Snake from raylib games

snake.c

+/*******************************************************************************************
+*
+*   raylib - sample game: snake
+*
+*   Sample game developed by Ian Eito, Albert Martos and Ramon Santamaria
+*
+*   This game has been created using raylib v1.3 (www.raylib.com)
+*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
+*
+*   Copyright (c) 2015 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+#if defined(PLATFORM_WEB)
+    #include <emscripten/emscripten.h>
+#endif
+
+//----------------------------------------------------------------------------------
+// Some Defines
+//----------------------------------------------------------------------------------
+#define SNAKE_LENGTH   256
+#define SQUARE_SIZE     31
+
+//----------------------------------------------------------------------------------
+// Types and Structures Definition
+//----------------------------------------------------------------------------------
+typedef struct Snake {
+    Vector2 position;
+    Vector2 size;
+    Vector2 speed;
+    Color color;
+} Snake;
+
+typedef struct Food {
+    Vector2 position;
+    Vector2 size;
+    bool active;
+    Color color;
+} Food;
+
+//------------------------------------------------------------------------------------
+// Global Variables Declaration
+//------------------------------------------------------------------------------------
+static const int screenWidth = 800;
+static const int screenHeight = 450;
+
+static int framesCounter = 0;
+static bool gameOver = false;
+static bool pause = false;
+
+static Food fruit = { 0 };
+static Snake snake[SNAKE_LENGTH] = { 0 };
+static Vector2 snakePosition[SNAKE_LENGTH] = { 0 };
+static bool allowMove = false;
+static Vector2 offset = { 0 };
+static int counterTail = 0;
+
+//------------------------------------------------------------------------------------
+// Module Functions Declaration (local)
+//------------------------------------------------------------------------------------
+static void InitGame(void);         // Initialize game
+static void UpdateGame(void);       // Update game (one frame)
+static void DrawGame(void);         // Draw game (one frame)
+static void UnloadGame(void);       // Unload game
+static void UpdateDrawFrame(void);  // Update and Draw (one frame)
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization (Note windowTitle is unused on Android)
+    //---------------------------------------------------------
+    InitWindow(screenWidth, screenHeight, "sample game: snake");
+
+    InitGame();
+
+#if defined(PLATFORM_WEB)
+    emscripten_set_main_loop(UpdateDrawFrame, 0, 1);
+#else
+    SetTargetFPS(60);
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update and Draw
+        //----------------------------------------------------------------------------------
+        UpdateDrawFrame();
+        //----------------------------------------------------------------------------------
+    }
+#endif
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    UnloadGame();         // Unload loaded data (textures, sounds, models...)
+    
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}
+
+//------------------------------------------------------------------------------------
+// Module Functions Definitions (local)
+//------------------------------------------------------------------------------------
+
+// Initialize game variables
+void InitGame(void)
+{
+    framesCounter = 0;
+    gameOver = false;
+    pause = false;
+    
+    counterTail = 1;
+    allowMove = false;
+
+    offset.x = screenWidth%SQUARE_SIZE;
+    offset.y = screenHeight%SQUARE_SIZE;
+
+    for (int i = 0; i < SNAKE_LENGTH; i++)
+    {
+        snake[i].position = (Vector2){ offset.x/2, offset.y/2 };
+        snake[i].size = (Vector2){ SQUARE_SIZE, SQUARE_SIZE };
+        snake[i].speed = (Vector2){ SQUARE_SIZE, 0 };
+
+        if (i == 0) snake[i].color = DARKBLUE;
+        else snake[i].color = BLUE;
+    }
+
+    for (int i = 0; i < SNAKE_LENGTH; i++)
+    {
+        snakePosition[i] = (Vector2){ 0.0f, 0.0f };
+    }
+
+    fruit.size = (Vector2){ SQUARE_SIZE, SQUARE_SIZE };
+    fruit.color = SKYBLUE;
+    fruit.active = false;
+}
+
+// Update game (one frame)
+void UpdateGame(void)
+{
+    if (!gameOver)
+    {
+        if (IsKeyPressed('P')) pause = !pause;
+        
+        if (!pause)
+        {
+            // Player control
+            if (IsKeyPressed(KEY_RIGHT) && (snake[0].speed.x == 0) && allowMove)
+            {
+                snake[0].speed = (Vector2){ SQUARE_SIZE, 0 };
+                allowMove = false;
+            }
+            if (IsKeyPressed(KEY_LEFT) && (snake[0].speed.x == 0) && allowMove)
+            {
