Add functions in snake.c

snakeInit(), snakeGrow(), snakeMove(), snakeSetDir(), snakeIsAlive(),
snakeSetHeadPos()

include/snake.h

@@ -21,6 +21,8 @@ typedef struct snake_t
     bool isAlive; // lebt die Schlange noch oder ist sie mit sich selbst kollidiert?
 } snake_t;
 
+extern gameData_t game;
+
 void snakeInit();
 // Snake mit bestimmter Startlänge an Startposition erstellen
 

src/snake.c

@@ -1,25 +1,116 @@
 #include "snake.h"
 
-void snakeInit(){
+
+void snakeInit()
+{
+    
+    //-----------------------------------
+    //-------------Default---------------
+    //-----------------------------------
+
+    // length 
+    config.snakeDefaultLength = 2;                   // inkl head
+    game.snake.length = config.snakeDefaultLength;
+
+    // coordinates of head
+    game.snake.headX = 5; 
+    game.snake.headY = 5;
+
+    // movement direction
+    game.snake.direction = 3;    // left
+
+    // coordinates of tail
+    game.snake.tail[0][0] = 5;   // X-coordinate
+    game.snake.tail[0][1] = 5;   // Y-coordinate
+    game.snake.tail[1][0] = 4;   // X-coordinate
+    game.snake.tail[1][1] = 4;   // Y-coordinate
+
+    // alive 
+    game.snake.isAlive = true;
     return;
 }
 
-void snakeGrow(){
+void snakeGrow()
+{
+    game.snake.length++;
+    // tail part is attached left of last tail part
+    // maybe problem while rendering --> MUST BE SOLVED THEN
+    game.snake.tail[game.snake.length][0] = game.snake.tail[game.snake.length - 1][0] - 1;
+    game.snake.tail[game.snake.length][1] = game.snake.tail[game.snake.length - 1][1];
     return;
 }
 
-void snakeMove(){
+void snakeMove()
+{   
+    int i = game.snake.length - 1;  // counter for snake moving
+
+    // update head position
+    snakeSetHeadPos();
+
+    // tail part of[x,y][0,1] get coordinates of tail part before
+    while(i)
+    {
+        game.snake.tail[i][0] = game.snake.tail[i-1][0];        
+        game.snake.tail[i][1] = game.snake.tail[i-1][1];
+        i--;
+    }
+    game.snake.tail[0][0] = game.snake.headX;
+    game.snake.tail[0][1] = game.snake.headY;
+
     return;
 }
 
-void snakeSetDir(snakeDirection_t dir){
+void snakeSetDir(snakeDirection_t dir)
+{
+    game.snake.direction = dir;
     return;
 }
 
-bool snakeIsAlive(){
+bool snakeIsAlive()
+{
+    for(int i = 1; i < game.snake.length; i++)
+    {
+        if(game.snake.tail[i][0] == game.snake.headX && game.snake.tail[i][1] == game.snake.headY)
+            return false;
+    }
     return true;
 }
 
-void snakeSetHeadPos(){
+void snakeSetHeadPos()
+{
+    switch(game.snake.direction)
+    {   
+        // DOWN
+        case DOWN:
+            game.snake.headX = game.snake.tail[0][0];
+            game.snake.headY = game.snake.tail[0][1] + 1;
+            if(game.snake.headY >= game.snake.height) 
+                game.snake.headY = 0;
+            break;
+
+        // UP
+        case UP:
+            game.snake.headX = game.snake.tail[0][0];
+            game.snake.headY = game.snake.tail[0][1] - 1;
+            if(game.snake.headY <= 0)
+                game.snake.headY = game.snake.height - 1;
+            break;
+
+        // LEFT
+        case LEFT:
+            game.snake.headX = game.snake.tail[0][0] - 1;
+            game.snake.headY = game.snake.tail[0][1];
+            if(game.snake.headX <= 0)
+                game.snake.headX = game.snake.weight - 1;
+            break;
+
+        // RIGHT
+        case RIGHT:
+            game.snake.headX = game.snake.tail[0][0] + 1;
+            game.snake.headY = game.snake.tail[0][1];
+            if(game.snake.headX >= game.snake.weight) 
+                game.snake.headX = 0;
+            break;
+    }
     return;
 }