmtx_show(dmtx);
 		delay_ms(20);
@@ -149,7 +149,7 @@ static void audio_capture_done(void* unused)
 	dmtx_clear(dmtx);
 
 	float factor = (1.0f / bin_count) * 0.25f;
-	for (int i = 0; i < bin_count; i++) {
+	for (int i = 0; i < MIN(bin_count, SCREEN_W) + 1; i++) { // +1 because bin 0 is always 0
 		bins[i] *= factor;
 
 		for (int j = 0; j < 1 + floorf(bins[i]); j++) {

project/mode_life.c

@@ -9,8 +9,8 @@ static bool life_enabled = false;
 static void show_board(bool do_show);
 static void apply_paint(void);
 
-#define BOARD_W 16
-#define BOARD_H 16
+#define BOARD_W SCREEN_W
+#define BOARD_H SCREEN_H
 
 #define SIZEOF_BOARD (BOARD_H*sizeof(uint32_t))
 

project/mode_snake.c

@@ -1,13 +1,156 @@
 #include "mode_snake.h"
+#include "com/debug.h"
+#include "dotmatrix.h"
+
+#define BOARD_W SCREEN_W
+#define BOARD_H SCREEN_H
+
+/** Snake movement direction */
+typedef enum {
+	NORTH,
+	SOUTH,
+	EAST,
+	WEST
+} Direction;
+
+typedef enum {
+	CELL_EMPTY,
+	CELL_BODY,
+	CELL_FOOD,
+	CELL_WALL
+} CellType;
+
+/** Board cell */
+typedef struct __attribute__((packed)) {
+	CellType type : 2; // Cell type
+	Direction dir : 2; // direction the head moved to from this tile, if body = 1
+} Cell;
+
+/** Wall tile, invariant, used for out-of-screen coords */
+static const Cell WALL_TILE = {CELL_WALL, 0};
+static const Cell EMPTY_TILE = {CELL_EMPTY, 0};
+
+/** Game board */
+static Cell board[BOARD_H][BOARD_W];
+
+typedef struct {
+	int x;
+	int y;
+} Coord;
+
+/** Snake coords */
+static Coord head;
+static Coord tail;
+static Direction head_dir;
+
+/** blinking to visually change 'color' */
+static bool wall_pwm_on = 1;
+static bool body_pwm_on = 1;
+static bool head_pwm_on = 1;
+static bool food_pwm_on = 1;
+
+/** Get board cell at coord (x,y) */
+static Cell *cell_at_xy(int x, int y)
+{
+	if (x < 0 || x >= BOARD_W || y < 0 || y >= BOARD_H ) {
+		return &WALL_TILE; // discards const - OK
+	}
+
+	return &board[y][x];
+}
+
+/** Get board cell at coord */
+static Cell *cell_at(Coord *coord)
+{
+	return cell_at_xy(coord->x, coord->y);
+}
+
+/** Place food in a random empty tile */
+static void place_food(void)
+{
+	Coord food;
+
+	// 1000 tries - timeout in case board is full of snake (?)
+	for (int i = 0; i < 1000; i++) {
+		food.x = rand() % BOARD_W;
+		food.y = rand() % BOARD_H;
+
+		Cell *cell = cell_at(&food);
+		if (cell->type == CELL_EMPTY) {
+			cell->type = CELL_FOOD;
+
+			dbg("Food at [%d, %d]", food.x, food.y);
+			break;
+		}
+	}
+}
+
+/** Clear the board and prepare for a new game */
+static void new_game(void)
+{
+	// randomize (we can assume it takes random time before the user switches to the Snake mode)
+	srand(SysTick->VAL);
+
+	// Erase the board
+	memset(board, 0, sizeof(board));
+
+	// Place initial snake
+
+	tail.x = BOARD_W/2-5;
+	tail.y = BOARD_H/2;
+
+	head.x = tail.x + 4;
+	head.y = tail.y;
+
+	for (int x = tail.x; x < head.x; x++) {
+		board[tail.y][x].type = CELL_BODY;
+	}
+
+	place_food();
+}
+
+static void show_board(void)
+{
+	dmtx_clear(dmtx);
+
+	for (int x = 0; x < BOARD_W; x++) {
+		for (int y = 0; y < BOARD_H; y++) {
+			Cell *cell = cell_at_xy(x, y);
+
+			bool set = 0;
+
+			switch (cell->type) {
+				case CELL_EMPTY: set = 0; break;
+				case CELL_BODY: set = body_pwm_on; break;
+				case CELL_FOOD:
+					dbg("Food found @ [%d, %d]", x, y);
+					set = food_pwm_on;
+					break;
+
+				case CELL_WALL: set = wall_pwm_on; break;
+			}
+
+			if (x == head.x && y == head.y) set = head_pwm_on;
+
+			dmtx_set(dmtx, x, y, set);
+		}
+	}
+
+	dmtx_show(dmtx);
+}
+
 
 void mode_snake_init(void)
 {
 	//
 }
 
+
 void mode_snake_start(void)
 {
-	//
+	new_game();
+
+	show_board();
 }
 
 void mode_snake_stop(void)