add Snake example.

examples/readme.md

@@ -3,3 +3,4 @@
 1. [Hello world](https://github.com/Ethosa/nodesnim/blob/master/examples/hello_world)
 2. [Calculator](https://github.com/Ethosa/nodesnim/blob/master/examples/calculator)
 3. [Novel](https://github.com/Ethosa/nodesnim/blob/master/examples/novel)
+4. [Snake game](https://github.com/Ethosa/nodesnim/blob/master/examples/snake)

examples/snake/main.nim

@@ -0,0 +1,121 @@
+import nodesnim
+import random
+randomize()
+
+
+Window("Snake game")
+
+
+type
+  Snake = ref object
+    dir: Vector2Ref
+    size: Vector2Ref
+    food: Vector2Ref
+    body: seq[Vector2Ref]
+
+
+var
+  main_obj: SceneObj
+  main = Scene("Main", main_obj)
+
+  canvas_obj: CanvasObj
+  canvas = Canvas("Canvas", canvas_obj)
+
+  snake = Snake(
+    dir: Vector2(),
+    body: @[Vector2(0, 0)],
+    size: Vector2(40, 40),
+    food: Vector2(160, 160))
+  time = 0
+
+Input.addKeyAction("forward", "w")
+Input.addKeyAction("backward", "s")
+Input.addKeyAction("left", "a")
+Input.addKeyAction("right", "d")
+
+
+canvas.process =
+  proc() =
+    if Input.isActionJustPressed("forward"):
+      snake.dir = Vector2(0, -40)
+    elif Input.isActionJustPressed("backward"):
+      snake.dir = Vector2(0, 40)
+    elif Input.isActionJustPressed("left"):
+      snake.dir = Vector2(-40, 0)
+    elif Input.isActionJustPressed("right"):
+      snake.dir = Vector2(40, 0)
+    if time < 120:
+      inc time
+      return
+    canvas.resize(main.rect_size.x, main.rect_size.y)
+    let
+      grid_size = Vector2(
+        (main.rect_size.x.int div snake.size.x.int).float,
+        (main.rect_size.y.int div snake.size.y.int).float
+      )
+    canvas.fill(Color(0, 0, 0, 0))
+
+
+    if snake.dir.y < 0:
+      for i in countdown(snake.body.len()-1, 0):
+        if i > 0:
+          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
+        else:
+          if snake.body[i].y > 0:
+            snake.body[i].y += snake.dir.y
+          else:
+            snake.body[i].y = grid_size.y*snake.size.y - snake.size.y
+    elif snake.dir.y > 0:
+      for i in countdown(snake.body.len()-1, 0):
+        if i > 0:
+          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
+        else:
+          if snake.body[i].y < grid_size.y*snake.size.y - snake.size.y:
+            snake.body[i].y += snake.dir.y
+          else:
+            snake.body[i].y = 0
+
+    elif snake.dir.x < 0:
+      for i in countdown(snake.body.len()-1, 0):
+        if i > 0:
+          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
+        else:
+          if snake.body[i].x > 0:
+            snake.body[i].x += snake.dir.x
+          else:
+            snake.body[i].x = grid_size.x*snake.size.x - snake.size.x
+    elif snake.dir.x > 0:
+      for i in countdown(snake.body.len()-1, 0):
+        if i > 0:
+          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
+        else:
+          if snake.body[i].x < grid_size.x*snake.size.x - snake.size.x:
+            snake.body[i].x += snake.dir.x
+          else:
+            snake.body[i].x = 0
+
+    if snake.body[0] == snake.food:
+      snake.body.add(snake.body[^1])
+      snake.food.x = (rand(grid_size.x.int-1) * snake.size.x.int).float
+      snake.food.y = (rand(grid_size.y.int-1) * snake.size.y.int).float
+
+    # draw
+    for i in snake.body:
+      canvas.rect(i.x, i.y, i.x+snake.size.x, i.y+snake.size.y, Color(1f, 1f, 1f))
+    # head
+    canvas.rect(
+      snake.body[0].x, snake.body[0].y,
+      snake.body[0].x+snake.size.x, snake.body[0].y+snake.size.y,
+      Color(0xaaccffff'u32))
+    # food
+    canvas.rect(
+      snake.food.x, snake.food.y,
+      snake.food.x+snake.size.x, snake.food.y+snake.size.y,
+      Color(0xffccaaff'u32))
+    time = 0
+
+
+main.addChild(canvas)
+addScene(main)
+setMainScene("Main")
+windowLaunch()

examples/snake/nim.cfg

@@ -0,0 +1 @@
+--path:"../../src"

examples/snake/readme.md

@@ -0,0 +1,5 @@
+# Snake game
+
+See [`main.nim`](https://github.com/Ethosa/nodesnim/blob/master/examples/snake/main.nim) file.
+
+![gif here](https://github.com/Ethosa/nodesnim/blob/master/examples/snake/one.gif)