+                snake[0].speed = (Vector2){ -SQUARE_SIZE, 0 };
+                allowMove = false;
+            }
+            if (IsKeyPressed(KEY_UP) && (snake[0].speed.y == 0) && allowMove)
+            {
+                snake[0].speed = (Vector2){ 0, -SQUARE_SIZE };
+                allowMove = false;
+            }
+            if (IsKeyPressed(KEY_DOWN) && (snake[0].speed.y == 0) && allowMove)
+            {
+                snake[0].speed = (Vector2){ 0, SQUARE_SIZE };
+                allowMove = false;
+            }
+
+            // Snake movement
+            for (int i = 0; i < counterTail; i++) snakePosition[i] = snake[i].position;
+
+            if ((framesCounter%5) == 0)
+            {
+                for (int i = 0; i < counterTail; i++)
+                {
+                    if (i == 0)
+                    {
+                        snake[0].position.x += snake[0].speed.x;
+                        snake[0].position.y += snake[0].speed.y;
+                        allowMove = true;
+                    }
+                    else snake[i].position = snakePosition[i-1];
+                }
+            }
+
+            // Wall behaviour
+            if (((snake[0].position.x) > (screenWidth - offset.x)) || 
+                ((snake[0].position.y) > (screenHeight - offset.y)) ||
+                (snake[0].position.x < 0) || (snake[0].position.y < 0))
+            {
+                gameOver = true;
+            }
+
+            // Collision with yourself
+            for (int i = 1; i < counterTail; i++)
+            {
+                if ((snake[0].position.x == snake[i].position.x) && (snake[0].position.y == snake[i].position.y)) gameOver = true;
+            }
+
+            // Fruit position calculation
+            if (!fruit.active)
+            {
+                fruit.active = true;
+                fruit.position = (Vector2){ GetRandomValue(0, (screenWidth/SQUARE_SIZE) - 1)*SQUARE_SIZE + offset.x/2, GetRandomValue(0, (screenHeight/SQUARE_SIZE) - 1)*SQUARE_SIZE + offset.y/2 };
+
+                for (int i = 0; i < counterTail; i++)
+                {
+                    while ((fruit.position.x == snake[i].position.x) && (fruit.position.y == snake[i].position.y))
+                    {
+                        fruit.position = (Vector2){ GetRandomValue(0, (screenWidth/SQUARE_SIZE) - 1)*SQUARE_SIZE + offset.x/2, GetRandomValue(0, (screenHeight/SQUARE_SIZE) - 1)*SQUARE_SIZE + offset.y/2 };
+                        i = 0;
+                    }
+                }
+            }
+
+            // Collision
+            if ((snake[0].position.x < (fruit.position.x + fruit.size.x) && (snake[0].position.x + snake[0].size.x) > fruit.position.x) &&
+                (snake[0].position.y < (fruit.position.y + fruit.size.y) && (snake[0].position.y + snake[0].size.y) > fruit.position.y))
+            {
+                snake[counterTail].position = snakePosition[counterTail - 1];
+                counterTail += 1;
+                fruit.active = false;
+            }
+
+            framesCounter++;
+        }
+    }
+    else
+    {
+        if (IsKeyPressed(KEY_ENTER))
+        {
+            InitGame();
+            gameOver = false;
+        }
+    }
+}
+
+// Draw game (one frame)
+void DrawGame(void)
+{
+    BeginDrawing();
+
+        ClearBackground(RAYWHITE);
+        
+        if (!gameOver)
+        {
+            // Draw grid lines
+            for (int i = 0; i < screenWidth/SQUARE_SIZE + 1; i++)
+            {
+                DrawLineV((Vector2){SQUARE_SIZE*i + offset.x/2, offset.y/2}, (Vector2){SQUARE_SIZE*i + offset.x/2, screenHeight - offset.y/2}, LIGHTGRAY);
+            }
+
+            for (int i = 0; i < screenHeight/SQUARE_SIZE + 1; i++)
+            {
+                DrawLineV((Vector2){offset.x/2, SQUARE_SIZE*i + offset.y/2}, (Vector2){screenWidth - offset.x/2, SQUARE_SIZE*i + offset.y/2}, LIGHTGRAY);
+            }
+
+            // Draw snake
+            for (int i = 0; i < counterTail; i++) DrawRectangleV(snake[i].position, snake[i].size, snake[i].color);
+
+            // Draw fruit to pick
+            DrawRectangleV(fruit.position, fruit.size, fruit.color);
+
+            if (pause) DrawText("GAME PAUSED", screenWidth/2 - MeasureText("GAME PAUSED", 40)/2, screenHeight/2 - 40, 40, GRAY);
+        }
+        else DrawText("PRESS [ENTER] TO PLAY AGAIN", GetScreenWidth()/2 - MeasureText("PRESS [ENTER] TO PLAY AGAIN", 20)/2, GetScreenHeight()/2 - 50, 20, GRAY);
+
+    EndDrawing();
+}
+
+// Unload game variables
+void UnloadGame(void)
+{
+    // TODO: Unload all dynamic loaded data (textures, sounds, models...)
+}
+
+// Update and Draw (one frame)
+void UpdateDrawFrame(void)
+{
+    UpdateGame();
+    DrawGame();
+}